A global scoping review of clinical practice guidelines for cataract surgery

Highlights

• •Scoping review of global existing guidelines from 34 sources for improving outcomes of cataract surgery, including.
• •Use of accurate biometric measurements for best refractive outcome.
• •Use of povidone-iodine and intracameral antibiotics to prevent infection.
• •Although more expensive to implement, phacoemulsification for best outcomes.
• •World Health Organization can use findings to develop guidelines for effective cataract surgery.

Abstract

Purpose

The World Health Organization (WHO) has specified a global target for “effective cataract surgery coverage” for monitoring progress towards tincreasing eye care quality across populations. The WHO is committed to providing evidence-based guidance for components of cataract surgerythat could lead to better outcomes. The first step is a scoping review of from existing guidelines, including the evidence base and gaps in the evidence for those guidelines.

Design

We developed a conceptual framework for the scoping review that compartmentalized stages of cataract surgery into pre-operative, operative, and postoperative phases and identified potential outcome indicators. A search strategy was developed.

Methods

In 2024, we used a multipronged approach to identify existing guidelines that support cataract surgery programs, reviewed known publicly available cataract surgery quality improvement programs, searched the Trip Medical Database, and reviewed materials sent to us directly from WHO. We noted the evidence-base of the guidelines.

Results

Of the 156 sources, 34 had guidelines. Seven guidelines were cited by multiple sources with good evidence; these include use of pre-operative povidone-iodine, a “time-out” checklist, intracameral antibiotics, and phacoemulsification. Some guidelines were inconsistent and require harmonization, such as the necessity for pre-operative medical visits and laboratory testing, and benchmarks for outcome assessment. Gaps in evidence were also found, such as details on what constitutes “accurate” biometry.

Conclusions

While these results are a reasonable starting point for WHO to begin the development of guidance for effective cataract surgery, there is an urgent need to generate data that will fill identified gaps in evidence and to harmonize inconsistencies going forward.

1. Introduction

Cataract is the leading cause of blindness affecting older persons in low- and middle-income countries.¹ High-quality cataract surgery is an effective intervention that removes the opacified lens and replaces it with an intraocular lens (IOL), resulting in restored vision function. Programs that address unoperated cataract have been shown to be among the most cost-effective healthcare interventions.^2,3 However, cataract surgery does not guarantee sight restoration, as several studies have documented high rates of poor visual outcomes following surgery.⁴ There is now focus on the concept of “effective cataract surgery,” defined as the proportion of individuals in a population who have undergone cataract surgery with a good visual outcome, relative to all those who have either received the surgery or are in need of it.⁵

Effective cataract surgery is a measure of service access adjusted for quality of service. The quality gap is measured by the difference between cataract surgery coverage and effective cataract surgery coverage.^5,6 The World Health Organization (WHO) currently suggests good visual outcome as follows ⁷: (1)Best-corrected visual acuity (BCVA): at least 90% of operated eyes should achieve 6/6–6/18 after best correction(2) Presenting visual acuity (PVA): At least 80% should reach 6/6–6/18 without correction. A recent report found that the highest rates of effective cataract surgery coverage were in high-income countries and the lowest in low-income countries, and rates were higher among men compared to women.⁵

The member states of WHO have agreed upon a global target for “effective cataract surgery coverage” as a reference indicator for monitoring progress towards the 2030 goal of increasing global access to quality eye care service. ³ This step is an important move away from simply assessing cataract surgical coverage. The recommended feasible global target is a 30% increase in effective coverage of cataract surgery by 2030 for member states.³ The WHO is committed to providing technical resources to enable its member states to achieve the target, and these include eventually providing as much as possible evidence-based guidance for components of cataract surgery that might led to improved outcomes. There are several steps in this process. A first step is to determine, through a scoping review, the recommendations in existing guidelines from a wide variety of sources globally, the data (or lack of data) that underpins the existing guidelines and areas where there are gaps. The second step for WHO is to convene a technical working group to review the scoping review and provide expert input. Finally, WHO plans to publish guidance for member states outlining evidence-based and expert-endorsed components of surgery likely to enhance the effectiveness of cataract surgery.

The aims of this study are to report on the results of the initial scoping review for WHO of existing guidelines, provide insight into the frequency of use and strength of the guidelines, and identify where harmonization is needed and gaps of evidence exist.

2. Methods

We first developed a conceptual framework for the review, then developed a strategy for the conduct of the review including data extraction, and analyzed the data for the number of sources, and the number with evidence base, which had specific guidelines within each element of each phase. Specifically, we determined whether the source directly cited evidence for the guideline, cited evidence for the category that included the guideline but may not have attributed evidence to specific guidelines, or did not cite any evidence for the guideline. We registered the protocol for the scoping review on the Open Science framework on April 12, 2024 (https://osf.io/rpjat). The methods are described in detail below.

2.1. Conceptual framework

We developed a conceptual framework (Fig. 1) that compartmentalizes key cataract surgery stages into pre-operative, intra-operative, and postoperative phases. We also included outcome indicators of interest to monitor effectiveness. We did not include any metrics related to training of surgeons (at the request of WHO), patient counseling, and we did not include femtosecond laser-assisted cataract surgery as it is not frequently used on a global scale at this time.

Fig. 1.

Conceptual framework for scoping review of cataract surgery guidelines.

The pre-operative phase includes anesthesia-related pre-operative visit, waiting time between the patient’s decision for surgery and actual procedure, timing of surgery in the fellow eye, and selection of the IOL. Patient factors, such as age and systemic and ocular co-morbidities, inform these components. The Intraoperative phase includes sterilization procedure, type of anesthesia, type of surgery, use of time out, incision size, and use of intracameral antibiotics. The postoperative phase includes use and type of eye drops, use of eye shields, and follow-up duration and frequency. Other factors were not considered.

All decisions about these components made during the preoperative, intraoperative, and postoperative phases may impact patient outcomes. Important postoperative outcomes include vision-related outcomes (e.g., BCVA), patient-reported outcomes (e.g., patient satisfaction), and incidence of postoperative complications (e.g., endophthalmitis, need to return to the operating room)

2.2. Identifying existing guidelines

We used a multipronged approach to identify existing guidelines, with dates (if available from the sources) from January 1, 2010 to June 1, 2024, when the search ended; if no date was available, it was still included. The guidelines could be available in 1 of the 6 official languages of the United Nations (English, Arabic, Chinese, French, Russian, and Spanish) or in Portuguese or German, and were translated. There was no restriction on the degree of evidence on which the guidelines were based, but we noted in the tables whether there was no or unknown evidence base, or if some references were provided for some guidelines, or if guidelines had directly supporting evidence.

The following lists the methods we used to find existing guidelines

• 1. We reviewed the websites of:

• a. Ophthalmology professional organizations. We searched websites of professional organizations worldwide, as found by searching within the 6 official WHO regions.⁸ If the web site required membership to search it, we contacted individuals known to be members to help search the web site. We identified organizations using a Boolean search within Google. The specific search terms were: “ophthalmology OR cataract OR eye surgery OR eye care OR eye health OR anterior chamber OR anterior segment OR cornea AND association OR administration OR agency OR organization OR council OR society OR Institute AND j(insertion of region).

• b. Non-governmental organizations that directly support cataract surgery programs. We identified the organizations using a Google search for “non-governmental organization AND cataract”, “NGO AND cataract surgery”, and “Eye care AND Foundations”. We included all organizations from the American Academy of Ophthalmology list of organizations concerned with Eye Care and Developing Nations (accessed 3/1/2024).

• c. We accessed the Worldwide NGO network (2/19/2024). The latter covers 54,000 NGOs so we searched for “eye” in the mission statement.

• 2. For moderate to large organizations where the web site had no surgery guidelines, we contacted them through a contact listed on the website to determine whether they have issued cataract surgery guidelines for their programs and would be willing to send them to us.

• 3. We searched the Trip medical database (https://www.tripdatabase.com/) with the assistance of a Librarian specializing in conducting searches for systematic and scoping reviews (i.e., information specialist) using the following phrases: “cataract surgeries” and “cataracts surgery”, “cataract surgery” and “cataracts surgeries”.

• 4. We reviewed materials sent to us directly from collaborators at WHO and WHO Collaborating Centers for evidence of guidelines.

• 5. We added material on post-operative outcomes after reviewing publicly available cataract surgery quality improvement programs at Cleveland Clinic, Massachusetts Eye and Ear Hospital, and Wilmer Eye Institute. No exhaustive search of other training sites was conducted.

2.3. Data extraction

One investigator (among AK, Wl, AP, FA, JM, CA, SKW) extracted information regarding each relevant guideline using a standardized data extraction form developed within the Systematic Review Data Repository.⁹ All extractions were reviewed by another senior reviewer (IS, FW, SKW) independently. All websites deemed to have no guidelines were re-reviewed by another reviewer independently. Discrepancies were resolved through discussion. The extractions were also reviewed for the strength of the evidence base, using three categories: the source cited evidence directly for the guideline; the guideline was part of series of recommendations and evidence was cited for the entire set but not attached to any specific guideline; no evidence was cited for the guideline.

2.4. Analyses

Tables were created under each cataract surgery stage that listed the guideline, how many sources reported having that guideline, and how many of the sources cited evidence or at least cited evidence for the set of recommendations that included the guideline of interest. We report conflicts between sources in the summaries of the guidelines and note them, and possible reasons for them, in the discussion section.

3. Results

3.1. Search results

Fig. 2 shows the summary of the searches. We identified 82 professional organizations through the search, of which 59 had no guidelines, 4 had no active web site, 4 potentially had guidelines and were contacted by us but no reply was received, and 15 organizations provided guidelines either on their website or after contact.

Fig. 2.

▓.

We initially identified 150 non-governmental organizations, cataract surgery improvement programs, or foundations through the search. After removal of duplicates and organizations not involved in eye care, we had 74 remaining. We noted that 4 of the non-governmental organizations were part of a single organization. One non-governmental organization did not have guidelines of its own but supplied guidelines from a professional organization. Of the 74 non-governmental organizations, 17 sent us guidelines or had guidelines on their web sites, 2 had no web site, 15 possibly had guidelines but after 2 contacts did not respond, and 40 had no guidelines. One article was found through the Trip search and 1 article, directly sent from WHO, was a report with guidelines.^10,11 The list of organizations reviewed and from whom guidelines were available for both professional societies and non-governmental organizations and others is shown in Supplemental Table 2.

A search of the Trip medical database yielded 271 guidelines. After screening, 7 guidelines were reviewed and 5 had guidelines from professional organizations that were incorporated, 1 was an article,⁹ and 1 was excluded because it was not related to cataract surgery.

Only 1 area, duration of use of eye shields, did not have a guideline from the sources reviewed above. We ran a search as described in the methods, which yielded 250 articles, of which 78 were older than 2010. A review of the titles of the 172 articles yielded 10 articles for full review. No article had a recommendation on duration. One organization subsequently sent their guidelines, which included use of eye shields, which was included.

In total we identified 34 sources of guidelines out of 156 organizations/articles that were screened. Between all the sources, we found guidelines for all phases of cataract surgery. We summarize the findings by phase and by factor below.

3.2. Pre-operative phase

The first set of guideline summaries pertains to key components of the preoperative phase and patient factors that may affect outcomes (Table 1).

• 1. Patient Characteristics

• a) Age

Table 1.

Preoperative phase: Patient factors that may affect outcomes of cataract surgery.

Factor	Guidelines	Total No of sources reporting on factor	No. of sources with guideline (No. w/Evidence-based guidelines*)
Age		6
	Age should be considered as a preoperative risk factor for poorer outcomes.		4 (3)
	Physician clearance for surgery should be obtained for patients > 70.		1
	Retinal detachment should be discussed with patients under 60 years at high risk.		1 (1)
Visual Acuity		13
	Impairment of function should be benchmark for cataract surgery, not visual acuity		10 (6)
	Visual acuity below 6/12 may be a useful benchmark:		2 (1)
	Visual acuity below 6/18 may be a useful benchmark:		1
	Visual acuity below 6/60 may be a useful benchmark		1 (1)
Ocular Co-morbidities		16
	Ophthalmological history should be taken		16 (10)
	Counsel patients on reduced efficacy of cataract surgery if certain ocular comorbidities are present.		3 (3)
	Treat ocular Infections before surgery.		2 (1)
	There is no consensus on specific ocular contraindications to surgery.		2 (1)
Systemic co-morbidities		13
	Assess and manage systemic health conditions prior to surgery, with no specific guidance on which conditions		10 (6)
	Specifically mentioned blood pressure and diabetes, some with target values provided		9 (5)
	Do not discontinue anticoagulants and antiplatelet medications		2 (2)
	Ensure patient is physically and cognitively able to cooperate during surgery		2
	Continue immunosuppressive therapy		2 (1)

^⁎in this table and all subsequent tables summarizing the guidelines, we combined those sources with direct evidence citation with those that grouped guidelines and provided evidence but did not link them to any specific guideline.

Minimal detail was provided as to specifically how age should be considered with minimal evidence cited. Five of the 6 organizations with guidelines on age stated that older age is a general risk factor for poorer outcomes after cataract surgery and emphasized that it should be noted during history taking. One organization mentioned retinal detachment as an adverse outcome that should be discussed with patients at high risk under the age of 60 years and 1 organization recommended preoperative medical clearance be obtained for all patients over 70 years.

• b) Pre-operative Visual Acuity (VA)

Thirteen organizations had guidelines around VA measurement, of whom 10 organizations stated that the impact of cataract on patient function should be the primary indicator for surgery, rather than an arbitrary VA cut-off. Suggestions for consideration of cut-offs ranged from 6/12 to 6/60. All these recommendations stressed that thresholds are meant to be suggestions for when cataract surgery may be appropriate and should not be used to deny cataract surgery to a patient with subjective functional impairment who nonetheless had vision better than any threshold. However, pre-operative documentation of VA is recommended because it would help determine the degree of improvement after surgery.

• c) Ocular Comorbidity

All 16 organizations with guidelines around ocular morbidity had recommendations on the need to document at least some aspect of ophthalmological history before cataract surgery. Organizations differed on specific morbidities to include, but generally recommended assessing ocular conditions that may affect surgical outcomes, medications, and patient-reported vision issues. Three organizations with evidence-based guidelines suggested counseling patients with comorbidities about potentially reduced efficacy of surgery, while not necessarily precluding surgery. Two organizations listed specific contraindications to surgery such as other causes of visual loss, iris atrophy, or elevated intraocular pressure but there was no consensus on specific contraindications to surgery.

• d) Systemic Comorbidity

Thirteen organizations had guidelines around systemic co-morbidities, but with no consensus on any co-morbidity that would preclude surgery except ensuring that the patient has resources to cognitively and physically manage the surgery and post-operative care. Ten organizations emphasized evaluating and managing systemic health conditions and 9 organizations specifically mentioned diabetes and hypertension. Specific recommendations include maintaining blood pressure below 140/90 mmHg and controlling blood sugar levels, with slight variations in target values among organizations. Two organizations with evidence-based guidelines advised against discontinuing anticoagulants and 2 recommended maintaining immunosuppressive therapy. While 1 organization had guidelines on a variety of pre-operative laboratory tests, another organization cited evidence that preoperative laboratory testing does not affect patient cataract surgical outcomes and adds cost.

The second set of guidelines pertains to the preoperative phase and guidelines regarding pre-operative medical visits and wait times. (Table 2). There is overlap between recommendations on patient age and systemic comorbidity in Table 1, and the need for a pre-operative medical visit in Table 2.

• 2. Preoperative visit and laboratory testing

Table 2.

Preoperative Phase: Other factors that may affect outcomes of cataract surgery.

Factor	Guidelines	Total No of sources reporting on factor	No. of sources with guideline (No. w/ Evidence-based guidelines)
Visit to physician before anesthesia		13
	Patient should undergo routine blood test and/or formal assessments.		10 (5)
	Pre-Operative Visit is at Ophthalmologist’s Discretion		1 (1)
	Pre-operative testing/medical assessment is not needed		2 (1)
Wait time between scheduled surgery and actual surgery		4
	Prioritize Immediate Surgery for Advanced Cataracts, very poor Vision, and other extenuating circumstances		2
	“Early” Surgery for Significant Lens Change, both eyes affected, or job demands		2
Wait time between 1st and 2nd eye surgery		9
	ISBCS* can be considered under certain conditions when no clear preference for delayed surgery		2
	Preference for ISBCS, comments about consulting with patient		4 (3)
	Discourage ISBCS and schedule 2nd eye once 1st eye surgical outcome is known		3 (2)

^⁎ISBCS:Immediate Sequential Bilateral Cataract Surgery.

Thirteen organizations had guidelines about pre-operative visits and routine laboratory testing prior to cataract surgery. Ten organizations recommended some pre-operative assessment and testing with 6 organizations specifically mentioning testing blood sugar and/or blood pressure. Two organizations cited evidence that found a pre-operative medical visit did not decrease the risk of ocular or surgical complications and evidence that pre-operative laboratory testing does not affect patient outcomes. These 2 recommended that unless the patient has pre-existing or concerning medical conditions, a pre-operative visit to an internist is not indicated.

• 3. Waiting time between decision for surgery and actual procedure

Only 4 organizations had guidelines about the length of time between scheduling and having surgery (Table 2). They all agree on the importance of minimizing the waiting time for cataract surgery, especially in cases where vision loss significantly impacts the patient's quality of life or functional abilities. Immediate surgery, or at least within 2 weeks, was recommended for patients with advanced cataracts or very poor vision. One organization recommended surgery within 2–3 months for all patients needing cataract surgery. Maintaining lean waiting lists through efficient and high-quality processes was also recommended to ensure timely surgery for those in need.

• 4. Timing of Surgery for Second Eye

Nine organizations had guidelines about timing of second eye surgery, without unanimity (Table 2). Five recommendations cited outcomes that supported same day surgery on the second eye, and 3 added the importance of discussion about patient preference. The recommendations suggested Immediate Sequential Bilateral Cataract Surgery (ISBCS) may be considered for patients with conditions necessitating the use of general anesthesia, for patients who must travel significant distances to access surgical eye care and may not be able to return, and for patients concerned with waiting. Three organizations recommended avoiding ISBCS because of reported risks of inability to select IOL power for the second eye based on the first eye’s post-surgical outcome and the small risk of bilateral endophthalmitis with ISBCS; however, 1 noted the importance of allowing it in uncomplicated cases if travel constraints or other patient factors permit. In general, there is support from a cost and patient convenience standpoint for ISBCS but only under certain conditions. Some guidelines discussed the risks of falling and patient functioning if the second eye surgery is delayed too long (or indeed not done which was discouraged), but other than a statement that the second eye can be done once the surgical outcome from the first eye can inform the second operation, there was only 1 guideline that specified a specific wait time of at least 1 week. The evidence is strong for the value of operating on the second eye, with good evidence for ISBCS for many cases. Evidence was weak for any particular period to wait.

The third set of pre-operative guidelines pertains to IOL selection (Table 3). The assumption made by all the organizations included is that an IOL will be inserted for the vast majority of routine cataract surgery, and aphakic glasses or insertion of one standard IOL for all patients are no longer acceptable means of post-surgical refraction.

• 5. Performance of Accurate Biometry

Table 3.

Preoperative phase: Factors in selection of intraocular lens that may affect outcomes.

Factor	Guidelines	Total No of sources reporting on factor	No. of sources with guideline (no. w/ evidence-based guidelines)
Accurate Biometry		23
	Accurate biometry must be performed for best refractive outcomes		17 (8)
	Regular calibration of equipment is essential		4 (1)
	Recommendations on calculating IOL power, but no consensus		5 (2)
	Axial Length: remeasure if axial length is <22 mm or >25 mm or difference between two eyes is above a target mm		4 (2)
	Three scans (ideally 5–10) are within 15 mm of one another; average 5–10 of most consistent with lowest standard deviation (<0.6 mm)		2
	Recommend optical biometry over A scan biometry (use ultrasound if can’t get optical biometric results)		3 (3)
	Recommend ultrasound A scan, or no preference		3 (2)
	Keratometry: Take at least three measurements		3 (1)
	No preference for keratometer devices		2 (2)
	Remeasure if Curvature is <40D or >47 D or difference between eyes is >1D		2 (1)
Selection of IOL Type: material		8
	Recommend foldable IOL		5 (5)
	Choose IOL material depending on patient features and type of surgery		3 (2)
	Choose Hydrophobic IOL		1 (1)
Choice of IOL:		16
	Choice should be discussed pre-operatively, shared decision with patient depending on expectations and needs		7 (4)
	Consider Toric IOLs for high pre-operative corneal astigmatism.		8 (5)
	Use extra caution when considering use of multifocal and Toric IOLs.		8 (5)

Twenty-three organizations had guidelines around biometry and keratometry with 17 organizations promoting its use to obtain the best refractive outcome. Three organizations cited evidence that using optical biometry was associated with better results than using A scans, although noted that ultrasound can be used if optical biometry cannot obtain a result. It should be noted that for many years, ultrasound was the gold standard, but at present, optical biometry is considered superior because of the precision of measurement, absence of corneal compression, and measurement of actual retinal thickness. However, it is a costly investment and that is a consideration for some organizations. Four organizations had guidelines for remeasuring axial length if the result was <22 mm or >25 mm, or if the difference between eyes was a set amount; the set amount varied from >0.3 mm to 1 mm or more.

Few guidelines covered keratometry. Two organizations had no preference for a measurement device. Two organizations specifically recommended re-measuring if the curvature was <40D or >47D or the difference between eyes was >1D. Three organizations recommended taking at least 3 measurements.

• 6. Selection of IOL

• a) IOL Material

A foldable IOL can engender out of pocket expenses so may not be preferred in low income populations; however, rigid lenses require larger incisions, which is less desirable (see section C.5). Eight organizations had guidelines concerning the material of an IOL, with 5 organizations recommending foldable IOLs (Table 3). Three organization recommended choosing the IOL material depending on patient characteristics and type of surgery.

• b) Choice of IOL

Sixteen organizations had guidelines around the choice of IOLs. Seven organizations recommended the surgeon should make a shared decision with the patient about postoperative refractive target and IOL type, taking into consideration the patient’s preferences, needs, lifestyle and expectations. Eight organizations recommended surgeons consider Toric IOLs in the presence of significant preoperative corneal astigmatism; there was no consensus on what constitutes “significant astigmatism. There were no recommendations and very few specific instances where presbyopia-correcting (multifocal) lenses were considered. However, when using presbyopia-correcting or toric IOLs, 8 organizations recommended exercising caution because they may not be cost effective and require many preoperative steps and knowledge. Some organizations recommend the use of monofocal IOLs as the standard, though this recommendation is dependent on the setting. Skill and experience in testing for and selecting IOLs are essential for good patient visual outcomes and satisfaction.

3.3. Intra-operative phase

The next set of guidelines pertain to factors at the intraoperative phase that may affect outcomes of cataract surgery. Within this grouping there are guidelines about room and patient preparation, the pause (“time out”) before surgery, and the surgery itself. We also describe measurement of adverse intra-operative outcomes.

• 1. Sterilization

• a) Operating Theater

Twelve organizations had guidelines specifically requiring sterilization of the operating theater. However, the protocols and standard operating procedures (SOP) differed, with organization referring to international or national standards, standards devised by American Society of Cataract and Refractive Surgeons,¹² or SOPs developed themselves. The importance of having a standard cleaning and sterilization protocol in place with ways of ensuring adherence was stressed by 9 of the 12 organizations. Some specific recommendations included ensuring proper instrument sterilization through autoclaving or other validated methods. Using sterilization indicators like autoclave tape was also specifically mentioned. One organization specifically discouraged the use of enzyme detergents for cleaning intraocular instruments due to risk of Toxic Anterior Segment Syndrome. Two organizations cautioned that equipment that becomes wet during procedures should be single use, if cost allows, because sterilization is not easy.

• b) Patient

Sixteen organizations had guidelines regarding patient sterilization before surgery (Table 4). Povidone-iodine was highlighted as the most important preoperative intervention to reduce endophthalmitis risk. The additional use of pre-operative antibiotic drops was controversial, but organizations with evidence -based guidelines cited recent evidence that showed no additional benefit.

• c) Draping

Table 4.

Intraoperative Phase: Factors with Patient sterilization, draping, and time out procedures that may affect outcomes.

Factor	Guidelines	Total No of sources reporting on factor	No. of sources with guideline (no. w/ evidence-based guidelines)
Patient Sterilization		16
	Topical 5% povidone iodine, or aqueous chlorhexidine 0.1% in conjunctiva sac		11 (4)
	Preoperative topical antibiotics: Recommend		3
	Preoperative topical antibiotics: not recommended		2 (2)
Draping		7
	Mentioned Sterile Drapes/Sterile Technique		7 (3)
	Isolation of Lid Margins and Lashes from Surgical Field		3 (1)
Time Out		12
	Time out/checklist is strongly recommended		12 (3)

Seven organizations had specific guidelines around draping. Two organizations specifically mentioned sterile drapes. Three organizations recommended isolating the lid margins and lashes from the surgical field, with recommendations to lift the lid margin off the globe and ensure lashes are tucked away. There was no consensus regarding draping techniques.

• 2. Time Out

A ”time out” immediately prior to onset of surgery was an explicit recommendation from 12 organizations (Table 4). There was unanimous recommendation for Standard Operating Procedures to ensure that the correct patient, eye, procedure and IOL were being considered for surgery. There is evidence that use of pre-surgical protocols results in fewer surgical errors. The recommended methods and checklists differed somewhat. Two sources for a checklist, the WHO correct surgical site checklist, and the American Academy of Ophthalmology surgery checklist, were specifically mentioned.

• 3. Type of Anesthesia

The terminology around “topical “ and “local” can be confusing. Generally, local refers to the absence of any systemic sedation and topical refers to the use of anesthetic drops or jelly, with or without light sedation. Regional anesthesia refers to the use of a sub-tenon, peribulbar, or retrobulbar block.

Eight organizations had recommendations stating surgeons should use their discretion and consider the patient’s needs to determine the type of anesthesia management, and 2 organizations with evidence-based guidelines noted a lack of evidence for a single optimal anesthesia strategy for cataract surgery (Table 5). Topical or regional blocks with or without systemic sedation and general anesthesia have individual indications that may prioritize them for some cases and 2organizations recommended avoiding retrobulbar anesthesia due to the rare risk of complications such as optic nerve damage.

• 4. Type of Surgery

Table 5.

Intraoperative stage: Type of anesthesia and surgery, incision size, intracameral antibiotics use that may affect outcomes.

Factor	Guidelines	Total No of Sources reporting on factor	No. of Sources with guideline (no. w/evidence-based guidelines)
Type of anesthesia		16
	Surgeon discretion and patient’s needs		8 (8)
	General anesthesia should be rarely used		6 (4)
	Topical anesthesia is preferred		4 (3)
	No preference between topical and regional		4 (2)
Type of Surgery		17
	Phacoemulsification		9 (7)
	Small incision cataract surgery is a minimum standard		4
Size of Incision		6
	Small incision (size not specified)		3 (2)
	Specified, between 2.2–6.0 mm		3(1)
Use of intracameral antibiotics		15
	Intracameral antibiotic use is best practice		14 (8*)
	Use only when higher rate of endophthalmitis is a concern		1 (1)
	Continue to use post-operative topical antibiotics		3 (3*)
Choice & dose of intracameral antibiotic		12
	No preference between moxifloxacin/Cefuroxime		5 (3)
	Use of Cefuroxime		4 (3)
	Use of Moxifloxacin (especially if known penicillin allergy)		2 (1)
	Use Cefazolin		2 (2)⁎⁎

^⁎Chinese Medical Association noted that there should be a gradual promotion of intracameral injections for cataract surgery in China, based on evidence.

^⁎⁎Both organizations from Australia noted at the time cefuroxime was not available.

Seventeen organizations had guidelines regarding the type of surgery (Table 5). Phacoemulsification was the standard recommended procedure for cataract surgery for 9 organizations, although many qualified the recommendation as for “high income countries” or when the equipment is available. Manual small incision cataract surgery was recommended as a minimum standard for surgery or preference by 4 organizations. One organization cited evidence that in randomized controlled trials, phacoemulsification produces better uncorrected distance VA (UDVA) and a lower risk of surgical complications, such as iris prolapse and posterior capsule rupture, than manual extracapsular cataract extraction (ECCE) with incision closure by sutures, or manual small incision cataract extraction.

• 5. Incision size

Six organization explicitly had guidelines around incision size, and all recommended small incision where feasible. (Table 5). There was no consensus regarding suggested small incision size, which ranged from 2.2 mm to 6.0 mm.

• 6. Intracameral Antibiotic

• a) Use of intracameral antibiotics

Of the 15 organizations, all but 1 recommending the routine use of intracameral antibiotics in cataract surgery to prevent endophthalmitis as best practice (Table 5). One organization recommended intracameral antibiotics only if there is a suspicion of higher risk of endophthalmitis. There is substantial evidence that intracameral antibiotic administration reduces the risk of post-operative endophthalmitis, in preference to pre- or post- topical antibiotic eye drops. However, 3 organizations continued to recommend use of topical antibiotics after surgery; 1 of the organizations recommended gradual promotion of use of intracameral antibiotic injection post-surgery. This recommendation requires access to properly prepared antibiotics for intracameral use, or infection and/or toxic anterior segment syndrome can result.

• b) Choice and Dose of intracameral antibiotics

Twelve organizations had explicit drug preferences/doses of intracameral antibodies in their guidelines (Table 5). Of note, 5 of the organizations were from low or middle income countries. Five organizations had no preference for either Moxifloxacin or Cefuroxime use. Four organizations recommended using intracameral cefuroxime. All organizations with guidelines supporting use of Cefuroxime propose a dose of 1mg/0.1 ml injection (in Australia and New Zealand, two organizations recommended cefazolin use at the same dose). There is no agreed upon dose for moxifloxacin but topical ophthalmic solutions should not be used for injection. Two organizations recommended against the use of intracameral vancomycin because of the lack of evidence for efficacy and its association with the rare complication of hemorrhagic occlusive retinal vasculitis.

3.4. Intraoperative outcomes

• 1. Intraoperative complication rates

Eleven organizations had explicit guidelines about intraoperative complications rates (Table 6). Seven organization required protocols to prevent and to manage intraoperative complications during cataract surgery. Matching surgical complexity with surgeon experience was recommended by 3 organizations. Four organizations require documentation and monitoring of intraoperative complications, with 1 guideline proposing a target rate of intraoperative complications of no more than 5%.

• 2. Duration of surgery

Table 6.

Intra-operative outcome measures: Intra-operative complications.

Factor	Guidelines	Total No of sources reporting on factor	No. of sources with guideline (no. w/ evidence-based guidelines)
Intraoperative complications		11
	Requires Establishment of Protocols for Prevention and Management of Complications		7 (3)
	Required Documentation of Intra-Operative Complications and Annual Monitoring of Complication Rate.		4 (1)
	Match surgeons experience with surgical complexity		3 (1)

One organization recommended only that the surgery should be done as expeditiously as possible considering the patient and the complexity of the case. It is reasonable that there are no explicit guidelines about the time to do surgery because each case will be different and present different challenges. The skill of the surgeon and the complexity of the case likely dictate an appropriate length of surgery, recognizing that efficiency is crucial because the less time the globe has an open wound the less opportunity for infection.

3.5. Post-operative phase

The final set of guidelines pertain to factors in the post-operative stage that could affect outcomes of cataract surgery, as well as guidelines for monitoring outcomes postoperatively. Within this grouping, there are guidelines for post operative eye drops, eye shields, and follow up duration and intervals.

• 1. Use of antibiotic eye drops

Thirteen organizations had guidelines regarding the use of postoperative topical antibiotics (Table 7). Nine organizations supported the use of antibiotic eye drops as part of post-operative care following cataract surgery but there was no consistent recommendation on the antibiotic to use. Four organizations (all from high income countries) recommended against the use of antibiotic eye drops, supporting these claims through studies that described a limited additional benefit for antibiotic eye drops used in patients who also received intracameral antibiotics. As noted above, if commercially prepared intracameral formulations are not available, antibiotic eye drops may be considered to avoid the risk of dilution errors and contamination if solutions must be prepared on site.

• 2. Post operative topical steroids

Table 7.

Post operative Phase: Use of eye drops, and follow up frequency and duration that may affect outcomes.

Factor	Guidelines	Total No of sources reporting on factor	No. of sources with guideline (no. w/ evidence-based guidelines)
Use of antibiotic eye drops post operatively		13
	Use antibiotic eye drops: Broad spectrum antibiotic		9 (6) 3 (2)
	Do not use antibiotic eye drops*		4 (4)
Use of Steroid Eye Drops		13
	Recommend use as standard of care		13 (9)
	Recommend use in some patient populations		2 (2)
Use of Eye Shields/pads		8
	Recommend use of at least pads Duration of use at night 1–2 weeks		6 1
	Eye shields not recommended for low-risk patients		1 (1)
Follow up visit: duration and frequency		9
	Complicated cases: first follow up within 24 hrs		4 (4)
	Low risk cases: first follow up: no consensus (24 h-4 weeks)		3 (3)
	Follow up visits at: 1 day, I week, 1 month		3
	Follow up duration recommendation varies		3

^⁎in context of use of intracameral antibiotics.

All 13 of the organizations contributing guidelines recommended the use of steroid eye drops but with no consensus on dose or duration (Table 7). Their role in reducing post-operative inflammation was discussed as broadly beneficial in reducing the risk of post-operative complications. There was variability in the recommended course of steroid eye drops and the tapering periods; reported courses ranged from administration of drops 4 times per day for 2 weeks to administration of 6 drops per day for 7 days, followed by a month-long tapering period.

• 3. Post- Operative eye shields

Seven organizations had guidelines regarding use of postoperative eye protection although none of them had any evidence supporting their use. Six organizations supported use of some eye protection post-surgery. Only 1 organization had a recommendation about the duration of use of eye protection, from 1–2 weeks while sleeping.

• 4. Follow up duration and frequency

Nine organizations had guidelines about the frequency and duration of follow up after cataract surgery (Table 7). For the first follow up, 4 organizations recommended that complicated or high-risk cases be evaluated within 24 h post-surgery. There was no consensus on the timing of the first visit for low-risk patients, with recommendations from within 48 h (1 organization with evidence-based guidelines) to 4 weeks (1 organization with evidence-based guidelines). Three organizations had guidelines recommending post operative visits at 1 day, 1 week, and 1-month after surgery to test final refraction. Other organizations had other follow up schedules, with no consistent pattern.

3.6. Post-Operative outcomes

Measures of postoperative outcomes, in terms of vision improvement or reaching target vision, patient satisfaction, and rate of post-operative complications, were reported by several organizations (Table 8).

• 1. Post operative vision testing

Table 8.

Postoperative outcome measures of effective cataract surgery.

Factor	Guidelines	Total No of sources reporting on factor	No. of sources with guideline (no. w/ evidence-based guidelines)
Measure Visual acuity		18
	Post-operative measurement of visual acuity outcomes is necessary.		18 (4)
	Recommendations for percentage of patients that achieve a benchmark VA (no uniformity of benchmark)		11 (2)
	Use WHO benchmark indicators for visual outcome after surgery		3
	Monitor and compare the target refraction to the post-operative refraction		3
	A goal of ± 1 diopter or less from target refraction		2
Patient Reported satisfaction w/ outcome		7
	Patients give feedback and system demonstrates responsiveness.		3
	Recommend use of standardized questionnaire for patient reported outcomes		2 (2)
	Collect data on satisfaction from patients		5 (2)
Post -operative complica-tions		16
	Have guidelines to manage post operative complications.  Monitor Endophthalmitis  Monitor TASS*  Unplanned return to Theater		13 (7) 8 (4) 3 (2) 2
	Rates of endophthalmitis <1/1000 ⁎⁎		4 (2)
	Have YAG laser available for treatment of posterior capsule opacification		2
	Rate of Capsule complication <2–3%		2

^⁎Toxic Anterior Segment Syndrome.

^⁎⁎some qualified using this rate only with use of intracameral antibiotics.

Eighteen organizations all supported measuring VA post-operatively. Eleven organizations had specific VA targets, but there was no consensus, varying from 97% of post-operative eyes with 20/20 vision to 80% with 6/18 or better. The target of 6/18 or better may reflect guidelines of WHO before 2022, whereas now the target is 6/12 or better.⁸ Three organizations recommended using WHO indicators of visual outcome after surgery. Two organization also recommended a benchmark of 5% or fewer post-operative eyes with final VA of <6/60. Three organizations recommended achieving the target refraction, with 2 recommendations for achieving a goal of ± 1 diopter or less from target refraction.

• 2. Patient reported outcomes

Seven organizations reported guidelines regarding patient satisfaction or patient reported outcomes. Five organizations had recommendations requiring collecting data on patient satisfaction. Three organizations also had guidelines recommending explicitly the data be fed back to the system to improve services. Two organizations recommended collecting data on patient reported outcomes using standardized questionnaires. However, no single instrument has been widely adopted internationally to assess post-operative patient satisfaction and/or outcome following surgery.

• 3. Post-operative complications

Sixteen organizations had guidelines around identifying, managing, and monitoring 1 or more post operative complications (Table 10). Endophthalmitis was specifically targeted by 8 organizations, with 4 organizations specifying rates of endophthalmitis <1/1000 operated eyes. Monitoring Toxic Anterior Segment Syndrome was specifically recommended by 3 organizations. Some organizations had extensive protocols for managing a variety of adverse outcomes. Two organizations had benchmarks of capsule complications <2–3% and 2 organizations had recommendations of monitoring unplanned return to theater, one with a benchmark of <1/1000 operations. Two organizations had specific benchmarks for a variety of postoperative complications such as Descemet tear and corneal edema. Besides protocols to manage post operative complications, quality of surgery should be monitored by setting benchmarks and monitoring complication rates against these benchmarks and having clear guidelines regarding what to do if benchmarks are exceeded.

4. Discussion

Our scoping review found cataract surgery guidelines from 34 sources that together covered the factors in each of the phases that we pre-specified. The factors were chosen because they have the potential to affect the outcome of surgery. Some of the factors, like age, ocular and systemic co-morbidities, are patient characteristics and not part of pre-, intra-, and post-operative procedures. However, because they can affect outcome they were included and guidelines around these factors largely dealt with noting them and counseling patients around possible impacts on visual outcomes.

Our findings from the review can be summarized as guidelines that have largely unanimous support and evidence, guidelines for which there is inconsistency and harmonization is needed, and guidelines where evidence is lacking. These are discussed in detail below.

Many of the guidelines were cited by several sources and there is good evidence for using them. These include the following:

• 1) Continue use of anticoagulants, antiplatelet medication and immunosuppressive therapy;

• 2) immediate pre-operative use of povidone-iodine topical solution. This guideline, with evidence of decreased rates of endophthalmitis with use, promotes an inexpensive and readily available sterilizer and should become standard of care.;

• (3) Use of a “time out” check list prior to surgery. The pause prior to surgery, with details spelled out of a “time out” where the correct eye, patient, procedure, and IOL were re-checked, has been shown to reduce surgical errors and is standard operating procedure in many cataract centers.

• (4) Use of intracameral antibiotics. The major hurdle to implementing this guideline is the unavailability in several countries of a pre-mixed single use formulation; Europe and India have such a formulation but otherwise it must be compounded.

• (5) Post operative use of topical steroids;

• (6) Use of phacoemulsification, as the evidence points to superior outcomes. However, phacoemulsification may not be available in areas in low and middle income countries due to the significant cost, the need for technology to support the equipment, and logistical barriers in maintaining a reliable supply chain. This was noted by 4 organizations (none using evidence), and they stated that manual small incision surgery should be at least a minimum standard. There are indeed impediments to the adoption of phacoemulsification, but cataract surgery programs wishing to improve outcomes need to consider how to move forward using approaches that have proven better visual outcomes.

• (7) The use of accurate biometry for determining IOL was another guideline stated by several sources and with good evidence supporting it. This represents a move away from using a single standard or maintaining just a few IOLs for refractive correction in favor of obtaining the best possible refractive correction for the patient.¹³ This recommendation is also reflected in the post operative outcome guidelines from 2 organizations that suggest a benchmark of obtained refractive correction within ± 1 diopter of planned correction. Several sources noted that the choice of the IOL should be left between the patient and the surgeon. Of note, there was no consensus on the number of scans, when to re-measure, or the calculation of the power of the IOL. Thus, there is a need to further define and build consensus on the parameters of “accurate biometry”, and ideally, the training and experience needed to perform accurate biometry.

There is a move towards people-centered care in these guidelines. Thirteen organizations had guidelines on indications for cataract surgery, and while some suggested VA benchmarks, all stated that VA is not the sole criteria for cataract surgery, but that patient’s function and visual symptoms should be paramount. This trend is mirrored in the move toward ISBCS, where several organizations highlighted the benefit for persons who had to travel or for whom waiting would be onerous; 6 of 9 organizations with guidelines on timing for second eye surgery recommended ISBCS in certain conditions, including if patients had traveled far or from remote areas. The scoping review of literature by Yoshizaki, et al. went even further in summarizing findings suggesting ISBCS reduced provider and patient cost and achieved quicker and sustained improvement in quality of life without compromising safety.¹⁴

A meaningful issue for cataract surgery patients is the wait time for surgery. There were no evidence based guidelines found on the maximum wait time between scheduling and performance of surgery, although 4 organizations stressed minimizing wait time, especially when the cataract causes very poor vision. This area should be revisited as there is evidence that those who wait >6 months for cataract surgery experience higher rates of negative outcomes, reduced quality of life and increased risk of falls than those who wait ≤6 weeks.¹⁵ In a large Austrian study, the mean maximal acceptable waiting time for surgery was 3.17 months, with patients who reported loss of visual function more likely to report a maximum acceptable wait time of <3 months.¹⁶ A 3 country study found that patients accepted wait times of up to 3 months, but considered a wait time of >6 months to be excessive. Those with more self-reported difficulty were least tolerant of prolonged wait time.¹⁷

Our scoping review found guidelines that are inconsistent for the same factor and for which some harmonization going forward should be considered. This includes the necessity of pre-operative medical visits and laboratory testing. In the case of pre-operative testing, we found 10 organizations stating that pre-operative medical assessment and/or laboratory testing was recommended, and 3 (2 with evidence base) stating it was not necessary, 1 qualifying it as to be undertaken at the ophthalmologist’s discretion. There is no good evidence that pre-operative laboratory testing improves cataract surgery outcomes. Studies have found that a pre-operative medical visit did not decrease the risk of ocular or surgical complications and evidence that pre-operative laboratory testing does not affect patient outcomes.^18,19 However, some organizations working in underserved areas justify testing for diabetes and high blood pressure as public health opportunities to detect common diseases and move people into care. Programs in India, Africa, and Southeast Asia (e.g., Aravind‑affiliated outreach, LV Prasad, Himalayan Cataract Project) often incorporate opportunistic screening for this reason, but not because it improves cataract outcomes.

Pre-operative and post-operative use of topical antibiotics is another area with inconsistent guidelines. Those promoting pre-operative topical antibiotic use do not have evidence for benefit. Those that discourage pre-operative use cite literature that generally converges on the message that in the presence of proper povidone-iodine antisepsis, topical antibiotics do not add any clear benefit.²⁰ Likewise for post-operative use of topical antibiotics, if using intracameral antibiotics, there is no added benefit for prevention of endophthalmitis from post-operative topical antibiotic use.²¹ Two organizations, both from China, stated as qualifiers in their guidelines that topical antibiotic use post-operatively is recommended while the country transitions to intracameral antibiotic use. We conclude that in the presence of proper antisepsis with povidone-iodine and use of intracameral antibiotics there is no benefit to use of topical antibiotics pre or post- surgery, and the added cost and exposure do not justify the risk of using them.

More harmonization is needed on the benchmark for outcomes. Eighteen organizations had guidelines requiring measuring post-operative VA and 11 had benchmarks for quality outcomes based on final VA and final refractive correction versus target. However, the benchmarks were inconsistent. In some cases, this inconsistency reflects a lack of updating guidelines based on former WHO criteria for good visual outcomes, which now state that at least 80% of operated eyes should have presenting VA of 6/6 to 6/18 (“good visual outcome”) and at least 90% of operated eyes should achieve BCVA of 6/6 to 6/18 after refraction.⁷ There is no agreement on standards proposed for differences between actual versus target refraction. Monitoring visual outcomes and providing feedback to programs is an integral part of several non-governmental organizations’ criteria for support and was cited as associated with improved visual outcomes.¹⁴ However, there should be agreement on at least the minimum standards that define “effective" cataract surgery outcomes.

Finally, there were guidelines provided that had virtually no support, and for which there is a gap that should be addressed. These include the following

• (1)Ocular or systemic co-morbidities which are contraindications for surgery. Some guidelines suggest the case should match the experience of the surgeon, but there is no consensus on contraindications.
• (2)The use of eye shields or eye patches post-surgery, or for how long. There is limited quality evidence supporting the use of eye patching,²² and clear eye shields are used primarily for physical protection, but with no clear data on the duration of use.

We note some qualifications regarding the selection of sources. First, some organizations without their own guidelines noted they followed guidelines developed by others, such as the American Academy of Ophthalmology or the Royal Society of Ophthalmology. We did not double count these sources. We noted that some of the guidelines provided were similar in language to the guidelines of other organizations; for example, the American Academy of Ophthalmology guidelines and the guidelines used by the Colombia Society of Ophthalmology are similar in wording. In such cases we used both organizations as sources because both had adopted their own version of guidelines for their members.

Even though an organization does not have a guideline in a particular area does not mean it does not promote a specific practice for which others have explicit recommendations. For example, the fact that 12 organizations had explicit guidelines for sterilizing the operating theater does not mean that the other organizations do not promote that practice; it may mean that the organization relies on standard operating procedures for operating rooms and does not feel the need for explicit guidelines for cataract surgeries.

Certain limitations to our scoping review should be acknowledged. First, for 19 organizations the availability of guidelines was uncertain, but despite reaching out we were unable to obtain a response. Many of these were small non-governmental organizations and the likelihood of guidelines that differed from what we had already collected is likely small. We restricted our search for professional organizations to those specific to the WHO regions and may have missed those that were not identified by region but rather by country. There are 193 member states in the UN, and we decided that the search would be too onerous to undertake at that level.

Another limitation is that we chose to review the websites of the organizations for guidelines, and to contact those for which there was a suspicion of guidelines from the description within the web site. In some instances, either one had to be a member to see the full website or the material was not on the website. It is possible that some of the organizations, particularly the 59 professional organizations that had no guidelines, may have had some guidelines but not alluded to them on the website.

Many of the guidelines found did not have dates associated with them, and while we tried to limit our search to those between 2010 and March 2024, most guidelines were undated. To be comprehensive, we included them anyway. However, some of the guidelines could be out of date given more recent data. This issue was evident for recommendations that used older parameters, such as VA outcomes less stringent than are promoted now. Nevertheless, we included those without dates in the interest of being comprehensive.

We did not include in our review the issue of patient counseling, except when it came up within the context of a guideline, such as counseling patients that ocular co-morbidities may have an impact on surgical outcomes. The issue of proper patient counseling about the importance of adherence to follow up visits or use of spectacles may improve outcomes.

The strength of this scoping review was the breadth of the search, the pre-specified areas of interest that were relevant to effective cataract surgery and the range of organizations that contributed guidelines. Potential areas for further work include research to strengthen the evidence base for several guidelines that qualify as best practices but for which the evidence base is weak. This issue was highlighted by Zhang et al. in their systematic review as well,²³ which identified only 4 organizations with evidence based guidelines. The limited number was due in part because of their stricter eligibility criteria. We had neither a language exclusion criterion nor a restriction to use only evidence-based guidelines. We included all 4 of their sources in our review, but our search was broad in scope to understand what was either being used or promoted for use by organizations worldwide.

Further work on creating an evidence base for guidelines about training cataract surgeons to improve outcomes is an urgent need, and beyond the scope of this review. Yoshizaki, et al., found that structured surgeon curriculum, including wet-lab and simulator training, reduced the incidence of serious complications, although evidence for the effectiveness of simulator training by itself was inconclusive.¹⁴ Adequate training of cataract surgeons and evaluating outcomes against metrics is a critical component of effective surgery and development of guidelines for training should be a top priority. Our scoping review differed from the scoping review by Yoshizaki, et al. on quality of cataract services.¹⁴ Their review had a broad scope that covered such areas as people-centeredness, timeliness, equity, and planetary health. Our scoping review focused on existing guidelines for the more technical aspects of the surgery that might improve outcomes. Nevertheless, there was overlap between our findings and those of Yoshizaki, et al., with similar recommendations in areas such as pre-operative laboratory testing and use of biometry.

While we identified a series of guidelines for which there was strong evidence and extensive use, there were guidelines for which harmonization is needed and some for which evidence should be generated. Nevertheless, the framework we have provided, and the scoping review of guidelines against that outline, is a reasonable template and should provide a starting point for a technical working group to undertake the creation of a set of minimum guidelines. We acknowledge that implementing some of these guidelines may face logistical and resource constraints. However, we strongly urge the development of ideal process indicators that cataract surgical programs can strive for to strengthen effective cataract surgery worldwide.

Table of contents

• •Scoping review of global existing guidelines for improving cataract surgery
• •Methods based on pre-specified multi-pronged approach
• •
  34 sources had guidelines for pre-, intra-, and post-operative surgery, including

  • ○
    Use of accurate biometric measurements for best refractive outcome
  • ○
    Use of povidone-iodine and intracameral antibiotics to prevent infection
  • ○
    Although more expensive to implement, phacoemulsification for best outcomes
• •World Health Organization can use findings to develop guidelines for effective cataract surgery

Funding

This research did not receive any specific grant from funding agency in the public, commercial, or not-for-profit sectors.

Author contributions

Sheila West: conceptualization, investigation, validation, analyses, Data curation, writing-original draft. Ian Saldanha: Conceptualization, methodology, Software, resources, writing-review/editing. Fasika Woreta: validation, writing-review/editing. Christina Ambrosino: investigation, validation, writing-review/editing. Jay Maturi: investigation, validation, writing-review/editing. Fekadu Ayalew: investigation, validation, writing-review/editing. Jordan Kaplan: investigation, validation, writing-review/editing. Annabelle Pan: investigation, validation, writing-review/editing. Winnie Liu: investigation, validation. Anna Kim: investigation, validation, writing-review/editing. Emily Joseph: Methodology, investigation, writing-rev iew/editing. Andreas Mueller: Conceptualization, writing-review/editing. Silvio Mariotti: Conceptualization, writing-review/editing

Declaration of competing interest

The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article. All the authors declare they have no financial or other relationships that would be conflicts of interest to disclose.