Attitudes and understanding of premium intraocular lenses in cataract surgery: a public health sector patient survey

Abstract

Objectives

To investigate patient understanding of, and attitudes to, premium (toric, extended depth of focus/multifocal) intraocular lenses (premIOLs) in public health sector patients undergoing cataract surgery (CS) in the UK.

Methods

A 12 question survey with Likert scale questions was designed, to assess patient attitudes to post-operative spectacle dependence, refractive target and desirability of spectacle independence whilst considering possible complications of dysphotopsias and need for premIOL exchange/adjustment.

Results

360 surveys were collected. CS had not been performed in 66.5%. Separate spectacles were worn for reading and distance in 28.8%, 19.2% had varifocals, 11.2% bifocals, 22.9% reading glasses only and 1.6% computer glasses only. Contact lenses were not worn in 95.7%. Only 41.6% were drivers. Most patients (85.8%) did not mind wearing glasses after CS, with 78.9% preferring reading glasses, compared with 29.7% preferring distance glasses. Most patients (75.3%) were not familiar with premIOLs, with 58.9% not willing to consider them in the context of a 2% risk of debilitating dysphotopsia and 54.2% rejecting a 5% risk of second surgery.

Conclusions

There is a lack of awareness of premIOLs in public health sector (NHS) patients in the UK, suggesting limitations in the “fully informed” consent process for CS. Most NHS CS patients are currently willing to wear spectacles after CS, especially reading glasses. There is reluctance in such patients to consider premIOLs on a background of small risks of debilitating dysphotopsias and increased risks of a second operation.

Introduction

Cataracts are a major cause of global visual impairment [1, 2] with cataract surgery (CS) being the most common surgical intervention undertaken for pathology. Over 4 million procedures were performed in the EU in 2016 [3] and 476,000 in the National health service (NHS) in 2019 [4]. With modern surgical techniques and intraocular lenses (IOLs), visual and refractive outcomes are excellent with 95% of eyes (without co-pathology) achieving 0.3 LogMAR corrected acuity or better [5]. Hence, CS is one of the most successful interventions in medicine, with high patient and surgeon expectations [6]. However, most CS is undertaken using monofocal IOLs, which only correct for a single point of focus. Therefore, despite successful CS, patients often have continuing dependence on spectacles with associated inconvenience and costs.

‘Premium’ IOLs (premIOLs) have been developed to reduce spectacle dependence following CS. They include extended depth of focus/multifocal IOLs (mIOLs) and toric IOLs (tIOLs). mIOLs utilise diffractive or bifocal optics [7] and have been shown to give better uncorrected near and intermediate vision and greater spectacle-independence compared to monofocal IOLs [7], but with higher risks of glare, halos, lower contrast sensitivity [7], and additional cost per lens. Their optics are also best limited to eyes with no ocular co-morbidities/anomalies other than cataract. Therefore, whilst implanted in the private sector in the United Kingdom (UK), the National Institute of Clinical Excellence (NICE), in its national CS guidelines in 2017, stated that NHS patients should not be offered mIOLs [8].

Corneal astigmatism is common, with over 40% of CS patients having over 1.00 dioptre (D) [9, 10] and 10% over 2.00D of astrigmatism [11]. Failing to address astigmatism during CS can result in sub-optimal unaided vision, less spectacle-independence, increased patient costs and reduced quality of life scores [12]. Whilst peripheral corneal relieving incisions and astigmatic keratotomies can address low levels of astigmatism [13, 14], tIOLs are more stable and predictable for moderate and high astigmatic errors [15–19]. Despite these advantages, in an audit of 601,084 CS operations between 2010 and 2018 in the NHS, only 2369 (0.4%) involved implantation of a tIOL [20]. Reasons for this include additional costs of tIOLs, additional paperwork/time for ordering tIOLs, requirement for extra equipment e.g toric markers, additional pre-operative investigations including corneal topography, additional time and skills required for surgical planning and correct lens alignment, and occasionally the need for a second surgery to optimise lens alignment.

Therefore, whilst NHS patients may undergo CS free at point of care for restoration of vision, limited consideration is often given to reducing spectacle dependence. In the NHS, patients will not be offered a mIOL and they are unlikely to be offered tIOLs and if they wish to pursue such options they must turn to the private sector. As such, it is likely that many NHS patients are given only limited information concerning premIOLs and their potential advantages/disadvantages and consequently a ‘fully informed’ CS consent process is incomplete.

To ascertain our public health sector (NHS) CS patients’ understanding of the existence of premIOLs and their attitudes towards these lenses with regards to benefits/complications and spectacle dependence/independence, we undertook this present questionnaire study. To our knowledge, this is the first such study.

Materials and methods

Questionnaire and question types

We designed an anonymous questionnaire comprising 12 questions and additional information i.e., age, gender, and ocular co-morbidities (Appendix 1). The first five questions ascertained the patient’s ‘baseline’ refractive condition, including whether they had had CS, spectacle wear, contact lens wear, current refractive error and driving status. The following five questions were designed with a 5-point Likert Scale and investigated attitudes towards post-operative spectacle wear and knowledge of premIOLs. Two further questions were asked on desirability of premium IOLs when considering possible complications of premIOLs, namely dysphotopsia (halos and starburst phenomena) and need for IOL exchange/manipulation.

This questionnaire was approved and registered by our NHS trusts’ Quality Improvement Project team. Data was collected in adherence with the tenets of the Declaration of Helsinki and the UK Data Protection Act.

Population

Patients attending the adult Cataract Clinics, between August 2021 and July 2022, at the Department of Ophthalmology at Guy’s and St. Thomas’ NHS Foundation Trust, who were listed for CS and where the study team were in attendance, were consented verbally and given a questionnaire to complete. Most completed the questionnaire themselves but were given the opportunity to ask questions if they required clarification. If assistance was required, doctors and medical students from the study team were made available to read the questions to the patient.

Power calculation

We used the online Raosoft calculator (http://www.raosoft.com/samplesize.html) to calculate the sample size. We perform ~3000 cataract operations a year. Based on a p value of 0.05%, a 95% confidence interval, and a population of 3000 patients our target patient sample was 341.

Statistical analysis

Basic descriptive statistical analysis was performed using Excel (Microsoft® Excel® for Microsoft 365 MSO Version 2207) and inferential statistical analysis was performed using Prism (9.4.1., Graphpad).

Spearman rank correlation was performed to assess associations between age and the Likert scale data for questions 6–12. Likert scale data from these groups were grouped into Agree (strongly agree + agree) and Disagree (disagree + strongly disagree). Data were compared with Chi Square test.

Likert scale responses from questions 6 to 12 were grouped by gender of respondent. Mann Whitney tests were performed to compare Male and Female responses.

For sub-group analysis patient data were divided into several groups: Patients awaiting surgery (phakic) and those that had undergone CS in at least one eye (pseudophakic); and patients who were ‘Non-Drivers’ and ‘Drivers’. Groups of data were analysed for normality with the D’Agostino-Pearson, Anderson-Darling, Shapiro-Wilk, and Kolmogrov-Smirnoff tests. Both groups of data were non-parametric, and therefore were compared using Mann-Whitney. Spearman’s rank correlation was performed to assess associations between the Likert scale data for differing questions.

Results

Three hundred and sixty questionnaires were completed/partially completed. The median age was 73 years (range 19–96 years), with 143 respondents being male (39.7%), and 212 female (58.8%) and 5 (1.5%) not answering (Table 1). There were no significant differences in the Likert scale responses between males and females for questions 6 to 12 and no significant correlations were seen between age and responses to questions 6 to 12.

Table 1.

Patient demographics.

a. Table denoting age group distribution of patients and gender distribution of patients.
Age Group	Number of patients
10–19	1
20–29	2
30–39	2
40–49	10
50–59	44
60–69	86
70–79	129
80–89	79
90–99	5
Did not answer	2
Gender
Male	143
Female	212
Did not answer	5

b. Table denoting distribution of gender of patients in Phakic and Pseudophakic groups. Chi squared & Fishers’ exact tests were performed. No statistically significant difference was found between the two groups in terms of gender distribution.
	Male	Female
Phakic	103	131
Pseudophakic	42	76

Most patients (66.5%, 238) had not yet had CS, with 29.6% (106) attending after their first eye, and 3.9% (14) after their second eye. Only 41.6% (150) of patients reported they were drivers.

Only 6.4% (24) of patients reported not wearing any glasses, with most (28.8%, 108) wearing separate reading and distance glasses, 19.2% (72) varifocals, 11.2% (42) bifocals, 22.9% (86) reading glasses only, 8.8% (33) distance glasses only and 1.6% computer glasses only (6). More than half did not know the nature of their refractive error (52.2%, 188), while 19.4% (70) identified as long-sighted, 29.7% (107) as short-sighted and 10.5% (38) reported an astigmatic error. Most (93.9%, 338) did not wear contact lenses, with a few wearing them for distance (3.33%, 12), and a minority for either monovision (0.6%, 2) or using multifocal contact lenses (0.83%, 3).

Most patients, 85.8% (309) (52.5%, 189 strongly agree; 33.3%, 120 agree) reported not minding wearing glasses after CS (Table 2a). If they had to choose, 53.3% (192) (17.2%, 62 disagree; 36.1%, 130 strongly disagree) preferred not to wear distance glasses. Most were more comfortable with reading glasses after surgery with a combined 78.9% (284) (53.9%, 194 strongly agree; 25%, 90 agree) preferring them.

Table 2.

Patient attitudes to spectacle dependence after cataract surgery.

a
I do not mind wearing glasses after cataract surgery	Number	Percentage
Strongly Agree	189	52.5
Agree	120	33.3
Neutral	26	7.2
Disagree	13	3.6
Strongly Disagree	9	2.5
No Answer	3	0.8
If I had to wear glasses after surgery for one activity, I would be most willing to wear glasses for distance vision
Strongly Agree	48	13.3
Agree	59	16.4
Neutral	56	15.6
Disagree	62	17.2
Strongly Disagree	130	36.1
No Answer	5	1.4
If I had to wear glasses after surgery for one activity, I would be most willing to wear glasses for midrange vision (computers, cooking, price tags)
Strongly Agree	40	11.1
Agree	79	21.9
Neutral	120	33.3
Disagree	56	15.6
Strongly Disagree	60	16.7
No Answer	5	1.4
If I had to wear glasses after surgery for one activity, I would be most willing to wear glasses for near vision (reading books, tablets, and smartphones, sewing)
Strongly Agree	194	53.9
Agree	90	25.0
Neutral	33	9.2
Disagree	20	5.6
Strongly Disagree	19	5.3
No Answer	4	1.1

b
I am familiar with pIOLs (Toric and Multifocal intraocular lenses.)	Number	Percentage
Strongly Agree	15	4.2
Agree	22	6.1
Neutral	32	8.9
Disagree	11	3.1
Strongly Disagree	260	72.2
No Answer	20	5.5
Regarding pIOL insertion: I would be willing to accept the possibility of seeing halos and starbursts at night, to reduce my dependence on spectacles? (1:50 chance of interfering with night driving)
Strongly Agree	30	8.3
Agree	48	13.3
Neutral	52	14.4
Disagree	54	15.0
Strongly Disagree	158	43.9
No Answer	18	5.0
Regarding pIOL insertion: I would be willing to accept the possibility of a second operation if this is needed, to reduce my dependence on spectacles? (1:20 risk of needing a second procedure)
Strongly Agree	42	11.7
Agree	54	15.0
Neutral	52	14.4
Disagree	42	11.7
Strongly Disagree	153	42.5
No Answer	17	4.7

Most patients (75.3%, 271) were not familiar premIOLs (72.2%, 260 strongly disagree; 3.1%, 11 disagree), with only 10.3% (37) (6.1%, 22 agree; 4.2%, 15 strongly agree) familiar with them (Table 2b). A significant difference was found between phakic and pseudophakic patient respondents, with 83.6% (189) of phakic patients not being familiar premIOLs (80.5%, 182 strongly disagree; 3.1%, 7 disagree) compared to 72.6% (82) (69.1%, 78 strongly disagree; 3.5%, 4 disagree) of pseudophakic patients (p = 0.01) (Table 3). Roughly the same percentages agreed/strongly agreed (10.6%, 24 phakic and 11.5%, 13 pseudophakic) that they were familiar with premIOLs, with the percentage of neutral opinions increasing in pseudophakic respondents (Table 4). Except for familiarity with premIOLs (question 10) there were no statistically significant differences between phakic and pseudophakic patient respondents for any of the 5-Likert scale questions (Table 3).

Table 3.

Statistical analysis of phakic versus pseudophakic patient groups for the Likert scale questions.

Question	P value
6 - Wearing glasses after CS	0.22
7 - Preference for distance glasses after CS	0.61
8 – Preference for mid-range gasses after CS	0.59
9 – Preference for reading glasses after CS	0.36
10 – Familiarity with premIOLs	0.01
11 – Acceptability of risk of halo/starbursts with premIOLs	0.79
12 – Acceptability of risk of second surgery with premIOLs	0.13

CS cataract surgery, premIOLs premium IOLs.

Data groups were assessed for normality. None were found to be normal, and accordingly Mann-Whitney test was used to look for differences in two non-parametric groups of data.

Table 4.

Percentage distribution of question 10 (familiarity with premium IOLs (premIOLs) for phakic and pseudophakic patients (who have already undergone cataract surgery in at least one eye.).

	Strongly Agree	Agree	Neutral	Disagree	Strongly Disagree
Phakic	5.3	5.3	5.8	3.1	80.5
Pseudophakic	2.7	8.9	15.9	3.5	69

Most patients (58.9%, 212) (43.9%, 158 strongly disagree; 15%, 54 disagree) reported not wanting to consider a premIOL with associated 1 in 50 risks of debilitating halos and starbursts interfering with driving at night. Most (54.2%, 195) (42.5%, 153 strongly disagree; 11.7%, 42 disagree) reported not wanting to consider a premIOL with associated 1 in 20 risks of needing a second operation (reposition or IOL exchange) (Table 2b).

Most drivers (53.2%) (150) stated that they would accept the risk of a second operation to have a premIOL (38.2%, 57 strongly agree, 15%, 23, agree) with a significant difference compared with non-drivers (n = 210) (22, 10% strongly agree, 34, 16% agree) (p = 0.001). There were no other significant differences between non drivers and drivers for any of the other 5- Likert scale questions (Table 3). The mean age of non-drivers was 72.2 years (19–96) which was significantly greater than drivers (mean age 68.5 years (38–94)) (p = 0.0004). Non-drivers were predominantly female (70.7%) while drivers were predominantly male (57.1%). This difference was statistically significant (p < 0.0001).

There was a strong positive correlation between those declining premium IOLs due to risk of halos/starbursts, and those declining premium IOLs due to risk of a second operation (0.74). There was moderate negative correlation between those who would prefer post-operative distance glasses and those who would prefer post-operative reading glasses (0.46) (Table 5).

Table 5.

Patient attitudes to Premium Intraocular lenses (premIOLs) Spearman’s rank correlation.

	Surgery	Glasses after surgery	Distance Glasses	Mid Range glasses	Reading Glasses	Familiarity with Premium IOLs	Risk of Dysphotospia	Risk of Second Operation
Surgery		0.04	−0.07	0.01	0.14	−0.23*	−0.01	−0.11
Glasses after surgery	0.04		0.07	0.02	0.34*	−0.06	−0.09	−0.07
Distance Glasses	−0.07	0.07		0.54*	−0.24*	0.43*	0.45*	0.56*
Mid-range glasses	0.01	0.02	0.54*		0.09	0.40*	0.40*	0.46*
Reading Glasses	0.14	0.34*	−0.24*	0.09		−0.03	−0.05	−0.13
Familiarity with Premium IOLs	−0.23*	−0.06	0.43*	0.40*	−0.03		0.46*	0.48*
Risk of Dysphotospia	−0.01	−0.09	0.45*	0.40*	−0.05	0.46*		0.76*
Risk of Second Operation	−0.11	−0.07	0.56*	0.46*	−0.13	0.48*	0.76*

Spearman’s rank correlation was performed on raw Likert scores from the entire cohort.

*p < 0.05

Discussion

The aim of this study was to ascertain public health sector (NHS) CS patients’ understanding of the existence of premIOLs, their attitudes towards them with regards to possible benefits/complications and their desire for spectacle dependence/independence following CS. We believe this is the first study to gather patients’ opinions regarding premIOLs within the public health.

Most patients were elderly, with a median age of 73 years (Table 1). There was a slight preponderance (58.8%, 212) of women. These demographics are in line with a recent report from the RCOphth NOD group on 601,084 CS operations, where the median age for first eye surgery was 76.4 years, with 57.8% of patients reporting as female. [20]

While in 2021, 77% of those age over 17 in England, and 75% of those over 70, hold a driving licence [21], only 41.6% of our patients reported they were drivers. This probably reflects the location of our hospital in central London, where socio-economic factors, traffic congestion, policies aimed at discouraging driving and wide availability of public transport are associated with less private car ownership and usage [22]. Indeed, in 2017–2018 only 40.4% of households were reported as owning a car in Inner London [22], in line with our reported percentage of drivers.

Over 93% of our patients reported dependence on spectacles, with over 82% using some form of spectacle correction for near vision. Given the ages of our patients, such levels of spectacle dependence, especially for presbyopia correction, would be expected.

93.8% of our patients did not wear contact lenses. In the UK only 9% of those aged 15–64 years were reported as contact lens wearers in 2016 [23] and in our generally older patient group, a slightly lower percentage of contact lens usage might be expected. Only a minority, less than 1%, of our patients were using contact lenses for monovision or were using multifocal contact lenses. This is in line with current trends of contact lens prescribing, with only about 17% of new contact lens prescriptions in the UK being reported as multifocal in 2021 [24].

More than 50% of our patients (52.2%) were unaware of the nature of their refractive error. This is likely to reflect a lack of knowledge regarding the nature of ophthalmic/refractive problems in general, which may present additional challenges for informed consent.

Most, over 85%, reported not minding wearing glasses after CS, with almost 80% expressing a willingness to wear reading glasses (Table 2a). This is compatible with the observation that most of our CS patients (over 93%) were accustomed to spectacle wear, especially for near vision (82.1%). It is unclear whether these figures might shift if patients were fully informed of, or given access to, alternative technologies (premIOLs, monovision) to reduce post-operative spectacle dependence.

Concerning familiarity with premIOLs (mIOls and tIOLs), over 75% of our patients reported they were unaware of them, with only approximately one in ten knowledgeable of their existence (Table 2b). Although this percentage was less in patients who has undergone CS eye, over 70% of pseudophakic patients still disagreed/strongly disagreed that they were aware of premIOLs (Tables 3 and 4) and all patients whether phakic or pseudophakic had been listed for CS and undergone a consent process for CS just prior to questionnaire completion. This suggests that IOL options, including premIOLs, and spectacle dependence/independence following CS are not being comprehensively discussed as part of the consent process. In our NHS Trust, we do provide both verbal, video, and written information as part of our consent process. Our written information is entirely akin to the NHS cataract advice website [25], which states that mIOLs are only available in private healthcare and makes no mention of tIOLs at all [25]. Indeed, tIOLs are only available in our trust for select patients with high astigmatic anisometropias or as part of clinical trials. Given our hospital in central London serves areas with significant levels of socio-economic deprivation, it would be interesting to determine whether a lack of familiarity with premIOLs exists amongst CS patients in other areas of the UK.

Our patients were generally risk adverse, with almost 60% not wanting to consider a premIOL associated with a 1 in 50 risk of debilitating halos and starbursts, and over 50% not wanting a premIOL with a 1 in 20 risk of needing a second operation (reposition or IOL exchange) (Table 2b). As expected, there was a correlation between those who were risk adverse in terms of debilitating halos and starbursts and those who were risk adverse in terms of a possible need for a second operation (r = 0.76, P = 0.05) (Table 5). It would be interesting to ascertain how these percentages might alter following more comprehensive patient counselling on the risks versus benefits of premIOL implantation, although these findings are akin to those of Wang et al [26] who performed ‘sentiment analysis’ on data mined from an online health forum, searching for posts which referred to ‘multifocal IOLs’ and demonstrated that sentiment towards multifocal lenses was overall slightly negative, with halos or glare amongst the most frequently reported concerns.

Interestingly, subgroup analysis of non-drivers and drivers, revealed that drivers were more likely to consider premIOLs despite the risks of a second operation (Table 3). Whilst we found no correlations between age and gender of the whole patient cohort, with regards to the Linkert scale responses to question 12, drivers in our cohort of patients were significantly younger and more likely to be male, which might perhaps account for them being less risk adverse and merits further investigation.

Research indicates that the provision of good-quality pre-operative information facilitates patients’ active involvement in their care, and therefore may contribute to an overall increase in patient satisfaction [27]. In addition, clear and documented information concerning indications for CS and possible complications, can be protective for medical practitioners from CS negligence claims, with Bhan et al., indicating that over 50% of CS negligence claims they studied would have been avoidable with an adequate consent process [28]. Elder and Suter reported that it was important for the patient to be informed of the advantages/disadvantages of possible treatments, the operative technique, and risks and complications [29]. Two thirds of the CS patients in their study group wanted to know about risks even as low as 1 in 1000 [29]. As such, the NICE 2017 CS guidelines state that patients should be provided with written information, and given ample time to discuss risks, benefits, and predicted outcomes of CS procedures [8]. This includes discussing the refractive implications of ‘different’ IOLs, basing the choice of IOL on the patients chosen refractive outcome and recording such a discussion and the patient’s choices in their medical notes [8]. However, despite the development of premIOLs over the last two decades, reports of their potential benefits for select CS patients [8–12, 18, 19] and their widespread usage in the private health sector, our study indicates that NHS patients may be given only limited knowledge of them. Indeed ‘Getting It Right First Time’, an NHS England initiative, created a model cataract consent, available online, in which there is no mention of IOL choice [29].

To provide ‘fully’ informed CS patient consent, it would seem necessary, to inform patients of all IOL technologies applicable to their individual needs and ocular condition. Even if such technologies are not available, the patient can then make an informed decision and understand what they might expect in terms of spectacle dependence following CS. Such information does not have to be exhaustive and must be balanced with the time constraints often present within the public health sector. Verbal information should be provided by doctors and as such they need to understand the benefits and limitations/complications of premIOLs. This needs to be reflected in the training of doctors within the public health sector where these IOLs are not generally implanted. Patients also report satisfaction with advice and help given by both nurses and doctors as a multidisciplinary team, so nursing teams, etc. also need to be taught and understand IOL options, and what is offered in public health sector services [30]. Finally, written information concerning premIOLs is necessary and some NHS Trusts in the UK do indeed provide background information concerning premIOLs, and their lack of availability within the NHS system, in their cataract information leaflets, which is simple yet informative [31].

This questionnaire study, which is the first to gather patients’ opinions regarding premIOLs in the public health sector, indicates a lack of awareness of such lens options suggesting imitations in the “fully informed” consent process for CS. Most of our patients are at present willing to wear spectacles after CS, especially reading glasses and are generally reluctant to consider premIOLs on a background of small risks of debilitating dysphotopsias and increased risks of a second surgery. An interesting subject for further research would be, whether improving patient education regarding the potential benefits and risks of premIOLs, might alter such perceptions.

Summary

What was known

• Multifocal intraocular lenses (IOLs) are not implanted in the UK public health sector and toric IOLs rarely implanted.

• To provide fully informed consent for cataract surgery it is necessary to discuss the refractive implications of different IOLs, basing the choice of IOL on the patients chosen refractive outcome.

What this study adds

• Public health sector patients in the UK have a lack of awareness of premium intraocular lenses, suggesting limitations in the fully informed consent process for cataract surgery.

• Most of UK public health sector patients are at present willing to wear spectacles after cataract surgery especially reading glasses.

• Most patients reluctant to consider premium IOLs on a background of small risks of debilitating dysphotopsias and increased risks of a second surgery.

Author contributions

KN, LD and DO’B designed the questionnaire with contributions from MB, SL and EA. Data were collected by all authors. AJ analysed the data and wrote the paper with DO’B. The project was overseen by DO’B.

Data availability

The datasets generated by the survey research during and/or analysed during the current study are available on application to the corresponding author.

Competing interests

DO’B holds non-commercial research grants with Rayner Ltd. and J&J Inc and is a consultant for Sparca Inc. The other authors declare no competing interests.

Supplementary information

The online version contains supplementary material available at 10.1038/s41433-023-02633-6.