Current Trends in Scleral Lens Prescription, Management, and Evaluation

Abstract

Objectives:

To report current trends in scleral contact lens prescription and management, including lens designs prescribed, care products recommended, and procedures performed during routine scleral lens evaluation.

Methods:

An online survey was designed by the SCOPE (Scleral Lenses in Current Ophthalmic Practice Evaluation) study team and administered to eye care practitioners attending a specialty contact lens meeting. The survey was available from November 8, 2019, through March 31, 2020. Participants’ demographic data were collected, along with information on lens diameters, landing zone designs, recommended care products, and components of routine scleral lens evaluation.

Results:

In total, 715 participants responded to at least 1 of the survey items of interest. Most lenses prescribed (63%) were 16 mm or more in diameter. Lenses with toric landing zones were the most frequently prescribed (48%), followed by spherical (40%), quadrant-specific (8%), and impression- or image-based designs (3%). Most participants (61%) recommended hydrogen peroxide products for lens care. Nonpreserved saline in a single-use vial was most frequently recommended to fill the bowl of the lens before application. Intraocular pressure was measured during scleral lens evaluation by 45% of participants; 38% of participants routinely measured corneal thickness.

Conclusions:

Practitioners increasingly are prescribing scleral lenses with advanced landing zone designs. Most practitioners recommend hydrogen peroxide–based disinfection systems and single-use vials of nonpreserved saline for lens care and application. Because differences in components of routine scleral lens evaluations were reported, clinicians may benefit from reaching a consensus on essential components of scleral lens evaluation.

An international survey of eye care practitioners was conducted in 2015 by the SCOPE (Scleral Lenses in Current Ophthalmic Practice Evaluation) study team to investigate preferred scleral lens (SL) designs and recommended wearing schedules and lens care regimens.¹ Since then, much has changed in SL research and the SL industry. Considerable research has been published about a variety of SL-related topics, such as the effects of SL wear on corneal^{2, 3} and conjunctival^4–6 tissues and on intraocular pressure (IOP).^7–9 Additional survey findings suggested that the rate of SL fitting increased from 2015 through 2019.¹⁰ Furthermore, a new lens surface treatment and several new SL designs have become available,^11–13 and new products have been introduced for the care of SLs.¹⁴ Outcomes also have been reported for new SL designs.^{12, 15, 16} Unfortunately, most reports of outcomes of SL wear originate from academic centers or specialty contact lens practices,¹⁷ whereas survey results show that most SL practitioners work outside such institutions.¹⁸ Because of this disparity, published research may not accurately represent overall trends in SL prescription and management. Also, continued maturation of the SL industry may have altered SL prescription and management practices. Therefore, updated information about SL prescription and management encompassing all practice types is needed to determine the extent to which research and industry advancements have affected clinical practice.

In 2020, the SCOPE study team conducted a survey-based study similar to the original 2015 investigation. The purpose of this study was to identify interval change for SL prescription and management practices and to assist practitioners in maintaining standards of care consistent with evolving practice patterns within the SL community.

Methods

This study was reviewed and approved by The Ohio State University Institutional Review Board. The research team designed and administered the survey using REDCap (Research Electronic Data Capture)^{19, 20} tool hosted at The Ohio State University. The survey was introduced at the International Summit of Specialty Contact Lenses on November 8, 2019, and was available until March 31, 2020. A copy of the complete survey is available as supplemental digital content. Also, invitations to complete the survey were emailed to practitioners who had participated in previous surveys and indicated their willingness to be contacted for additional studies, members of the Scleral Lens Education Society, and all attendees at both the International Summit of Specialty Contact Lenses (November 2019, Rome, Italy) and the Global Specialty Lens Symposium (January 2020, Las Vegas, Nevada). Additionally, links to the survey were posted in a private social media group for SL practitioners (Scleral Lens Fitters, Facebook, Meta Platforms Inc) and in 2 online newsletters (I-site and the British Contact Lens Association newsletter).

Data Collection

Only practitioners who had completed 5 or more SL fittings were eligible to complete the survey. Demographic information was collected about the participant’s country of residence and primary type of practice and the year in which the participant began to fit SLs. Participants were asked to estimate the relative percentages of large-diameter (≥16.0-mm) and small-diameter (<16.0-mm) SLs that they prescribed along with the percentages of various landing zone (LZ) designs (spherical, toric, quadrant-specific, or impression- or image-based) that they prescribed in their practices. Participants also were asked to identify the cleaning, disinfecting, and filling solutions they most frequently recommended for their patients and whether they ever recommended the use of tap water with SLs. Finally, participants were asked to identify specific procedures or tests that they routinely performed during follow-up examinations of SL patients. Participants were not required to respond to every item.

Demographic Groups

Descriptive data are reported for all participants. Responses were compared between the various groups of participants (by country of residence, primary practice type, and years of experience fitting SLs). Those reporting the US as their country of residence were compared with all other respondents (“non-US” practitioners). Academic practice was defined as university or academic institutions, hospitals, military, or industry, whereas respondents in private, group, or commercial practice were considered to be in community practice. Practitioners who reported that they began to fit SLs in 2014 or earlier were considered established, whereas those who fit their first SL in 2015 or later were considered new practitioners.

Statistical Analysis

The means and SDs were compared between groups. The lens diameter and LZ designs were compared by using the Mann-Whitney test. Lens solutions recommended were compared with the Pearson χ² test for association for group comparisons, followed by the Fisher exact test to compare each solution if the group comparison was significant. The yes/no questions about various examination components included in routine SL evaluation were analyzed with χ² tests, followed by the Fisher exact test for significance. A P value less than .05 was considered significant. Statistical analysis was performed by using Minitab 18 (Minitab LLC).

Results

A total of 922 practitioners responded to the survey. Of these, 8 opened the survey but did not respond to any items, 63 reported fitting fewer than 5 lenses and answered no further questions, 77 had fit more than 5 lenses but chose not to answer any additional questions, and 59 did not respond to any of the items described in this study. The remaining 715 practitioners responded to at least 1 item of interest (lens diameter, LZ design, recommendations for lens care, ancillary testing performed during routine follow-up examination) along with at least 1 item querying demographic information (country of residence, primary practice type, year in which they fit their first SL). Participants’ demographic data are shown in Table 1. Because participants were not required to respond to every item, the number of responses differed for each parameter reported.

Table 1.

Demographic Information for Practitioners Who Responded to the Survey^a

	No. (%)
Country of residence (n=713)
US	450 (63)
Non-USb	263 (37)
Primary practice type (n=704)
Community (private, group, commercial practice)	538 (76)
Academic (university, hospital, industry, military, academic institution)	166 (24)
SL-fitting experience (n=705)
Established (first SL fit before 2015)	474 (67)
New (first SL fit in 2015 or later)	231 (33)

Abbreviation: SL, scleral lens.

^aParticipants were not required to respond to every survey item; this table includes participants who responded to 1 or more items of interest along with at least 1 item querying demographic information.

^bCountries represented included the following: Italy (32 participants); Canada (27); India, Spain, and Sweden (14 participants each); United Kingdom (12); Mexico (11); Switzerland (10); France, New Zealand, and South Africa (7 participants each); Columbia, Greece, Netherlands, Norway, and Portugal (6 participants each); Australia and Israel (5 participants each); Brazil, Germany, and Nigeria (4 participants each); Belgium, Denmark, Ecuador, Guatemala, and Saudi Arabia (3 participants each); Algeria, Argentina, China, Costa Rica, Cyprus, Philippines, Poland, Serbia, Taiwan, Trinidad and Tobago, and Uruguay (2 participants each); and Bahrain, Chile, Finland, Iran, Ireland, Japan, Jordan, Kazakhstan, Lebanon, Malaysia, Malta, Morocco, Nepal, Pakistan, Peru, Russian Federation, Singapore, Slovenia, and Venezuela (1 participant each).

Lens Diameter and Design

When asked to estimate the percentages of large-diameter (≥16.0 mm) and small-diameter (<16.0 mm) SLs that they fit, 705 participants responded (Table 2). The mean percentages in each category were calculated. Overall, practitioners reported that 63%±35% (mean±SD) of SLs prescribed had a large diameter, and 37%±34% had a small diameter. US practitioners reported fitting a significantly higher percentage (67%±34%) of lenses 16.0 mm or more in diameter compared with their non-US counterparts (57%±35%) (P=.001), but no significant differences in the percentages of large-diameter and small-diameter SLs were noted between academic and community practitioners or between established and new practitioners.

Table 2.

Distribution of SL Designs Used by Survey Participants^a

	All	US	Non-US	P valueb	Community practice	Academic practice	P valueb	Established SL fitter	New SL fitter	P valueb
Lens diameter, No. (%) of respondents	705	445 (63)	258 (37)	NA	532 (77)	162 (23)	NA	470 (68)	225 (32)	NA
≥16 mm	63±35	67±34	57±35	.001	62±35	68±32	.07	64±34	63±36	1.0
<16 mm	37±34	33±34	43±35		38±35	32±32		36±34	37±36
Landing zone design, No. (%) of respondents	665	425 (64)	238 (36)	NA	495 (76)	159 (24)	NA	443 (68)	212 (32)	NA
Spherical	40±31	37±31	46±31	<.001	41±32	34±29	.005	39±30	41±32	.29
Toric	48±30	50±30	44±30	.01	47±30	50±29	.20	48±30	48±31	.85
Quadrant-specific	8±15	9±17	7±12	.69	7±14	12±20	<.001	9±16	8±14	.94
Image- or impression-based	3±13	4±15	2±6	.31	3±13	3±11	18	4±14	2±8	.03
Otherc	1±5	1±4	1±6	NA	1±5	1±6	NA	1±6	1±4	NA

Abbreviations: NA, not applicable; SL, scleral lens.

^aData are percentage (mean±SD) except where otherwise indicated. Participants were not required to respond to every survey item, so the number of responses differed for each parameter reported. The values in the demographic groups of country of residence, practice type, and experience do not total to the value in the “all” column if participants who responded to the SL design question did not respond to all demographic questions.

^bLens diameter and landing zone designs were compared with the Mann-Whitney test.

^cParticipants who indicated that they fit lenses with “other” landing zone designs reported that they design their own lenses but did not specify landing zone designs featured in their lenses.

In total, 665 participants reported the estimated percentages of SLs they fit that featured spherical, toric, quadrant-specific, or image-based or impression-based LZs (Table 2). Overall, participants estimated that 88% of SLs fit had either spherical or toric LZs. Non-US practitioners reported fitting more SLs with spherical LZs than US practitioners, whereas US practitioners reported prescribing SLs with toric LZs more often than non-US practitioners. Academic practitioners reported fitting SLs with quadrant-specific LZs more frequently than community practitioners, whereas community practitioners reported fitting more SLs with spherical LZs than academic practitioners.

Lens Care

Of the participants, 694 responded when asked to identify the disinfection/cleaning system they recommended most frequently for their patients who wear SLs (Table 3). (Participants were asked to identify only their most frequently recommended care products; additional care products that may be recommended were not explored.) Overall, practitioners reported recommending hydrogen peroxide solutions most frequently (61%), with multipurpose solutions for gas-permeable lenses as the next most frequently recommended products (27%). To compare solution use between groups with a χ² analysis, we removed the “combination” and “other” categories because of low numbers (n=2 for each of these categories). A comparison of the remaining groups found significant differences in the solutions recommended when we compared US vs non-US participants (χ²₄<.001) and established vs new participants (χ²₄=.006). US practitioners were more likely to report recommending hydrogen peroxide care products than non-US practitioners, whereas non-US practitioners were more likely than US practitioners to report that they recommend surfactant or alcohol-based cleaners. New practitioners were more likely to report recommending multipurpose solutions and less likely to report recommending surfactant cleaners than their more experienced counterparts. No significant differences were noted between community and academic practitioners (χ²₄=.67).

Table 3.

Solutions Recommended for SLs by Survey Participants

	All (n=694)a	US (n=438)	Non-US (n=254)	P valueb	Community practice (n=521)	Academic practice (n=162)	P valueb	Established SL fitter (n=461)	New SL fitter (n=223)	P valueb
Lens care products, No. (%)				χ24<.001			χ24=.67			χ24=.006
Hydrogen peroxide solutions	423 (61)	306 (70)	115 (45)	<.001	327 (63)	91 (56)	NA	280 (61)	138 (62)	.80
Multipurpose solution for GP lenses	188 (27)	108 (24)	80 (31)	.06	136 (26)	50 (31)	NA	112 (24)	72 (32)	.03
Surfactant cleaner	43 (6)	14 (3)	29 (11)	<.001	30 (6)	10 (6)	NA	37 (8)	5 (2)	.002
Alcohol-based cleaner	30 (4)	7 (2)	23 (9)	<.001	21 (4)	8 (5)	NA	24 (5)	6 (3)	.16
Multipurpose solution for soft lenses	6 (1)	3 (1)	3 (1)	.67	5 (1)	1 (<1)	NA	5 (1)	1 (<1)	.67
Combination of productsc	2 (<1)	0 (0)	2 (1)	NA	1 (<1)	1 (<1)	NA	1 (<1)	1 (<1)	NA
Otherc,d	2 (<1)	0 (0)	2 (<1)	NA	1 (<1)	1 (1)	NA	2 (<1)	0 (0)	NA
Fluid used to fill bowl of lens, No. (%)				χ25<.001			χ25=.33			χ25=.07
Preservative-free 0.9% sodium chloride (nebulizer saline)	284 (41)	212 (48)	70 (28)	<.001	215 (41)	65 (40)	NA	175 (38)	106 (48)	NA
Preservative-free saline for contact lenses in single-use vials	260 (37)	146 (33)	114 (45)	.003	192 (37)	63 (39)	NA	174 (38)	81 (36)	NA
Preservative-free bottled saline	118 (17)	76 (17)	42 (17)	.83	87 (17)	29 (18)	NA	87 (19)	29 (13)	NA
Preservative-free artificial tears	16 (2)	0 (0)	16 (6)	<.001	11 (2)	5 (3)	NA	14 (3)	2 (1)	NA
Multipurpose contact lens solution	9 (1)	2 (<1)	7 (3)	.01c	9 (2)	0 (0)	NA	7 (2)	2 (1)	NA
Bottled saline (preserved)	7 (1)	2 (<1)	5 (2)	.01c	7 (1)	0 (0)	NA	4 (1)	3 (1)	NA
Use of tap water for any aspect of SL care, No. (%)	40 (6)	26 (6)	13 (5)	.73c	34 (7)	5 (4)	.25c	31 (7)	7 (3)	.05c

Abbreviations: GP, gas-permeable; NA, not applicable; SL, scleral lens.

^aThe number of participants in the “all” column represents those (of 694 total participants who answered items regarding care products and at least 1 demographic question) who indicated that they recommended various solutions. A total of 692 (438 US+254 non-US) participants answered care product questions in addition to providing their country of origin; 683 participants (521 in community practice+ 162 in academic practice) answered care product questions in addition to providing their type of practice; 684 (461 established SL fitters+223 new SL fitters) answered care product questions in addition to providing their level of expertise.

^bA χ² analysis was used to evaluate differences between participant groups. The Fisher exact test was used to calculate P values only if χ² values were significant; if they were not significant, not applicable is indicated.

^cNot included in χ² analysis because of low numbers.

^dOne participant recommended povidone iodine, and 1 participant recommended a protein/lipid remover.

In total, 694 participants reported their most frequently recommended fluid reservoir solution (Table 3). Slightly more practitioners reported recommending off-label use of preservative-free 0.9% sodium chloride solution for nebulizers (41%) than preservative-free saline products designed specifically for contact lenses (37%). Results from a subsequent comparison of groups showed significant differences between US and non-US practitioners (P<.001). Non-US practitioners were more likely to report that they recommended single-use vials of preservative-free saline for contact lenses, preservative-free artificial tears, multipurpose contact lens solutions, or bottled preserved saline. US practitioners, however, were more likely to report that they recommended preservative-free 0.9% sodium chloride (nebulizer saline) (χ²₅<.001). No significant differences in filling solutions were noted between community and academic practitioners (χ²₅=.33) or between established and new practitioners (χ²₅=.07).

Of the 694 participants who responded to the item regarding using tap water with SLs, only 6% reported that they recommended the use of tap water (Table 3). Established practitioners reported that they recommended tap water more frequently than new practitioners.

SL Evaluation Procedures

Nearly half (45%) of all participants reported routinely measuring IOP during SL evaluations (Table 4). Non-US practitioners were more likely to report assessing IOP than US practitioners. Fewer participants (38%) reported regularly measuring corneal thickness in SL wearers. Non-US practitioners were more likely than US practitioners to report assessing corneal thickness.

Table 4.

Components of Routine SL Evaluation Reported by Survey Participants^a

	All	US	Non-US	P value	Community practice	Academic practice	P value	Established SL fitter	New SL fitter	P value
Measure IOP, No./total (%)	287/641 (45)	172/411 (42)	115/228 (50)	.04	210/479 (44)	74/152 (49)	.30	190/426 (45)	93/205 (45)	.86
Measure corneal thickness, No./total (%)	242/640 (38)	116/410 (28)	125/228 (55)	<.001	187/479 (39)	49/151 (33)	.15	170/425 (40)	71/205 (35)	.22
Evaluate for corneal staining after lens removal, No./total (%)	603/638 (95)	379/407 (93)	222/229 (97)	.05	449/477 (94)	144/151 (95)	.69	398/425 (94)	198/203 (98)	.05
Evaluate for conjunctival staining after lens removal, No./total (%)	584/640 (91)	374/409 (91)	208/229 (91)	.77	432/477 (91)	142/153 (93)	.19	381/425 (90)	195/205 (95)	.02
Evert eyelids, No./total (%)	332/641 (52)	172/411 (42)	160/228 (70)	<.001	248/478 (52)	77/153 (50)	.78	232/425 (55)	97/206 (47)	.07
Give dry eye questionnaire, No./total (%)	137/639 (21)	80/410 (20)	57/228 (25)	.11	107/477 (22)	28/152 (18)	.31	90/427 (21)	46/202 (23)	.68
Give visual QOL questionnaire, No./total (%)	100/636 (16)	46/410 (11)	54/224 (24)	<.001	78/474 (17)	20/152 (13)	.20	62/421 (15)	37/205 (18)	.29

Abbreviations: IOP, intraocular pressure; QOL, quality of life; SL, scleral lens.

^aParticipants were not required to respond to every survey item, so the number of responses differed for each parameter reported. Analysis was performed by using χ² with the Fisher exact test.

Overall, most participants reported that they assessed both the cornea (95%) and conjunctiva (91%) for staining with sodium fluorescein after SL removal at each visit, and 52% reported routinely everting the patient’s upper eyelids to evaluate the condition of the superior tarsal conjunctiva (Table 4). Differences in reported rates of corneal evaluation between US and non-US practitioners and between established and new practitioners did not meet the level of significance, but new practitioners were more likely to evaluate for conjunctival staining than established practitioners. Non-US practitioners were more likely to evert the upper eyelids during routine SL evaluation than US practitioners.

Few participants reported administering dry eye or quality of life (QOL) assessments to their SL-wearing patients (Table 4). Of 639 respondents to this item, only 21% reported that they routinely administered a dry eye questionnaire. Even fewer participants reported that they regularly administered a visual QOL questionnaire (16%). Non-US practitioners were more likely to report that they routinely administer QOL questionnaires than their US counterparts.

Discussion

Evidence-based guidelines have not been established yet for optimal SL design characteristics and long-term management of patients wearing SLs. In this discussion, we highlight the changes in practice patterns that have occurred since 2015. This information may allow clinicians to reflect on whether their SL protocols represent the current standard of care for lens design, recommended care products, and examination components of standard SL evaluations.

What Is New in SL Prescribing, Care, and Evaluation

The results from the current study revealed some changes in practitioner-reported SL prescribing and care since the 2015 SCOPE survey. Additionally, the survey provided new data regarding specific LZ designs and components of routine SL evaluation (eg, measuring IOP and corneal thickness).

One of the trends observed is that practitioners now appear to prescribe nonspherical LZ designs more frequently than noted in a study conducted in 2017 describing SL fits in 220 patients (406 eyes).²² In 2015, few laboratories offered lenses with nonspherical LZ designs, and queries regarding the use of various LZ profiles were deemed to be nonrelevant for the 2015 SCOPE survey. Availability of advanced LZ designs just 2 years later led to inclusion of these data in the study conducted in 2017.²¹ At that time, 64% of lenses prescribed featured spherical LZs vs 26% toric or bitangential LZs.²¹ In the current study, participants estimated that just 41% of lenses prescribed had spherical LZs, compared with approximately 48% of SLs featuring toric or bitangential LZs.

The types of SL filling solutions that practitioners reported using have changed considerably as well. In 2015, just 62% of participants recommended preservative-free saline in single-use vials; at that time, products specifically designed for use with contact lenses were not available.¹ Now the percentage of practitioners who primarily recommend single-use vials of saline has increased to 78% if both nebulizer saline and contact lens–specific products are included. This shift could have been influenced by the following reasons: 1) the discontinuation of a popular nonpreserved bottled saline widely used in 2015 (despite the introduction of a similar product shortly after its discontinuation) and 2) the introduction of single-use, nonpreserved saline products designed specifically for SL use. Fewer practitioners are recommending tap water for the care of SLs; only 6% of participants in this study reported recommending tap water for their patients, compared with 38% of participants in the 2015 study.¹ The shift away from recommending preserved saline, nonpreserved saline in multiuse bottles, and tap water in favor of nonpreserved saline delivered in single-use vials is encouraging and may represent an increased appreciation for the effects that fluid in the postlens fluid reservoir might have on the health of corneal epithelial cells.^22–25

In 2015, the effects of SL wear on the eyelids, corneal thickness, and IOP were primarily theoretical, and scant peer-reviewed research was available to guide longer-term management. Questions on whether these metrics were evaluated in patients using SLs were not even included in the 2015 SCOPE survey. Since then, several publications have described the interplay between the SL and the cornea^{2, 26–30} and the SL’s effects on IOP^{9, 30–34} and the eyelids.³⁵ According to the current study, virtually all practitioners reported routinely assessing for corneal and conjunctival staining after lens removal; however, just over one-third of practitioners reported assessing corneal thickness, almost half reported measuring IOP, and just over half of practitioners reported that they evert the upper eyelids to evaluate the superior tarsal conjunctiva during routine SL evaluation. This finding raises questions as to why routine evaluation of corneal thickness, IOP, and the superior tarsal conjunctiva is not performed regularly by a higher percentage of practitioners. Because most patients who wear SLs do so for the management of ocular disease,¹⁸ the relative benefits of their use may outweigh any potential risks of SL-induced glaucomatous optic neuropathy or corneal hypoxia. Recognizing these relative risks and benefits and supported by new research evidence, practitioners may be more carefully monitoring their patients for other indicators of SL-induced complications. If these trends mirror the typical lag between adoption of clinical practice and research, more SL fitters will incorporate these components into their follow-up examinations.

Analysis of published SL-related articles shows that a small number of studies include patient-reported outcomes that could be affected by SL wear.^36–39 Research in this area is still in its infancy, and the present study findings suggest that few practitioners routinely use standardized assessment tools to collect outcomes data. Although it would be inaccurate to imply that practitioners are not soliciting patient feedback, low utilization of standardized assessment tools makes it difficult to quantify improvements in patient symptoms or QOL after initiation and continuation of SL wear.

Continuing Practices in SL Prescribing

The new survey results showed little change in the distribution of SL diameters that respondents reported prescribing, compared with 2 previous studies.^{21, 40} The choice of SL diameter is based on many clinical factors such as aperture width, eyelid tension, and ocular surface pathology. It is not surprising that this feature of lens prescriptions has remained stable.

Regarding LZ designs, quadrant-specific and image-based or impression-based designs are still prescribed infrequently. Large SDs in the distribution of data for both SL diameter and LZ design suggest that considerable differences remain for individual prescribing patterns. These differences may result from the practitioner’s preference or fitting philosophy. Although 42% of participants reported using no quadrant-specific designs, 7 participants (1%) reported using quadrant-specific designs more than 90% of the time. Although 79% of participants reported no use of impression-based or image-based designs, a single participant (<1%) reported prescribing impression-based or image-based designs 90% of the time. Practitioners who have not incorporated more advanced LZ designs into their clinics may achieve adequate results with spherical or toric LZs. The expense for additional equipment and training may also hamper widespread adoption of impression-based or image-based designs, as may the limited number of lens reorders provided by lens manufacturers during the fitting process. The increased cost of more customized lenses may make them a less-desirable option for patients on a limited budget.

Product recommendations for SL disinfection have also changed little since the 2015 survey about SLs. Hydrogen peroxide–based care products continue to be prescribed most frequently; 61% of practitioners reported prescribing these products most frequently in both the 2015 SCOPE survey and the present study. During the COVID-19 pandemic, availability of disinfectants and filling solutions was affected.

Limitations

This study is limited by the constraints present in all survey-based research (eg, potential sampling or response bias) and by participants’ potential inaccuracy of recall or estimation of their actual prescribing practices. When conducting survey-based research, investigators must assume that survey participants accurately report data based on their experience. Although it may be assumed that practitioners accurately reported their experience with aspects of SL fitting investigated in this survey, we could not precisely assess specific prescribing patterns of study participants; nor does the study provide information that would facilitate reasonable speculation about how potential inaccuracies in participants’ estimates may have introduced error into data reported here. However, comparisons between the current and previous study findings lend credence to conclusions regarding SL prescribing and management. Consistency between the results of the 2015 SCOPE survey (based, like the current study, on practitioner recall) and a subsequent study in 2017 (in which participants were asked to provide specific information on a single patient) also suggests that this study design can provide reasonably accurate data.

Conclusion

Based on data reported by study participants, it appears that most SLs being prescribed are at least 16 mm in diameter and that practitioners are increasingly using advanced LZ designs. Study participants report that they most frequently recommend single-use vials of nonpreserved saline to fill the bowl of the SL before application and largely have ceased recommending exposing SLs to tap water. Additionally, most practitioners report measuring clinical metrics of IOP, corneal thickness, and eyelid integrity at follow-up examinations. As best practices within the SL community continue to evolve, it may be helpful to reach a consensus on the essential components of SL evaluation and to regularly administer standardized assessment instruments of patient-reported outcomes, which could more effectively quantify benefits of SL wear.

Abbreviations

IOP

intraocular pressure

LZ

landing zone

QOL

quality of life

REDCap

Research Electronic Data Capture

SCOPE

Scleral Lenses in Current Ophthalmic Practice Evaluation

SL

scleral lens