BCLA evidence-based research for clinical practice

Purpose: Dry Eye Disease (DED) is increasingly prevalent in younger populations. The current study investigated lifestyle factors, and clinical signs and symptoms, in young adults with evaporative DED, compared with healthy participants, and for progression over one year.

Method: Fifty young adults aged 18 to 25 were recruited; 42 were followed up after 1 year. Participants with any recent history of allergy or use of medications known to affect the eyes were excluded. All participants completed the Ocular Surface Dry Eye Index questionnaire and a lifestyle questionnaire, including questions about screen use, contact lens wear, and self-perceived health, diet, and stress. Detailed clinical parameters of the ocular surface, tear film and meibomian glands were assessed. 

Results: The mean age at visit 1 was 19.9 ± 1.6 years, 72% females and 56% with DED (TFOS DEWS II diagnostic criteria). A significant overlap in signs and symptoms, particularly meibomian gland loss, was found between participants; at both visits, over 90% had at least one diagnostic sign of DED, even when symptoms were absent. Contact lens wear and female sex were the most significant risk factors; screen use and stress the key modifiable ones, and conjunctival staining the best clinical predictor. Progression was observed, characterised by significant increases in ocular redness, lid wiper epitheliopathy and blink rate. 

Conclusions: This study has documented subtle but significant progression of ocular surface disease in a young population through changes in several key clinical parameters, suggesting that young adults should be counselled for the modifiable risk factors of DED identified, regardless of whether they are symptomatic

Purpose: Some neophyte contact lens wearers have fitted themselves with contact lenses in the first instance, without any input from an eyecare practitioner in the fitting process. The aim of this project was to investigate the phenomenon of self-fitting.

Method: A literature review was carried out in order to identify existing research which mentioned self-fitting. In order to also collect original data; at an educational event held by the Association of Optometrists Ireland (AOI) in November 2022, those attending were asked about their experience of patients who had self-fitted. A multiple choice question was posed via a mobile phone application and responses were anonymous. A sample of 40 university students who were contact lens wearers were also asked in person who had fitted them initially with contact lenses.

Results: No research was found that specifically addresses the question of self-fitting. A group of Spanish researchers anonymously surveyed customers of an online contact lens seller from November 2018 to May 2019 and they found that 387 respondents (30.6% of all respondents) reported that they carried out the initial fit themselves. A study from Saudi Arabia published in 2021 found that “159 participants used contact lenses and most obtained them without proper professional consultation”. This study surveyed adolescents (11-20 years) in schools in Riyadh. A 2021 study from Sudan found that 137 respondents (31% of all respondents) were “self-prescribed” with contact lenses. At the AOI study day 45 respondents (52% of all respondents) reported that they had encountered at least one patient who had self-fitted contact lenses. Of the 40 university students surveyed two were found to have self-fitted.

Conclusion: In Spain, Saudi Arabia and Ireland access to eyecare professionals is generally good. The Spanish, Saudi Arabian and Sudanese surveys were all carried out before any Covid lockdowns. Therefore, it is likely that many (but not all) patients choosing to self-fit contact lenses are doing so, not because of any difficulty in accessing an eyecare professional, but because of the easy availability of contact lenses via the internet.

Purpose: Clinical trials exploring the efficacy of optical interventions designed to manage myopia have yielded promising results. With such interventions becoming more accessible to practitioners in clinical practice, this research explored the global prescribing patterns of spectacles and contact lenses (CLs) to young myopes.

Methods: An internet-based questionnaire was distributed in 13 languages, through professional bodies to eyecare practitioners globally. This formed the third contribution to a series of surveys, previously conducted in 2015 and 2019. Questions included: perceived efficacy of available strategies, frequency of prescribing and reasons for not adopting specific strategies.  

Results: Of the 3195 respondents, orthokeratology was perceived to show a 56.2% reduction in myopia progression. For myopia control (MC) spectacles, this was 46.2%, being highest in Africa (59.8%, p<0.05). Similarly, perceived efficacy of MC soft CLs was 46.8%, ranging between 51.7% in Australasia and 43.1% in Asia (p<0.05). Single vision (SV) spectacles were most frequently prescribed (32.2%). Frequency of prescribing SV soft CLs was 7.5%, 15.2% for MC spectacles, and 8.7% for MC soft CLs. Practitioners prescribed spectacles to younger children than soft CLs and orthokeratology (6.4, 9.8, and 9.2 years, respectively). Across all continents, the dominant reason for not prescribing MC techniques was cost to the patient.

Conclusion: MC spectacles were considered as nearly equal in efficacy as MC soft CLs, and orthokeratology was considered as more efficacious than both. However, practitioners more frequently prescribed MC spectacles to young myopes. The frequency of prescribing SV spectacles was over four times that of SV soft CLs despite the use of CLs having been shown to improve how children feel about their appearance and participation in activities. This hesitancy often stems from safety concerns, however research has shown children and adolescents to be as safe as adults in CL wear. Increased affordability of myopia interventions may improve practitioner and patient uptake.  

Purpose: The opportunity exists to prescribe soft multifocal contact lenses (MFCLs) to more presbyopes, although achieving fit success without extended chair time remains a barrier. The aim of this analysis was to determine the ease of fitting contemporary MFCLs based upon the number of lenses to be trialled.

Method: Retrospective analysis of three prospective 1-week studies with the same protocol, each study fitting two of three MFCLs: MyDay® multifocal ([MDMF, n=210), Biofinity® Multifocal ([BioM, n=45) and 1-DAY ACUVUE® MOIST MULTIFOCAL ([1DAMM, n=165). The fitting process followed the lens’ specific fitting guide. Ease of fitting was the number lens pairs to determine the prescription to dispense from one (initial pair determined by the fitting guide) to three; changing one or two lenses at the same time was considered a subsequent pair.

Results: A total of 210 participants (152 female & 58 male, age 53.8±76.5 years; near addition 1.63±0.45D), with similar distribution of low, medium and high add spectacle presbyopes (p = 0.863), were enrolled. The studies showed high overall first pair success rate (85.7%) with most others fitted with the second pair (13.3%). By lens, first pair success was MDMF 85.2%, BioM 86.7%, 1DAMM 86.0%, and second was MDMF 13.8%, BioM 13.3%; 1DAMM 12.7%) were very similar for all three contact lens types.

Conclusion: The study showed that for a range of MFCLs, following the respective fitting guides led to over 85% first fit success, demonstrating their ease of fit with limited chair time.

Purpose: The aims of this research were; to establish a range of values for corneal sensitivity in normal subjects as measured using the Cochet-Bonnet aesthesiometer; to determine if the measurement of corneal sensitivity in one eye affected subsequent measurements in the fellow eye; and to determine if there is a difference in corneal sensitivity between fellow eyes.

Method: PuThirty-four subjects aged between 18 and 30 who did not wear contact lenses had their central corneal sensitivity measured in both eyes. The average of three readings was taken as the measurement for each eye. In 15 subjects, measurement was taken from the right eye first and the left eye second, and vice versa for the other 19 subjects. One researcher made all the first eye measurements, and a second researcher made all the second eye measurements. Six subjects had the maximum measurable corneal sensitivity in both eyes so the data from these subjects was not included in analysis. The Cochet-Bonnet aesthesiometer used had a nylon filament diameter of 0.12mm. The sensitivity measurements were made in mm lengths of nylon filament and converted to pressure using the conversion chart supplied with the aesthesiometer.

Results: The range of sensitivity found for normal subjects was from 0.4g/mm2 to 0.8g/mm2. The average sensitivity was 0.51g/mm2. Median corneal sensitivities in first and second eyes measured were 0.39 g/mm2 and 0.51g/mm2; the distributions in the two groups did not differ significantly (Mann–Whitney U = 279.5, n1 = n2 = 28, P < 0.05 two-tailed). The range of differences found between fellow eyes was from 0 g/mm2 to 2.8 g/mm2.

Conclusion: Measurement of corneal sensitivity on one eye does not appear to affect the subsequent measurement on the fellow eye. The maximum corneal sensitivity measurement that can be made using this type of Cochet-Bonnet aesthesiometer is 0.4g/mm2. It is possible that the range of corneal sensitivity in normal subjects may in fact extend beyond this value. Using an undiseased eye as a control to check for decreases in corneal sensitivity in a fellow eye should be done with caution, bearing in mind that in this study inter-eye differences of 2.8 g/mm2 (corresponding to a filament length of 20mm) have been found in normal subjects.