The use of a modern web-application to assist reusable toric lens fitting success

The use of a modern web-application to assist reusable toric lens fitting success


Doerte Luensmann PhD Dipl Ing (AO)*
Jill Woods MSc MCOptom*
Marcella McParland BSc(Hons) MCOptom^

*Centre for Ocular Research & Education (CORE) University of Waterloo, Canada
^CooperVision, Inc.


Purpose: Increasing numbers of online tools are available to assist ECPs in fitting contact lenses. In this study, the contact lens prescription of a reusable toric silicone hydrogel lens was determined using a traditional fitting guide and the results were compared to the prescription recommended by the lens fitting app OptiExpert™.

Method: Forty-seven habitual lens wearers were fit with monthly replacement toric silicone hydrogel contact lenses (comfilcon A; CooperVision, Inc.).The manufacturer’s fitting guide was followed and the final lens prescription was determined based on the subjective refraction, the over-refraction and lens rotation (Final-Rx). Following this clinical study, the participant’s subjective refraction data and back vertex distance were entered in the OptiExpert online app to determine the recommended initial trial lens prescription (App-Rx). In this secondary analysis, the fitting results from both approaches were compared using Pearson correlation analysis. Different allowances for sph (±0.25, ±0.50D), cyl (±0.00DC) and axis (±10, ±20degrees) were combined to calculate the percentage of matching fitting results between both methods. Additionally, Bland-Altman graphs were plotted.

Results: A high correlation was found in respect to sphere, cylinder and axis between the Final-Rx and the App-Rx (all r ≥0.88). For the allowance combination of sphere ±0.25D / cylinder ±0.00DC / axis ±10, the lens prescriptions from both methods matched in 79% of eyes. For the allowance combination of sphere ±0.50D / cylinder ±0.00DC / axis ±20, the Final-Rx and the App-Rx matched in 86% of eyes. Bland-Altman comparisons between methods determined a mean difference of +0.06D for sph, +0.01D for cyl and 1.38 degrees for axis.

Conclusions: For most participants, the initial trial lens power recommended by the OptiExpert app was in close agreement to the final power dispensed in the clinical setting. The OptiExpert app can confidently be used as a clinical tool to aid comfilcon A toric lens fitting success.

1st Author Biography: After finishing an Optician apprenticeship, Doerte attended the University of Applied Sciences in Aalen, Germany to study Ophthalmic Optics. In 2000 she completed her diploma thesis at the Queensland University of Technology in Australia. After four years in private practice, Doerte conducted her PhD at the Centre for Ocular Research & Education (CORE formerly CCLR), University of Waterloo, under the supervision of Dr. Lyndon Jones. She studied the protein deposition profile on contact lenses and intraocular lenses using confocal laser scanning microscopy. Doerte is a Senior clinical scientist at CORE, conducting clinical and laboratory-based contact lens and vision research.

*Data correct at the time of submission to BCLA by NCC.