Using computational optical modelling to better understand the clinical performance of a contact lens (CL) with a novel optical design.

Authors 
Karen Walsh¹, Jose Vega¹, Robert Chisholm², Benjamin Cvarch³, James Schwiegerling³, Doerte Luensmann⁴, Rachel Marullo¹
 

Affilations
1 CooperVision, Inc., San Ramon, CA 94583, USA
2 CooperVision Int Ltd, Chandlers Ford, UK
3 James C. Wyant College of Optical Sciences, University of Arizona, Tucson, AZ 85721, USA
4 CORE, University of Waterloo, Canada
 

Title
Using computational optical modelling to better understand the clinical performance of a contact lens (CL) with a novel optical design.
 

Purpose
The clinical vision performance of stenfilcon A with +0.3 dioptre central power boost (sten-A+0.3D) compared to stenfilcon A sphere (sten-A) (CooperVision Inc. USA) was determined and compared to images produced by computational optical modelling (“3D Imaging”) of the lens designs at different vergences.
 

Method 
A prospective, multi-centre, open label, bilateral wear, one-week dispensing study with habitual soft lens wearers (18-35 yrs) evaluated distance visual acuity (VA) and subjective responses. A 3D imaging optical modelling technique enabled the depiction of real photographs through CL optics. The office scene showed: outside (4 m), a computer screen (67 cm) and a smartphone (50 cm). Each CL optical design was combined with the photograph to generate reconstructed images using ZEMAX (Ansys Zemax OpticStudio) and Matlab.
 

Results 
77 subjects (57 female; mean age 27.9±5.1) were recruited. There was no significant difference in binocular logMAR high contrast distance VA (-0.05±0.06 vs -0.05±0.06, p=0.99) between sten-A and sten-A+0.3D. 3D imaging showed similar clarity of the distance scene through both lenses. 3D Imaging showed the optical effect of sten-A+0.3D: when the computer screen was in focus, the smartphone image was clearer through sten-A+0.3D than sten-A;  when the window scene was in focus, the computer screen was clearer through sten-A+0.3D than sten-A. Subjectively, sten-A+0.3D was rated more comfortable than sten-A (9.0±1.5 vs 8.7±1.8, p=0.02). For subjects reporting dryness, eye tiredness and blurriness, these symptoms occurred after a significantly longer wear time (hours) with sten-A+0.3D compared to sten-A.
 

Conclusions 
The novel sten-A+0.3D design enabled clear distance vision per both high contrast VA and 3D imaging. The 3D imaging showed better image quality at intermediate and near with sten-A+0.3D compared to sten-A. Subjective ratings confirmed the benefits of sten-A+0.3D.