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Lan Chi Nguyen, Gareth D Hastings, Roxana T Hemmati, Raymond A Applegate, Jason D Marsack; Optimizing scleral lens prescriptions in highly aberrated eyes. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1278.
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© ARVO (1962-2015); The Authors (2016-present)
Given the limitations of manufacturing and fitting wavefront-guided scleral contact lenses (WFG) that target higher order aberrations (HOAs), this investigation models visual image quality to examine whether the actual benefits afforded by WFG lenses in highly aberrated eyes might equally result from an optimized sphero-cylindrical correction. Secondly, we quantify the potential improvement in visual image quality that could be achieved by escalating the complexity of the correction from spherical to WFG, with and without optimization.
Wavefront error (WFE) data were collected using the COAS HD wavefront sensor on 8 highly aberrated eyes of 4 subjects corrected with 1) a spherical scleral contact lens and 2) a wavefront-guided scleral contact lens targeting aberration through the 5th radial order. The visual image quality metric visual Strehl (VSX) was calculated for each of the WFEs. An optimization algorithm that seeks the best VSX as a function of sphere and sphero-cylindrical corrections was applied to each of the WFEs. The clinically meaningful comparisons for VSX were 1) sphere lens (Sph) to optimized spherical lens (opSph) 2) sphero-cylindrical lens (SCA) to optimized sphero-cylindrical lens (opSCA); 3) SCA to WFG; 4) opSCA to WFG. A significant difference was defined as a just noticeable difference (JND) in blur (change in log VSX of 0.049; and 6.1 JNDs in one line of VA)[i].[i] Ravikumar et al. 2011 J Cataract Refract Surg.
The results for the above comparisons were 1) Sph to opSph: opSph was better than Sph for 6 eyes (range 4 to 20 JNDs), 2) SCA to opSCA: opSCA was better than SCA for all 8 eyes (range 2 to 27 JNDs); 3) SCA to WFG: WFG was better than SCA for 7 eyes (range 1 to 28 JNDs); 4) opSCA to WFG: opSCA was better for 6 eyes (range 3 to 16 JNDs) and WFG was better for 2 eyes (1 JND).
Our findings suggest that better visual image quality can be achieved in most cases by objectively optimizing traditional corrections or by applying WFG prescriptions. The 6 of 8 eyes where the theoretical opSCA lens outperformed actual WFG lens indicate that better visual image quality can potentially be achieved with this simpler form of corrections in some patients with highly aberrated eyes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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