Abstract
Purpose :
In treating highly aberrated eyes, the eye care professional is faced with many decisions. In some cases a scleral lens may be adequate by itself, but in others wavefront guided correction may provide better results. Various metrics have been used for guidance, but with mixed success. Metrics are needed that provide clear guidance between the treatment options.
Methods :
In a research study, 22 eyes of 18 patients were measured and fit with both standard (i.e. sphere/cylinder correction only) and wavefront corrected scleral contact lenses. Using published normative data for the wavefront variations in the population, an optical severity ratio is computed for each measurement. This metric was used to evaluate the efficacy of the treatment for each phase of the correction.
Results :
The optical severity ratio was obtained by dividing the higher order root mean square (RMS) wavefront aberrations by the published age and pupil normal RMS wavefront error (WFE) for each measurement. For our study group, the subjects with sph/cyl scleral lenses were 1.77 ± 0.99 times as aberrated as the normal age and pupil matched population. The bare eye higher order aberration (HOA) RMS was 1.03 ± 0.38 um and with sph/cyl corrected lenses reduced by 51 ± 18% to 0.80 ± 0.42 um. Among 22 eyes, three eyes were in the normal range with sph/cyl correction alone. The wavefront guided lenses further reduced the aberrations by 61 ± 14% to 0.23 ± 0.12 um. After wavefront correction 16 eyes were in the normal range and all eyes showed significant improvement. All eyes with severity ratio < 2.5 were in the normal range after wavefront correction.
Conclusions :
The severity ratio is well correlated with the effectiveness of the treatment. Some eyes are already in the normal range, and thus can be treated with sph/cyl correction (SR <1). For moderately aberrated eyes (1 < SR < 2.5), the wavefront correction resulted in normal amount of HOA. The more highly aberrated eyes were improved significantly but might not reduce to normal levels. All patients experienced reduced levels of HOAs with wavefront correction.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.