An Analysis of Correlation with Visual Acuity, Refractive Error and Corneal Astigmatism after Wearing of Reverse Geometry Lenses

Choi, Jeong Hoon; Ryu, Jeong Wan; Lee, Young Chun; Kim, Hyun Seung

Abstract

PURPOSE: To evaluate correlations with refractive error, astigmatism and uncorrected visual acuity after Ortho-K LKTM lens wear.
METHODS
Sixty-one eyes of 32 patients who had been wearing reverse geometry lenses for over 5 weeks were recruited. Uncorrected visual acuity, subjective refraction on retinoscopy, objective refraction measured by an autorefractometer, and corneal astigmatism were measured by corneal topography before, at 2 days, and 1, 3, and 5 weeks after lenses fitting.
RESULTS
Uncorrected visual acuity improved from 0.12+/-0.10 to 0.95+/-0.15 after 5 weeks. Subjective refraction on retinoscopy and objective refraction measures with the autorefractometer were -3.52+/-1.65D and -4.06+/-1.73D, respectively before wearing the lenses. These decreased to -0.08+/-0.40D and -1.98+/-2.04D, respectively after 5 weeks. The astigmatism detected by corneal topography improved from 0.93+/-0.49 to 1.20+/-1.03 after 5 weeks. Uncorrected visual acuity was correlated with the refractive error measured by subjective refraction with retinoscopy rather than that by objective refraction with the autorefractometer. Corneal astigmatism measured by corneal topography correlated with the refraction detected by the autorefractometer.
CONCLUSIONS
Subjective refraction by retinoscopy rather than refraction found objectively using the autorefractometer, was highly correlated with uncorrected visual acuity (r=0.77~0.87) which seems to be useful in evaluating myopia patients. The astigmatism determined by autorefractometer examination had high correlation with that determined by corneal topography (r=0.51~0.76). This result appears useful in decisions related to the decentering of lenses.