Relationship between minimum corneal thickness and refractive state, keratometry, age, sex, and left or right eye in refractive surgery candidates.

PURPOSE: To evaluate the relationship between the thinnest point in corneal thickness and the refractive state, keratometry, age, sex, and the ocular side.

SETTING

Eye clinics in Germany and Austria and the Department of Ophthalmology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

DESIGN

Cross-sectional study.

METHODS

Medical records of refractive surgery candidates from 2006 to 2010 were reviewed. Univariate variance analysis, covariance analysis, Bravis-Pearson correlations, Spearman rank correlations, and t tests were performed to analyze the relationship between the thinnest point in corneal thickness and the biometric parameters.

RESULTS

The study evaluated 4600 eyes. The mean thinnest point in corneal thickness was 549 μm ± 33 (SD). Refractive state, mean keratometry, and age had a statistically significant impact on the thinnest point in corneal thickness. The mean thinnest point in corneal thickness was 548 ± 33 μm in myopia, 555 ± 34 μm in hyperopia, and 553 ± 35 μm in high astigmatism, with a statistically significant difference between hyperopic eyes and myopic eyes (P<.001). No correlation was found between the thinnest point in corneal thickness and sex or ocular side. Refractive state (r = 0.07, P<.001) and age (r = 0.05, P<.001) showed a positive correlation and keratometry (r = -0.09, P<.001) a negative correlation with the thinnest point in corneal thickness.

CONCLUSIONS

Refractive state, mean keratometry, and age had a statistically significant, although marginal impact, on the thinnest point in corneal thickness. Sex and the ocular side had no effect.