Multivariate Analysis Of The Relationship Between Refractive Error And Corneal Transparency In Refractive Surgery Candidates

This study aims to evaluate the potential effect of different levels of myopia and astigmatism on corneal transparency (densitometry) as measured using a Scheimpflug-camera device. It employs advanced multivariate modeling to explore this correlation while adjusting for other variables that may affect the results, providing strong evidence on whether this association exists.

Private high-volume refractive surgery practice in Medellín, Colombia

This retrospective study assessed correlations between myopia, astigmatism, and corneal densitometry using a Scheimpflug camera. It included 194 healthy refractive surgery candidates. Manifest refraction was performed under standard conditions. Corneal densitometry was measured using the Pentacam AXL Wave, analyzing light backscatter in specific corneal regions. Statistical analysis included ANOVA and multivariate regression adjusting for potential confounders, building multivariate models to explain potential correlations. Ethical approval was obtained, and no conflicts of interest were reported. Signed informed consent was not required under Colombian law.

This study included 194 eyes from 194 patients, predominantly female (n = 122; 62.9%), with a mean age of 28.8 ± 5.4 years. Right eyes comprised 52.1% of the sample. One-way ANOVAs showed no significant differences in corneal densitometry across myopia or astigmatism levels. Multivariate models assessed the effects of manifest refraction (myopia, astigmatism), sex, age, UDVA, SimK Km, and SimK astigmatism on densitometry. Most models were statistically significant (p ≤ 0.05), but age was the primary contributing factor. Myopia was linked only to posterior 6–10 mm densitometry (p = 0.026) but had a smaller effect than age. Astigmatism did not significantly influence any model.

This study confirms that most densitometry variables have a strong correlation with age. However, increasing levels of myopia or astigmatism were found not to correlate with corneal densitometry at any level, except for a marginal correlation in the posterior 6-10 mm annulus. Upon critical biostatistical appraisal, this single correlation appears to be a false positive. By using multivariate modeling to adjust for potential confounding variables, this study provides evidence that different levels of ametropia do not influence Scheimpflug-based corneal densitometry values in healthy candidates for refractive surgery.