Specular Microscopy to demonstrate morphological changes of corneal endothelial cells (EC) with Corneal Oxigen Deficiency (COD) in Contact Lens (CL) Wears.

Abstract

Purpose: To demonstrate a methodology to analyze the EC morphology from results of specular microscopy (SM) as marker with the purpose to detect EC changes in low Dk CL wears after the change for very high Dk CL.

Methods: Ten eyes from 5 disposable contact lens wears with Dk<30. Examination times: Time(T)1 at the moment of COD diagnosis by SM, T2 - 4 every 4 months after the change the CL material to Lotrafilcon-A (Dk=140). Bio-Optics specular microscope calculates: Coefficient of variation (CV) for polymegethism; % EC with less than 6 sides (%<H), % hexagonal EC (%=H), and % EC with more than six sides (%>H) for pleomorphism. SM with sample error<5% indicated by the Reliability Indexes calculated by Cells Analyzer software - Corneal Endothelial Statistical Lab _{USA Patent} (Technical, Brazil) with a reliability degree of 95% and relative error<5%. T1 Expected Pattern Behavior is increasing values for CV, %<H, and %>H; and decreasing values for %=H. Hypotetical Pattern Behavior 12 months after the change of the CL is the inversion of the tendency of the CV, %<H, %>H, and %=H. Established Pattern Behavior will be determined by the statistical analysis: linear regression model was calculated with the profile of the studied data (p<0.05) with Microsoft Office Excel 2010.

Results: There is an statistic significant tendency of decrease of the CV during the use of the Lot-A CL (p<0.001), the angular coefficient (AC) estimated at -0.017 with 95% confidence interval (CI): -0.023 to -0.011.There is an statistic significant tendency of increase of the %H during the use of Lot-A CL (p =0.013) and the AC estimated at 0.037 with 95% CI: 0.206 to 1.668. There is a statistic significant tendency of decrease of the %>H during the use of the Lot-A CL (p <0.001) and the AC estimated at -0.657 with 95% CI: -1.071 to -0.242. There is a stability of the % <H during the use of the Lot-A CL (p = 0.125) and the increase is equal to -0.281 with 95% CI: -0.643 to 0.082.

Conclusions: The presented methodology using endothelial cell morphological data from specular microscopy as marker was able to demonstrates the improve of the morphological situation after the change of CL material with decreases of CV (polymegethism) and %<H, %>H (pleomorphism).

Keywords: 477 contact lens • 481 cornea: endothelium • 548 hypoxia