EC Ophthalmology

Purpose: To evaluate the long-term impact of Gas permeable (GP) contact lens wear on corneal endothelial cell density and morphology in keratoconus patients compared with keratoconus controls without lens use.

Methods: This comparative cross-sectional study included keratoconus patients divided into GP contact lens wearers 50 and non-wearers 50. Visual acuity, refractive error, and keratometric parameters were documented. Endothelial parameters including endothelial cell density (cells/mm²), coefficient of variation (%), hexagonality (%) and Central Corneal Thickness (CCT) were measured using the Tommy Specular Microscope EM-4000. Intergroup comparisons were performed with Student’s t-test, with p < 0.05 considered significant.

Results: The mean age of lens wearers was 24.34 ± 5.65 years, while controls averaged 23.81 ± 7.59 years. Lens wearers demonstrated poorer uncorrected and corrected distance visual acuity and greater myopic refractive error than controls. Mean endothelial cell density was significantly lower in GP lens wearers (2474.27 ± 349.89 cells/mm²) compared to controls (3426.93 ± 4201.30 cells/mm²; p = 0.025). The coefficient of variation was higher in lens wearers (30.18 ± 7.11%) versus controls (27.56 ± 4.18%; p = 0.002), indicating increased polymegathism. Hexagonality was also greater in lens wearers (66.77 ± 11.65%) compared to controls (61.88 ± 11.23%; p = 0.002), and CCT decrease from 472.09 ± 51.74 µm to 432.13 ± 69.78 µm as compared with controls, reflecting altered endothelial morphology.

Conclusion: Prolonged contact lens wear in keratoconus is associated with reduced endothelial cell density and distinct morphological changes. Regular endothelial monitoring using specular microscopy is recommended for keratoconus patients undergoing long-term lens wear.

 Keywords: Contact Lens Wear; Corneal Endothelium; Endothelial Cell Density; Hexagonality; Keratoconus; Polymegathism; Specular Microscopy

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