The Long-Term Effects of Soft Contact Lens Wear on Corneal Thickness, Curvature and Endothelium

ABSTRACT

PURPOSE: To investigate the effects of long-term contact lens (CL) wearing on corneal thickness, curvature, and endothelium. METHODS: Using ultrasonic pachymetry, Orbscan topography and specular microscopy, we evaluated the cornea of 53 subjects who had used soft CL for more than 5 years compared with 47 controls who had never used CL. RESULTS: There was a significant decrease of central corneal thickness in CL wearers. The difference of central corneal thickness between the two groups was 16.39 micrometer. The percentage of central corneal thickness less than 500 micrometer was 24.5% in the CL wearers and 12.2% in the controls. The mean corneal thickness of the CL wearers in the center and eight peripheral areas, as measured with Orbscan topography, was significantly reduced by about 7.28 to 17.87 micrometer compared with that of the controls. The corneal curvature and elevation were significantly steeper in the CL wearers than in the controls but no difference in the mean corneal astigmatism was found between the two groups. Endothelial density and percentage of hexagonal cells were decreased and the coefficient of cell area variation was increased in the CL wearers compared to the controls. The percentage of endothelial cell densities less than 2500 cells/mm2 was 24.5% in the CL wearers and 4.25% in the controls. CONCLUSIONS: Long-term soft contact lens use may have a significant effect on corneal thickness, curvatures and endothelial morphology.