Purpose
Visual rehabilitation in keratoconus is best done with contact lenses (CLS) that vary extensively in designs and parameters. However, it has not been well established that changes in corneal morphology in keratoconus depend on type of contact lens (CL) used. A longitudinal, randomised clinical study was performed to compare the changes in corneal cell morphology after 6 months of CL wear with baseline observation in keratoconus patients wearing different types of CLS.
Methods
Twenty eyes of 14 patients aged between 18 to 50 years with stage 1 to 3 (Amsler-Krumeich, 2006) keratoconus were included. Ten eyes were fitted with regular RGP (RRGP) and rests were fitted with specially designed RGP (SRGP). A single patient was fitted with a mini-scleral CL. Corneal cell morphology was evaluated using a slit scanning confocal microscope at base line and after 6 months of CL wear. A semi-automated method using “NAVIS” software was employed to calculate cell area and density of corneal layers in a fixed frame of 0.06 mm².
Results
After six months of CL wear, the mean anterior (844.70 ± 37.59) and posterior (677.51 ± 38.94) stromal keratocyte density were significantly less (p=0.000 & 0.017) compared to baseline observation (891.27 ± 45.21 &714.20 ± 45.43 respectively) in RRGP group. Mean area of anterior and posterior stromal keratocyte were also significantly different (p=0.001 & 0.021) from baseline. Changes observed in endothelium were not statistically significant. Level of corneal haze increased in 60% patients in this group.<br /> For the SRGP group, statistically significant changes were observed only in anterior stroma (p= 0.002 & 0.017 for cell density & area respectively) after 6 months. Increase in corneal haze was observed only in 50% patients. Patient, wearing mini-scleral demonstrated noticeable qualitative and quantitative morphological alterations after 6 months.
Conclusions
Degree of morphological alterations in keratoconic corneas may vary depending on the CL used. SRGP lenses made fewer changes in corneal morphology compared to RRGP lenses after 6 months of CL use. However, increase sample may further assist in understanding the cellular changes in keratoconus with mini-scleral CLS.