ROLE OF CORNEAL COLLAGEN CROSS LINKING IN KERATOCONUS

To evaluate the outcome of collagen cross linkage using riboflavin 0.1% and ultraviolet A radiation of a wavelength 370nm. PURPOSE: To determine the effect of collagen cross linking for keratoconus on pachymetry, corneal topography, uncorrected visual acuity, specular count, IOP at 1, 3, 6 months. METHODS: The current study was designed as a prospective interventional trial of corneal collagen cross-linking in subjects with progressive keratoconus between a period of January 2013 to July 2014 including 50 eyes of 30 patients. This study received approval from Ethics committee. Informed written consent was obtained from all patients prior to treatment. RESULTS: Mean follow up period of 6 months. There was statistically significant decline in effective k readings from mean pre op (51.7D) to post op value (49.65D). Pachymetry showed initial increase post operatively followed by reduction in corneal thickness in 3 months follow up, followed by gradual increase in thickness over a period of 6 months though it was not equivalent to pre-operative values. paired t test p value was 0.001 in 1 n 3 month and 0.043 in 6 month, concluding significant reduction in early post op period with improvement over time. Specular count reduced from pre-op (2673.80) levels to post-op (2654.60) levels, the reduction in specular count was not statistically significant P value (0.014) The uncorrected visual acuity showed decrease in refractive error with increase in visual acuity gradually over 6 months, log MAR scale visual acuity was used for statistical analysis with P value (0.001) which was statistically significant. visual acuity improved by 1.5 lines in snellens equivalence or from 0.5 to 0.4 in log MAR chary +/-20cells/mm(3), P value(0.001). IOP statically showed no significant change in preoperative and post operatively, paired t test p value was 0.44 showing it was not significant. CONCLUSIONS: 1. Visual acuity improved in keratoconus patients by 1.5 lines of snellens equivalent, henceforth CXL can be treatment modality for visual improvement along with other techniques. 2. Keratometric readings showed statistically significant reduction there was no progression in effective and steepest K values showing that CXL halts the progression of keratoconus. 3. Pachymetry reduction was not statistically significant and over a period of time increase in pachymetric values was noted suggesting that they would return back to pre-operative values over a period of time (Ranging from 6 months to 1 year). 4. Endothelial cell count was not affected post operatively, suggesting it was a safer procedure with no toxic effects on lens retina and in anterior chamber. 5. IOP showed no significant elevation post operatively this could be good prognostic sign.