Evaluation of photo refractive keratectomy with corneal topography

ABSTRACT

To analyze the incidence and clinical characteristics of different topographic patterns after photorefractive keratectomy and the effect of different topographic patterns on best corrected visual acuity. This prospective study was carried out at Al Shifa Trust Eye Hospital a series of 100 eyes of 50 patients who had undergone PRK, were evaluated postoperatively with video Keratograph [HS Keratograph 922]. The different topographical patterns were studied and there relationship to visual acuity was considered. The patients were evaluated at 4 weeks and 12 weeks follow up. The patients were mostly in the age group of 20 to 30 years. Fifty patients were selected for the study. The incidences of the various ablation patterns on corneal topography were studied. The corneal topography at one. month showed that fifty- one eyes [60.71%] had a homogenous pattern and the contours of the cornea were uniform. Twenty -one eyes [25%] were found to have the central islands while six eyes [7. 14%] had the semicircular pattern. The remaining six [7.14%] eyes had the keyhole pattern of ablation. The incidence of the various ablation patterns on corneal topography at three months showed that seventy- five eyes [89.28%] had a homogenous pattern. Five eyes [5.95%] were found to have a central island while two [2.38%] eyes had the semicircular pattern. The remaining two eyes [2.38%] had the keyhole pattern of ablation. The postoperative topographies revealed that the most common ablation zone pattern was homogenous pattern [60.71%] followed by central island pattern [25%]. The loss of best spectacle corrected visual acuity at one month was more in the eyes with postoperative central island pattern [23.81%] as compared to the homogenous pattern [5.45%]