Changes in Astigmatism Before and After Pterygium Surgery

Rojeeta Parajuli,Leena Bajracharya

doi:10.3126/bjhs.v4i1.23929

Abstract

Introduction: Pterygium is a degenerative condition of the subconjuctival tissue, which proliferates as vascularised granulation tissue to invade the cornea resulting in destruction of the superficial layer of the corneal stroma and bowman's membrane. This change in cornea leads to corneal opacity, visual impairment and significant induced astigmatism. The ensuing pathologic changes consist of elastoid degeneration of collagen and the appearance of subepithelial fibrovascular tissue Objective: To measure the change in corneal astigmatism after pterygium surgery and the relationship of astigmatism with respect to size of pterygium. Methodology: Hospital based prospective, non-randomized study, comprising 61 eyes of 56 patients who underwent pterygium excision and autologus conjuctival graft during the period October 2009 to September 2010. A total of 56 participants were enrolled and followed upto 3 months after surgery. Corneal topography was used to measure corneal astigmatism before and after pterygium surgery. Results: The mean age of patient was 46.11 years, standard deviation was 18.86 Male: female ratio: 0.8:1 Preexisting induced astigmatism among study group patients was 2.6D and mean astigmatism after pterygium surgery was 0.8D. This finding was found to be statistically significant(P value <0.001). Over all change in mean astigmatism was 1D in our study. In grade I Mean astigmatism before surgery was 0.96D and Mean astigmatism after surgery was 0.46D, Changes in mean astigmatism after surgery was 0.50D. In grade II Mean astigmatism before surgery was 1.99D and Mean astigmatism after surgery was 0.54D, Changes in mean astigmatism after surgery was 1.45D. In grade III Mean astigmatism before surgery was 10.71D and Mean astigmatism after surgery was 3.10D, Changes in mean astigmatism after surgery was 7.61D. The change in mean astigmatism is greatest in patients with grade III pterygium. Conclusion: After pterygium surgery astigmatism significantly reduces and astigmatism increases with the grade of pterygium.

Highlights

IntroductionPterygium is a degenera ve condi on of the subconjuc val ssue, which proliferates as vascularised granula on ssue to invade the cornea, destroying the superficial layer of the stroma and bowman's membrane, the whole being covered by conjuc val epithelium
Pterygium is a degenera ve condi on of the subconjuc val ssue, which proliferates as vascularised granula on ssue to invade the cornea, destroying the superficial layer of the stroma and bowman's membrane, the whole being covered by conjuc val epithelium.The occurrence of pterygia is strongly correlated with Ultraviolet-exposure, dryness, inflamma on and exposure to wind, dust or other irritants
Preexis ng induced as gma sm among study group pa ents was 2.6D and mean as gma sm a er pterygium surgery was 0.8D

Summary

Introduction

Pterygium is a degenera ve condi on of the subconjuc val ssue, which proliferates as vascularised granula on ssue to invade the cornea, destroying the superficial layer of the stroma and bowman's membrane, the whole being covered by conjuc val epithelium. The occurrence of pterygia is strongly correlated with Ultraviolet-exposure, dryness, inflamma on and exposure to wind, dust or other irritants. Ultraviolet B is mutagenic for the p53 tumor suppresor gene in limbal basal stem cells. The ensuing pathologic changes consist of elastoid degenera on of collagen and the apperance of subepithelial fibrovascular ssue. The cornea shows destruc on of Bowman's layer of fibrovascular ingrowth, frequently with mild inflammatory changes. The epithelium may be normal, thick or thin and occassionaly shows feaures of dysplasia. The lesion appears as a triangular encroachment of the conjuc va upon the cornea with numerous small opaci es lying deeply in the neighbouring part of cornea in front of its blunt apex

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