Pterygium and induced astigmatism

الملخص EN

Background : There is an association between increasing size of pterygium and the degree of induced corneal astigmatism. Objectives : to assess the relation between pterygium size and induced corneal astigmatism and to conclude whether astigmatism secondary to pterygium is an indication for surgery. Methods : Ninety patients were included in this study with primary unilateral pterygium of different sizes, we evaluate pterygium using : • Slit-lamp beam measurements of size of pterygium (in millimeters) from the limbus. • Corneal topography using OPD (SCAN II NIDEK). • • Best corrected visual acuity was determined using Snellen's chart and subjective clinical refraction. Results : primary pterygium induces with-the-rule astigmatism, significant astigmatism was found in 5 (16.6 %) of eyes with pterygium size less than 2 mm and in 18 (47.3 %) of eyes with pterygium of 2-4mm in size.

20 (90.9 %) of eyes with pterygium of more than 4 mm in size showed significant astigmatism. Conclusions : when primary pterygium reaches more than 2mm in size from the limbus, it induces astigmatism( ≥ 1.0 diopter) this astigmatism tends to increase with any increase in the size of the lesion.

Recommendations : According to the results of our study, early surgical removal of pterygium is indicated when the lesion is more than 2mm from the limbus to correct clinically significant pterygium induced astigmatism.