A study on corneal astigmatism before and after pterygium excision

The prevalence of pterygium shows a substantial increase for increasing age and UV irradiation. There is paucity of available literature regarding the total area of pterygium, percentage of extension of pterygium on to the cornea and its effects on corneal astigmatism. Hence this study was undertaken to evaluate the pre and post-surgical effect of the size of the pterygium on corneal astigmatism. 100 out patients aged between 22 to 50 years diagnosed with pterygium were included in the study. Slit lamp bio microscope was used to measure the length and width of pterygium in millimetres. Slit beam was used to measure the diameter of cornea. Corneal astigmatism was measured pre and postoperatively on day 1 and 1 month follow up using keratometery. In this study 2.13±1.39 was the mean preoperative astigmatism, 1.36±1.03 was the mean post-operative astigmatism on day 1 and on 1 month follow up 0.86±0.91 was the mean post-operative astigmatism which was statistically significant(p<0.001)). The corneal astigmatism was directly proportional to pterygium area. As the area of pterygium increased the post-operative astigmatism significantly decreased. There was increase in corneal astigmatism with the increase in the percentage of pterygium extension onto cornea. In post-operative period the corneal astigmatism decreased with the increase in the percentage of pterygium extension onto cornea (p<0.001). As per our findings we draw a conclusion that surgical removal of pterygium significantly reduces pterygium induced astigmatism and also there is an improvement in visual acuity.