Author(s): Y. B. Bajantri1, Rajashekar Dyaberi2, Anuja D3
Pterygium is a very common degenerative condition seen in Indian subcontinent. It is a wing-shaped fibrovascular encroaching up on the cornea from either sides. The prevalence rate is 5.2%. Pterygium is known to affect refractive astigmatism. The induced astigmatism may become significant to cause visual distortion, even though the pterygium remains distant from visual axis induced astigmatism maybe either “with-the-rule” or “against-the-rule.”
The aim of the study is to-
1. Compare preoperative with postoperative astigmatism in case of pterygium.
2. Assess the amount of astigmatism in case of pterygia of different lengths measured from the limbus over the cornea.
MATERIALS AND METHODS
The study included 70 eyes of 70 patients with primary pterygium. Preoperative evaluation included pterygium size, visual acuity, keratometry and refraction with subjective correction. Patients included in the study were divided into three groups based on length of pterygium encroaching on cornea (1 to 2 mm, 2 to 3 mm, >3 mm). Each eye underwent bare sclera pterygium excision. Postoperative visual acuity, keratometry and refraction were evaluated on 1st day, at the end of 1st week, 4th week and 9th week. The pre and postoperative results were compared and analysed.
An average of all 70 cases with mean pterygium length 3.2 mm had a mean keratometry astigmatism of 1.84 ± 0.89D preoperatively and 0.514 ± 0.52D postoperatively indicating a reduction of pterygium-induced corneal astigmatism by 1.45 ± 0.77D (p value <0.0001), which was statistically significant.
Pterygium-induced corneal astigmatism is directly proportional to the size of the pterygium. Thus, early surgical excision reduces the corneal astigmatism, and hence, improves the visual acuity.