Anterior Segment Optical Coherence Tomography Evalution Of The Primary Pterygium Morphology

Primary pterygium is a common cause of consultation. It develops mainly in patients exposed to sunlight. Its treatment is only surgical essentially in cases with severe astigmatism that interfere with visual acuity. 

The purpose of our study was to evaluate the morphological state of the primary pterygium using the anterior Segment Optical coherence tomography (AS-OCT) and find an eventual relation between morphometric state and induced astigmatism.

military hospital of tunis, tunisia

we conducted a cross sectional study that included patients with primary pterygium. We measured the best corrected visual acuity (BCVA) and noted the refractive values. The patients were divided into three groups depending on the grade of the pterygium: G1: atrophic pterygium, Group 2 intermediate pterygium involving 4 mm of the cornea, and G3 with progressive pterygium involving more than 4 mm of the corneal epithelium.  AS-OCT was made and we evaluated  the central corneal thickness (µm), horizontal length of pterygium(mm), its head thickness(µm) and its thickness at limbus(µm).

Fifty three patients with primary pterygium were included. The mean BCVA and refractive astigmatism were 0.9 ± 1.8 diopter(D) and 0.3±0.5 (decimal scale), respectively. Forty per cent of the population has grade 2 pterygium.  On AS-OCT, the mean CCT , the horizontal length of the pterygium, its head thickness and the limbal thickness were 509.1±12.3 µm, 2± 0.23 mm 113.1±40.2 µm and 457.28±112.12 µm, respectively.

There was a significant correlation  between the pterygium grade and length of the pterygium with keratometric astigmatism (p < 0,05 in both cases). Epithelial thickness at limbus was significantly associated with refractive astigmatism (P < à 0,05).

The grade of the pterygium and its thickness at limbus as assessed by AS -OCT are correlated with keratometric and refractive astigmatism respectively.