Comparative Evaluation of Postoperative Corneal Astigmatic Correction Following Pterygium Excision by Bare Sclera Technique Versus Conjunctival Limbal Autograft: A Prospective Observational Study

Abstract

Background: Pterygium excision reconstitutes corneal topography and may reduce induced astigmatism, yet whether the magnitude of correction differs meaningfully between surgical techniques and pterygium grades remains insufficiently characterised.

Aims and Objectives: To compare astigmatism reduction following bare sclera technique (BST) versus conjunctival limbal autograft (CLAG) across four pterygium grades in a prospective cohort.

Study Design: Prospective observational comparative study.

Setting: Department of Ophthalmology, Murshidabad Medical College and Hospital, Berhampore, West Bengal, India.

Materials and Methods: One hundred and ninety-two adults with primary pterygium were allocated to BST (n = 96) or CLAG (n = 96). Grade was assigned per Verma et al. (Grade 1: 0–2 mm; Grade 2: 2–4 mm; Grade 3: 4–6 mm; Grade 4: 6–8 mm corneal encroachment from the limbus). Pre-operative and three-month post-operative keratometry (K1, K2) and corneal astigmatism were recorded.

Statistics: Within-group comparisons employed the paired t-test; between-group comparisons employed the independent t-test; p<0.05 denoted significance.

Results: Pre-operative astigmatism was comparable between groups (BST 3.37±2.38 D; CLAG 3.52±2.55 D; p>0.05). Both techniques significantly reduced astigmatism at three months (p<0.001 each). Post-operative values were 1.75±1.42 D (BST) and 1.08±0.83 D (CLAG). Grade-stratified between-group analysis revealed equivalence in Grades 1 (p=0.273) and 2 (p=0.368), but CLAG conferred superior correction in Grade 3 (t=−2.32; p=0.027) and Grade 4 (t=−3.77; p=0.0007).

Conclusion: CLAG confers statistically superior astigmatic correction over BST in Grade 3 and Grade 4 pterygium, while both techniques perform equivalently in early-grade disease. Grade-stratified surgical planning is recommended for optimal refractive outcomes.