Effect of pterygium excision on corneal astigmatism at the University Teaching Hospitals-Eye Hospital Lusaka Zambia

Abstract Introduction: A pterygium is a fibrovascular growth that extends from the conjunctiva to the cornea. It causes tractional forces which result in a flattened cornea, typically causing astigmatism. The study objective was to evaluate the effect of pterygium excision on corneal astigmatism. Methodology: This was a prospective single arm cohort study which was conducted at the University Teaching Hospital from May 2024 to March 2025. A total of 46 participants were recruited yielding 48 eyes with primary pterygium. Adult pterygium patients ≥18 years were evaluated before surgery and at 2 and 6 weeks postoperatively for best corrected visual acuity, keratometry, and refractive astigmatism. Results: Of the 48 eyes recruited, one eye was excluded due to loss to follow, hence 47 eyes were analysed. The mean age of the participants was 47.85 years, with the oldest and youngest participants aged 74 and 24 years, respectively. The results revealed best corrected visual acuity (BCVA) improved from 0.27±0.25 before surgery to 0.19±0.15 (p<0.001) and 0.14±0.12 (p<0.001) at 2- and 6-weeks post-surgery, respectively. The mean corneal astigmatism was 2.62±2.75D preoperatively. The mean corneal astigmatism at 2 and 6 weeks was 0.47±1.10 and 0.01±0.50D at 6 weeks post-operation. Significant differences in BCVA and astigmatism were maintained even between the 2 and 6 week post-operatively. Conclusion: Pterygium excision with autograft leads to a significant reduction in astigmatism and improvement in BCVA. Stability in BCVA and astigmatism was not established by week 2 postoperative follow up, highlighting the need for further follow-up assessments. Key words: Best Corrected Visual Acuity, Keratometry readings