Evaluation of conjunctival graft thickness after pterygium surgery by anterior segment optical coherence tomography

Background: To evaluate changes in thickness of the conjunctival graft after pterygium surgery by anterior segment optical coherence tomography (AS-OCT). Materials and Methods: Eleven eyes of 11 patients with primary nasal pterygium underwent excision followed by free conjunctival autograft. Imaging with AS-OCT was performed at 1 week, 1 month and 3 months after surgery to measure thickness of the conjunctival graft at 1, 2 and 3mm posterior to the scleral spur. As the control, thickness of the normal bulbar conjunctival epithelium in the temporal area was also measured at the same locations. Results: Average thickness of the graft decreased from 458±171 m at 1 week after surgery to 306±64 m at 1 month (p<0.0001). Although the graft thickness decreased to 291±124 m at 3 months postoperatively, the difference between 1-month and 3-month values was not statistically significant (p=0.94). Average thickness of the normal conjunctival epithelium was 58±13 m, 60±19 m and 61±12 m at 1 week, 1 month and 3 months after surgery, respectively, with no statistically significant difference. Graft thickness was significantly greater than thickness of the normal conjunctival epithelium at various time points (p<0.05). Conclusion: Evaluation by AS-OCT showed that there was significant thickening of the conjunctival graft at 1 week after pterygium surgery which continued to decrease up to 3 months. Quantitative data by AS-OCT allows accurate evaluation of the conjunctival changes over time.