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 3 mm 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 µm at 1 week after surgery to 306 ± 64 µm at 1 month (p < 0.0001). Although the graft thickness decreased to 291 ± 124 µm 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 µm, 60 ± 19 µm and 61 ± 12 µm 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.