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

To evaluate changes in thickness of the conjunctival graft after pterygium surgery by anterior segment optical coherence tomography (AS-OCT).

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.

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).

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.