Pterygium excision with conjunctival autograft: true survival rate statistics

To evaluate the factors influencing long-term survival rate (ie, probability of recurrence-free eye over time) after pterygium excision with conjunctival autograft.

A retrospective cohort study was performed. All patients who underwent excision of pterygium and conjunctival autograft at a single institution by the same surgeon during the years from 1997 to 2008 were included. Preoperative and postoperative patient data were collected. The patients were invited for follow-up examinations performed by the surgeon, and the recurrence was analyzed using survival rate statistics.

There were 20 recurrences (20/176, 11.4%) during an average follow-up time of 34.4 ± 36.2 months (range, 0.03-129.7 months), with no apparent leveling of the graph. Using survival rate statistics, the estimated mean time to recurrence was 104.5 ± 4.9 months (95% confidence interval, 94.9-114.0 months). Patients younger than 30 years (P = 0.031) and grafts attached with thicker sutures (6/0-8/0, P = 0.005) were more prone to have recurrences. Thin (9/0 or 10/0) nylon and polyglactin sutures had similar results (P = 0.819). Interestingly, pterygia invading less into the cornea probably had more recurrences (P = 0.054). There was an average improvement of logarithm of the minimum angle of resolution from 0.26 (preoperative) to 0.19 (postoperative) (P < 0.014). There were no major complications.

Use of survival rate statistics is indicated because the potential for pterygium recurrence is continuous. Worse prognosis is expected for younger patients, use of thicker sutures and possibly in less invading pterygia.