Analysis of variation in success rates in conjunctival autografting for primary and recurrent pterygium

Aims-To evaluate the success rates of conjunctival autografting for primary and recurrent pterygium performed in a tertiary ophthalmic centre. Methods-The outcome of 139 cases with primary pterygia and 64 cases with re current pterygia who underwent excision with conjunctival autografting was retrospectively reviewed. Outcome was evaluated in terms of recurrence of p terygia onto the cornea. The recurrence rates were determined using Weibull survival functions, in a mixture model that included a component allowing for cure. The suitability of this model was verified using Turnbull's non-p arametric method for interval censored data (1974). Estimated recurrence fr ee probabilities were based on the fitted Weibull survival curves. Results-Mean follow up was 8.4 months in the primary group, and 9.5 months for the recurrent group. 29 out of 139 cases of primary pterygia recurred ( 20.8%) while 20 out of 64 cases in the recurrent group (31.2%) recurred. Re currence rates varied widely among surgeons, ranging from 5% to 82%. Recurr ence rates were inversely related to previous experience in performing conj unctival grafting. The recurrence free probability was 84% at 3 months, 73% at 1 year for primary pterygia, and 80% at 3 months, 67% at 1 year for rec urrent pterygia. There was no statistical difference in recurrence rates be tween primary and recurrent groups (p=0.80). Conclusion-The success of conjunctival autografting for pterygium in this s eries varies widely, and may be related to a significant learning curve or differing surgical techniques for this procedure. This may account for the wide variation in reported success of this procedure in the ophthalmic lite rature.