Abstract
Purpose::
To describe techniques of pupil reconstruction (pupilloplasty) at the time of penetrating keratoplasty (PKP) for pupil abnormalities, and to evaluate the effect on graft survival and visual outcome.
Methods::
A case control study involving 35 cases of PKP combined with pupilloplasty, and 70 matched controls consisting of PKP alone was undertaken at the Singapore National Eye Centre. Case selection was obtained from the Singapore Corneal Transplant Study (SCTS).Various iris/pupil abnormalities and specific surgical techniques used were analyzed. Chi-square and student t tests to compare risk factors between treatment and control groups, and Kaplan Meier and Cox’s regression for graft survival analysis were performed.
Results::
Pupil/iris abnormalities were classified based on size and location of the pupil and the degree of iris tissue loss, which included dilated, distorted, or eccentric pupils, or large iris defects or iridodialysis. 20 patients were male and 15 were female in the treatment group. Age range was from 27 to 77 years (mean=62.4 years). Indications for combined PKP and pupilloplasty included pseudophakic (n=11) or aphakic (n=6) bullous keratopathy, mechanical trauma (n=5) and regrafts (n=9). Mean follow-up in treatment group was 39.1 months (range=4.4 to 82.3 months) and in control group was 30.3 (range=0.1 to 98.2 months). During follow up, 8 (22.9%) grafts failed in the treatment group and 28 (40%) failed in the control group. No cases resulted in breakdown of iris sutures or anatomical reversal of the pupilloplasty. Univariate analysis of 10 known risk factors affecting graft survival revealed that only pupilloplasty and donor source variables were statistically significant different between study groups. Kaplan Meier analysis showed graft survival to be higher in the pupilloplasty group (p=0.031)Multivariate analysis by Cox-regression similarly confirmed pupilloplasty [hazard ratio (HR) 2.52 (95% CI of 1.14-5.57, p=0.022)] and donor source [HR 0.34 (95% CI -0.16-0.73, P=0.005)] to be significant. There was a trend towards a better visual outcome in the pupilloplasty group compared to that of the control group, but this did not attain statistical significance.
Conclusions::
Iris reconstruction should be performed in eyes with substantial pupil abnormalities at the time of penetrating keratoplasty. Pupilloplasty significantly improves graft survival and renders the pupil cosmetically acceptable and may improve visual outcome.
Keywords: cornea: clinical science • pupil • visual acuity