Astigmatic changes following pterygium removal: comparison of 5 different methods

To investigate the effect of surgery type on the postoperative astigmatism in pterygium surgery.

Retrospective comparative clinical trial.

Data of 240 eyes that underwent pterygium excision were investigated. Following removal of the pterygium, patients underwent 5 different types of surgeries: Conjunctival autograft with sutures (CAG-s) or fibrin glue (CAG-g), conjunctival rotational flap (CRF), or amniotic membrane transplantation with either suture (AMT-s) or with glue (AMT-g). The preoperative and postoperative keratometric measurements, evaluated using an automated keratorefractometer, were noted.

The overall changes in BCVA and astigmatic degree were evaluated using Wilcoxon signed rank test. The difference in astigmatic values between groups was calculated using one way analysis of variance (ANOVA).

The most commonly performed procedure was CAG-s (N = 115), followed by CAG-g (N = 53), CRF (N = 47), AMT-s (N = 15), and AMT-g (N = 10). Following surgery, astigmatic values decreased from 3.47 ± 2.50 D to 1.29 ± 1.07 D (P < 0.001, paired t test). The changes in astigmatism was significantly related to the preoperative size of the pterygium (ρ = 3.464, P = 0.005). The postoperative astigmatism correlated with preoperative astigmatism (ρ = 0.351, P < 0.001, Spearman correlation analysis). The changes in astigmatic values was not related to the method of surgery (P = 0.055, ANOVA).

Pterygium results in high corneal astigmatism, which decreases to an acceptable level following excision. According to our study, the type of grafting as CAG, CRF or AMT or the use of suture or glue to fixate the graft does not have a significant effect on the change in astigmatism degree.