Effects of pterygium on the biomechanical properties of the cornea: a pilot study.

OBJECTIVE To investigate the changes induced by a pterygium or its surgical removal on the biomechanical properties of the cornea and to determine factors that might affect these parameters. METHODS This prospective pilot interventional, non-randomized, observer-masked study included 20 eyes of 20 patients with a unilateral primary pterygium (pterygium group) and 19 fellow healthy eyes (control group). The bare sclera technique with one-minute application of 0.02% mitomycin C intraoperatively was performed in all cases. The follow-up period was one month. The preoperative and postoperative biomechanical properties of the cornea were measured using the Reichert ocular response analyzer (ORA). RESULTS The corneal hysteresis (CH) decreased significantly (P<.01) in eyes with a pterygium compared to the control eyes, while surgery did not significantly change the CH compared to preoperatively. There were no significant changes in the corneal resistance factor or the central corneal thickness. CONCLUSIONS Primary active pterygium (grades 1 or 2) induce a reduction of corneal biomechanical features. Further studies are needed in populations, with longer follow-ups and bigger pterygium that may involve wider keratectomy to confirm our results.