Sensory Changes in the Ocular Surface After Pterygium Removal

We measure changes in ocular surface sensation after pterygium surgery with a conjunctival autograft.

This prospective, interventional study was carried out in patients, with nasal primary pterygium undergoing pterygium surgery with conjunctival autograft. Sensation was measured by applying the tip of the Cochet-Bonnet esthesiometer filament perpendicular to the ocular surface in the cornea and conjunctiva. Patients were tested preoperatively (baseline), and at 2 weeks, 2 and 4 months, postoperatively.

Nineteen eyes of 18 patients completed the 4-month follow-up. Mean age was 61±10.1 (range 36-76) years. Corneal sensation returned to normal values in all at 2 and at 4 months. The central cornea was significantly more sensitive compared to the average of the four peripheral measurements pre- (59.2 mm vs 48.3 mm, p=0.000) and postoperatively (59.2 mm vs 48.4 mm, p=0.000). Conjunctival sensation was reduced significantly 2 months postoperatively in the inferior region (p=0.04). Four months postoperatively, it was more sensitive in the superior area (13.9 mm vs 17.1 mm, p=0.01) and the inferior area (13.7 mm vs 19.5 mm, p=0.003). In each matching area, the cornea was significantly more sensitive than the conjunctiva pre- and postoperatively (p=0.00). Sensation was not significantly different between the sexes or age groups.

This study demonstrates the presence of inferior and superior conjunctival hyperesthesia at conjunctival autograft sites after pterygium surgery. The healing process, sensory input, tear film instability and epitheliopathy of the ocular surface are possible explanations for these novel findings.