EFFECT OF PANRETINAL PHOTOCOAGULATION ON CORNEAL SENSATION AND TEAR FUNCTION IN PATIENTS WITH DIABETIC RETINOPATHY

Purpose: To evaluate the early effects of panretinal photocoagulation (PRP) on corneal sensation and dry eye signs in patients with diabetic retinopathy. Methods: Fifty patients with Type 2 diabetes mellitus and very severe nonproliferative or non-high-risk proliferative diabetic retinopathy who required PRP for the treatment of their retinal condition were enrolled. All patients were treated using a pattern PRP device. Esthesiometry, tear breakup time test, Schirmer test, and corneal staining pattern were evaluated at baseline and 2 months after the last session of PRP. Results: Data from 88 eyes of 50 patients (41 right eyes and 47 left eyes) were analyzed. The mean tear breakup time test (right eyes) was decreased from 9.51 at baseline to 7.66 seconds after PRP (P < 0.001). The post-PRP eyes showed more advanced grades of corneal staining than pre-PRP assessment (P < 0.001). The average value of Schirmer test was 14.39 versus 12.29 mm (without anesthesia; P < 0.001) and 8.17 versus 7.15 mm (with anesthesia, P < 0.001) for baseline versus post-PRP measurements, respectively. The corneal sensation also showed decrease after laser therapy (4.93 versus 4.31 cm; P < 0.001). Conclusion: This study demonstrates that decreased corneal sensation and signs of dry eye are more common immediately after PRP for diabetic retinopathy. These conditions should be discussed with the patient preoperatively and managed postoperatively.