Evaluation of the Effect of Pan Retinal Photocoagulation on Optic Nerve Head Parameters Using HRT3

Purpose: To evaluate the optic disc topography after pan retinal photocoagulation (PRP) in diabetic retinopathy patients using confocal scanning laser ophthalmoscopy (HRT3). Methods: Thirty eyes of 30 diabetic patients (non-insulin-dependent diabetes mellitus) underwent PRP for proliferative diabetic retinopathy. Subjects with glaucoma or family history of glaucoma, any coexisting neuroophthalmic disease, uveitis, retinal artery or vein occlusion, corneal opacity or lasered previously were excluded from the study. Optic nerve head (ONH) of these patients were evaluated by confocal scanning laser ophthalmoscopy (HRT3) at baseline, 3, and 6 months after completion of PRP. Results: There were 23 males and 7 females with a mean age of 51.8 years (36 to 67 y). The mean intraocular pressure was 13.1 +/- 2.57 mm Hg at baseline, 13.4 +/- 2.6 mm Hg at 3 months, and 13.3 +/- 2.2 mm Hg at 6 months (P = 0.6). The global values of ONH parameters showed no significant change from baseline at 3 months. At 6 months, there was a significant increase in vertical cup: disc ratio (P = 0.021), cup volume (P = 0.036), mean cup depth (P = 0.042), and maximum cup depth (P = 0.05) as compared with baseline values. Conclusions: PRP induces significant changes in the ONH in patients with diabetic retinopathy as measured with HRT3. This is an important consideration in the diagnosis and evaluation of progression in glaucoma patients with diabetic retinopathy who have undergone PRP.