Evaluation of retinal nerve fiber layer thickness in diabetic retinopathy after panretinal photocoagulation

Retinal nerve fiber layer (RNFL) thickness analysis has been used in glaucoma and some other ocular diseases. In this study, we measured RNFL thickness using scanning laser polarimetry in 27 eyes with diabetic retinopathy after panretinal photocoagulation (PRP). Symmetry, ellipse modulation, ellipse average, average thickness, number (a measure of RNFL change), and superior, inferior, nasal, and temporal average RNFL thicknesses were measured. Mean symmetry was 0.90, mean ellipse modulation 1.80, mean ellipse average 63.6 microns, mean average thickness 63.0 microns, and mean number 45.8. Average superior RNFL was 65.8 microns, average inferior RNFL 75.1 microns, average nasal RNFL 44.47 microns, and average temporal RNFL 38.78 microns. The superior/temporal and inferior/temporal ratios were 1.77 and 2.00, respectively; superior/nasal and inferior/nasal ratios were 1.51 and 1.72, respectively. Retinal edema did not increase laser retardation. The superior/temporal and inferior/temporal ratios were more reliable in evaluating nerve fiber analyzer data in patients with diabetic retinopathy after PRP.