Characteristics of patients with a localized retinal nerve fiber layer defect and normal optic disc appearance

Abstract

To investigate the characteristics of patients with a localized retinal nerve fiber layer (RNFL) defect and normal optic disc appearance compared with normal tension glaucoma (NTG) patients. A total of 40 patients with an unchanged RNFL defect for more than 5 years and normal optic disc appearance, who were presumed as non-glaucomatous patients, were enrolled (group A). We recruited 40 age-matched patients with NTG (group B). On the RNFL photographs, we evaluated angles of RNFL defects. Angle α and β were the angles made by the line 'L' from the center of the fovea to the disc center and the lines 'A' and 'B' from the disc center to the disc margin where the proximal and the distal border of the defect met, respectively. Angle θ was the angular width of the defect. Angle γ was the angle made by lines 'L' and 'R', which divides angle θ into a 2 :1 ratio from line 'A' to line 'B'. We compared systemic diseases, baseline IOP, and location and angles of the RNFL defects between the two groups. Systemic diseases and superotemporal RNFL defects in group A were significantly greater than those in group B (P<0.001). Angle α was greater in group A, but angle β, θ, and γ were smaller in group A (P<0.05). If the patients with a superotemporal RNFL defect and normal optic disc appearance had systemic diseases and distal borders of the defects are closer to the macula, glaucoma is less likely.