Does the Enlargement of Retinal Nerve Fiber Layer Defects Relate to Disc Hemorrhage or Progressive Visual Field Loss in Normal-tension Glaucoma?

Abstract

We investigated the difference in clinical characteristics between cases with enlarged retinal nerve fiber layer defects (RNFLD) and stable RNFLDs in normal-tension glaucoma (NTG). We retrospectively reviewed NTG patients that were diagnosed and followed up for at least 3 years at 1-month to 2-month intervals by the same examiner, and selected eyes with distinct RNFLD borders. Using fundus photographs, for which we extracted only a blue ingredient and processed it into black and white, we measured RNFLD angles and divided NTG cases into 2 groups, enlarged RNFLD and stable RNFLD, and compared the clinical characteristics between both groups. Ninety-three eyes from 93 patients (mean follow-up, 8.2 y) were selected and enlargement of RNFLD was detected in 55 eyes. Disc hemorrhage (DH) was found in 35 of 55 eyes (63.6%) in the enlarged group and in 6 of 38 eyes (15.8%) in the stable group (P<0.0001). Twenty-one eyes (38.2%) from the enlarged group exhibited recurrent DH. In 48 eyes (87.3%) from the enlarged group, the enlargement of RNFLD was toward the fovea. When DHs located apart from RNFLD were excluded, RNFLD enlarged in the direction of DH in 21 of 25 eyes (84.0%). The cumulative probability of non progression in the visual field was significantly lower in the enlarged group (10-year survival rate: 0.52±0.11) than in the stable group (10-year survival rate: 0.89±0.08) (P=0.0019). The enlargement of RNFLD in NTG was closely associated with DH occurrence and the deterioration of visual field.