Peripapillary choroidal thickness in untreated normal-tension glaucoma eyes with a single-hemifield retinal nerve fiber layer defect

The aim of this study was to evaluate the regional variations of peripapillary choroidal thickness (PCT) in normal-tension glaucoma (NTG) patients with a retinal nerve fiber layer (RNFL) defect localized to a single superior or inferior hemifield. This is a retrospective, cross-sectional study. Ninety-five NTG patients and 53 normal subjects were divided into 3 groups: 34 eyes with a superior RNFL defect (group A), 61 eyes with an inferior RNFL defect (group B), and 53 normal eyes (group C). The average, quadrant, and clock-hour RNFL thickness (RNFLT) and PCT were measured using spectral-domain optical coherence tomography. Choroidal thickness ratio (CTR) was defined as the ratio of the measured PCT at a quadrant or a clock-hour position to the average PCT of an individual. The PCT, CTR, and RNFLT were compared among 3 groups. The average PCT of NTG patients was thinner compared to that of healthy subjects (154.17 vs. 180.65 μm, P < .001). Although the average, quadrant, and clock-hour PCTs were not different between groups A and B, the CTR at 11 o’clock was significantly lower in group A compared to that of group B. The 11 o’clock CTR was an independent factor for the initial location of a RNFL defect (P = .03). Eyes with NTG showed regional differences in CTR according to the hemisphere location of their initial RNFL damage. Therefore, CTR may be more useful than the absolute PCT value to assess regional PCT differences in eyes with NTG.