The association between prelaminar tissue thickness and peripapillary choroidal thickness in untreated normal-tension glaucoma patients

To evaluate the association between prelaminar tissue thickness (PLT) and peripapillary choroidal thickness (PCT) in untreated normal-tension glaucoma (NTG) patients. A cross-sectional study was conducted in 65 untreated NTG patients. All of the subjects were imaged with swept-source optical coherence tomography (SS-OCT, DRI OCT; Topcon, Tokyo, Japan) to obtain the horizontal scan crossing the optic nerve head center. The PLT was calculated by subtracting the anterior prelaminar depth (APLD) from the anterior lamina cribrosa depth (ALCD). The retinal nerve fiber layer thickness and PCT were measured automatically using the in-built automated software of the OCT device. Spearman correlation analysis was conducted to investigate the ocular factors that were associated with PLT. The average PLT, APLD, ALCD, and PCT values were 134.05 ± 55.54, 314.59 ± 113.59, 448.64 ± 125.69, and 121.23 ± 59.56 μm, respectively. PLT was correlated with the axial length, visual field index (VFI), ALCD, and PCT. When the subjects were divided into 2 groups according to their PLT values (median value, 125.114 μm), the thin PLT group showed worse mean deviation, VFI values, and thinner PCT when compared to the thick PLT group. The PLT was significantly associated with the PCT, and the thinner PLT showed the greater glaucomatous damage in untreated NTG. The thickness of the prelaminar tissue may be related with the choroidal blood flow in untreated NTG patients.