Abstract
Purpose: :
To assess the difference in the morphology of lamina cribrosa pore (LCP) and optic nerve head between the eyes with normal-tension glaucoma (NTG) and those with primary open-angle glaucoma (POAG)
Methods: :
Unilateral NTG or POAG subjects with visual field defect only in one hemifield of either eye were included. Each visible LCP was given a score of 1 (round), 2 (oval), or 3 (slit or striate), and the mean and total LCP scores were compared between the affected half of the optic disc in the eye with glaucoma (GE) and the same counterpart in the normal contralateral eye (NE). The stereometric parameters of optic nerve head measured with HRT II were compared between the affected superotemporal (or inferotemporal) sector in the GE and the same sectorial counterpart in the NE.
Results: :
A total of 27 NTG and 19 POAG subjects were included. Mean age (54.6 vs. 52.2 years), disc area (2.43/2.50 vs. 2.54/2.44 mm2 [GE/NE]), and mean deviation (MD) (-4.11/-0.30 vs. -3.36/-0.13 dB [GE/NE]) showed no significant difference between the NTG and the POAG group (NTG vs. POAG; P>0.3). The mean and total LCP scores were significantly greater in the affected half of the GE than in the same counterpart of the NE, both in the NTG (P<0.011) and the POAG (P<0.002) group. However, the inter-eye difference in the mean or total LCP scores between the two counterparts were significantly greater in the POAG than in the NTG group (P<0.038). The mean and maximum cup depths were not significantly different between the affected superotemporal (or inferotemporal) sector of the GE and the same counterpart of the NE (P>0.1) in the NTG group, while these sectorial mean and maximum cup depths were significantly greater in the GE than in the NE in the POAG group (P<0.003). (See Table)
Conclusions: :
Significantly less change in the morphology of LC pore and the cup depths of optic nerve head were revealed in the NTG than in the POAG group. This suggests that intraocular pressure-independent pathogenic factors may be involved in NTG.
Keywords: lamina cribrosa • optic disc • intraocular pressure