Comparison of lamina cribrosa thickness in normal tension glaucoma patients with unilateral visual field defect.

PURPOSE

To compare the lamina cribrosa thickness, measured by swept-source optical coherence tomography (SS OCT), between each eye of normal tension glaucoma (NTG) patients with unilateral visual field (VF) defect and to investigate the correlation between lamina cribrosa thickness and VF loss.

DESIGN

Prospective, cross-sectional study.

METHODS

Optic nerve heads were scanned using SS OCT, and laminar thickness was measured on mid-superior, central, and mid-inferior regions of vertical midline of the optic disc. The inter-eye differences of lamina cribrosa thickness in NTG patients with unilateral VF defect and the intra-eye difference of lamina cribrosa thickness in VF-affected eyes were analyzed using the paired t test. We evaluated the correlation between lamina cribrosa thickness and mean deviation, measured using standard automated perimetry, in NTG patients.

RESULTS

This study included 102 eyes in 51 NTG patients with unilateral VF defect and 47 eyes in 47 normal subjects without glaucomatous change in either eye. The mean lamina cribrosa thickness of normal fellow eyes was thicker than VF-affected eyes in NTG patients (P < .001), but thinner than normal subject eyes (P < .001). Within VF-affected eyes, lamina cribrosa thickness of regions correlated with visual field defect was thinner than horizontally contralateral locations (P < .001). The mean deviation was statistically correlated with inter-eye difference of lamina cribrosa thickness in NTG patients (n = 51; r(2) = 0.12; P = .01).

CONCLUSIONS

The lamina cribrosa was thinner in VF-unaffected eyes of NTG patients than in normal subject eyes, in VF-affected eyes than in normal fellow eyes of NTG patients, and in regions correlated with visual field loss than in horizontally contralateral ones in VF-affected eyes.