Posterior displacement of the lamina cribrosa in glaucoma: in vivo interindividual and intereye comparisons

Abstract

Purpose: We assessed in vivo lamina cribrosa (LC) position within the optic nerve head in glaucoma.

Methods: For interindividual comparison, glaucoma patients at various stages and normal subjects were recruited. For intraindividual, intereye comparison, glaucoma patients with visual field (VF) defects in only one eye were recruited separately. Serial horizontal and vertical enhanced depth imaging optical coherence tomography (EDI OCT) B-scans of the optic nerve head were obtained prospectively from each participant. Mean and maximum anterior LC depths were measured in 11 equally spaced horizontal B-scans, excluding the LC insertion area under the Bruch's membrane and scleral rim.

Results: Totals of 47 glaucomatous eyes (47 patients; VF mean deviation, -12.7±8.2 dB) and 57 normal eyes (57 subjects) were enrolled for the interindividual comparison. Mean and maximum LC depths were significantly greater in the glaucomatous than in the normal eyes in all 11 scans (all P<0.03). There were 54 glaucoma patients with VF defects in only one eye (VF mean deviation, -15.6±8.8 dB) included in the intereye comparison. Mean and maximum LC depths were significantly greater in the eyes with VF defects than in the fellow eyes with no VF defects in all 11 scans (all P<0.01).

Conclusions: The central and midperipheral LC is located more posteriorly in glaucomatous than in normal eyes, as well as in eyes with VF defects compared to fellow eyes with no VF defects. These results support the concept of posterior LC displacement in glaucoma and provide the basis for future in vivo human studies.

Keywords: glaucoma posterior segment; lamina cribrosa; optical coherence tomography.