Association between Lamina Cribrosa Position Change and Glaucomatous Visual Field Progression

Abstract

 

Purpose

 

To investigate the association between longitudinal lamina cribrosa (LC) position change and the rate of glaucomatous visual field (VF) progression.

 

Methods

 

Glaucoma patients at various disease stages were recruited. Serial vertical enhanced depth imaging (EDI) optical coherence tomography (OCT) B-scans of the optic nerve head were obtained for one eye of participants (interval between scans, ~30 μm) at baseline and at a follow-up visit after 2 years. Three LC depths (reference plane, Bruch’s membrane edges) were measured in the midline vertical B-scan of the optic nerve head (Fig 1) and averaged to generate the mean LC depth of the eye. Standard automated perimetry (Humphrey Field Analyzer II, 24-2 SITA-standard program, Carl Zeiss Meditec, Inc., Dublin, CA) was performed at baseline and at 2- to 6-month intervals thereafter. For each eye, a slope of VF mean deviation (MD) over time was calculated in decibels per year (dB/yr) using reliable VFs. Eyes with fewer than 5 VFs were excluded. Mean LC depth change (‘LC depth at follow-up’ - ‘LC depth at baseline’) was correlated with MD slope, intraocular pressure (IOP) change (‘follow-up IOP’ - ‘baseline IOP’), and baseline MD.

 

Results

 

43 eyes (43 subjects) were included. Baseline age, IOP, VF MD and LC depth were 62±14 years, 14.7±4.1 mmHg, -8.25±9.34 dB and 501±141 µm, respectively. Mean follow-up period, number of VFs and MD slope were 26.8±2.2 (range, 24.0 to 30.9) months, 5.4±0.8 (range, 5 to 8) and -0.47±0.70 (range, -2.30 to 0.41) dB/yr, respectively. In a univariate model, LC depth change correlated significantly with MD slope and IOP change (R=-0.454 and 0.564, respectively; all p<0.003), but not with baseline MD (p=0.105) (Fig 2). In a multivariate model, LC depth still correlated significantly with MD slope and IOP change (R=-0.385 and 0.517, respectively; all p<0.013).

 

Conclusions

 

Greater IOP reduction induced larger anterior repositioning of the LC. Eyes with larger anterior LC repositioning had slower VF progression.