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Akram Belghith, Christopher A Girkin, Robert N Weinreb, Felipe Medeiros, Christopher Bowd, Jeffrey M Liebmann, Massimo Antonio Fazio, Linda M Zangwill; The African Descent and Glaucoma Evaluation Study (ADAGES): Racial differences in the posterior displacement of the anterior laminar cribrosa surface depth. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4015.
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The lamina cribrosa (LC) is considered to be a primary site of axonal injury in glaucoma. Several studies have shown that eyes with glaucoma often have deformities of the LC in particular posterior LC displacement. The objective of this report is to assess the change in depth of the anterior laminar cribrosa surface (ALCSD) over time in healthy and glaucoma eyes of individuals of European (ED) and African descent (AD).
A total of 295 eyes, including 120 healthy eyes (60 AD and 60 ED) and 175 glaucoma eyes (93 AD and 82 ED) were followed for an average of 3 years. Enhanced-depth imaging (EDI) Spectralis OCT (Heidelberg Engineering) optic nerve head scans were acquired using 48 equally spaced radial scan lines, each with 1024 A-scans. The San Diego Automated Layer Segmentation Algorithm (SALSA) was used to estimate ALCSD (the ALCSD was measured at each B-scan, and defined as the average distance from the Bruch's membrane opening level to the anterior LC surface). Eyes were classified as glaucomatous if they had 3 repeatable abnormal standard automated perimetry results. Multivariable mixed effects models were used to estimate the rate of change after controlling for age, axial length, IOP and optic disc size.
In healthy eyes, no racial differences in the rate of age-related change in ALCSD were observed. In multivariable analysis of OAG eyes, the rate of change of ALCSD was faster in ED than AD eyes: 3.5 μm/year and 2.1 μm/year, respectively (p =0.02, see Figure). Because IOP change can have a strong influence on ALCSD, we included acceleration of IOP change over time (second derivative of IOP over the whole follow-up time) in the multivariable model. There was no effect of the IOP fluctuation on change in ALCSD in AD (p =0.59) but it was statistically significant in ED (p=0.03). In glaucoma eyes, SAP MD (-7.27± 7.12 and -8.22±7.54 dB) , axial length (23.7± 2.7 and 23.9±0.8 mm) and optic disc size (2.08± 0.48 and 2.3±2.3 mm2) were similar in the ED and AD groups at baseline (p ≥0.05) respectively. However, ED subject were significantly older (70.8±8.7 vs 65.6±1.25 years, p =0.002).
Posterior displacement of ALCS was observed in both ED and AD glaucoma eyes but with different amplitudes. These results suggest that lamina cribrosa rigidity may be different in AD and ED glaucoma eyes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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