In-Vivo Relationship Between 3D Lamina Cribrosa (LC) Microarchitecture and Retinal Nerve Fiber Layer (RNFL) Thickness

Abstract

 

Purpose

 

To investigate the relationship between 3D LC microarchitecture obtained in-vivo using adaptive optics spectral-domain OCT (AO-SDOCT) and RNFL thickness.

 

Methods

 

44 subjects (7 healthy, 6 glaucoma suspect, 31 glaucoma) were scanned using an AO-SDOCT imaging system (Physical Sciences Inc, Andover, MA) and a commercial SDOCT device (Cirrus HD-OCT; Zeiss, Dublin, CA). The AO-SDOCT scans were semi-automatically analyzed (PMID: 24298418) to determine the 3D LC microarchitecture, including the beam thickness and pore diameter of the entire LC, in the central and peripheral regions, and with respect to depth. A linear model was used to determine the association of LC microarchitecture with RNFL thickness (measured by Cirrus), while accounting for age and scan quality, and weighed by the fraction of visible LC.

 

Results

 

Peripheral LC pore diameter was significantly and inversely related to RNFL thickness in the anterior 100μm of LC. Larger peripheral pore diameter (per 1μm) was associated with thinner RNFL by 0.98±0.39μm (p < 0.05) in the anterior most 50μm of the LC and 1.88±0.54μm (p < 0.01) in the 50-100μm depth. LC beam thickness was significantly and inversely related to RNFL thickness in the posterior LC. Larger beam thickness (per 1μm) in the posterior third of the LC was associated with thinner RNFL by 1.05±0.49μm (p < 0.05).

 

Conclusions

 

Thin RNFL is associated with 1) larger pore diameter in the anterior LC, perhaps representing pressure-related stretching in the lateral direction of the LC plane, and 2) larger beam thickness in the posterior LC, perhaps representing glaucoma related remodeling. Further studies are necessary to understand the complex interplay between LC microarchitecture and glaucoma.

 

 

(A) C-mode of the AO-SDOCT of the LC was (B) semi-automatically segmented (beams - cyan, pores - green). The (C) beams structure and (D) beam thickness (brighter color indicates thicker) of the same eye is shown in 3D. (E) While there was no significant change in beam thickness with RNFL in the anterior LC (red), a negative trend is visible in the posterior LC (blue). (F) The opposite is seen in the pore diameter in the peripheral LC, which changed with RNFL in the anterior LC (red), but not the posterior LC (blue).

 

Keywords: 550 imaging/image analysis: clinical • 577 lamina cribrosa