In Vivo Three-Dimensional Lamina Cribrosa (LC) Microarchitecture in Healthy Subjects Using Adaptive Optics Spectral-Domain Optical Coherence Tomography (AO-SDOCT)

Abstract

 

Purpose

 

To characterize the in vivo 3D LC microarchitecture of healthy eyes using AO-SDOCT.

 

Methods

 

A multimodal retinal imaging system (Physical Sciences Inc, Andover, MA) which includes AO-SDOCT with a 1050nm light source and AO confocal scanning laser ophthalmoscopy (AO-CSLO) was used in this study. One randomly selected eye from each of 32 healthy subjects was scanned in a 6°x6° window centered on the LC. Subjects also underwent scanning with Cirrus HD-OCT (Zeiss, Dublin, CA). Scans with poor scan quality or movement artifact were excluded from analysis. LC microarchitecture was semi-automatically segmented and quantified for beam and pore structure using a previously described method (PMID: 24298418). Disc delineations automatically output from Cirrus scans were used to divide the LC into quadrants and into central and peripheral regions of equal areas. Microarchitecture was also considered with depth by dividing the LC into anterior, middle, and posterior thirds. A paired t-test weighted by the fraction of LC visible was used to compare structure between regions.

 

Results

 

The study population included 18 females and 14 males (18 OD, 14 OS) with a mean age of 40.7±16.9 years. After quality exclusion, 17 eyes qualified for analysis (53.1%). LC microarchitecture measurements are summarized in the Table. The nasal quadrant was excluded due to poor visualization. The central sector showed greater connective tissue volume fraction (CTVF) and thicker beams as compared to the periphery. There was no statistically significant difference between superior and inferior quadrants. Both superior and inferior quadrants showed greater CTVF , beam thickness and pore thickness than the temporal quadrant. CTVF decreased at greater depths (p<0.05), while the middle third showed the greatest beam thickness (p<0.01).

 

Conclusions

 

In vivo analysis of healthy eyes using AO-SDOCT showed significant, albeit small, regional variation in LC microarchitecture by quadrant, radially, and with depth, which should be considered in further studies of the LC.

 

 

Regional measurement means for LC microarchitecture

 

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