Abstract
Purpose :
To characterize variations of anterior lamina cribrosa surface (ALCS) shape with elevated fixation IOP, age, and race.
Methods :
124 eyes of normal human donors of European (ED, n=74 eyes) and African descent (AD, n=50) were collected within 6h postmortem. Eyes from 37 donors were bilaterally pressurized with saline at 10mmHg for 30 min then fixed at pressure with 2% glutaraldehyde/1% paraformaldehyde through vitreous infusion and immersion. Eyes of 25 donors were pressurized and fixed at 10mmHg and 45mmHg in the right and left eyes respectively. The optic nerve head (ONH) was trephined from the globe and digitally reconstructed at an isotropic 1.5μm voxel resolution with an automated episcopic fluorescence technique. The ONH tissue surfaces were delineated using custom software. Differences in the morphometric parameters associated with the differential fixation IOP, age, and race were analyzed by generalized estimating equations (GEEGLM package–R) adjusting for intradonor correlations of the regression residuals. In particular, ALCS bowing was defined as the difference in central and peripheral ALCS depth with respect to the anterior scleral canal opening reference plane.
Results :
Differences in the fixation IOP significantly associated with increase in ALCS depth only in the EDs (21.9mm, p=0.0382, Figure, top). Canal opening radius was not associated with elevated fixation IOP (p=0.8). ALCS was differentially associate with age and race, showing an increased bowing at a rate of 1.2 mm/year in the AD group (p<0.001) and a flattening of -0.3 mm/year in the ED group (p=0.1689, Table, Figure, bottom). A thinner LC corresponded a more bowed ALCS (p<0.001, Table),
Conclusions :
Increased bowing of the LC was seen at higher fixation IOP in eyes of ED donors. Increased bowing of the LC was associated a thinner LC and increasing age in eyes from AD donors, suggesting greater age-related remodeling of the ONH connective tissue in this group.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.