Abstract
Purpose :
POAG is characterized by an increased excavation of the optic nerve head (ONH) while segmental or diffuse pallor without cupping is the typical ONH appearance after NAION. RNFL thinning is to be expected in both patient groups in a similar amount, which should not be true for ONH parameters. In the present study Bruch‘s membrane opening based minimal rim width (BMO-MRW), which has been introduced as anatomically and geometrically accurate neuroretinal rim parameter with a higher diagnostic accuracy for glaucoma, as well as circumpapillary RNFL thickness values have been compared between the two patient groups, POAG and NAION.
Methods :
A sample of age-matched 20 healthy control subjects, 20 moderate to severe POAG and 20 NAION patients (>6 months after the event) with comparable visual field defects regarding mean deviation (MD) and localization (hemisphere) of the defect, underwent SD-OCT (Spectralis®) measurements of the ONH and the circumpapillary area. BMO-MRW and RNFL thickness were compared between the groups using ANOVA and post-hoc t-tests.
Results :
ANOVA showed statistically significant differences between groups for both parameters (p<0.001). Both glaucoma and NAION patients showed significantly smaller RNFL thickness values compared to healthy subjects in t-tests (p < 0.001), while only the glaucoma patients showed significantly smaller BMO-MRW values compared to healthy subjects (p<0.001), see table 1.
Conclusions :
Atrophic ONHs after an attack of NAION have similar RNFL thickness values as do glaucomatous eyes with the same severity of visual field damage, whereas MRW parameters in NAION eyes were similar to those seen in healthy controls. This difference might help discriminating these conditions.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.