Abstract
Purpose :
To examine the histological characteristics of myopic parapapillary beta zone and of macular retinal pigment epithelium (RPE) defects in myopic macular patchy atrophies, and their differentiation from glaucomatous parapapillary beta zone.
Methods :
Using light microscopy, we histomorphometrically examined human enucleated eyes.
Results :
The histomorphometric study included 17 eyes (17 patients; mean age: 70.5±13.5 years; axial length:26.6±3.6mm;range:22.0-32.0mm), differentiated into a group of glaucomatous, non-highly myopic eyes (axial length <26mm;n=8) and highly myopic eyes (axial length ≥26mm;n=9). The prevalence (8/8 versus 1/9;P<0.001) and length (21±62µm versus 367±163µm;P<0.001) of parapapillary alpha zone was lower, prevalence of parapapillary drusen of the retinal pigment epithelium (4/8 versus 0/9;P<0.01) was higher, and Bruchs membrane (BM) was thicker (5.1±3.9µm versus 2.7±1.2µm;P=0.07) in the glaucomatous group versus the highly myopic group. BM thickness did not differ significantly in the region peripheral to alpha zone and beta zone between both groups (2.82±0.45µm versus 2.55±0.45µm;P=0.33), as did the RPE cell density outside of alpha/beta zone (11.8±7.7 cells/unit versus 16.5±5.5 cells/unit;P=0.28). RPE density was significantly lower in alpha zone than in the region peripheral to alpha zone (8.0±8.4 cells/unit versus 14.7±6.6 cells/unit;P=0.008).
Conclusions :
In the parapapillary region, glaucomatous beta zone differs from myopic beta zone by the presence and size of a surrounding alpha zone and a thicker BM in beta zone, while both types of beta zone did not differ significantly in the RPE cell density outside of alpha/beta zone. These findings may be of interest to discuss the etiology of glaucomatous versus myopia parapapillary beta zone.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.