Objective: To evaluate the appearance of the optic nerve head in chronic high-pressure glaucoma and normal-pressure glaucoma.
Design: Clinic-based cross-sectional study.
Participants: The study included 52 eyes with normal-pressure glaucoma and 28 eyes with juvenile-onset primary open-angle glaucoma that served as models for chronic high-pressure glaucoma.
Methods: Color stereo optic disc photographs and wide-angle retinal nerve fiber layer photographs were morphometrically examined.
Main outcome measures: Localized retinal nerve fiber layer defects; parapapillary chorioretinal atrophy; disc hemorrhages; optic cup shape; retinal arteriole narrowing.
Results: Both study groups did not vary significantly in count of localized retinal nerve fiber layer defects, size of parapapillary atrophy, optic cup depth, steepness of disc cupping, rim/disc area ratio, diameter of retinal arterioles, and frequency and degree of focal retinal arteriole narrowing. In normal-pressure glaucoma versus juvenile open-angle glaucoma, localized retinal nerve fiber layer defects were significantly broader, disc hemorrhages were found significantly more often and were larger, and neuroretinal rim notches were present more frequently and were deeper.
Conclusions: Chronic high-pressure glaucoma and normal-pressure glaucoma show morphologic similarities in the appearance of the optic nerve head. The lower frequencies of detected disc hemorrhages and rim notches in high-pressure glaucoma may be due to a smaller size of hemorrhages and localized retinal nerve fiber layer defects in high-pressure glaucoma. Both glaucoma types have morphologic features in common, suggesting that they may possibly belong to a spectrum of the same pathologic process.