Comparison of Optic Nerve Head Morphology in Patients with Primary Open Angle Glaucoma and Non-Arteritic Anterior Ischemic Optic Neuropathy

Abstract

SUMMARY -Th e aim of this study was to assess damage to retinal ganglion cells (RGC) and morphology of the optic nerve head (ONH) in patients with primary open angle glaucoma (POAG) and non-arteritic anterior ischemic optic neuropathy (NAION). Th e study included three groups of patients, as follows: 40 eyes with POAG, 40 eyes with NAION and 40 eyes with refraction anomaly. All patients underwent standard automated perimetry and analysis of ONH topography by using confocal scanning laser ophthalmoscopy (CSLO)-HRT II. Visual fi eld defects such as decreased retinal sensitivity prevailed in the eyes with POAG, whereas in the eyes with NAION they were mostly manifested as concentrically narrowed visual fi eld and quadrant excesses. Topographic ONH alterations, examined by HRT II, showed the same number of sectors to be aff ected in the eyes with POAG and NAION. A larger number of sectors in the upper part of ONH were aff ected in the eyes with NAION. Optic disc morphology diff ered signifi cantly between the eyes with POAG and NAION by a higher rate of neuroretinal rim thinning and higher mean cup depth in the POAG group.

Quantitative analysis of the optic nerve head parameters in patients with age-related macular degeneration

“…Recently, confocal scanning laser ophthalmoscopy has become popular because it allows quantitative analysis of the optic nerve head. This scanning method is frequently used for diagnosing and monitoring glaucoma, optic nerve pathologies, and various retinal diseases [18][19][20]. In the present study, the cup-to-disc ratio was higher in the patients with neovascular and nonneovascular AMD than in the control subjects, which was in contrast to that reported by the EDDC study group.…”

“…Recently, confocal scanning laser ophthalmoscopy has become popular because it allows quantitative analysis of the optic nerve head. This scanning method is frequently used for diagnosing and monitoring glaucoma, optic nerve pathologies, and various retinal diseases [18][19][20].…”

Differentiating ischemic optic neuropathy from glaucoma using diagnostic tests

“…Optic Nerve Head Clear differences in ONH parameters were identified through OCT (and HRT) imaging: glaucomatous eyes had a greater cup area, C/D ratio, cup volume, and cup depth and a lower (vertical) rim volume and rim area compared to AION eyes [9,11,12,14,17,21,40]. Danesh-Meyer et al [17] presented a hypothesis that both OAG and AION result in damage to the prelaminar and laminar zone of the ONH but at a different degree of severity and with a different preference for damaging specific structures.…”

“…Two of them used VF perimetry, HRT, color fundus photography, and GDx [12,14], and another study used CDI to examine hemodynamic parameters [50]. Two studies examined morphological ONH differences by HRT II and concluded that NAION eyes showed significantly lower cup area, C/D ratio, and mean cup depth, whereas NRR and rim area were significantly greater compared to OAG eyes [12,14]. A larger number of sectors affected in the upper part of ONH in NAION than in POAG eyes were also identified.…”

“…Ischemic optic neuropathies can be broadly classified as anterior or posterior, with anterior ischemic optic neuropathy (AION) being by far the most prevalent. AION is a neuro-ophthalmologic condition that is caused by occlusion in one (or more) of the ciliary arteries in the optic nerve head (ONH), resulting in acute (monocular) vision loss, and is often accompanied by an altitudinal VF defect (VFD) [12][13][14]. Although the exact etiopathogenesis of nonarteritic AION (NAION) is still unclear, risk factors such as an anatomically crowded ONH, nocturnal hypotension, local thrombosis, or atherosclerosis of the circulation may contribute to the hypoperfusion of the optic nerve [15].…”