Myopia and diabetes mellitus as modificatory factors of glaucomatous optic neuropathy

Abstract

Myopic deformation of the eye and metabolic alterations of the nerve tissue of patients with diabetes may modify glaucomatous optic neuropathy (GON). Blockage of axonal transport of neurotrophic factors (NTFs) is the event crucial to understanding the factors that affect GON. The primary, but not sole, blockage site is at the lamina cribrosa (LC). Other than this primary site of damage at the LC, 7 other factors may explain atypical nerve fiber layer (NFL) defects and the vulnerability of the nerve fibers in eyes with high myopia and glaucoma: a second point of blockage at the edge of the posterior scleral foramen; ectatic strain on the NFL; ectasia and distortion of the LC; association of a hypoplastic optic disc; thin and weak collagen fibers; peripapillary chorioretinal atrophy; and myopic neuropathy. Among diabetic patients, diabetic neuropathy in the retinal NFL is present initially, and increased resistance to aqueous outflow leads to ocular hypertension. Superimposition of GON on diabetic neuropathy and ocular hypertension in patients with diabetes may enhance their susceptibility to nerve damage. Results of a meta-analysis study suggested a positive association between diabetes mellitus and glaucoma whereas other reports suggested that leakage of vascular endothelial growth factor, a survival mechanism of ischemic neural tissue, and enhanced stiffness of the LC as a result of diabetic glycation may protect neurons from apoptosis. Thus, modification of GON as a result of diabetes remains controversial.

Social, health and ocular factors associated with primary open‐angle glaucoma amongst Chinese Singaporeans

“…Interestingly, studies that have reported myopia as a risk factor for POAG were mostly based on Asian populations, with a minority involving White and African populations . Myopia may predispose to POAG as the elongated myopic eye has reduced physical support for retinal ganglion cells . Additionally, hypoxia from peripapillary choroidal atrophy in myopia may accelerate glaucomatous nerve damage …”

“…Myopia may predispose to POAG as the elongated myopic eye has reduced physical support for retinal ganglion cells . Additionally, hypoxia from peripapillary choroidal atrophy in myopia may accelerate glaucomatous nerve damage …”

“…17 Myopia may predispose to POAG as the elongated myopic eye has reduced physical support for retinal ganglion cells. 18 Additionally, hypoxia from peripapillary choroidal atrophy in myopia may accelerate glaucomatous nerve damage. 18 Our study did not demonstrate a significant association between medical comorbidities such as cardiovascular risk factors, migraine or thyroid disease.…”

“…18 Additionally, hypoxia from peripapillary choroidal atrophy in myopia may accelerate glaucomatous nerve damage. 18 Our study did not demonstrate a significant association between medical comorbidities such as cardiovascular risk factors, migraine or thyroid disease. Evidence for these associations is inconsistent and contradictory in the literature thus far.…”

Cerebral Blood Flow Alterations in High Myopia: An Arterial Spin Labeling Study

“…This condition also has an elevated rate of ocular complications in the macula, peripheral retina, and optic nerve, and an increase in intraocular pressure (IOP) often accompanies it [7,8]. Additionally, HM is an independent risk factor for glaucoma and is frequently associated with atypical retinal nerve fiber layer (RNFL) defects and nerve vulnerability [9,10]. Glaucoma, characterized by retinal impairment, has been found to be accompanied by cortical metabolism alterations [11], abnormal neuronal activity [12], and brain tissue loss [4,13,14].…”