Optical coherence tomography can measure axonal loss in patients with ethambutol-induced optic neuropathy

Abstract

The OCT results in these patients with EMB-induced optic neuropathy show considerable loss especially of the temporal fibers. This is consistent with prior histopathological studies that show predominant loss of parvo-cellular axons (or small-caliber axons) within the papillo-macular bundle in toxic or hereditary optic neuropathies. OCT can be a valuable tool in the quantitative analysis of optic neuropathies. Additionally, in terms of management of EMB-induced optic neuropathy, it is important to properly manage ethambutol dosing in patients with renal impairment and to achieve proper transition to a maintenance dose once an appropriate loading dose has been reached.

The Expression of TAG-1 in Glial Cells Is Sufficient for the Formation of the Juxtaparanodal Complex and the Phenotypic Rescue of Tag-1 Homozygous Mutants in the CNS

“…The loss of small caliber axons observed in Tag-1 Ϫ/Ϫ mice is a common feature in various types of metabolic optic neuropathies in humans, where degeneration of the optic nerve takes place (Saadati et al, 1998;Carelli et al, 2002;Zoumalan et al, 2005). The small caliber axons in the optic nerve fire at rapid rates and are thinly myelinated.…”

Multifocal electroretinography changes in patients on ethambutol therapy

“…Studies using optical coherence tomography have also shown that ethambutol therapy is associated with reduction in the retinal nerve fibre layer thickness, suggestive of retinal ganglion cell loss. 21,22 On the basis of these evidence, it is likely that ethambutol not only affects the optic nerve but also causes retinal changes, causing a neuroretinopathy.…”

Tobacco–alcohol amblyopia: can OCT predict the visual prognosis?

“…1 TAA belongs to the larger class of toxic/nutritional optic neuropathies in which the primary insult is to the mitochondria that disrupts the process of oxidative phosphorylation resulting in axonal loss, preferentially in the fast-firing, parvocellular neurons within the papillomacular bundle. [1][2][3][4] Increased RNFL thickness has been reported in TAA and may occur because of axonal swelling and intraretinal fluid accumulation in the acute phase of visual loss. 4 following cessation of toxic insult and vitamin B12 supplementation correlated with improvement in visual function.…”

“…Clefts typically occur after trauma or intraocular surgery and may be complicated by a shallow anterior chamber, hypotony, and maculopathy. 1 Slit-lamp-adapted optical coherence tomography (SL-OCT) is a light-based, noninvasive non-contact method of obtaining cross-sectional images of the anterior segment that provides rapid and objective information on the anterior segment dimensions and angle configuration. 2,3 We used SL-OCT (1310-nm diode laser, optical axial image resolution o25 mm, and lateral resolution of 20-100 mm; Heidelberg Engineering GmbH, Dossenheim, Germany) to detect a cyclodialysis cleft, and accompanying ciliochoroidal effusion after blunt trauma in an 8-year-old child.…”