Retinal nerve fiber

There has been a report of retinal changes in 60 users of crack (164). Microtalc retinopathy and retinal nerve fiber layer rake or slit defects were detected by threshold visual field testing and fundus photography. 

Rofsky JE, Townsend JC, Ilsen PF, Bright DC. Retinal nerve fiber layer defects and microtalc retinopathy secondary to free-basing crack cocaine. J Am Optom Assoc 1995 66(11) 712—20. 

Preacute signs and symptoms do occur. In some patients atrophy of retinal nerve fibers, an altered Farnsworth-Munsell 100-hue test, and altered visual evoked potentials occur before the actual attack. 

Structural Assessment of the Optic Nerve Head and Retinal Nerve Fiber Layer... 

Assessment of the optic nerve head and retinal nerve fiber layer should occur for all glaucoma patient and glaucoma suspects. 

Indirect ophthalmoscopic assessment of the optic nerve head and retinal nerve fiber layer at the slit lamp should, whenever possible, be augmented by other techniques such as direct ophthalmoscopy, retinal photography, and/or scanning laser ophthalmoscopy. 

An assessment of the optic nerve and retinal nerve fiber layer should include an assessment of the following disc size, shape, symmetry, color, angle, vessels, and extrapapillary features such as the presence of a zone beta. 

Retinal photography is an important adjunctive tool in the assessment of the optic nerve and retinal nerve fiber layer. 

Disc (Drance) hemorrhages and retinal nerve fiber layer defects that are visible with retinal photography can be overlooked during clinical and/or laser ophthalmoscopy. 

Do not expect visual field findings to correspond to the structural assessment of the optic nerve or retinal nerve fiber layer in early glaucoma. 

Microtalc dusting of the retina may represent minute crystalline deposits of crack cocaine s adulterants lodged in the retinal microcirculation, the inner retinal layers, or both. It has been hypothesized that the retinal nerve fiber layer changes seen in these patients may occm from ischemia induced by focal drug-induced vasospasm of the short posterior ciliary arteries. 

Optical coherence tomography uses reflected light in a manner analogous to the use of sound waves in ultrasonography to create computerized cross-sectional images of the retina and optic disc, and also gives quantitative information about the peripapillary retinal nerve fiber layer thickness. 

Emerging tests include retinal nerve fiber analyzers or confo-... 

The optic nerve head is the portion of the optic nerve observed in the fundus formed by the meeting of all the retinal nerve fibers. The lamina cribrosa is a thin sieve-like membrane composed of neuroglia and connective tissue that bridges the posterior scleral foramen and is continuous with the choroid and the deepest third of the sclera. Fiber bundles of the optic nerve pass through the perforations of the lamina cribrosa toward the optic chiasm. Because glycosaminoglycans and... 

Satue, M., et al. Use of Fourier-domain OCT to detect retinal nerve fiber layer degeneration in Parkinson s disease patients. Eye 27(4), 507-514 (2013)... 

Four children who had been exposed to vigabatrin in utero all had normal visual fields and retinal nerve fiber layer thicknesses, suggesting that vigabatrin does not cause visual toxicity in children exposed to vigabatrin prenatally [435 J. 

In a prospective evaluation of various visual parameters for early detection of ethambutol toxicity in 52 patients with tuberculosis attending a Directly Observed Treatment Strategy Centre [67 visual acuity, visual fields, visual-evoked responses, stereoacuity, and retinal nerve fiber layer thickness on optical coherence tomography were assessed after 1 and 2 months of treatment, and 1 month after withdrawal. There was no visual functional defect at baseline. On follow-up, visual acuity, color vision. 

---