Changes in the retinal-nerve-fiber layer due to ethambutol toxic optic neuropathy

Author: Richard G. Kho ; Heriberto G. Guballa ; John Michael L. Daquioag ; Christopher Napoleon G. Delos Reyes
Publication Type:Case Reports
MeSH: Tomography Optical Coherence
From: Philippine Journal of Ophthalmology 2009;34(1):23-27
CountryPhilippines
Language:English
Abstract: Objective: To describe changes in the retinal-nerve-fiber layer (RNFL) in patients diagnosed with ethambutol toxic optic neuropathy (ETON) using optical coherence tomography (OCT). Methods: Ophthalmological examinations were performed in 3 patients diagnosed with ETON. Visual acuity (VA), contrast sensitivity, color vision testing, slitlamp examination, applanation tonometry, dilated funduscopic examination, fundus and disc photography, automated perimetry and OCT were performed. Results: Three patients with ETON had VA ranging from 20/150 to counting fingers (CF). They were unable to resolve contrast sensitivity and discriminate fingers (CF). TWo patients with VA of CF in both eyes had RNFL thinning of 48.8% and 49.5%. A third patient 3 with VA of 20/150 in both eyes showed RNFL thickening of 14.10%. Conclusion: The results suggest that OCT may be useful ancillary procedure in early detection and monitoring of ophthalmological changes due to ETON.