Longitudinal analysis of retinal nerve fiber layer and ganglion cell-inner plexiform layer thickness in ethambutol-induced optic neuropathy.
OBJECTIVE
The aim of the study was to evaluate longitudinal analysis of peripapillary retinal nerve fiber layer (RNFL) and perifoveal ganglion cell-inner plexiform layer (GCIPL) thickness in patients being treated with ethambutol (EMB).


METHODS
This prospective longitudinal cohort study enrolled 37 patients who were treated with EMB for pulmonary tuberculosis. Best-corrected visual acuity, color vision test, automated perimetry, fundus photography, and RNFL and GCIPL thickness were measured at baseline and at 4 and 6 months after the start of EMB treatment, using Cirrus optical coherence tomography.


RESULTS
Among 37 patients, EMB-induced optic neuropathy occurred in one patient (2.7 %). In this patient, thickening of the RFNL and thinning of the GCIPL were noted at the onset of symptoms. After discontinuation of EMB, RNFL and GCIPL thickness progressively normalized. Changes in RNFL and GCIPL thickness were not statistically significant in the 36 patients who did not exhibit EMB-induced optic neuropathy-related symptoms during follow-up (all P values > 0.05).


CONCLUSIONS
Thickening of the peripapillary RNFL and thinning of the perifoveal GCIPL is an effective quantitative and early marker for diagnosis of EMB-induced optic neuropathy.
Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea.
Jinu
J
Han
Division of Pulmonology, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Min Kwang
MK
Byun
Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea.
Junwon
J
Lee
Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea.
So Young
SY
Han
Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea.
Jong Bok
JB
Lee
Department of Ophthalmology, Severance Hospital, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea. shhan222@yuhs.ac.|Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 135-720, Korea. shhan222@yuhs.ac.
Sueng-Han
SH
Han
D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000009:adverse effects*; D055253:Color Vision / Q000502:physiology; D004977:Ethambutol / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000139:chemically induced* / Q000175:diagnosis*; D011446:Prospective Studies; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests
D000995:Antitubercular Agents; D004977:Ethambutol
Ethambutol-induced optic neuropathy; Ganglion cell–inner plexiform layer; Mitochondrial optic neuropathy; Retinal nerve fiber layer