Visual function in recovered ethambutol optic neuropathy.
The visual acuity of the patient with ethambutol optic neuropathy will recover within 3 to 4 months after discontinuing the drug. We studied the extent of the recovery of other visual functions. Thirty-six axial type ethambutol optic neuropathy patients, who visited our neuro-ophthalmology clinic from January, 1990, to December, 1993, were included in this study. Fifteen patients (29 eyes) regained their visual acuity to better than 1.0. The average follow-up period following the recovery is 21.7 months. Pattern reversal VEP, Farnsworth-Munsell 100-Hue color vision test, critical flicker frequency (CFF), visual field perimetry, contrast sensitivity and edge-light pupil cycle time were assessed for every affected eye. Latency (P100) of visually evoked potential was delayed in 34.5% (10/29) of eyes. In color vision, 48.3% (14/29) of eyes had deutan or tritan defect. An abnormality of red CFF with value lower than 31 Hz was revealed 51.7% (15/29) eyes. In the visual field, 58.6% (17/29) of eyes had paracentral scotoma, arcuate scotoma, or enlargement of physiologic blind spot. Contrast sensitivity was depressed in 62.1% (18/29) of eyes, mainly at middle and low spatial frequency. Pupil cycle time was prolonged in 72.4% (21/29) of eyes. Aside from visual acuity, other visual functions of the recovered ethambutol optic neuropathy patients were incomplete. The extent of recovery of the visual function is as follows: visual acuity-VEPs-color sense-CFF-visual field-contrast sensitivity-pupil cycle time.
Woung
L C
LC
Department of Ophthalmology, National Taiwan University School of Medicine, Taipei, Republic of China.
Jou
J R
JR
Liaw
S L
SL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000995:Antitubercular Agents / Q000009:adverse effects*; D003118:Color Perception / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology; D004977:Ethambutol / Q000009:adverse effects*; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D005425:Flicker Fusion / Q000502:physiology; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009901:Optic Nerve Diseases / Q000139:chemically induced / Q000503:physiopathology*; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology*; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology
D000995:Antitubercular Agents; D004977:Ethambutol