Longitudinal evaluation of visual function and structure for detection of subclinical Ethambutol-induced optic neuropathy

• Published in: PloS one 2019-04, Vol.14 (4), p.e0215297
• Main Authors: Jin, Ki Won, Lee, Joo Yeon, Rhiu, Soolienah, Choi, Dong Gyu
• Format: Article
• Language: English
• Subjects: Acuity; Adolescent; Adult; Aged; Aged, 80 and over; Antitubercular agents; Biology and Life Sciences; Care and treatment; Cataracts; Clinics; Coherence (Optics); Color; Color Perception - drug effects; Color sensitivity; Color vision; Consent; Contrast Sensitivity - drug effects; Defects; Drug dosages; Drugs; Ethambutol; Ethambutol - administration & dosage; Ethambutol - adverse effects; Eye; Eye (anatomy); Female; Humans; Identification methods; Internal medicine; Longitudinal Studies; Male; Medical research; Medicine; Medicine and Health Sciences; Middle Aged; Neuropathy; Optic neuropathy; Optical Coherence Tomography; Optics; Patients; Photography; Research and Analysis Methods; Retina; Retrospective Studies; Risk analysis; Risk factors; Sensitivity; Social Sciences; Structure-function relationships; Thickness; Time Factors; Tomography; Tomography, Optical Coherence; Toxic Optic Neuropathy - diagnostic imaging; Toxic Optic Neuropathy - pathology; Toxic Optic Neuropathy - physiopathology; Toxicity; Tuberculosis; Tuberculosis - diagnostic imaging; Tuberculosis - drug therapy; Tuberculosis - pathology; Tuberculosis - physiopathology; Visual acuity; Visual field; Visual Field Tests; Visual fields; Visual impairment; Visual perception
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0215297

To longitudinally evaluate the visual function and structure of patients taking ethambutol by various modalities and identify useful tests for detection of subclinical ethambutol-induced optic toxicity. This retrospective study enrolled 84 patients with newly diagnosed tuberculosis treated with ethambutol. Best-corrected visual acuity (BCVA), color vision, contrast sensitivity, fundus and retinal nerve fiber layer (RNFL) photography, automated visual field (VF) test, and optical coherence tomography (OCT) were performed: prior to starting; every month during administration, and 1 month after stoppage. We longitudinally compared visual function and structure with the baseline and identified the occurrence of subclinical toxicity. BCVA, color vision, and contrast sensitivity showed no change from the baseline. Mean temporal RNFL thickness was significantly increased at 6 months (p = 0.014). Subclinical toxicity was found in 22 eyes of 14 patients (i.e., 13% of 168 eyes), in the forms of VFI decrease (VF index, 9 eyes of 6 patients), quadrant RNFL thickness increase (5 eyes of 4 patients), and VF pattern defect (12 eyes of 6 patients). 73% of the patients showed recovery to the baseline at 1 month post-stoppage. The risk factors for occurrence of subclinical toxicity were age, cumulative dose, and medication duration. Mean temporal RNFL thickness increased after administration. The VFI, quadrant RNFL thickness, and VF pattern defect could prove useful in assessment of subclinical toxicity. Medication duration was shown to be a strong risk factor for occurrence of subclinical toxicity.