Knowledge, Attitudes, and Practices Toward Drug-Induced Visual Impairment Due to Antitubercular Therapy Among Medical Officers of Primary Health Care Centers in Karnataka, South India

Purpose: Ethambutol, a key first-line drug used in fixed-dose combinations for tuberculosis (TB) treatment, is associated with a well-known adverse effect, optic neuropathy, that can result in irreversible vision loss. Despite this risk, in high-burden countries such as India, the primary emphasis remains on disease elimination, often leading healthcare professionals to overlook the potential for serious vision-related side effects of ethambutol. This study sought to evaluate the knowledge, attitudes, and practices (KAPs) of medical officers at primary health centers (PHCs) in Karnataka regarding visual impairment caused by antitubercular therapy (ATT). Methods: A questionnaire-based, prospective, observational, cross-sectional study was conducted. Participants were recruited via a convenience sampling approach from PHCs in Karnataka. The data were analysed via IBM SPSS version 27. Results: Seventy-three medical officers responded to the questionnaire within the set period. Of these, 34.2% (25) were specialists, whereas 65.8% (48) were general practitioners. A majority (91.8%; 67) of the medical officers were actively involved in the diagnosis and treatment of TB patients, and 72.6% (53) of the medical officers claimed to have undergone a sensitisation program. A total of 75.3% (55) of the participants were aware of the visual complications of ATT. However, 69.9% (51) had never referred a patient with drug-induced visual impairment. A majority (95.9%) of the participants thought that there was a need for better awareness campaigns, and 91.8% of them felt that regular ophthalmic evaluations should be mandatory for patients on ATT. The mean KAP scores of specialists were significantly greater than those of general practitioners (p=0.002 unpaired t test), indicating better knowledge and practices among them. Conclusion: The medical officers of PHCs in Karnataka believe that grassroots-level training, increased awareness, mandatory visual screening of visual function by a physician or optometrist at every PHC, and prompt referrals to tertiary care centers can help address the challenges in identifying drug-induced visual impairment. Keywords: tuberculosis, adverse drug reaction, ethambutol, drug toxicity, optic neuropathy