Evaluation of Ethambutol Toxic Optic Neuropathy Module as Training Approach for Tuberculosis Directly Observed Treatment Short-course Health Workers in Manila: A Pilot Study

Aim: To determine the effectiveness of the ethambutol toxic optic neuropathy (ETON) module as a training approach and to increase the competency of primary health workers in assessing the visual health of TB DOTS patients.

Methods: Thirty-six (36) TB DOTS sites in Manila were included in the evaluation and were randomly allocated into 2 groups. Group 1 was assigned as the treatment group, received the ETON module, and Group 2, the control group, was provided with information, education, and communication materials only. A questionnaire on knowledge, attitudes, and practices on vision screening was administered before and after intervention. An objective structured clinical examination (OSCE) was also performed. The ETON module and the evaluation process were facilitated by a group of ophthalmologists.

Results: There was a significant difference in the post-intervention knowledge scores for the treatment group (M=9.27, SD=2.191) and control group (M=7.27, SD=3.121) conditions; t(34)=2.22, p = 0.03. No quantifiable change in attitudes between groups was assessed at the time of intervention. There was a significant difference in the increase in practice scores for the treatment group prior to intervention (M=28.3, SD=12.169) and post-intervention (M=56, SD=10.53) conditions; t (34)=-7.30631, p<0.0000001, and there was also significant difference in the increase in practice scores for the control group prior to intervention (M=22.3, SD=5.45) and post-intervention (M=45.9, SD=17.031) conditions; t (34)=-7.30, p<0.0000001. With regard to the implementation of the OSCE, it can be noted that participants from both groups scored least in obtaining the correct Best Corrected Visual Acuity (BCVA) and scored most in straight-forward types of eye-screening tests such as Ishihara Color Vision Test and Amsler Grid. This research showed that participants under the treatment group performed significantly better than the control group.

Conclusion: The ETON Module can be used to improve the standard of care by extending access to visual health services by building the capacities of primary health workers to be a reliable referral pivot point in monitoring ETON among TB patients. This study can be used as a foundation to initiate an expanded primary health services to improve the visual health outcomes for TB patients.

Keywords:Ethambutol; Optic neuropathy; Tuberculosis