Diminuição da sensibilidade ao contraste espacial de luminância em sujeitos com história de uso de terapia medicamentosa anti-tuberculose

Abstract

The drugs isoniazid and ethambutol, usually administed for tubercolosis treatment, are well known to cause damage in the visual system of the patients that use them. As vision is an important sense for the quality of life and the luminance contrast is considered a good biomarker for visual evaluation, the present study aimed to compare the contrast sensitivity estimated from subjects that used anti-tuberculosis drug therapy and age-matched healthy subjects. The study was performed in Imperatriz city, Balsas city, Davinópolis city and Governador Edson Lobão city, in Maranhão state, Brazil from 2009 to 2012. The current study had a transversal, analytic, and case control profile. Three group of subjects participated from the present study: Control group (n=40), group of subjects treated with isoniazid (n = 19), and group of subjects that used isoniazid associated with ethambutol (n=18). It was used a CRT monitor, 21”, 6 x 5 degrees of visual angle to investigate the contrast sensitivity function. The comparison of the contrast sensitivities at different spatial frequencies among the three studied groups showed statistical differences (Two-way ANOVA, Tukey test, p < 0,05). Control group had higher contrast sensitivity at 10 and 15 cpd than the group that used only isoniazid as drug therapy for tuberculosis treatment and control group had higher contrast sensitivity at 4, 6, 10, 15 and 20 cpd than the group the received isoniazid and ethambutol together. There were no differences between the groups that received anti-tuberculosis therapy.