Evaluation of contrast sensitivity in thalassemic patients

Abstract

Background and purpose: Threshold contrast sensitivity could be considered as an important indicator of visual function in thalassemic patients. In this study the threshold of contrast sensitivity was investigated in patients with major and minor thalassemia and normal individuals. Material & methods: This cross-sectional study was conducted in 30 patients of thalassemia major (Desferal dependent), 30 patients of thalassemia minor and 30 healthy individuals as control group. After determining the best-corrected vision, contrast sensitivity was measured using Freiburg Vision Test at frequencies of 1, 5, 15 cpd at distance of 4 meters. The results were then analyzed using SPSS. Results: Contrast sensitivity was higher in patients with thalassemia major at all spatial frequencies (P<0.001), however, there was no significant difference between minor and healthy subjects. We found no correlation between transfusion duration, dose of chelator and Ferritin with contrast sensitivity. Conclusion: Patients with thalassemia develop visual disorders that could result in reduction of contrast sensitivity. Therefore, contrast sensitivity testing could be of great benefit in detecting early changes in the visual function of beta-thalassemic patients