Contrast sensitivity function in patients with beta-thalassemia major

Abstract

Purpose: To investigate contrast sensitivity function in patients with beta-thalassemia major, after regular transfusion and chelation therapy. Methods: We measured contrast sensitivity at four spatial frequencies in 30 patients with beta-thalassemia major and in 30 matched normal control subjects. All subjects underwent an ophthalmic examination that included fluorescein angiography. The contrast sensitivity results from the two groups were compared between them. Patients' contrast sensitivity values were correlated to the variables age, duration of transfusion, duration of chelation therapy and serum ferritin levels, to select the important predictors. Results: Contrast sensitivity function in all beta-thalassemic patients was significantly lower (p<0.0001) compared to the normal control subjects, for all spatial frequencies tested. The most important predictor of contrast sensitivity loss was patients' age. Conclusion: Contrast sensitivity testing can detect early changes in the visual function of beta-thalassemic patients and should be considered as a monitor for patients under chronic transfusion-chelation therapy.