Abstract
Purpose: :
To determine the prevalence and the spectrum of retinal phenotypes in thalassemia major and intermedia.
Methods: :
In a prospective cross-sectional study, patients with β-thalassemia major and intermedia confirmed by mutation analysis were recruited in a tertiary referral center in Milan, Italy. All patients underwent best corrected visual acuity, indirect ophthalmoscopy and fundus photography. Confocal scanning laser ophthalmoscopy (Spectralis HRA-OCT) was used to document fundus abnormalities in the fundus autofluorescence and the near-infrared reflectance modes. In addition, blood levels of ferritin, AST-ALT and Calcium were assessed.
Results: :
290 patients were examined: 182 (63%) with β-thalassemia major (TM) and 108 (37%) with β-thalassemia intermedia (TI). The mean (SD) age was 34 (±8) years for TM and 41 (±11) years for TI. Retinal abnormalities were evident in 105/290 patients (36%) and included angioid streaks (12%), peau d’orange (19%), retinal vessel tortuosity (16%), optic drusen (2%), choroidal neovascularization (1%) or macular changes on fundus autofluorescence (7%). TI showed a higher frequency of all phenotypes than TM. In TI, iron-chelating therapy was associated with a higher frequency of retinal abnormalities (p<0.001, Chi-Square Test). In TM, patients with retinal abnormalities showed higher levels of AST-ALT and ferritin (p<0.05, t-test for independent samples) and a longer history of chelating therapy (p<0.01, t-test for independent samples). The risk to develop retinal phenotypes increases with age.
Conclusions: :
To our knowledge, this is the largest and most comprehensive study that investigates the retinal abnormalities in patients with β-thalassemia reported to date. Retinal phenotypes in β-thalassemia are frequent, age-related and similar to those reported for PXE except for comet tail lesions. This suggests a common pathophysiological pathway leading to the characteristic fundus changes observed in patients with PXE and thalassemia. Retinal vessel tortuosity may present an additional disease manifestation independent from PXE-like fundus changes.
Keywords: retina • calcium • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)