Ocular changes in multi-transfused children with β-thalassaemia receiving desferrioxamine: A case-control study
Objectives. This study was planned to determine the prevalence of ocular abnormalities in multi-transfused children with β-thalassaemia receiving desferrioxamine and to determine the association of abnormalities with the patients’ age, serum ferritin level, haemoglobin concentration, and dosage and duration of treatment with desferrioxamine. Methods. Twenty-five thalassaemic children receiving desferrioxamine and attending the day-care centre of a tertiary care hospital in Delhi, India, and 25 healthy age-matched controls were examined to determine the prevalence and pattern of ocular abnormalities. A refraction test, the visual evoked response and fluorescein angiography were done where applicable. Ocular changes were correlated with serum ferritin levels, the dosage and duration of chelation with desferrioxamine, and pre-transfusion haemoglobin levels. Results. None of the children reported any visual symptoms. The prevalence of ocular abnormalities in the thalassaemic group was 36% (9/25). Ocular changes seen included cataract (5/25), blurred optic disc margins (6/25) and dilatation and tortuosity of retinal vessels (2/25). The thalassaemic children had a significantly higher prevalence of cataract than the controls (p<0.05). Prevalence of cataract was associated with serum ferritin values above 4500 ng/ml (p<0.05), and blurring of disc margins was significantly associated with increased duration ((5 years) and frequency ((5 times/week) of desferrioxamine administration. A positive correlation was seen between the incidence of cataract and blurred disc margins. Conclusions. Children with thalassaemia should be screened periodically for ocular abnormalities. Rational usage of desferrioxamine and use of newer chelating agents will reduce the prevalence of these abnormalities.