The purpose of this study is to examine choroidal thickness in beta-thalassemia patients and compare it to the one of healthy controls.

An equal number of transfusion dependent beta-thalassemic patients and age and sex matched healthy volunteers will undergo spectral-domain optical coherence tomography utilizing the enhanced depth imaging application to visualize and measure the choroid.

Beta thalassemia is an inherited hemoglobinopathy, associated with defective production of beta-chain globin resulting in problematic HbA production. It is classified according to the severity as minor, intermedia and major. Patients suffering from beta-thalassemia intermedia and beta-thalassemia major require regular blood transfusions. Transfusion related hemosiderosis in these patients necessitates the use of chelating agents to prevent iron overload in vital organs such as the liver and heart.

A number of ocular abnormalities can present in beta-thalassemia patients. Those are categorized as pseudoxanthoma elasticum (PXE)-like changes that include angioid streaks, peau d'orange like fundus and optic nerve head drusen and non-PXE-like changes such as increased venous tortuosity.

Furthermore, it is well established that prolonged treatment with some of the chelating agents such as deferoxamine are associated with ocular toxicity, namely nyctalopia, colour perception anomalies, visual field disturbances, cataract formation, optic neuropathy and pigmentary retinopathy.

The pathophysiology of those ocular manifestations has not been fully clarified. The role of the choroid has not been determined since this particular tissue was previously unaccessible to imaging. Enhanced depth imaging optical coherence tomography is able to image the choroid providing reasonable clarity compared to spectral domain optical coherence tomography.

The aim of this study is to evaluate possible alterations of choroidal thickness in beta thalassemia as compared to healthy controls.

Inclusion Criteria:

• Beta thalassemia patients undergoing blood transfusions

Exclusion Criteria:

• History of glaucoma, keratoconus, retinal disease, ocular trauma, ocular surgery, uveitis, amblyopia, strabismus, ocular vascular abnormalities
• Spherical refractive error greater than 4 diopters or cylindrical refractive error greater than 2 diopters
• History of other systemic disease such as uncontrolled hypertension, diabetes mellitus, or connective tissue disease.

Patients with beta-thalassemia major or intermedia undergoing blood transfusions will be examined utilizing EDI-OCT.

A group of equal healthy volunteers will also be included to serve as controls.