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.
Study Type
OBSERVATIONAL
Enrollment
60
EDI-OCT (enhanced depth imaging spectral domain optical coherence tomography) wiil be performed in all study participants. Three sets of measurements in the macular (horizontal and vertical) and peripapillary area will be averaged.
Department of Ophthalmology, General University Hospital of Patras
Pátrai, Achaea, Greece
Subfoveal choroidal thickness
Manual measurements of the choroid starting from the end of the retinal pigment epithelium throughout the outline of the sclera, will be conducted subfoveally
Time frame: 8-10 am
Choroidal thickness nasally to the fovea
Manual measurements of the choroid starting from the end of the retinal pigment epithelium throughout the outline of the sclera, will be conducted at anatomic locations nasally to the subfoveal point
Time frame: 8-10 am
Choroidal thickness inferiorly to the fovea
Manual measurements of the choroid starting from the end of the retinal pigment epithelium throughout the outline of the sclera, will be conducted at anatomic locations inferiorly to the subfoveal point
Time frame: 8-10 am
Choroidal thickness temporally to the fovea
Manual measurements of the choroid starting from the end of the retinal pigment epithelium throughout the outline of the sclera, will be conducted at anatomic locations temporally to the subfoveal point
Time frame: 8-10 am
Choroidal thickness superiorly to the fovea
Manual measurements of the choroid starting from the end of the retinal pigment epithelium throughout the outline of the sclera, will be conducted at anatomic locations superiorly to the subfoveal point
Time frame: 8-10 am
Peripapillary choroidal thickness (inferior, superior, nasal and temporal fields)
Manual measurements of the choroid starting from the end of the retinal pigment epithelium throughout the outline of the sclera, will be conducted at the inferior, superior, nasal and temporal quadrants in the peripapillary area.
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Time frame: 8-10 am