Beta-Thalassemia
Conditions
Keywords
beta-thalassemia, choroidal thickness, enhanced depth imaging, optical coherence tomography
Brief summary
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.
Detailed description
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.
Interventions
DIAGNOSTIC_TESTEDI-OCT
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.
Sponsors
University Hospital of Patras
Study design
Observational model
OTHER
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 85 Years
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Subfoveal choroidal thickness | 8-10 am | Manual measurements of the choroid starting from the end of the retinal pigment epithelium throughout the outline of the sclera, will be conducted subfoveally |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Choroidal thickness temporally to the fovea | 8-10 am | 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 |
| Choroidal thickness nasally to the fovea | 8-10 am | 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 |
| Choroidal thickness inferiorly to the fovea | 8-10 am | 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 |
| Choroidal thickness superiorly to the fovea | 8-10 am | 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 |
| Peripapillary choroidal thickness (inferior, superior, nasal and temporal fields) | 8-10 am | 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. |
Countries
Greece
Outcome results
None listed