Spectralis HRA+OCT Imaging of the Retina With Autofluorescence in Sickle Cell Disease
Spectralis HRA+OCT Imaging of the Retina With Autofluorescence in Sickle Cell Disease
To determine the retinal and choroidal thickness in patients with sickle cell disease
 compared to age, race matched population without sickle cell disease to allow a better
 understanding of the clinical manifestations of sickle cell retinopathy. The purpose of this
 research study is to evaluate the relationship between sickle cell disease and the eye. The
 research study is recruiting African American population with or without Sickle Cell Disease.
 The investigator in charge of this study is Dr E. Bowie. Approximately 60 subjects of both
 sexes will be enrolled at the Medical University of South Carolina.
About 10% of African Americans have an abnormal hemoglobin gene. About 8% of African
 Americans are heterozygous for Hb S. In the United States, sickle cell anemia primarily
 occurs in the black population, with approximately 0.2% of African American children
 afflicted by this disease. The prevalence in adults is lower because of the decrease in life
 expectancy. The Storm Eye Institute at the Medical University of South Carolina (MUSC) is
 uniquely situated geographically and epidemiologically to study the interaction between
 sickle cell disease and the retina. The frequency of sickle cell trait (Hb AS) in
 African-Americans of Charleston County is 16%, twice the national average of 8% in
 African-Americans. This is thought to be due to the autosomal recessive inheritance of sickle
 cell disease, and the genetic roots and relative isolation of the Sea Island Gullah
 population (Pollitzer 1999).

 Variations in the alteration of the amino acid sequence on the globin chain produce
 variations in the disease's expression. The four forms of the disease are often referred to
 by their genotype: sickle cell trait (AS), sickle cell anemia (SS), sickle cell disease (SC)
 and sickle cell thalassemia (SThal).

 Systemically, the sickle cell anemia variation (SS) produces the most symptoms. With respect
 to the eye, the sickle cell disease mutation (SC) produces the most effects.

 The widely accepted pathogenesis for sickle cell retinopathy is vasoocclusion that leads to
 retinal hypoxia, ischemia, infarction, neovascularization, and fibrovascularization. In
 sickle cell anemia, the amino acid substitution valine for glutamate occurs on the beta chain
 at the sixth position. This substitution, combined with conditions that may promote sickling
 (ie, acidosis, hypoxia), triggers the deoxygenated Hb S to polymerize, making the erythrocyte
 rigid. This rigidity is partially responsible for the vasoocclusion.

 Vasoocclusion also is in part due to the interaction between sickled cells and the vascular
 endothelium. The adherence of sickled cells to the endothelium triggers an inflammatory
 process with the release of inflammatory agents. The result of this cascade is vascular
 stasis, hemolysis, and vasoocclusion of the capillary beds.

 Classically, posterior segment changes are classified by either nonproliferative sickle
 retinopathy (NPSR) or proliferative sickle retinopathy (PSR). In NPSR, the retinal changes do
 not involve neovascularization as they do in PSR. The use of Spectralis HRA+OCT gives us
 visualization of the individual layers of the retina to determine if there are underlying
 changes not seen clinically in the gross ophthalmic posterior segment exam. This knowledge
 will aid the care of African-Americans with sickle cell disease to enable greater
 understanding of the ocular disease progression leading to earlier eye screenings, possible
 novel treatments and ultimately visual loss prevention.
Inclusion Criteria:

 -  SUBJECTS approximately 60 subjects of both sexes of African American race with or
 without sickle cell disease.

 Patient Inclusion Criteria:

 -  Subjects MUST fulfill the following conditions to qualify for enrollment into the
 trial

 -  Twelve years of age or older.

 -  Patients diagnosed with sickle cell disease (n=40) and an age, race matched control
 group of subjects (n=20) without sickle cell disease. Sickle disease is defined as a
 genetic blood disease due to the presence of an abnormal form of hemoglobin, namely
 hemoglobin S. It includes four genotypes: sickle cell trait (AS), sickle cell anemia
 (SS), sickle cell disease (SC) and sickle cell thalassemia (SThal). Patients with any
 of these genotypes will be included.

 -  Willing and able to comply with scheduled visit and other study procedure

 Exclusion Criteria:

 -  Subject must not have a history of prior intraocular retinal surgery, prior laser
 photocoagulation, cryotherapy, active ophthalmic disease or abnormality (e.g.
 blepharitis, corneal infection), clinical evidence of trauma (including scarring).

 -  Any clinically significant, serious or severe medical or psychiatric condition that
 may increase the risk associated with study participation or may interfere with the
 interpretation of study results.

 -  Participation in (or current participation) any investigational drug or device trial
 within the previous 30 days prior to the start date of this trial.

 -  Pregnant and nursing mothers.