How Sickle Cell Disease Affects the Eye

 

 

The Sanguine team attended the 48th Annual Sickle Cell Disease Association of America Convention in October of 2020. Dr. Adrienne W. Scott, an associate professor of ophthalmology at Johns Hopkins Wilmer Eye Institute, gave a presentation on sickle cell disease (SCD) and how it can affect the eye. Dr. Scott also discussed her research in sickle cell retinopathy. 

 

SCD affects about 3.2 million worldwide with the highest prevalence in Africa. There are about 100,000 sickle cell patients in the United States and SCD is most common in African-Americans, hispanics, and people of Caribbean descent. SCD is caused by a specific mutation in the gene for hemoglobin molecules. 

 

Sickle cell disease may affect many parts of the body including the eye. SCD can cause orbital bone infarction which is when the bones around the eye experience a sudden loss of blood flow. SCD can also cause bleeding in front of the eye, which is called hyphema. Abnormal blood cells can clog fluid drainage through the eye causing elevated eye pressure, glaucoma, or even loss of vision. SCD retinopathy is one of the main concerns relating to the eye in sickle cell patients. 

In 1971, Dr. Goldberg described the 5 stages of sickle cell retinopathy. These include the following:

Stage 1: Abnormal closures of blood vessels 

Stage 2: Vascular loops of blood vessels 

Stage 3: Abnormal new blood vessels grow in the corners of the retinas (the most worrisome stage)

Stage 4: SCD retinopathy occurs when abnormal blood vessels burst and fill up the middle of the eye causing a vitreous hemorrhage

Stage 5: Retinal detachment 

 

Sickle cell retinopathy can be described as proliferative sickle retinopathy (PSR) or non-proliferative sickle retinopathy. Proliferative sickle retinopathy has a prevalence as high as 43% in those with sickle cell HbSC and 14% in those with HbSS. PSR usually occurs in individuals around 24-26 years of age. 

 

The goal in sickle cell retinopathy is to prevent progression. Treatment with lasers and surgery can be utilized to decrease risk of progression. Currently, sickle cell patients without symptoms are recommended to get dilated retinal exams every 1-2 years starting at the age of 10. 

 

Dr. Scott and her team are conducting a research study relating to tele-ophthalmology in detection of sickle cell retinopathy. The researchers want to evaluate how feasible it is to obtain retinal photos of patients with sickle cell disease in the hematology clinic. These photos are then analyzed to see whether specialists could use them to assess retinopathy. Researchers also aimed to collect data that could better inform screening models. The study involves non-expert photographers for the retinal photos and undilated patients. The images would are then compared with standard scd retinopathy exams to assess whether the obtained images are of sufficient quality. 60 patients are currently enrolled in the study and the research team has found that the photos are of good quality and are quick and easy to take. Furthermore, retina specialists are able to judge whether there is proliferative sickle retinopathy, non-proliferative sickle retinopathy, or no retinopathy using the images. 

 

The data from this study is also being used in a second project involving machine learning to automate detection of PSR retinopathy. This project is being conducted in collaboration with the Johns Hopkins Malone Center. The goal of the project is to validate the accuracy of the development team’s algorithm in detecting proliferative sickle retinopathy. The ultimate goal of these research studies is to obtain retinal pictures of patients from medically underserved areas, feed the images into a computer program, and be able to tell whether the patient has sight-threatening sickle cell retinopathy.

Researches studies like these are streamlining diagnosis processes so that physicians can detect medical changes before they progress and can treat them accordingly. We look forward to keeping up with research regarding sickle cell disease and the eye. 

 

By Neelem Sheikh