Diagnosing Retinitis Pigmentosa
Many people with retinitis pigmentosa (RP) are diagnosed as children, adolescents, or young adults, which is when symptoms generally start to show.
If an eye doctor suspects that a patient has RP, they will refer the patient to an ophthalmologist (an eye disease specialist) for further testing and consultation. The ophthalmologist will conduct a comprehensive exam and series of tests in order to accurately diagnose the issue and recommend appropriate treatments for consideration.
What to expect at the ophthalmologist’s office
The initial exam usually begins with a patient’s personal and family medical history, to help uncover patterns of family illness that may be contributing to the patient’s current issues. You may be asked about:
- Past and current vision issues, along with any eyes injuries,
- Past and current medications taken, and
- Family history of eye disease or other genetic conditions.
Following the medical history intake, the doctor is likely to:
- Perform a comprehensive clinical exam,
- Take a variety of images of your eyes,
- Conduct an electrical response test, and
- Order genetic tests.
Comprehensive clinical exam
Clinical diagnostic tests that the ophthalmologist may perform include:
- Eye dilation, in which eye drops are used to widen your pupil, allowing the doctor to better see and evaluate your retina
- Refraction, or looking at a chart through a device, which measures your ability to see details both up close and far away
- The slit lamp test, which involves the use of a bright light and a microscope to view different parts of the inside of your eye
Your doctor, or a technician, may also take several different kinds of non-invasive imaging tests, including:
- Retinal photographs, which are high-resolution digital images showing the retina, optic nerve, and blood vessels at the back of your eye
- Optical coherence tomography (OCT), which uses light waves to take cross-sectional photos of your retina,
- Fundus autofluorescence, which helps the doctor map the density of your retina’s layers, and
- Infrared autofluorescence, which monitors the health of your retinal pigment epithelium cells (RPEs). RPEs regulate the flow of nutrients and wastes to and from your retina.
Visual field testing
A visual field test consists of covering one eye and being shown a series of flashing lights in various areas of your field of vision, particularly your peripheral (side) vision. You let your doctor know each time you see one of the lights. This tells the doctor where you have blind spots, and how much your field of vision has narrowed.
Electroretinography measures your retinas’ electrical activity in response to light. This test is performed with electrodes placed on each of your eyes, after numbing drops are used to prevent discomfort.
Since RP is a genetic condition, your ophthalmologist may either order genetic tests or refer you to a genetic counselor to determine which specific tests should be ordered. Genetic tests are typically done by sending blood, saliva, and/or other tissue samples to a lab for analysis. These tests can confirm (or dispute) a diagnosis, including the specific genetic form of the disease. Genetic tests may also be required for enrollment in clinical trials and other research studies.