What are inherited retinal diseases?
Inherited retinal diseases (IRDs) describe a diverse group of eye conditions with a genetic basis that can cause severe vision loss or blindness. The many diseases categorised under this title are caused by one of the thousands of known genetic anomalies in more than 250 genes. Most IRDs are degenerative, meaning that symptoms will slowly progress over time.
Inherited retinal diseases are the leading cause of blindness in working-age adults. In fact, around one in 4000 people worldwide have been diagnosed with an IRD.
Some of the more common inherited retinal diseases include:
Retinitis pigmentosa is caused by the slow and progressive degeneration of photoreceptor cells in the retina, often leading to loss of night and side vision and, in some cases, can eventually impact on central vision.
Stargardt disease is a form of macular degeneration, in which central vision progressively declines, usually during childhood or adolescence. Because it generally does not affect peripheral vision, people with this condition rarely lose all sight.
Inherited retinal disease symptoms
As the term inherited retinal disease covers many conditions, symptoms will depend on the type of IRD and the individual patient. In some cases, people with an IRD experience a gradual loss of vision over time, while others may be born with or go through vision loss during infancy or early childhood. Another thing to note is that every IRD case is different – some people will lose more vision than others, even amongst family members with the same condition.
Some symptoms that you may experience, however, include:
- Night blindness
- Reduced peripheral vision
- Reduced central vision
- Light sensitivity
- Changes in colour vision or colour blindness
Causes of inherited retinal disease
Inherited retinal diseases are caused by a change or mutation in one or more genes that contribute to proper retinal function. Such a variant can interfere with the gene’s ability to work correctly. For example, a mistake in a gene could mean that a protein has not been made correctly or at all, causing cells in the retina to degenerate and deteriorate. Currently, there are around 250 genes that are known to cause inherited retinal disease.
Inherited retinal disease prevention
As inherited retinal diseases are genetically determined, there is nothing that anyone can do to prevent them. If you are diagnosed with an IRD, you can do several things to look after and maximise your vision. This may include things such as:
- Undergoing regular eye checks
- Maintaining a healthy diet
- Not smoking
- Wearing sunglasses
- Using extra lighting if help is needed in dark environments
- Using low vision aids
- Undergoing orientation and mobility training
Diagnosis of inherited retinal disease
Diagnosing an inherited retinal disease can sometimes be difficult. Your ophthalmologist will complete various eye tests, including a visual field test, testing colour vision, as well as taking retinal photographs and scans. Further testing of the electrical activity or function of different parts of the retina may also be required.
Ultimately, genetic testing may be indicated – this is done by collecting a small blood or saliva sample to send to a lab for analysis.
Undergoing genetic testing can help determine the exact gene that is causing an inherited retinal disease. Knowing this can help a patient understand their diagnosis, direct them to the right treatment, connect them to supportive services, and provide them with information about clinical trials and new therapies.
Inherited retinal disease treatment
Unfortunately, for most inherited retinal diseases, no medicine, surgery, or treatment can cure vision loss. However, active and ongoing research into genetic treatments for some IRDs is occurring right now. In the meantime, monitoring progression, treatment of any complications and maximising visual function are the mainstay of treatment. Patients will usually receive support from various professionals, including their ophthalmologist, low vision service providers and other specialised support service providers.
Get in touch to see Dr Juanita Pappalardo
Dr Pappalardo is a Specialist Ophthalmologist with vast experience treating a range of common eye diseases, including inherited retinal diseases. If you believe that you have an IRD, get in touch to plan your visit with Dr Pappalardo.