Retinitis pigmentosa is a congenital inherited condition where there is degeneration of the rods and cones in the retina. There are many different genetic causes. Some causes involve isolated retinitis pigmentosa whereas others result in systemic diseases associated with the condition. They vary in age at presentation and prognosis.
In most genetic causes the rods degenerate more than cones, leading to night blindness. They get decreased central and peripheral vision.
The presentation can vary between different underlying causes. Family history is very important. In most causes the symptoms start in childhood.
- Night blindness is often the first symptom
- Peripheral vision is lost before the central vision.
Fundoscopy will show pigmentation. This is described as “bone-spicule” pigmentation. Spicule refers to sharp, pointed objects. Bone-spicule is used to refer to the similarity to the networking appearance of bone matrix.
The pigmentation is most concentrated around the mid-peripheral area of the retina.
There can be associated narrowing of the arterioles and a waxy or pale appearance to the optic disc.
Associated Systemic Diseases
There are several genetic systemic diseases that involve retinitis pigmentosa. It is not worth learning the names and details but it is worth being aware they exist. Some examples are:
- Usher’s Syndrome causes hearing loss plus retinitis pigmentosa
- Bassen-Kornzweig Syndrome is a disorder of fat absorption and metabolism causing progressive neurological symptoms and retinitis pigmentosa
- Refsum’s Disease is a metabolic disorder of phytanic acid causing neurological, hearing and skin symptoms and retinitis pigmentosa
General management involves:
- Referral to an ophthalmologist for assessment and diagnosis
- Genetic counselling
- Vision aids
- Sunglasses to protect the retina from accelerated damage
- Driving limitations and informing the DVLA
- Regular follow up to assess vision and check for other potentially reversible conditions that may worsen the vision such as cataracts
There isn’t a huge amount of evidence supporting options to slow the disease process. Some options that may be considered by a specialist in certain scenarios include:
- Vitamin and antioxidant supplements
- Oral acetazolamide
- Topical dorzolamide
- Steroid injections
- Anti-VEGF injections
Gene therapy is a potential future treatment that could alter the disease process and lead to better outcomes.
Last updated April 2019