Retinitis pigmentosa is a family of genetic conditions that result in loss of vision through the degeneration of photoreceptor cells – rods and cones – in the retina. It is caused by a mutation in any one of many known genes – recessive, dominant and X-linked – and others as yet to be identified. RP is often identified initially visually by distinctive clumping of pigmentation on the fundus, often by an optician during routine examination or as a result of examinations prompted by the condition being in the family.
Other terminology includes those such as night blindness, tunnel vision, rod-cone dystrophy, cone-rod dystrophy and retinal dystrophy. Some specific types of RP are also named, such as Leber’s Congenital Amaurosis, Choroideremia, Usher’s Syndrome, Stargardt’s Disease, and others.
Typically, but with great variation, sight loss is gradual, starting with night blindness, then loss of peripheral vision, then tunnel vision, and ultimately in some cases, total loss of vision. RP affects both sexes, all races (though is more prevalent in some Asian groups), and all ages. It is, in fact, one of the largest causes of sight loss in children and in people of working age. In aggressive early onset types of RP, which are fortunately rare, a baby can be born with poor or no sight.
Being a progressive condition it brings ongoing problems for your patient. He or she is faced with a continually worsening condition and at present there is no treatment or cure, though clinical trials of several potential therapies (Stage I and II) are in progress. One of the dangers faced by RP patients is the prevalence of misinformation and even outright scams about treatment prospects.
There are also forms of syndromic RP which lead to other problems and disabilities. One of the more common of these is Usher’s Syndrome which results in hearing loss as well as sight loss.
As well as referring to an ophthalmologist your patients may require referral to a counsellor to help come to terms with the prospect of sight loss, to a genetic counsellor to discuss the implications of the genetic nature of the condition, for genetic testing, or to specialists in particular types of RP or RP syndromes.
At a high lay-level, there is information about RP available from the RP Fighting Blindness website, and more specialist medical links on the following pages.