Retinitis Pigmentosa

What happens in retinitis pigmentosa

The retina, at the back of the eye, contains two types of light-sensing cells:

• Rods: spread across the outer retina; work in dim light and detect motion at the edges of vision.
• Cones: concentrated in the center (macula); provide sharp detail and color.

In typical RP, a genetic fault causes rods to degenerate first. Cones depend on rods to survive, so they decline later. Pigment from a deeper layer clumps in the retina, creating the dark "bone spicule" deposits that give the disease its name. Despite "-itis", it is not an inflammation.

Symptoms

Symptoms usually start in childhood or adolescence, but can begin in adulthood. They progress slowly, often over decades.

1. Night blindness: often the first symptom. Difficulty seeing at dusk, in dim restaurants or cinemas, and slow adjustment when lights go out.
2. Loss of side (peripheral) vision: a ring of lost vision forms in the mid-periphery and gradually expands, leaving tunnel vision. People trip on curbs, bump into door frames or miss people approaching from the side.
3. Glare and light sensitivity.
4. Reduced contrast and color vision as cones become involved.
5. Loss of central vision: usually late, sometimes not until age 50 or older. Many people keep useful central vision for most of their lives.
6. Photopsia: shimmering or flashing lights.

Few people with RP become completely blind, but many become legally blind because of a very narrow visual field.

Causes and inheritance

RP is caused by changes in more than 80 genes that affect photoreceptors or the supporting retinal pigment epithelium.

Many people have no known family history, because recessive genes can be passed silently for generations.

Syndromic RP

RP can be part of a wider condition:

• Usher syndrome: RP with hearing loss (the most common cause of combined deaf-blindness).
• Bardet-Biedl syndrome: RP with extra fingers or toes, obesity, kidney problems and learning difficulties.
• Others: Refsum disease, Kearns-Sayre syndrome and some metabolic disorders.

Conditions that mimic RP include vitamin A deficiency, retinal damage from certain medicines (thioridazine, chloroquine), infections such as syphilis, and autoimmune retinopathy.

How retinitis pigmentosa is diagnosed

• Dilated eye exam: shows pigment clumps, thin blood vessels and a pale optic nerve.
• Visual field testing: maps the extent of peripheral vision loss.
• Electroretinogram (ERG): measures the retina's electrical response to light. It is reduced or absent in RP, often before visible changes appear.
• Optical coherence tomography (OCT): scans retinal layers and detects macular edema.
• Fundus autofluorescence: shows areas of damaged retina.
• Genetic testing: identifies the causative gene in roughly 60% to 70% of people. It confirms the diagnosis, clarifies inheritance and determines eligibility for gene therapy and clinical trials.

Treatment

Gene therapy

Voretigene neparvovec (Luxturna) is approved for RP and related dystrophies caused by mutations in both copies of the RPE65 gene. A healthy copy of the gene is injected under the retina, improving light sensitivity and navigation in dim light. It helps only this specific genetic type, which is why genetic testing matters. Many other gene therapies are in clinical trials.

Treating complications

• Cataract: develops earlier than usual in RP and is treated with surgery, often improving vision.
• Cystoid macular edema: swelling at the center of the retina; treated with carbonic anhydrase inhibitor eye drops or tablets, or steroid treatment.

Other options

• Retinal implants and optogenetics: retinal prostheses have been used in advanced RP; newer approaches are in trials.
• Supplements: high-dose vitamin A palmitate was studied for slowing RP but evidence is limited and it has risks (liver toxicity, birth defects). Discuss with a retinal specialist before taking it. Avoid it in Stargardt disease and some other dystrophies.
• Sun protection: UV-blocking, tinted sunglasses reduce glare.

Low-vision rehabilitation

Low-vision services help people adapt: magnifiers, high-powered lighting, night-vision devices, screen readers, orientation and mobility training, a white cane and guide dogs. Occupational therapy and support groups help at work, school and home.

Living with RP

• Driving: night driving often becomes unsafe early. Many people eventually stop driving because of field loss. Legal requirements vary by state and country.
• Regular eye exams: at least yearly to track progression and treat complications.
• Genetic counseling: for family planning and informing relatives.
• Emotional support: gradual vision loss can cause anxiety and depression; counseling and peer support help.

Frequently asked questions

What are the first signs of retinitis pigmentosa?

The first sign is usually trouble seeing in dim light or at night, often noticed in childhood or the teenage years. Next comes gradual loss of side vision, causing people to bump into things or trip. Central vision is usually preserved until later.

Does retinitis pigmentosa always lead to blindness?

No. Most people with RP keep some vision throughout life, but many become legally blind because their field of vision becomes very narrow. The speed and severity vary widely depending on the gene involved, ranging from mild late-onset disease to severe childhood forms.

Is retinitis pigmentosa hereditary?

Yes. RP is genetic and can be inherited in autosomal recessive, autosomal dominant or X-linked patterns. Many people with RP have no known affected relatives because recessive carriers do not have symptoms. Genetic testing and counseling clarify the risk for children and other family members.

Is there a cure for retinitis pigmentosa?

There is no cure for most types. Gene therapy (Luxturna) restores some function in people with RPE65 mutations. Other gene therapies, cell therapies and retinal implants are in development. Treating cataract and macular edema and using low-vision aids help preserve function.

How fast does retinitis pigmentosa progress?

Progression is usually slow, over years to decades. Peripheral vision commonly shrinks by a few percent each year. X-linked and some recessive forms progress faster, while many dominant forms are milder. Regular visual field tests track individual progression.