Retinitis pigmentosa: the night blindness disease

Retinitis pigmentosa is an inherited retinal dystrophy. It is one the most common rod-cone-dystrophies, a group of genetic eye disorders that affect the light-sensitive cells of the retina, which are known as the cones and rods. The condition can lead to night-time blindness or tunnel vision.

We’ve asked expert ophthalmologist Mr Niaz Islam to explain just how retinitis pigmentosa affects vision, whether it can lead to complete blindness and if there’s hope for finding a cure for the retinal condition.

What is retinitis pigmentosa?

Retinitis pigmentosa is due to a loss of retinal receptors, leading to bone spicule pattern in the peripheral retina. The bone spicule is the pattern on the back of the retina that an optician picks up when diagnosing the condition.

How does retinitis pigmentosa affect vision?

Visual loss may be noted in the far periphery or side vision, which could progress towards tunnel vision but where central vision is maintained. Some patients may notice central vision problems but this may also be due to other ocular associations or eye conditions such as:

• Posterior subcapsular cataracts – which are common and surgery is often beneficial
• Open-angle glaucoma
• Cystoid macular oedema – this is frequent, but treatable with prescribed tablets

What causes retinitis pigmentosa?

This is an inherited genetic retinal condition. The age of onset and rate of progression could be related to the mode of inheritance, which is how the genes are passed from the carrier to another person. There are different categories of how they have been passed from one person to another and include:

1. Sporadic - which is very common
2. Autosomal dominant (AD) - also common with the best prognosis of the outcome
3. Autosomal recessive (AR) - less common with an intermediate prognosis
4. X-linked (XL) – the least common, but the most severe

There are also syndromic forms, which are usually autosomal recessive, where Usher’s syndrome is commonest.

Does everyone with retinitis pigmentosa go blind?

There is a spectrum of the disease depending on the genetic background and mode of inheritance. Many patients have tunnel vision and good central vision. Few may also lose central vision by 40 years of age. Throughout one’s working life approximately 25% maintain good central vision and can read despite poor peripheral vision.

How do people adapt their lives to work and live alone with the disease?

I would recommend partial sight registration to obtain a certificate of visual impairment (CVI). This certificate proves that the patient has genuine sight problems, which is useful for employers.

I would also recommend referral to a low vision aid clinic, where low vision magnifying aids may optimise central reading vision.

Then there is occupational therapy assessment where people from social services would come to visit the patient’s home and see if they need handrails for stairs or a walking aid/stick. This does not mean that this is necessary for all patients but it is appropriate for some people.

Can retinitis pigmentosa be reversed or cured?

Unfortunately no, there is no treatment available at present to reverse or cure the condition. There is much genetic research that is currently ongoing. Specific genes linked to retinitis pigmentosa have been identified, for example, Usher’s syndrome. There is hope over the next 5-10 years for appropriate gene therapy.

Do not hesitate to book an appointment with Mr Islam if you’re concerned about your eye health. You can arrange your first consultation via his Top Doctors profile.