Living with Retinitis Pigmentosa (RP)

Retinitis Pigmentosa is a hereditary eye disease that primarily affects the field of vision of the person afflicted. Commonly known as RP, Retinitis Pigmentosa is degenerative in nature. Many people born with RP have normal or nearly normal fields of vision in early life, and find that their fields constrict over time, usually rendering them legally blind at some point during adulthood.

What is Retinitis Pigmentosa (RP)?
A genetic disorder of the retina, Retinitis Pigmentosa causes degeneration of the rod and cone cells. Rod and cone cells make up the photoreceptor cells in the retina, which capture light and process it in a way that allows the eye to see. The rod cells allow for peripheral vision, and for vision during night and in dark places. The cone cells allow for more accurate vision in the center of the visual field, and for recognition of color. In people with RP, the photoreceptor cells are steadily degenerating over time, causing a progressive inability to see anything from the peripheral fields, and affecting visual acuity as well.

What do People with Retinitis Pigmentosa (RP) Experience?
In most cases, the first and most severe change in vision for people with Retinitis Pigmentosa is the loss of peripheral vision, as the rods begin their degeneration early. Also affected by the loss of rod cells is night vision, leaving people with RP nearly or totally blind in areas with dim or no light. Conversely, light sensitivity is also a problem for people with Retinitis Pigmentosa, and will be particularly sensitive to glare and bright sunlight.

The loss of peripheral vision leaves the person with RP with a smaller than usual amount of visual field. What this means is that they are looking at the world as if through one or several holes in a wall. Some people with Retinitis Pigmentosa may have quite large fields of vision, and most do early on. Their field restriction may resemble looking at the world with a diving mask on. As the condition progresses, it is common for people to wind up with a field as large as a dime, a hole punched in a piece of paper, or even a pinhole.

However, the fields of vision are often not uniform. Some patients experience a circular area of vision loss, with acuity around the perimeter and inside it. Other people with RP may be left with a few pockets of vision that they can look through. Commonly, these patches of vision are not perfectly centered, but may be off to one side, or toward the top or bottom of their vision. This often causes people with Retinitis Pigmentosa to look at things from odd angles.

As the cone cells begin to degenerate, a person living with RP will also begin to experience loss of acuity (meaning visual sharpness) and color recognition. Most people with Retinitis Pigmentosa can see color, but their color perception will different from that of people with normal vision. Brown may become purple, red may become brown, etc.

What is the Likelihood of Having a Child with Retinitis Pigmentosa (RP)?
In most cases, Retinitis Pigmentosa is a hereditary condition. This means that, baring the occurrence of a spontaneous mutation (meaning being the first in a hereditary line), people born with RP will be born into families where the condition exists.

There are three types of genetic inheritance of RP: autosomal dominant, autosomal recessive, and X-linked inheritance. In families with autosomal dominant RP, one or both parents are affected with the disease, and can have children that are affected and unaffected. In families with autosomal recessive RP, one or both parents are unaffected, but carry a recessive gene. They can also have children that are affected and unaffected. In families carrying X-linked RP, the males of the family may be affected by Retinitis Pigmentosa, but the females will not. The females, however, often carry the gene for RP and may pass it on to their sons.

In the case of autosomal dominant transmission of Retinitis Pigmentosa, there is a 50% chance of the affected parent passing RP onto their children. With autosomal recessive RP, the chances drop to a 25% chance for each parent with the recessive gene. X-linked inheritance is a little more variable, as only the males of the family are directly affected, while the females are generally only carriers. Females carrying the X-linked gene have a 50% chance of passing it onto their children. The males it is passed onto will become affected by RP, while the females will become carriers. Males carrying the X-linked gene will always pass the disease onto their daughters through the affected X chromosome, but will never pass it to their sons, to whom they pass the Y chromosome.

Can Retinitis Pigmentosa (RP) be Treated?
There is currently no cure for Retinitis Pigmentosa. There is work being done on the development of retina transplantation and artificial retina implants. At the current time, some cases of artificial retina implant have been performed with rates of success varying from none to moderate.

Some doctors believe that regular high doses of Vitamin A may slow the progression of the disease.

Almost all people with Retinitis Pigmentosa will become legally blind during their lifetime, often early in adulthood. Because of the hereditary nature of RP, most families know to be watching for it, and it is often recognized early.