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Retinitis

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This is a close up of a retina that has been infected with Retinitis.

Retinitis pigmentosa is an inflammation of the retina of the eye, which may lead to blindness. It is bilateral inherited condition that involves both eyes, but can be caused to a number of infectious agents. This usually starts to affect an individual later in life and soon will progress to blindness. Low-vision rehabilitation provides some help in coping with the disease but there is no cure currently. It begins as rod degeneration, which would cause the patient to have difficulty in night vision use. As time passes the patient will experience more vision restrictions. Tunnel vision will soon occupy the patient’s line of sight. A small area of central vision in both eyes perishes for years. Tunnel vision can last for years or decades, but ultimately complete blindness is what occurs. Blindness ranges from as early as childhood to an adult of 40 years old. This disease causes a person to go blind at a very young age without prevention. Even though there is no cure yet, doctors are eagerly performing research so that a cure is possible. If your family or if anyone you know has a history of retinitis pigmentosa go see a doctor. [1]

Types

Retinitis affected by CMV.

There are two different group types of retinitis that a person could get; Retinitis pigmentosa (RP) and CMV retinitis. RP is a group of genetic eye diseases a person can inherit from both parents, CMV, however develops from a viral infection of the retina. Some examples of RP include: Usher syndrome, Leber’s congenital amaurosis (LCA), Rod-cone disease, and Bardet-Biedl syndrome. [2].

Usher syndrome is the most common condition that affects both hearing and vision. Also, this causes night blindness and a loss of peripheral vision through the progressive degeneration of the retina. There are three clinical types of Usher syndrome: Type 1, Type 2 and Type 3. In the US types 1 and 2 are the most common. This is a recessive disorder, meaning a person must inherit a change in the same gene from each parent in order to have the disorder. Type 1 includes profound deafness and blindness in both ears from birth and decreases night vision at the age of 10. Type 2 includes a moderate to severe hearing loss from birth and night vision begins to decrease in late childhood or teens. Type 3 is when the child is born normally, but the vision and eye sight begin to decrease in the early teens. [3].

Leber congenital amaurosis (LCA) is an eye disorder that affects the retina. People with LCA are sensitive to light, make involuntary movements with the eye, and have extreme farsightedness. The pupils do not react normally to light as they should, instead they respond more slowly than normal. LCA is inherited through an autosomal recessive pattern. This means that both copies of the gene passed down have mutations. At least 13 types of LCA have been described that are distinguished by the persons vision loss and eye abnormalities. LCA occurs in 2 to 3 per 100,000 newborns and is one of the most common causes of blindness in children. [4].

Rode Cone disease is caused by the degeneration of the photoreceptor rods and cone cells. The symptoms of this disease include the gradual loss of night vision and peripheral vision, sensitivity to bright light, and errors of seeing color. Rode Cone disease occurs when a gene disorder occurs in a child. To help a child, do some eye exercises to get more blood to the eye. [5].

Bardet-Biedl syndrome disorder affects most parts of the body. Vision loss is one of the major effects of this syndrome. Problems with night vision develop by mid-childhood, followed by blind spots that develop in the peripheral vision. Other symptoms include obesity, the presence of an extra toe or finger, and impaired speech. This syndrome has a prevalence of 1 in 140,000 to 1 in 160,000 newborns. Bardet-Biedl syndrome can result from mutations in at least 14 different genes. This is inherited by an autosomal recessive pattern which means both copies of the BBS genes have mutations. [6].

Symptoms

This picture is comparing what a person with normal eye site sees, to what a person sees with Retinitis Pigmentosa.

The symptoms of Retinitis vary depending on the person suffering from the virus. Early RP symptoms include the loss of night vision, making it very difficult to drive at night or at dusk. It is also harder to see in dimly lit rooms. Later RP symptoms have to do with the loss of peripheral vision, leading to tunnel vision. A person can loss their central vision first. If this occurs than reading or doing close work is not easy. The ability to identify color can be slowly lost as well. Some symptoms may develop in one eye and then over the course of a few days, than spread to the other eye. Specks or clouds can form in a persons field of vision. A person ability to read can be greatly affected. [7].

Causes

Retinitis pigmentosa (RP) is an inherited condition that effects a persons vision. This disease can start in one eye and one eye only. But if not treated right, it can spread to the other eye in a number of years. Most of the people that suffer from this disease are caused by family inheritance. It is inherited in various ways, including dominate, recessive, and sex-linked recessive. Although some cases are sporadic and lack a family history of the disease. Although if a family member or a past relative has ever had this disease, that individual is more likely to get the disease. Retinitis pigmentosa is usually diagnosed during the teenage years but can be present at birth. The conditions that are developed latter on in life are often milder and may progress more slowly. 75,000 people in the United States approximately have been diagnosis with retinitis pigmentosa. A person with RP may also be associated with some other disease, like Usher syndrome. The most common side effects of having this disease are deaf-blindness. Although the hearing loss is diagnosed before the eye changes occur. [8]

Treatment

There is currently no specific cure for retinitis pigmentosa. For many years vitamin A treatment has been recommended for many RP victims. With a controlled trail of vitamins A and E treatment, doctors found that 15,000 IU a day can slow the course of the condition among adults with typical forms of RP. Taking a dose of 400 IU a day of vitamin E however can have an adverse effect on the course of RP in the same study.

Another way that has been proven to slow the disease is having an omega-3-rich diet containing docosahexaenoic acid. This kind of diet includes one to two servings per week of oily fish such as salmon, tuna, herring, mackerel, or sardines. Studies have shown that the combination of vitamin A plus this diet could provide almost 20 more years of useful vision adults who start in the 30’s. This is progress in finding a cure. Some tests have been performed on rats for further research in finding a cure. It is very important to make a diagnosis as soon as possible for the patients benefit. Vision therapy may be helpful in the being so that the patient can reach their vision potential. Expanding glasses are in the effort of being explored to provide more help. Although they are not open to the pubic yet, but hopefully in the future they will be. As of now doctors can only treat the disease, not cure it completely. [9]

Video


References

  1. Lee, Dennis. Retinitis Pigmentosa. “MedicineNet.com”. Web. 10-25-14.
  2. Wachler, Brian S. Retinitis. “WebMD”. Web. 10-11-14.
  3. Information Clearinghouse, NIDCD. Usher Syndrome. “NIH”. Web. 10-11-14.
  4. Bainbridge, JW. Leber congenital amaurosis. “Genetics Home Reference”. Web. 10-11-14.
  5. .Edson, Michael. Rode Cone Dystrophy. “Natural Eye Care”. Web. 10-11-14.
  6. Ansley, SJ. Bardet-Biedl syndrome. “Genetics Home Reference”. Web. 10-11-14.
  7. Boxer, Brian S. Eye Health Center. “WebMD”. Web. 10-11-14.
  8. Lee, Dennis. Retinitis Pigmentosa. “MedicineNet.com”. Web. 10-25-14.
  9. Marks, Jay W. Retinitis Pigmentosa (cont.). “MedicineNet.com”. Web. 10-25-14.