- Retinitis pigmentosa is a genetic disease
- The main problem is about reseptor dystrophy
- It has two reseptors dystrophy, rod dystrophy and con dystrophy
- Reinitis Pigmentosa is progressive
- Retinitis Pigmentosa can result in blindness
- Retinitis Pigmentosa can be systemic such as
- Usher syndrom and Bardet-Biedl Syndrome
Usher Syndrome : Retinitis Pigmentosa is associated with deafness
- Retinitis Pigmentosa
- Polydactyly (might be connected with insulin releasing disorders)
- Kidney problems
2- There are two types of reseptors dystrophy:
- If the patient suffers from rod dystrophy, the problem will be related with peripheric vision loss which means the patient has a “tunnel vision”
- If patient suffers from Con Dystrophy, central vision loss will be unavoidable
- Eventually It paves the way to blindness
- Night blindness
- Adaptation disorders
- Patient can ‘t adjust well to dark and dimly lit environments
- Bumping into furniture or doorframes
- Diffuculties in playing games,tenis baseball and baskedball
- Vision is often worse under bright lighting
- Color discrimination is also a serious problem
- Myopy and astigmatism shoudn’t be mislead in terms of diagnosis
- Patient can report small flashes of light or a twinkling shimmering
This abberant impuls shows the degenerating retina in retinityis pigmentosa cases
- Mutation of -Rodopsin and Peripherin
- Mutation of c-GMP phosphodiesteras
- c-GMP phosphodiesterase affects visual transduction cascade in general vision process,
- c-GMP is destroyed by c-GMP phosphodiesterase
- Apoptosis of Photoreceptor cells
- Splycing complex failure
- Being unable to restore external segments of rod cells
- Pigmentation in Retina
- Attenuation in retinal arteries
- Wawy pallor of the optic nevre head
- Vision field
- • Cataract
- Cystic macular oedem and Macular degeneration
- Optic Atrophy
8- Treatment / Cure :
- Genes Theraphy
A.A.V (Adeno-Assosiated Virus) and Lentiviruses are used as vectors.
There are 2 major problems in theraphy
- vectors can’t be placed in the target area
- virus expression can’t be controlled
Other problem also is that it damages antibody production.
So; Immun system deficiency causes cancer and patient deaths
At the present starting from 2007 gene therapies are forbidden by FDA.
Biyonic Eye Applications
1-Bionic eye and video camera are hand made and its production takes 6 months.
In addition; The patient using bionic eye has to live near a cure center for 3 years and has to be under control. Only patients with %0 or near %0 sight can benefit from this cure which means patients whose vision are above %5 are completely taken out of this practice.
2- What are the risks at bionic eye applications?
Because of the distance of the electrods to retina the communication is getting difficult. However,if the electrods would brought near to retina then retina cells may be damaged due to heat.
Bionic eye works with electricity thus a level of heat comes out and its unavoidable that the tissues in retina are seriously and permanently damaged due to the excess heat.
3- How can be bionic eye implanted?
With the electrods placed at retina tissue the vision cortex of brain is stimulated.This is called bionic eye. First experiments started with 16 electrodes than the number of electrodes were increased to 60.There is a hope that if the number of electrods will be increased to 80 vision might get better either.
Except the system placed in the eye,with the help of a video camera put into the glasses images are taken and are moved with a cable to the electrods. It is reported that this camera system can only be used in hospitals,its not possible yet to use it outside. When the patient with bionic eye has to make rapid head movements the eye can perceive the new image only 10-15 minutes later.Briefly,the adaptation process takes too long.
4- What type of vision can provide bionic eye?
It’s become known that a vision like black-and-white and a silhoutte is possible.