Retinitis Pigmentosa (Nyctalopia-Night Blindness)
What is Retinitis pigmentosa?
Retinitis pigmentosa, or nyctalopia colloquially known as night blindness, is a hereditary (parental) disease characterized by progressive damage to the retina and loss of vision. The thin nerve layer that surrounds the inner surface of the eye like a sheet and creates visual signals is called the retina.
There are cells called photoreceptors in the retina that detect the light coming into the eye and create visual signals. In people with retinitis pigmentosa, these vision cells and the underlying pigment layer are destroyed and progressive vision loss develops.
What are the symptoms of retinitis pigmentosa?
Since there are different types of genetic transmission in retinitis pigmentosa, the manifestation and time of the disease differs from patient to patient. Although retinitis pigmentosa begins in early childhood, symptoms appear later in life.
The reason for this is that the disease progresses from the outer part of the retina towards the center and the visual center is affected in the last stage.
These symptoms are deterioration of vision at night or in the dark, narrowing of peripheral (external) vision. Central vision is affected and the patient realizes the situation in the last stage.
Color vision is also impaired when the central retina is involved. When patients with retinitis pigmentosa reach the age of 50, vision loss reaches a very advanced level.
Is there any other reason for decreased vision in patients with retinitis pigmentosa?
Some eye diseases may occur in patients with retinitis pigmentosa and worsen their vision loss. Treating these diseases can sometimes contribute positively to visual function. These are as follows:
- Cataract
- Keratoconus
- Macular edema
- Intraocular bleeding
. According to the situation assessment, if the additional disease affects vision more than retinitis pigmentosa itself, its treatment may positively affect the level of vision.
How is retinitis pigmentosa diagnosed?
In the patient with a history of familial retinitis pigmentosa diagnosis, it is diagnosed by the presence of typical findings in the fundus examination with drops. In the fundus examination, pigment accumulation in the retina, thinning of the veins and pale color of the optic nerve are diagnostic. If necessary, a visual field test can be performed.
There is a narrowing of the visual field. Additionally, electroretinography test helps to make a definitive diagnosis in patients whose definitive diagnosis cannot be made on examination by measuring the electrical response of visual cells.
Why should genetic testing be done in retinitis pigmentosa?
Retinitis pigmentosa has many subtypes and different genetic inheritance patterns. By performing a genetic test, the subtype of the disease and the type of genetic transmission are determined.
In this way, RP patients who want to have children can have information about the possibility of this disease in their children. Additionally, if genetic treatments become available in the future, it can be determined whether the patient is suitable for this treatment.
Is there a treatment for retinitis pigmentosa?
Unfortunately, there is currently no treatment available to cure this disease or to stop its progression. Research on treatments such as stem cells, retinal gene therapy or chip insertion that can cure this disease is advancing rapidly.
Special glasses and magnifying glasses can sometimes be beneficial for patients to use the remaining vision more effectively.