Gyrate Atrophy is a hereditary disease of the retina and the choroid and it starts early in the childhood.
Pathogenesis of Gyrate Atrophy
Metabolic dysfunction due to defects in an enzyme called Ornithine Aminotransferase . Defect or deficiency of this enzyme will cause Ornithine to accumulate in the body especially in urine, CSF and aqueous humor of the eye.
Ocular Manifestations of the disease
1- Gradual loss of vision which usually starts after the age of 10 years.
2- Axial Myopia which cause nearsightedness.
3- Atrophy in the peripheral chorioretinal layer which leads to nyctalopia (difficulties to see in dim light or in the dark) and lose of side vision.
4- The central vision is affected later in the disease but sometimes early complications in the macula such as macular edema and formation of epiretinal membrane can lead to loss of central vision early in the disease.
5- Peripheral pigmentary changes that are associated with abnormal crystals depositions.
6- Cataract can develop.
7- Blood vessels are thinner than in normal retina.
Management of Gyrate Atrophy
1- Vitamin B6 (Pyridoxine) can be helpful in normalize the blood and urine level of Ornithine.
2- Low Arginine diet can also be helpful.