What is Retinoschisis?
Retinoschisis is a degeneration of the neurosensory retina (inner layer) and splitting at the outer plexiform layer of the retina. In retinoschisis, the area of the retina has separated into two layers. The part of the retina affected by retinoschisis will have suboptimal vision. There are several different types of retinoschisis. Retinoschisis can be found in the fovea or the periphery of the retina. Patients may have either or both types together.
- Retinoschisis is a separation of the retinal layers.
- Retinoschisis can be congenital (x-linked juvenile) or acquired (senile).
- Retinoschisis is often mistaken for a rhegmatogenous retinal detachment, but it rarely requires treatment.
Retinoschisis can affect both the central and peripheral vision. Central vision can be affected and acuity may range from 20/30 to less than 20/200. Vision loss is due to the formation of tiny cysts between the separated layers of the retina. These cysts often form a “spoke-wheel” pattern and can be very subtly seen on examination. Peripheral vision can also be reduced if the inner layer of nerve cells split off from the outer layer of cells.
X-linked juvenile and senile retinoschisis are the two main types of retinoschisis.
Senile retinoschisis is also called degenerative retinoschisis or acquired retinoschisis. The prevalence is estimated to be about 4% in those over age 40. Senile retinoschisis can affect both men and women because it is not a genetic condition.
X-linked Juvenile Retinoschisis
X-linked Juvenile Retinoschisis occurs only in male school-age children and is characterized by visual loss that begins in early childhood and causes visual disturbances especially in reading. It is estimated to affect 1 in 5000-25,000 men, worldwide.
Risk Factors for Retinoschisis
Retinoschisis can be congenital or acquired with age. Foveal schisis may be congenital, acquired, or secondary to an associated ocular pathology such as optic pit, glaucoma, or pathological myopia.
Most patients with retinoschisis are asymptomatic and it is discovered on a comprehensive eye exam. These patients may be referred to the retinal specialist because retinoschisis can look similar to a retinal detachment. Most people with senile retinoschisis do well and can be followed without intervention. Retinoschisis can extend into the posterior pole, and outer and inner breaks leading to retinal detachment are possible but unlikely.
Retinoschisis can be viewed by an eye doctor during a dilated fundus exam. Typical senile retinoschisis is a shallow elevation of the retinal layers, where reticular retinoschisis has a bullous appearance. Retinoschisis will be dome shaped with uniform convexity and without the corrugations visible in a rhegmatogenous retinal detachment. Retinoschisis is relatively immobile with a transparent elevation of the inner wall. It is most often located inferior-temporally within the retina.
Retinoschisis is a diagnosis of exclusion, and pathology must be ruled out to make the diagnosis specifically a rhegmatogenous retinal detachment. A scleral depressor, an instrument used to better view the retina, can be used to make the diagnosis. An optical coherence tomography (OCT) can also confirm diagnosis as the OCT shows a break in the outer plexiform layer in retinoschisis and not detachment of the retina from retinal pigment epithelium.
The condition rarely progresses from where it’s first observed so laser treatment is unnecessary. Most cases of posterior retinoschisis will not progress beyond 3 disc diameters from the macula and only a few cases of degenerative retinoschisis involving the macula have been reported. No treatment has been shown to halt the progression of retinoschisis. It is estimated that three-quarters of lesions will at most extend post equatorial, only about three percent will progress posteriorly, so most still can be observed. Cataract surgery or posterior vitreous detachment will not have an effect on retinoschisis because the retinoschisis is within the retina and not at the vitreous-retina interface.