Retinoschisis

What is Retinoschisis?
Statistics on Retinoschisis
Risk Factors for Retinoschisis
Progression of Retinoschisis
Symptoms of Retinoschisis
Clinical Examination of Retinoschisis
How is Retinoschisis Diagnosed?
Prognosis of Retinoschisis
How is Retinoschisis Treated?
Retinoschisis References

What is Retinoschisis?

Retinoschisis means the splitting of the retina into 2 layers. It is a disease affecting the nerve tissue in the eye. The retina in the eye consists of various layers of nerve and pigment cells which are all interconnected. The retina layer allows vision to be possible in humans.However, in retinoschisis, these interconnecting layers split into separate layers, therefore resulting in loss of vision in the corresponding area where it is affected.There are two main types of retinoschisis:

hereditary/idiopathic/juvenile retinoschisis- which occurs mainly in male children
Acquired retinoschisis- affects men and women and usually develops in middle age. Also refered to as degenerative/senile retinoschisis.

Statistics on Retinoschisis

The commonest form of retinoschisis is the degenerative or senile retinoschisis. Degenerative retinoschisis affects 4-22% of individuals older than 40 years old, commonly in the age group of 50-60.However, the rarer form of retinoschisis affecting mostly children is very rare, happening in the figures of 1 in 5000 to 1 in 25000 of the population. The condition is inherited on the X chromosome so tends to affect males (XY) instead of females (XX) as they still have another normal functioning X chromosome.

Risk Factors for Retinoschisis

For senile retinoschisis, it is the aging process that leads to the disease. Men and women are affected equally.For juvenile retinoschisis, it is associated with a genetic defect, which affects young boys more than girls. Because of this, family history is also a predisposing risk factor for juvenile retinoschisis.

Progression of Retinoschisis

Retinoschisis is basically a benign disease. Not only do most of the patients have no symptoms, the disease itself can remain static or progress extremely slowly over time.However, serious complications can develop from retinoschisis. Retinal detachment can occur from retinoschisis. This means that the retinal layer (which is important for vision) becomes separated from the inner wall of the eye, leading to some loss of vision.

Symptoms of Retinoschisis

In the early stages of the senile form you are unlikely to experience symtoms but as the condition progresses you may notice visual loss, 'seeing' floating objects in the eye, or 'seeing' flashes of lights in the eye. The juvenile form usually has some degree of visual loss which children may notice as difficulty in resding at school.

Clinical Examination of Retinoschisis

A general clinical eye examination will be done to assess the general functions of the eyes. This should include visual acuity, visual fields, ophthalmoscopy and slit lamp examination. The visual acuity may be affected. Also ophthalmoscopy would show the lesions in the eye.

How is Retinoschisis Diagnosed?

General investigations of the eyes are usually included in the clinical examination. This can include the staining of the cornea (the clear, front part of the eyeball) to see if there are any defects, mapping of the visual fields (i.e. to determine if the scope of eyeball is complete) and slit lamp examination (a piece of equipment that can look at the eyeball in great detail).

Prognosis of Retinoschisis

Generally speaking, the prognosis for retinoschisis is favourable as the disease tends to progress extremely slowly, or remains unchanged for a long period of time.

How is Retinoschisis Treated?

Retinoschisis is a disease where there is little progression or no progression at all over time. Yet if progression occurs, it can potentially cause serious visual problems. Hence treatment options for retinoschisis can be from 'watchful monitoring' to surgery depending on the symptoms and disease progression.It is important to understand that there is no definitive medical or surgical treatments for retinoschisis. The following are the explanations of the different treatment options:Watchful monitoring: if there is no symptoms, no treatment will be needed. However, depending on the severity of disease, ongoing screening with fundoscopy mayl be required annually or biannually.Surgery: surgery is considered if there is progression of the disease, e.g. retinal detachment

Retinoschisis References

Byer NE. Long-term natural history study of senile retinoschisis with implications for management. Ophthalmology 1986;93:1127-37.
Phillpotts B, Gounder R, Retinoschisis, Senile, eMedicine, Web MD, 2004. Available [online] from URL http://www.emedicine.com/oph/topic640.htm
Song M, Small K, Retinoschisis, Juvenile, eMedicine, Web MD, 2005. Available [online] form URL: http://www.emedicine.com/oph/topic639.htm
Tantri A, Vrabec t, Cu-Unjieng A, Frost A, Annesley W, Donoso L, X-linked retinoschisis: A clinical and molecular genetic review, Survey of Ophthalmology 2004; 49 (2); 214-230.