What is Retinoschisis (Split Retina)?
Retinoschisis is an eye condition that causes the eye’s retina to split into two layers.
Retino- refers to the retina, while -schisis refers to split. It affects both young and old, males and females.
While retinoschisis is a commonly used name, eye doctors may also refer to it as:
- Congenital retinal cyst
- Congenital vascular veils in the retina
- Giant cyst of the retina
- Vitreoretinal dystrophy
Vision Loss in Retinoschisis
Retina splitting can cause slow vision loss in one of the following:
Center of vision (fovea)
A person with impaired central vision can have visual acuity (sharpness) between 20/30 and 20/200. The decreased vision happens because of tiny cysts (sac-like blisters).
They form between the separated layers of the retina and damaged nerve tissue. When this occurs, glasses or contact lenses won't be able to improve visual acuity.
Peripheral vision
A person with retinoschisis can lose some peripheral vision. This is if the inner layer of nerve cells breaks off from the outer layer of cells.
Primary Forms of Retinoschisis
Additionally, there are different types of retinoschisis. The two primary categories include:
1. Senile Retinoschisis
The common characteristics of senile retinoschisis include:
- Acquired form
- Affects both men and women
- Usually occurs from middle age and beyond
- May be asymptomatic
2. Juvenile Retinoschisis
The common features of this type of retinoschisis are:
- Present at birth (congenital)
- Mostly affects both boys and young men
- Both eyes are almost always affected (bilateral affectation)
- Considered as the more serious form of retinoschisis
It's crucial to visit an eye care specialist for:
- Proper diagnosis
- Appropriate care
- Follow-up of the condition
Different diagnostic tools are available. Some people with retinoschisis may be eligible for specific treatments.
Retinoschisis may be confused with other eye diseases. This includes amblyopia or lazy eye.
Speak with an ophthalmologist if retinoschisis runs in your family. If you've been diagnosed with amblyopia, an experienced ophthalmologist can rule it out.
Types of Retinoschisis
Eye doctors can detect specific clinical characteristics and health conditions.
These may point toward more specified forms of retinoschisis, such as:
1. Degenerative Retinoschisis
Health professionals may use the following terms to describe senile retinoschisis:
- Degenerative retinoschisis
- Acquired retinoschisis
This eye disorder affects both males and females in middle age. But it can also appear in some people at an earlier age. A person with degenerative retinoschisis may be asymptomatic.
Often, the diagnosis is incidental. It can occur after a referral to a retinal specialist under the presumptive diagnosis of retinal detachment. This is when there's loosening of a thin layer in the retina.
In typical cases of degenerative retinoschisis, there is a shallow rise of inner retinal layers.
Disease progression is not typical. Many times, it involves the peripheral retina. Many people with this eye disorder do well and only require a follow-up.
The prevalence rate of degenerative retinoschisis is 4% of people aged 40 years and up.
American Academy of Ophthalmology (AAO)
2. X-linked Juvenile Retinoschisis (XLRS)
Juvenile retinoschisis (or congenital X-linked retinoschisis) is a hereditary eye disorder. It affects males. It's a genetic disease of the retina that almost always affects both eyes (bilateral).
When a person develops juvenile retinoschisis, vision worsens early in life. Visual acuity may be between 20/60 and 20/120.
Juvenile retinoschisis is estimated to impact one in 5,000 to 25,000 people. It's one of the leading causes of juvenile macular degeneration.
3. Tractional Retinoschisis
Tractional retinoschisis is a disorder often confused with tractional retinal detachment.
Some unique characteristics define tractional retinoschisis. These include:
- People with this condition will have a tractional (pulled or drawn up) elevation of the retina
- The layer will be transparent
- Pigment lines will not develop
- Holes can be present in the raised retina, no change in its contour will occur
People with diabetes or sickle cell disease may have an increased risk of tractional retinoschisis.
4. Exudative Retinoschisis
This is a subclassification of retinoschisis. There is a lipid (fat) in color fundus photography and clinical examination.
Color fundus (retinal) photography uses a type of camera to collect color images of the condition of the eye’s interior surface.
What Causes Retinoschisis?
Retinoschisis has two primary causes:
Genetics
Retinoschisis can occur in males who have a mutation or abnormal gene on the X chromosome. While females can be carriers of the mutation, it's not common for them to develop this eye disorder.
One of the two X chromosomes in females is inactivated (usually that with the mutation).
As a result, there is no consequential clinical manifestation. Males with X-linked disorders like retinoschisis will pass the abnormal gene to all of their daughters.
Degeneration
It's uncommon to find this eye disorder among people younger than 40.
Degenerative retinoschisis often occurs in people in their 50s, 60s, or 80s.
Is Retinoschisis Hereditary?
Yes. Retinoschisis can be hereditary.
Juvenile retinoschisis is the genetic form of this retinal disease.
Males are the most affected by the condition. But females can still be carriers of the recessive trait.
Men with congenital retinoschisis will pass along the X chromosome with the abnormal gene to their daughters.
Signs & Symptoms of Retinoschisis
A central database called the Human Phenotype Ontology (HPO) provides a detailed and up-to-date list of symptoms related to retinoschisis.
According to the HPO, approximately 80 to 90% of people with juvenile retinoschisis will have:
- Abnormal eye movement
- Abnormal vision (a decline in foveal or peripheral vision)
-
Cataracts (clouding of the lens of the eye)
-
Glaucoma (an ocular disease in which the optic nerve is damaged)
According to the HPO, approximately 30 to 79% of people with juvenile retinoschisis will have:
- Macular atrophy (deterioration of the macula, which is the central part of the retina call)
- Retinal pigment epithelial atrophy (weakening of the pigment tissue that lines the retina)
How Serious is a Split Retina?
A split retina is a serious condition.
It's not common for retinoschisis to progress or result in retinal detachment. However, if there is disease progression, symptoms may appear before the loss of central vision, including:
- Flashing lights
- Loss of peripheral vision
- Floaters
Affected individuals with retinoschisis should visit their local eye clinic at least once a year to make sure the eye disorder remains stable.
Potential Complications of Retinoschisis
Retinoschisis isn't something that should be left untreated. The condition presents potential complications.
Can Retinoschisis Cause Blindness?
Yes. In severe cases, retinoschisis can cause blindness.
Severe complications can happen, such as:
- Retinal detachment
- Vitreous hemorrhage (blood vessel leakage in the retina)
- Permanent vision loss
Finally, the risk of legal blindness is higher in those with juvenile retinoschisis.
Is Retinoschisis Progressive?
In cases of senile retinoschisis, the eye disorder rarely progresses.
For juvenile retinoschisis, vision often decreases at a young age. It becomes stable during early or mid-adulthood.
It's also common for people with juvenile retinoschisis to experience another decline in vision when they’re in their 50s or 60s.
Diagnosis & Treatment for Retinoschisis
An eye care specialist will use different diagnostic approaches for retinoschisis, including:
Optical Coherence Tomography (OCT)
This test uses light waves to create images of the retina.
An Electroretinogram (ERG)
This test measures light-stimulated electrical impulses, which determine if there’s an impairment of retinal functioning.
Ultrasonography or Ultrasound
This diagnostic tool can help view abnormalities if the eye has suffered a hemorrhage.
Concerning treatment, it can vary according to the form of the eye disorder:
- People with senile retinoschisis don't usually need medical treatments. It's recommended to undergo annual eye exams to make sure the condition remains stable.
- For those with juvenile retinoschisis, health professionals may use carbonic anhydrase inhibitors. It's a type of medication to help reduce cystic spaces.
- If there is bleeding within the eyeball, laser or cryotherapy (cold) may be an option. This will cut off the damaged retinal area. Nonetheless, most people with juvenile retinoschisis keep functional vision.
- Finally, genetic counseling may be worth considering for families of children with juvenile retinoschisis.
