Retinal detachment
The retina is a thin tissue which lines the inner aspect of the back of the eye ball. When light falls on the eye, it is focused by the optical apparatus of the eye onto the retina which converts it into electrical signals which are carried through the optic nerve to the brain. These signals are perceived and interpreted in the brain.
Causes
Retinal detachment is a condition in which the retina completely or partly detaches from its attachment to the underlying tissues in the eye. The primary cause is usually a retinal tear.
Vitreous, a clear gel like fluid which fills two thirds of the eye ball may sometimes exert a pull on the retina leading to holes or tears in the thin retinal tissue. If fluid from within the eye passes through this retinal tear, it can separate the retina from its underlying tissue and that causes retinal detachment.
Congenital retinal detachment though rare, is not very uncommon. A premature newborn suffering from a condition called retinopathy of prematurity can soon develop retinal detachment after birth, if left untreated. Other conditions associated with retinal detachment in children include hereditary vitreoretinal disorders, malformations in the eye and retinal detachment following paediatric cataract surgery. In a few cases, retinal detachment is caused by uveitis and by Coats disease.
Risk factors
The common risk factors of retinal detachment are
- Aging — retinal detachment is more common in people older than age 40
- Previous retinal detachment in one eye
- A family history of retinal detachment
- Extreme nearsightedness (myopia)
- Previous eye surgery, such as cataract removal
- Previous severe eye injury or trauma
- Previous eye disease or disorder
Symptoms
Retinal detachment itself is painless, but can have warning signs and symptoms.
- The sudden appearance of many floaters — small bits of debris in the field of vision that look like spots, hair or strings and seem to float before your eyes.
- Sudden flashes of light in the affected eye.
- A shadow or curtain over a portion of your visual field that develops as the detachment progresses.
Diagnosis
Retinal detachment can be diagnosed clinically after a dilated eye examination by a trained vitreoretinal surgeon. In cases where the retina cannot be visualised clinically, an ultrasonography of the eye will confirm the diagnosis.
Treatment
The treatment options for retinal detachment are –
- Laser treatment (thermal) or freezing (cryopexy): They are approaches that can repair a tear in the retina if it is diagnosed early enough. This procedure is often done in the doctor’s clinic.
- Pneumatic retinopexy: Itis a procedure that can be used to treat retinal detachment if the tear is small and easy to close. A small gas bubble is injected into the eye (specifically, into the the clear, gel-like substance between the lens and the retina), where it then rises and presses against the retina, closing the tear. A laser or cryopexy can then be used to seal the tear.
- Scleral buckle: It involves surgically sewing a silicone band (buckle) around the white of the eye (called the sclera) to push the sclera towards the tear until the tear heals. This band is not visible and remains permanently attached. Cryo (freezing) treatment may then be necessary to seal the tear.
- Vitrectomy: This surgery for retinal detachment is used for large tears. During a vitrectomy, the doctor removes the vitreous (the clear, gel-like substance between eye’s lens and retina) and replaces it with an appropriate substitute like silicone oil or gas, followed by strict postoperative head positioning, as instructed by the doctor.
Complications
If left untreated, retinal detachment may lead to -
Permanent loss of vision: If there is delay in treatment or involvement of the macula (central area of retina with maximum visual acquity) vision may not recover completely and visual prognosis is poor.
Epiretinal membrane: A thin layer of fibrous tissue grows over the retina if it is detached for a long time due to chronic low grade inflammation. This membrane later contracts causing retinal folds leading to distortion in vision.
Vitreous hemorrhage: Blood in the clear vitreous gel can be associated with retinal detachment causing further loss in vision and a change in the modality of treatment.
Secondary Glaucoma: Untreated old retinal detachment can cause abnormal blood vessels to grow on the retina and iris causing intractable increase in ocular pressure leading to secondary glaucoma associated with painful permanent blindness.
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