The retina is a thin layer of light sensitive tissue on the back wall of the eye. The optical system of the eye focuses light on the retina much like light is focused on the film or sensor in a camera. The retina translates that focused image into neural impulses and sends them to the brain via the optic nerve. Occasionally, posterior vitreous detachment, injury or trauma to the eye or head may cause a small tear in the retina. The tear allows vitreous fluid to seep through it under the retina, and peel it away like a bubble in wallpaper.
SIGNS AND SYMPTOMS
A retinal detachment is commonly preceded by a posterior vitreous detachment which gives rise to these symptoms:
Although most posterior vitreous detachments do not progress to retinal detachments, those that do produce the following symptoms:
severe myopia, retinal tears, trauma, family history, as well as complications from cataract surgery. Retinal detachment can be mitigated in some cases when the warning signs are caught early. The most effective means of prevention and risk reduction is through education of the initial signs, and encouragement for people to seek ophthalmic medical attention if they have symptoms suggestive of a posterior vitreous detachment. Early examination allows detection of retinal tears which can be treated with laser or cryotherapy.
Trauma-related cases of retinal detachment can occur in high-impact sports or in high speed sports. Although some recommend avoiding activities that increase pressure in the eye, including diving and skydiving, there is little evidence to support this recommendation, especially in the general population. Nevertheless, ophthalmologists generally advise people with high degrees of myopia to try to avoid exposure to activities that have the potential for trauma, increase pressure on or within the eye itself, or include rapid acceleration and deceleration, such as bungee jumping or roller coaster rides.
Retinal detachment can be examined by fundus photography or ophthalmoscopy. The examination of the fundus with the use of depression of the eye with a cotton tip applicator or other blunt instrument in order to view the entire retina is done. Patients with retinal detachment are largely diagnosed by this examination.
Ultrasound scan provides a safe and useful means of evaluating intraocular structural characteristics that cannot be determined by visual examination techniques.
Rhegmatogenous retinal detachment – A hole, tear or break in the neuronal layer of retina allowing fluid from the vitreous cavity to seep in between and separate sensory and RPE layers.
Exudative, serous, or secondary retinal detachment – Exudation of material into the subretinal space from retinal vessels such as in hypertension, central retinal venous occlusion etc.
Tractional retinal detachment – Traction from inflammatory or vascular fibrous membranes on the surface of the retina which tether to the vitreous.
A minority of retinal detachments result from trauma, including blunt blows to the orbit, penetrating trauma, and concussions to the head.
There are several methods of treating a detached retina, each of which depends on finding and closing the breaks that have formed in the retina. All three of the procedures follow the same three general principles:
Find all retinal breaks
Seal all retinal breaks
Relieve present (and future) vitreoretinal traction
Cryotherapy(freezing) or laser photocoagulation are occasionally used alone to wall off a small area of retinal detachment so that the detachment does not spread.
Scleral buckle surgery
Scleral buckle surgery is an established treatment in which the eye surgeon sews one or more silicone bands (bands, tyres) to the sclera (the white outer coat of the eyeball). The bands push the wall of the eye inward against the retinal hole, closing the break or reducing fluid flow through it and reducing the effect of vitreous traction thereby allowing the retina to re-attach. Cryotherapy (freezing) is applied around retinal breaks prior to placing the buckle. Often subretinal fluid is drained as part of the buckling procedure. The buckle remains in situ. The most common side effect of a scleral operation is myopic shift. That is, the operated eye will be more short sighted after the operation.
Vitrectomy is an increasingly used treatment for retinal detachment. It involves the removal of the vitreous gel and is usually combined with filling the eye with either a gas bubble (SF6 or C3F8 gas) or silicone oil. An advantage of using gas in this operation is that there is no myopic shift after the operation and gas is absorbed within a few weeks. Silicon oil (PDMS), if filled needs to be removed after a period of 3-6 months depending on surgeon's preference. Silicone oil is more commonly used in cases associated with proliferative vitreo-retinopathy (PVR).
85 percent of cases will be successfully treated with one operation with the remaining 15 percent requiring 2 or more operations. After treatment patients gradually regain their vision over a period of a few weeks. Success of surgery depends upon the age of the patient, duration of detachment, location (peripheral/central) and extent of the detachment, and an early surgical intervention.
If there is peripheral RD and the macula has not been detached, the result of early surgical repair can be excellent. 90 percent of patients have 20/40 vision or better after reattachment surgery. Some damage to vision may occur during reattachment surgery, and 10 percent of patients with normal vision experience some vision loss after a successful reattachment surgery.
Involvement of the macula portends a worse prognosis.
Treatment failures usually involve either the failure to recognize all sites of detachment, the formation of new retinal breaks, or proliferative vitreoretinopathy.