What is retina?
The retina is the light-sensitive layer of tissue that lines the inside of the eye and sends visual messages through the optic nerve to the brain.
When the retina detaches, it is lifted or pulled from its normal position. If not promptly treated, retinal detachment can cause permanent vision loss.
The retina is about the size of a postage stamp. It consists of a central area called the macula and a much larger peripheral retina. The light receptor cells within the retina are of two types, called the rods and the cones. Rods allow us to see in reduced illumination. Cones provide us with sharpness of vision. The peripheral retina allows us to see objects on either side (peripheral vision) and, therefore, provides the vision needed for a person to move about safely.
Retinal detachment:Retinal detachment may be caused by trauma, advanced diabetes or an inflammatory disorder. But it often occurs spontaneously, as a result of changes in the jelly-like vitreous that fills the vitreous cavity of your eye.
In some cases there may be small areas of the retina that are torn. These areas, called retinal tears or retinal breaks, can lead to retinal detachment.
Retinal detachment refers to separation of the inner layers of the retina from the underlying retinal pigment epithelium (RPE, choroid). The choroid is a vascular membrane containing large branched pigment cells sandwiched between the retina and sclera. Separation of the sensory retina from the underlying RPE occurs by the following 3 basic mechanisms:
A hole, tear, or break in the neuronal layer allowing fluid from the vitreous cavity to seep in between and separate sensory and RPE layers (ie, rhegmatogenous RD)
Traction from inflammatory or vascular fibrous membranes on the surface of the retina, which tether to the vitreous
Exudation of material into the subretinal space from retinal vessels such as in hypertension, central retinal venous occlusion, vasculitis, or papilledema
Detached retina will result in a loss of vision where the retina has been damaged. A person’s retina may detach for many reasons. Retinal detachment is more common among middle aged people and short sighted people. Detached retina may appear like a dark shadow over part of the eye or the person may experience bright flashes of light or showers of dark spots called floaters. These symptoms are not painful. Many people experience flashes and floaters that are not harmful and these are not necessarily a cause for alarm. However, if they seem to be getting worse and part of vision is reducing then the person needs to see an eye specialist urgently. In many cases, the damage can be repaired.
Tears or holes in the retina may lead to retinal detachment by allowing fluid from the middle of the eye to collect under the retina.
Traction pulls the retina away from the layers beneath it.
No treatment has been shown to control central retinal artery occlusion. However, an attempt is made to release the occlusion into the peripheral circulation. To reduce intraocular pressure, therapy includes acetazolamide I.V., eyeball massage, thrombolysis by intra-arterial injection or I.V., high concentrations of inhaled oxygen, and anterior chamber paracentesis (to try to move the arterial obstruction into the peripheral field).
