Retinal detachment is a medical emergency, which involves peeling away of retina from the underlying tissue (choroid) which holds it. Initially the detachment may be only localized, but without prompt and appropriate treatment the entire retina may detach from the underlying supporting tissue. Unless promptly corrected by surgical intervention, retinal detachment may result in blindness.
The retina is a thin layer of light sensitive tissue on the inner side of the back wall of eyeball, where light rays fall after refraction in cornea and lens curvatures and we can see an object. That is why when there is detachment of a part or whole retina, vision disturbance or blindness results.
Types and Causes of Retinal Detachments
Types of retinal detachments include rhegmatogenous retinal detachment, exudative (also known as secondary or serous retinal detachment) retinal detachment and tractional retinal detachment.
The rhegmatogenous retinal detachment usually occurs due to development of break in the passage between sensory retina and retinal pigment epithelium, through which liquid passes from vitreous to subretinal space. The break may be tear or hole.
The exudative retinal detachment occurs due to inflammation, injury or vascular abnormalities due to accumulation of fluid in subretinal space, but without any tear or hole in retina, unlike rhegmatogenous retinal detachment.
The tractional type of retinal detachment occurs due to pulling of sensory retina from the retinal pigment epithelium, injury, inflammation or any neovascularization.
Retinal detachments can also occur due to trauma (such as penetrating injury, head injury or direct blunt blow to the eyeball).
What are the risk factors of development of retinal detachment?
The risk factors include trauma, older age (more common after age of 40), history of previous retinal detachment in one eye, previous eye surgery (such as cataract surgery), severe myopia (nearsightedness) and long standing diabetes (especially if diabetic retinopathy has developed).
How Common are Retinal Detachments?
The incidence of retinal detachment is estimated to be approximately 5 in every 100,000 per year. But the incidence is much higher in older population at about 20 in 100,000 per year and total lifetime risk of retinal detachment is 1 in 300 individuals (600 eyes). Severe myopia (more than 5 diopters) increases the risk of retinal detachment to 1 in 20. Retinal detachment usually occurs in one eye only, but the risk of developing in the other eye is 15%, which increases to 25-30% if cataract surgery is done in both eyes.
What are the symptoms of a retinal detachment?
The symptoms of retinal detachment include sudden appearance of floaters or sudden increase in number of floaters, appearance of sudden flashes of light known as photopsia in one or both eyes in extreme peripheral part of vision and feeling of heaviness in the eye. All of these are due to posterior vitreous detachment which commonly precedes retinal detachment.
When posterior vitreous detachment progress to retinal detachments it produce symptoms such as a shadow or curtain which starts peripherally and progresses towards the center of vision and it feels that someone had drawn a curtain over the field of vision, the straight lines appear curved and finally loss of vision. If any of the initial symptoms of retinal detachments appear, it is the time to see an eye doctor.
An eye doctor (ophthalmologist) will be able to diagnose retinal detachment easily by examining retina with the help of ophthalmoscope and see a retinal hole, tear or detachment. If your eye doctor can not visualize retina due to presence of blood, ultrasound examination can clinch the diagnosis accurately.
Treatment of retinal detachment
Surgery is the only effective way of treating a retinal detachment. Whatever surgical procedure is followed it's aimed at finding all retinal breaks (holes, tears), sealing all the retinal breaks and relieving vitreoretinal traction.
Surgery for retinal tear, before retinal detachment occurs, includes laser surgery of laser photocoagulation and freezing or cryopexy. These procedures can prevent retinal detachment and normalize vision. Healing generally takes two weeks.
In laser surgery (photocoagulation) a beam of laser is directed to burn around retinal tear which cause scar formation, which in turn "weld" the tear to underlying tissue. The laser beam is sent through a contact lens or ophthalmoscope especially designed for this purpose.
In cryopexy a freezing probe is introduced to the retinal tear which causes a scar and seals the tear.
Once retinal detachment has occurred three different types of surgeries namely Pneumatic retinopexy, Scleral buckling and Vitrectomy can be done based on type, size and location of the retinal detachment.
Pneumatic retinopexy is commonly preferred for uncomplicated cases of retinal detachment and can be done as outpatient procedure under local anesthesia. Scleral buckling is very commonly done to treat retinal detachment. Vitrectomy or removal of vitreous may be sometimes required when it becomes cloudy and blocks the surgeon's view of the detached retina or retinal scarring. Since many patients experience eye floaters also, a vitrectomy will help clear the vitreous humor and free the patient from eye floaters.
Is it possible to prevent retinal detachment?
The preventive measures include educating people to seek help of eye surgeon if they have any of the symptoms of initial stage of retinal detachment, such as sudden increase in number of floaters, bright flashes of light, or a shadow or curtain that seems to fall across your visual field, especially in people of 40 years of age or more.
There is no method which can prevent retinal detachments, but certain measures such as strict control diabetes (to prevent diabetic retinopathy), avoidance of other risk factors if possible, can reduce the incidence of retinal detachments to some extent. Regular consultation with your ophthalmologist if you have any risk factors of retinal detachment can reduce incidence significantly.