Retinal detachment refers to the process in which the neurosensory layer of the eye called the retina, which is responsible for receiving and transmitting light signals to the brain and enabling vision, is pulled off or peels off the underlying retinal pigment epithelium. In many cases, there is a posterior vitreous detachment.
If untreated, retinal detachment causes severe loss of vision. In some cases, it improves though it may take a few months for some degree of vision to return.
Factors that affect prognosis
The prognosis following a retinal detachment depends upon various factors, such as:
- The type of detachment
- The time that has elapsed since it occurred
When macular detachment is detected at the time of first presentation and the event occurred within the last week, it is possible to treat the detachment and hope to regain some useful vision. Normal sight, however, is not attainable. After a week, it is very probable that whatever vision is regained will be limited. In many patients, vision will be so low as to fall below the limit for legal blindness.
The underlying cause
Wet age-related macular degeneration, for instance, causes profuse exudation (discharge) which predisposes to macular detachment, associated with poor vision preservation. A limited tear due to vitreous traction at a peripheral site may be repaired and may never recur, allowing the patient to have good vision thereafter.
The location of the detachment
This also plays an important role in the prognosis. When the macula is affected, retinal detachment threatens the future vision severely. However, with peripheral detachment, preventive treatment such as laser retinopexy or pneumatic retinopexy may help avoid a macular detachment and conserve good central vision. The patient should act promptly when there are any symptoms of vitreous or retinal detachment. Symptoms may include floaters (specks, dark strands or cobweb-like appearances moving across the field of vision at random and appear to dart away when looked at), flashes of light -especially towards the side of the visual field, and in the dark, or the fall of a dark or gray curtain over the field of vision.)
This will ensure that the right prophylactic treatment is employed on the same day, if possible. This is of great help in preventing macular detachment which results in the patient losing much of the capacity to look at something and obtain a fine detailed image. Even when a patient presents with macular detachment already present, but the onset was less than a week before, total blindness may be prevented by appropriate treatment, though normal vision is impossible to regain.
The size of the detachment
Return of visual acuity depends also on whether the detachment is limited in extent, in which case the prognosis is excellent, provided the macula is spared.
Prognosis for retinal reattachment and vision
When the above factors increase in severity, a significant improvement in vision is unlikely. This is why patients with symptoms like floaters (specks, dark strands or cobweb-like appearances moving across the field of vision at random, and appear to dart away when looked at), flashes of light especially towards the side of the visual field, and in the dark, or the fall of a dark or gray curtain over the field of vision, are urged to have a full eye examination within 24 hours. These symptoms may or may not represent the start of a retinal detachment, but should be attended to promptly. These are indications of an emergency situation requiring immediate resolution, with respect to the eye.
Modern treatment techniques have made for a good outcome in 9 out of every 10 patients with retinal detachment, as far as the reattachment is concerned. However, a successfully reattached retina does not always mean a satisfactory recovery of vision. In most cases, one or two attempts are sufficient to reattach the retina. In a few cases, more procedures may be required. The number of attempts does not influence the likelihood of sight recovery.
In a tenth of patients, retinal detachment in one eye is followed by the same in the other eye. This is regardless of whether or not any predisposing factors were present or not. In some cases prophylactic treatment is advised. In all patients, regular scheduling of follow-up examinations is essential. In addition, it is important to educate all patients who have had a previous detachment to make them aware of the symptoms that could be indicative of etinal detachment in the other eye. They should be advised of the need for prompt reporting of such symptoms.
Reviewed by Yolanda Smith, BPharm