RETINAL DETACHMENT
What is retinal ablation (detachment)?
Retinal detachment is an emergency condition in which the retina (nerve tissue at the back of the eye) separates from its surface losing its nutrition. The retina converts the light stimuli into the electric signal which travels through the optic nerve into the brain where we actually experience the “picture” of the outer world.
There are three different forms of retinal detachment:
Rhegmatogenous ablation
This type of retinal detachment is the most common one. It is caused by the hole or tear in the retina that allows the fluid to pass and accumulate beneath the retina, which separates it from its base. In this way, detached area loses its nutition, resulting in loss of vision.
The most common cause of rhegmatogenous detachment is aging. With aging the vitreous (a gelatinous substance that fills the eye giveing it its volume) changes its properties and becomes more diluted. Vitreous usually separates from the surface of the retina without any complications – a condition called posterior vitreous detachment (PVD). One of the complications of such separation is the retinal tear.
Tractional ablation
This form occurs when scar tissue grows on the the retinal surface, consequently pulling the retina and separates it from its base. It usually occurs in people who have poorly controlled diabetes or similar conditions.
Exudative ablation
In this form, the fluid accumulates beneath the retina, but there is no hole or gap in the retina. Exudative ablation may be caused by Age-related macular degeneration, eye injury, tumor or inflammatory disorders.
Retinal Detachment – Risk Factors
The following factors increase the risk of retinal detachment:
• Aging – retinal detachment is more common in people over the age of 50
• Previous detachment of the retina on one eye
• Retinal detachment in family members
• High shortsightedness (myopia)
• Previous eye surgery, such as cataract surgery
• Previous serious eye injury
• Previous other eye conditions, including retinoshisis, uveitis, or peripheral retinal degeneration (“lattice” degeneration)
Retinal Detachment – Symptoms
Detachment of the retina is painless, but certain warning signs are almost always present:
• Sudden appearance of many dark “dots” – tiny particles that pass across the visual field
• Experiencing certain light phenomena in one or both eyes (photopsies, light flashes)
• Blurred vision
• Gradually reduced peripheral vision
• A shadow-like acurtain over your visual field
Retinal Detachment – Examination
A complete ophthalmological examination with dilated pupils is carried out. Ophthalmologist examines your eye background in detail. Other examinations such as ocular ultrasound or OCT may also be used.
Retinal Ablation – Treatment
Apart from the earliest stage of this condition, when any retinal defect can be fixed by laser “seals” around the lesion, there is almost always a need for surgical treatment to repair the holes, the gap or retinal tear. There are several different operating techniques.
Retinal Tear
When the retinal holes have not yet advanced in separation from the base, the ophthalmologist may propose one of the following procedures to prevent futher retinal separation and maintain vision.
Laser Treatment (Photocoagulation)
The surgeon directs the laser beam through the pupil. The laser creates “seals” around the retinal defect, creating scars that usually seal the retinal defect.
Freezing (cryopexy)
Once a local anesthetic is applied, the surgeon applies freezing probe to the outer surface of the eye directly at the site of the defect. The freezing causes a scar that helps secure the retina to the eye wall.
Both interventions are performed in outpatient setting and it is suggested to avoid physical activities – such as running – for a few weeks or more.
Retinal detachment
If the retina has completely detached – surgical procedure is required to repair the defect, preferably within a few days of diagnosing. The type of surgery will be recommended by vitreoretinal surgeon depending on several factors, primarily how severe detachment is.
Injecting air or gas in the eye
In this type of surgery, called pneumatic retinopexy, a vitreoretinal surgeon injects bubble of air or gas into the middle of the eye. Properly positioned, the bubble pushes the area of the retina with defect to the eye wall, stopping further fluid penetration into the subretinal space. The surgeon then uses cryopexy (freezing) to repair the retinal defect.
The liquid that accumulates beneath the retina itself rebsorbs, and the retina can then return to its natural place, that is, to the wall of the eye. The patient usually needs to hold the head in a certain position after the operation and for up to several days to keep the bubble in the required position. The bubble is resorbed after a few days.
Identing of the surface of the eye
In this procedure, called scleral buckling, the surgeon places a silicone seal across the affected area, thus nullifying the force by which the vitreous pulls the retina.
If the patient has several holes or defects, the surgeon can place a scleral buckle that surrounds the entire eye like a belt. The buckle is positioned in a way that does not disturb the eyesight and usually remains permanently.