Retinal Detachment
The retina is the part of the eye that is ultimately responsible for creating the images that we see. In order to function properly, the retina must remain firmly attached to the back wall of the eye. If the retina detaches, or comes away from the wall of the eye, it will not be in the proper position to send messages to the brain or to receive the oxygen and nutrients that it requires to function properly.
The most common form of retinal detachment is termed a rhegmatogenous retinal detachment. This is most typically a result of a posterior vitreous detachment (PVD). The vitreous may pull on the retina and cause a tear or break to form. Fluid from the vitreous cavity may then seep in through the retinal tear and start to push the retina away from the wall of the eye, causing the retina to detach.
Since a posterior vitreous detachment is a part of the normal aging process of the eye, there does not need to be anything else wrong with the eye for a retinal detachment to occur. However, there are several factors that make the development of a rhegmatogenous retinal detachment more likely. People who are myopic (near-sighted) may have a peripheral retinal degeneration called lattice degeneration which predisposes to the development of retinal holes or tears. Direct trauma to the eye can also lead to the development of a retinal tear- anytime from days to years after the incident. Retinal detachment may also occur after a perfectly uncomplicated cataract operation, probably due to alterations in the vitreous that occur during or after the operation.
The initial signs and symptoms of a retinal detachment often include flashes and floaters, which are associated with the development of the posterior vitreous detachment. However, sometimes a PVD can develop with no signs or symptoms. In addition, since most retinal tears occur in the peripheral portions of the retina, and not near the center of the retina, central vision may not be affected immediately and the loss of peripheral vision may not be noticeable.
Signs and symptoms of a retinal detachment may include:
- flashes and floaters
- a shadow or veil involving the peripheral vision
- loss of central vision (if the detachment progresses to the macula)
Under ideal circumstances, if a retinal tear is discovered before a retinal detachment ensues, the tear can be treated in order to prevent the development of a retinal detachment. This is typically performed using a laser, creating a series of burns around the retinal tear. These burns will evolve into a scar and create a firm adhesion between the retina and the underlying tissue, thus preventing the fluid from pushing the retina away from the wall of the eye. Even if laser burns surround the tear, the retina can still detach before the burns evolve into a firm scar. It is also possible for new tears to develop and so close follow-up is essential. Fortunately, treatment of most cases of retinal tears is successful.
If a retinal detachment occurs, then some form of surgery is required. The most common techniques include pneumatic retinopexy, scleral buckling, or vitrectomy surgery.
In pneumatic retinopexy, a gas bubble is injected into the vitreous cavity and laser is applied around the retinal tear. The gas bubble helps push the retina back to its normal position while the laser scars form, and prevents more fluid from entering the tear. This technique may be performed in an office setting, but is usually reserved for less complicated detachments involving the upper part of the eye (because the gas bubble floats up).
Scleral buckling surgery involves sewing a piece of silicone sponge or solid silicone onto the outside surface of the eye, directly behind the area of the retinal tear. The buckle indents the wall of the eye up against the tear, thereby closing the tear. Laser is used to surround the retinal tear.
Vitrectomy means to remove the vitreous humor, and is often reserved for the more difficult retinal detachments, or for those that have failed other attempts at repair. A vitrectomy is often performed along with other procedures, including laser, gas injection, and scleral buckling.
Fortunately, over 90% of retinal detachments can be repaired with just one operation. The ultimate visual results depend on whether the macula, the central portion of the retina, was detached. The longer the macula was detached, the more likely permanent damage occurred, making a return of normal vision unlikely.
