To understand what a retinal detachment is, first it is necessary to know a little about the structure of the eye, at least the posterior portion, behind the lens. This part, in simplistic terms, is made up of three layers. The outer most layer is the sclera, which is the white part of the eye one sees around the colored iris. The inner layer is the retina, and these two layers are separated by a vascular layer called the choroid. When the retina separates from the outer two layers the retina (“the wall of the eye “), it is said to have detached. There are two types of retinal detachments. The first, and most common, is due to a tear/s in the retina (rhegmatogenous retinal detachment) and the second is a result of scar tissue pulling on the retina (traction retinal detachment). Retinal detachments are considered an ocular emergency and under most conditions should be treated within 24 hours.
How Does A Retinal Detachment Occur?
Within the hollow of the eye, there is a gelatinous material called the vitreous. Vitreous, in early life, is very clear and attached to the retina. This attachment weakens over time, but in some areas may be more firmly attached. With age, the vitreous degenerates and collapses upon itself, thus pulling away from the retina, causing a separation called a (PVD) “posterior vitreous detachment”. However, in an area where there is a tight attachment of the vitreous to the retina, the constant pulling can result in a tear. Once a tear occurs, and there is sufficient traction on the edge of the tear, allowing fluid within the eye to migrate under the retina resulting in a retinal detachment. Depending on the location of the tear/s, the separation can occur very gradually, however under the right conditions, it can occur very rapidly. Traction retinal detachments are due to scar tissue formation within the eye. They most commonly occur in patients with advance diabetic eye disease, after severe ocular trauma, and in patients who have complications after rhegmatogenous retinal detachment surgery.
What Are The Symptoms Of A Retinal Detachment?
Classically the onset of a retinal detachment starts with symptoms of light flashes (photopia) followed by floaters, followed by either a loss of peripheral vision and/or a loss of central vision. Occasionally, patients will present without any symptoms of light flashes and floaters, and complain only of a loss of peripheral visual. Rarer still are those patients who will have a subclinical retinal detachment without any symptoms, whose detachment is discovered on a routine eye exam.
How Are Retinal Detachments Treated?
There are three ways of treating a retinal detachment. The one that would be recommended by your retinal surgeon would depend upon the extent of the retinal detachment, the location of the retinal tear/s, the evidence of any scar tissue formation, and the presence of prior cataract surgery.
The first method, which can be performed in the office setting is call a “pneumatic retinopexy “. It generally, involves two steps, the first is the injection of a small long-acting gas bubble into the eye, and positioning the patient is such a manner that the gas bubble covers the retinal tear/s. This prevents further migration of fluid into the subretinal space, allowing the normal function of the eye to pump out the fluid which has already accumulated under the retina. Once all the fluid under the retina has been removed and the retina around the retinal tear/s is flat, then the second step would be either laser and/or freezing (cryo-therapy) is performed around the tear, creating a low-grade inflammatory reaction which then results in an adherence of the retina to the wall of the eye. Retinal detachments treated in this manner are usually associated with few and small retinal tears with a detachment located above a horizontal line across the center of the eye.
As stated, after the gas bubble is injected into the eye, the patient has to be positioned in such a way as to cover the tear. This, in some cases, will require the patient to lie on their side for several days. This is often considered a hardship, but the procedure takes a much shorter time, as is the recuperative period, and the patient can usually return to normal activity in approximately 3 weeks.
The second method is called a “sclera buckle “. This procedure requires an admission into either the hospital or a surgical outpatient facility and is performed in an operating room, either under local or general anesthesia. It requires placing a solid silicone band or a silicone sponge under the tear/s and detached retina, draining the fluid from under the retina by cutting through the wall of the eye, thus allowing the retina to settle on the wall of the eye (flattening), and either freezing or lasering around the retinal tear/s to create an adhesion between the retina and the wall of the eye. The silicone remains in place throughout the patient’s lifetime unless a complication occurs with regards to the silicone band or sponge. The recuperative period can last up to 6 weeks and requires more frequent follow-up visits.
The third method of treating a retinal detachment, is to perform a “vitrectomy “, which is the removal of most of the gelatinous material (vitreous) within the eye. Once this is completed, the retinal tears are marked from the inside of the eye with diathermy, the fluid under the retina is drained from within, a large gas bubble is placed in the eye to hold the retina flat against the wall of the eye, the tear/s are treated with either freezing or laser, and the patient is positioned appropriately for the gas to cover the retinal tear/s. Occasionally, this method also involves the placement of a scleral buckle, if it is determined that the gas bubble cannot flatten the retina against the wall of the eye due to the location of the retinal tear/s, and/or there is scar tissue preventing the retina from flattening. This method is also performed in an operating room, under local or general anesthesia, and takes about the same amount of time for recovery and the same number follow-up visits as a sclera buckle. This procedure is more complicated than a sclera buckle, but its greatest advantage is that there is improved visualization of the retina during surgery. Tears, which could not be located prior to surgery, are identified, early scar tissue formation can be removed, and often, a sclera buckle is unnecessary. All complicated retinal detachments, especially those with traction, are treated with vitrectomy.
What Is The Success Rate of Surgery?
When we talk about surgical success, we break it down into two categories, surgical success and visual success. Surgical success is very high, at a rate of 95% or more. This is particularly true in the less complicated retinal detachments, which are of recent onset, limited extent, and associated with few and/or small retinal tears. Complicated retinal detachments involving the center of the retina (the macula), are extensive, have been present for a long period of time, associated with large and/or multiple retinal tears, and the presence of any scar tissue have a much poorer surgical success rate.Visual success can also have a very high success rate, but its success depends on the complexity of the case, and the occurrence of any complications during and after surgery. These latter complications cannot often be predicted prior to surgery, and are discussed completely under complications. Despite these limiting conditions, good visual function is often still achieved.
What Are The Complications?
As in all surgical procedures, there is the potential for complications. The most common complications associated with retinal detachment surgery are infection, hemorrhaging, scar tissue formation, recurrent retinal detachment, and increased intraocular pressure. All of these problems can be handled well when addressed in a timely manner. Another complication which can occur in patients who have not had cataract surgery, who undergo a vitrectomy, is an acceleration of a cataract. This could occur very rapidly during surgery and hinder successful management of the retinal detachment. In this situation the cataract is removed during the surgical procedure. More often the progression of the cataract evolves over several months after surgery. Except for the cataract, which can occur in up to 70% of patient, especially those over the age of 70 years, the complication rate is 5% or less.
What Is The Recovery Period and Are there Restrictions?
Retinal detachments which can be successfully treated with a pneumatic retinopexy, recover completely within 2 to 4 weeks during which time vigorous activity is to be avoided. The gas bubble is long-acting, remaining in the eye up to 6 weeks, and because it will expand with decreasing external pressure, traveling to higher elevations and flying are not permitted. The reason for this limitation is because the expansion of the gas bubble at higher elevations will result in an acute rise in intraocular pressure. This in turn will cause severe headache, eye pain, nausea and vomiting. It could also result in permanent loss of vision due to optic nerve damage if the pressure is severely elevated for a prolonged period of time.
Scleral buckles and vitrectomies have a recovery period of up to 6 to 8 weeks before returning to normal activity. For the initial 2 to 3-weeks activity is limited to no running, jumping, stooping or lifting over 10 pounds, then gradually increased over the following 3 to 5 weeks. If a gas bubble is used in conjunction with a vitrectomy, positioning will be necessary as well as limitations on air travel. Topical eye meds are administered for 3 to 4 weeks post-surgery, and are tapered off by the fourth week.
Return to work depends upon the type of work the patient performs. With the exception of those patients treated with a pneumatic retinopexy, those who do a significant amount of strenuous work, will have a longer recuperative course than those who do not, but it rarely extends longer than 6 weeks, assuming there are no complications, even though the full recovery period for follow-up is 3 months.