Retinal Detachment

There are three basic types of retinal detachment: rhegmatogenous, tractional, and exudative. Each of these types of retinal detachment is discussed below.

Indications for Retinal Detachment Repair

• Rhegmatogenous retinal detachment (secondary to retinal hole or tear)
• Tractional retinal detachment (secondary to vitreous membranes, such as that which may occur in proliferative diabetic retinopathy)
• Proliferative vitreoretinopathy (PVR), secondary to long-standing retinal detachment

Rhegmatogenous Retinal Detachment

Rhegmatogenous retinal detachment is the most common type of retinal detachment. It occurs when a break (tear or hole) in the retina allows fluid from the vitreous humor to enter the potential space beneath the retina. This causes the retina to separate from the layer beneath, known as the retinal pigment epithelium (RPE). This type of retinal detachment represents an emergency, and surgery is typically scheduled urgently (within 24 hours of diagnosis).

Most cases of rhegmatogenous retinal detachment are associated with a posterior vitreous separation, which is a natural part of aging. This is due to the natural contraction, or shrinkage, of the vitreous humor, which occasionally creates traction on the retina, producing a retinal break (hole or tear). The process of posterior vitreous separation is often accelerated by cataract surgery, trauma, YAG laser capsulotomy following cataract surgery (for a hazy capsule behind the lens implant), diabetes, vitreous hemorrhage, and uveitis (inflammation inside the eye). Certain other conditions predispose one to retinal detachment, such as high myopia (nearsightedness), a peripheral retinal degeneration known as lattice degeneration, and a number of different inherited syndromes.

Patients will often experience flashes of light, floaters, and a curtain-like loss of vision as the retinal detachment ensues. Many patients will present when the retinal detachment involves only the peripheral retina. These patients have the best prognosis for retained vision. Other patients present when central vision is lost, which may represent retinal detachment involving the macula (central retina). Because the macula is responsible for central vision, these patients have a less favorable prognosis than patients with a peripheral retinal detachment. The duration of retinal detachment is critical to the prognosis, i.e., the longer the detachment, the worse the prognosis. Patients with macular detachment for even one day have reduced postoperative visual acuity, i.e., preoperative acuity correlates with postoperative acuity. Eighty-five to 90% of patients with preoperative acuity of 20/30 or better will have postoperative acuity of 20/30 or better. Overall, retinal detachment surgery is successful in reattaching the retina in more than 90% of cases.

The primary surgical methods employed to treat rhegmatogenous retinal detachment include scleral buckling (placement of an encircling band around the eye), vitrectomy (surgical removal of vitreous humor), and pneumatic retinopexy (injection of a gas bubble into the vitreous cavity combined with cryotherapy of the retinal break).

Tractional Retinal Detachment

Tractional retinal detachment occurs when fibrous membranes (essentially scarring processes) in the vitreous humor and retina produce mechanical traction on the retina, literally pulling the retina from the underlying layer, known as the retinal pigment epithelium (RPE). This type of retinal detachment is most common in the advanced stages of diabetic retinopathy, known as proliferative diabetic retinopathy. Retinopathy of prematurity and sickle cell retinopathy are other conditions that may be associated with tractional retinal detachment. The symptoms of tractional retinal detachment generally include loss of vision and/or blind spots. Some patients will have light flashes, floaters, and a curtain-like visual loss.

The treatment of tractional retinal detachment requires relieving the traction, and therefore, almost always requires vitrectomy to remove the vitreous humor and tractional membranes. Some patients may also require the intraocular injection of air, gas, or silicone oil, which may help to prevent recurrent retinal detachment. Because many patients will have severe underlying retinopathy, the prognosis is usually guarded.

Exudative Retinal Detachment

Exudative retinal detachment occurs with conditions that disturb the blood-retinal barrier, i.e., conditions that allow the build-up of fluid beneath the retina. Many conditions may cause exudative retinal detachment. Inflammatory conditions such as Vogt-Koyanagi-Harada syndrome, collagen-vascular diseases, and posterior scleritis are often implicated. Other conditions such as tumors of the eye (e.g., choroidal melanoma), congenital abnormalities (e.g., Coat's syndrome), and nanophthalmos (extremely small eyes) may also be associated with exudative retinal detachment. The treatment of exudative retinal detachment is frequently non-surgical. That is, the underlying condition, which is often systemic, must be treated. If the underlying condition can be rapidly controlled, the prognosis for recovery of vision is often good.

Retinal Detachment Repair

The retina, which lines the inside of the posterior wall of the eye, may occasionally become detached for various reasons. Most commonly, retinal detachment occurs as a result of a tear or hole in the retina, which develops as a result of a posterior vitreous separation (PVS). The retinal tear or hole allows fluid to enter the subretinal space, thus detaching the retina.

The retina receives oxygen and nutrients from the underlying choroid (vascular layer) of the eye. When a retinal detachment occurs, the detached retina begins to dysfunction, and ultimately, necrosis (death) ensues as a result if the retina is not reattached to the underlying choroid. As such, a retinal detachment is an urgent condition. The detached retina should be recognized and treated promptly.

Retinal Detachment Surgical Procedures

The surgical management of retinal detachment may include several different procedures, depending on the circumstances. These procedures include pneumatic retinopexy, scleral buckling, and vitrectomy. Each of these procedures is discussed below.

Pneumatic Retinopexy

Pneumatic retinopexy is a procedure in which a gas bubble is placed inside the vitreous cavity, either before or after, the retinal hole is treated with laser or cryotherapy (freezing) to help seal the hole permanently. The gas bubble, which must be positioned over the hole, prevents fluid from entering the hole while the retina heals. Ophthalmologists sometimes use the phrase, "put the bubble on the trouble" to describe this aspect of the procedure to patients. Since the positioning of the bubble is dependent on positioning of the patient, pneumatic retinopexy is usually only appropriate for retinal detachments (with holes) in the superior (top) part of the eye.

Scleral Buckling

Scleral buckling surgery is probably the most commonly required procedure for repair of retinal detachment. In this procedure, a soft silicone band is placed around the eye, which indents the outside of the eye towards the detached retina, thereby relieving vitreous traction on the retinal hole. The buckle is much like a belt around one's waist. It is kept in place with tiny sutures to the sclera of the eye. In many cases, the vitreo-retinal surgeon drains the fluid under the retina at the site of the retinal detachment, and then seals the hole (or holes) with laser or cryotherapy.

Vitrectomy

In some cases, a vitrectomy is also necessary for repair of a retinal detachment. In this procedure, the vitreous humor is removed from the eye with an instrument known as a vitrector. This instrument utilizes a tiny guillotine cutting device to safely remove the vitreous while replacing it with saline. Laser photocoagulation or cryotherapy are still typically used if a retinal hole or tear is present, and in some cases, a special fluid known as Perfluoron may be used to help push the retina back into position. A scleral buckling procedure may also be combined with the vitrectomy for certain types of retinal detachment.

Retinal detachment can be successfully repaired in about 90% of cases with a single surgical procedure. However, anatomical success does not always mean functional success. Those patients with retinal detachments that do not involve the macula (central retina) have the best prognosis. Fortunately, the great majority of patients will have a successful outcome, especially if they seek attention as soon as vision is lost.

After Your Retinal Detachment Repair

Following retinal detachment surgery, you will likely be required to use antibiotic and anti-inflammatory eye drop medications, perhaps for a few weeks or more following surgery. Your surgeon will prescribe a regimen of medication and follow-up, which you should carefully follow.

Recovery following retinal detachment repair will depend largely on the location and extent of retinal detachment prior to repair. Patients who have had only a peripheral retinal detachment will likely have faster recovery and a better outcome than patients who had a retinal detachment involving the macula (central retina). Patients who had a total retinal detachment, which had been present for a few weeks or more, have a much worse prognosis for a favorable visual result. In any case, the final visual result may not be known for up to several months following surgery. Your surgeon will be the best judge of what individual results you should expect.

>back to "Opthalmology"