Eye treatment modalities
Cryotherapy involves the application of a very cold probe to the outside of the eye, which, because of the thin nature of the eye wall (sclera), transmits the freezing temperature to the retina. Like a laser, the intense cold stimulation to the retina can seal abnormal leaky retinal blood vessels or seal retinal tears. This technique is often preferable to laser in treatment of certain conditions in the far periphery (corners) of the retina, especially when problems such as vitreous hemorrhage or cataract obscure the passage of light into the eye, limiting the effectiveness of laser. Cryotherapy is often performed in conjunction with surgical treatments for retinal detachment, such as scleral buckle or pneumatic retinopexy. It is also sometimes used in the treatment of proliferative diabetic retinopathy, in a manner similar to panretinal photocoagulation. Patients usually require small anesthetic injections before cryotherapy is performed. A patch is often applied for the remainder of the day of the treatment, and a short course of drops may be necessary afterwards.
This is an in-office method of repairing certain types of retinal detachment. It relies on an injection of a small amount of medical grade gas into the vitreous cavity in the center of the eye. The gas bubble floats in the eye, and it can be positioned against the retinal tear responsible for the retinal detachment by holding the head in a certain position. This prevents fluid from passing through the retinal defect, allowing the detachment to resolve. The bubble also presses the tear flat against the wall of the eye, and laser or cryotherapy then produces a strong bond between these layers.
After placement of the gas, the patient must maintain the appropriate head position for one to two weeks to allow maximum gas-retinal hole contact. The intravitreal gas spontaneously dissolves several weeks after its placement, at which time the retina is hopefully permanently reattached. Patients with a gas bubble in the eye cannot travel at high altitude due to the risk of gas bubble expansion and severe elevation of the intraocular pressure.
A scleral buckle is a flexible piece of silicone material, which is permanently sewn to the outside wall (sclera) of the eye in order to repair or prevent retinal detachment. The buckle indents the wall of the eye, bringing the eye wall into contact with the retina. Placement of the scleral buckle is combined with other techniques, such as drainage of fluid under the retina, injection of air or gas into the eye (as in pneumatic retinopexy), cryotherapy, or laser, in order to flatten the retina.
The procedure is performed in a hospital operating room and usually takes 1-2 hours. It is typically performed under local (injection) anesthesia, with sedation. In other words, the patient is awake during the procedure, but does not feel pain or see the procedure being performed. General anesthesia may be used instead in some cases. It is an outpatient procedure; no hospital stay is required.
Patients go home with a patch on the eye, which is removed in the doctor's office on the day after surgery. There may be several follow-up visits during the first month, and visits less frequently for a few months beyond. Eye drops are used for a few weeks after the surgery. These typically include steroid drops to minimize inflammation, antibiotic drops to prevent infection, and dilating drops to provide comfort and minimize scarring of the pupil. Drops to lower the pressure in the eye are also sometimes necessary.
The patient may have to maintain a certain head position for a few days after the surgery, especially if an air bubble is injected. Patients are usually able to return to normal activity within a few weeks. Most of the healing occurs during the first month, but full visual recovery may take a few months. The shape of the eye changes with scleral buckle placement, and new glasses may be necessary to compensate for this change once the eye has healed.
In-Office Temporary Balloon Scleral Buckle
This procedure reattaches the retina using similar repair mechanisms as the in-hospital scleral buckle procedure, except that it can be performed in the office and does not result in the placement of a permanent silicone sponge sewn to the eye wall. Instead, a small balloon (about the size of a pea) is positioned on the outside of the eye in an area corresponding to the retinal hole. Gentle pressure exerted on the hole by the balloon, combined with laser or cryotherapy, results in permanent retinal re-positioning against the inner curvature of the eye. Usually, the balloon buckle is withdrawn 7-10 days after placement. This procedure is less invasive and has a quicker recovery time than standard scleral buckle surgery.
In an attempt to control cytomegalovirus retinitis, a common manifestation of acquired immune deficiency syndrome (AIDS), a long-acting capsule of the antiviral drug ganciclovir is placed into the anterior vitreous cavity during short an operative procedure. By slowly releasing the medication into the vitreous cavity, the retinal infection can be held in check, and vision can be preserved. After 6-7 months, this implant may need to be replaced by a fresh one. This type of localized treatment for this serious eye infection obviates the need for daily intravenous injections.