Cryotherapy

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 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.

Pneumatic Retinopexy

Retinal Detachment
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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.

Ganciclovir Implant

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 a 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.