Cryotherapy to the retina is a surgical technique that involves the application of extreme cold to the retina using a freezing probe or cryoprobe. This procedure serves different purposes depending on the specific condition being treated. Here are two scenarios where cryotherapy is commonly employed:
- Formation of Retinal Adhesion in Retinal Tear or Detachment:
- Retinal Tear: When a tear occurs in the retina, it can lead to a risk of retinal detachment if not addressed. Cryotherapy is used to create an adhesion or scar tissue around the tear, sealing it and preventing the passage of fluid that could lead to retinal detachment.
- Retinal Detachment: In cases where a retinal detachment has already occurred, cryotherapy may be used to create adhesions between the detached retina and the underlying tissue. This adhesion helps reattach the retina to its proper position.
- Procedure:
- During cryotherapy, the cryoprobe is applied externally to the sclera (the white part of the eye) near the affected area.
- The extreme cold causes freezing of the tissue, leading to the formation of scar tissue or adhesion as the tissue heals.
- The scar tissue acts as a barrier, preventing the progression of the tear or detachment.
- Goal:
- The primary goal of cryotherapy in these cases is to stabilize or reattach the retina, preventing further vision loss associated with retinal tears or detachments.
- Destruction of Lesions in the Retina, such as Vascular Tumors:
- Vascular Tumors: Cryotherapy can be used to treat certain lesions in the retina, including vascular tumors. By applying extreme cold to the tumor, cryotherapy destroys the abnormal blood vessels, reducing the risk of bleeding and other complications.
- Procedure:
- The cryoprobe is applied directly to the lesion or tumor on the retina.
- The freezing temperatures cause cellular damage and destroy the abnormal tissue.
- Goal:
- The objective is to eliminate or reduce the size of the vascular tumor, preventing further growth and associated complications.
- Considerations:
- Cryotherapy for lesions in the retina is often used in conjunction with other treatments, and the choice of therapy depends on the nature of the lesion and the patient’s overall health.
In both scenarios, cryotherapy is a localized treatment that aims to address specific issues in the retina. The formation of retinal adhesions helps prevent the progression of tears or detachments, while the destruction of lesions, such as vascular tumors, aims to eliminate abnormal tissue and reduce associated risks. The use of cryotherapy is determined by the ophthalmologist based on the specific characteristics of the retinal condition being treated.
First, the eye is anesthetized, often with an injection of numbing medicine just beneath the skin-like covering of the eye called the conjunctiva. The patient usually feels nothing during this injection. Topical anesthesia before the injection keeps the injection of anesthesia from hurting. Sometimes the eye will get red from the injection and or from the cryotherapy. After the eye is appropriately numbed, the doctor uses a head light and a lens to look into the eye so the freezing probe can be placed in the correct position, immediately adjacent to the retinal tear. The retina surrounding the tear is frozen, usually with several separate cryotherapy spots. Its common to feel pressure on the eye during cryotherapy.
Rarely, cryotherapy is used to treat tumors or to destroy peripheral retina. Small tumors can be frozen and destroyed. This is done for small retinoblastomas, hemangiomas, and angiomas. Sometimes patients with proliferative retinopathy are treated with cryotherapy in the very far periphery of the retina where it is difficult to reach with the laser. Since cryotherapy is applied from the outside of the eye, it is also useful in treating the retina when the view into the retina is poor. The laser has to travel through the eye to reach the retina and can be hindered by a vitreous hemorrhage (blood inside the eye) or a dense cataract. Cryotherapy can be used in those situations because it does not need to traverse the cornea, lens, or vitreous like the laser does.