Definition & Overview
A cryopexy or retinal cryopexy is an ophthalmologic procedure that treats various retinal conditions by destroying retinal tissue and inducing chorioretinal scar using extremely cold temperature. The procedure has been in use in ophthalmologic medicine since the 1960s and can be performed on both young and adult patients. Although it comes with a certain degree of risk, possible complications rarely occur, making it a relatively safe and highly beneficial treatment.
Who Should Undergo and Expected Results
Cryopexy can be recommended for patients with conditions that affect the retina, such as:
- Retinal detachment
- Retinal ischemia or when retinal tissue lacks adequate oxygen supply
- Neovascularisation or the abnormal proliferation of blood vessels in the retina
- Coats’ disease or the presence of abnormal retinal blood vessels that can cause vision loss
- Retinoblastoma or intraocular tumours
- Advanced glaucoma
Diseases affecting the retina are some of the most common causes of blindness or vision loss in major countries. These diseases also affect a wide spectrum of patients, with retinal detachment more commonly affecting older individuals and Coat’s disease more commonly affecting male children under 10 years of age. Retinoblastoma, on the other hand, can affect practically any age range, including children and adolescents, with a majority of cases affecting young children aged 2 and under.
The success rating of cryopexy is directly affected by the stage or degree of the retinal disorder involved. If a problem is caught early and cryopexy is performed immediately, the potential for success is very high.
In the event that the problem is not detected early, the patient may require more than one round of cryopexy to achieve the desired results. This is common in cases involving retinal detachment.
How is the Procedure Performed?
To ensure the safety and comfort of patients, cryopexy is performed under local anesthesia. Once the patient is fully prepped, the ophthalmologic surgeon proceeds to place the cryopexy probe, an extremely cold instrument, against the eye. The cold temperature is achieved with the help of cold gases, typically nitrous oxide, which are embedded within the tip of the probe. Once the probe has been applied to the sclera and it begins to form water crystals as a result of extreme cold, the surgeon rapidly thaws it, resulting in tissue destruction and scar formation. In the case of a retinal tear, this action effectively seals the edges of the retina, thus treating and preventing tears. In the case of retinal detachment, the probe seals the retina to the pigment epithelium, causing the retina to come into contact with the tissue underneath, resolving the detachment issue in the process.
After the procedure, patients are placed under observation for up to an hour. They are typically given some pain medications to help with any discomfort they may be feeling. If no complications occur, they are sent home, usually two hours after the procedure, with instructions on how to clean the eyelids every day.
Complete recovery following a cryopexy may take as long as 10 to 14 days, with many patients reporting some common symptoms such as brief blurring of vision as well as mild redness and swelling of the area around the eye. These symptoms are expected to resolve without treatment within 2 weeks after the surgery. To speed up healing, patients are advised to apply cold compresses to the affected eye/s. If symptoms persist beyond 2 weeks, patients are advised to schedule a follow up visit to their ophthalmologist.
Possible Risks and Complications
A cryopexy is associated with the following risks:
- Perforation of the eye, usually due to the anesthetic needle
- Double vision
- Subconjunctival hemorrhage
Mittelman D., Bakos I. “The role of retinal cryopexy in the management of experimental perforation of the eye during strabismus surgery.” Journal of Pediatric Ophthalmology and Strabismus. September/October 1984; Vol. 21
Bagheri A., Salim RE., Ahmadieh H., et al. “Cryopexy or laser therapy versus observation for management of accidental scleral perforation during experimental study.” Shahid Beheshti University of Medical Sciences. http://www.binajournal.org/browse.php?aid=334&sid=1&slclang=en
Johnson R., Irvine A., Wood I. (1987). “Endolaser, cryopexy, and retinal reattachment in the air-filled eye.” Arch Ophthalmol. 1987;105(2):231-234. http://archopht.jamanetwork.com/article.aspx?articleid=636518