Cryotherapy freezes small tumours in the eye.
When Cryotherapy Is Used
Cryotherapy is used to treat small or relapsed tumours in the periphery of the retina, or when tumours recur after other treatments.
Cryotherapy is often used after chemotherapy to reduce tumour size. This is called consolidation.
A single freeze of two spots of cryotherapy to peripheral retina may be given within 48 hours before chemotherapy, to increase penetration of chemotherapy drugs into the vitreous. This is called prechemotherapy-cryotherapy.
How Cryotherapy Is Given
The child receives a general anaesthetics. Nitrous oxide is applied through a small probe placed against the outside of eye, opposite the tumour.
The tumour is frozen while it is viewed with the indirect ophthalmoscope or RetCam. As the tumour thaws, ice crystals puncture cell membranes, destroying the cancer cell.
At each treatment session, each location is frozen three times, with complete thawing of the tumour in between. This is called triple freeze-thaw cryotherapy.
Cryotherapy can be repeated until a flat scar is obtained.
Cryotherapy can be used repeatedly to treat small tumours, reducing the need for more aggressive treatments.
Cryotherapy is not suitable for tumours involving the macula (central vision) because it causes significant scarring that will damage sight.
Cryotherapy causes the eyelids to become puffy and sore for several days. The discomfort can be reduced with eye drops and simple painkillers.
Questions To Ask the Doctors
- Where are my child’s tumours located that you plan to freeze?
- How big are these tumours?
- Will my child need more than one cryotherapy treatment?
- How often will you freeze the tumour/s?
- Will my child need chemotherapy or laser with the cryotherapy?
- How will you combine the chemotherapy and cryotherapy?
- How might this cryotherapy treatment impact my child’s vision?