Silicon Oil May Protect Vision From Radiation for Eye Cancer

It absorbed nearly 50% of potentially damaging rays, but more study is needed, researchers say

THURSDAY, July 15 (HealthDay News) -- Shielding the eye with silicon oil may safeguard the eyesight of patients who must undergo radiation therapy for an eye cancer known as ocular melanoma, new research suggests.

Although the study authors caution that more research is needed, they say that their current investigation reveals that the pre-radiation procedure appears to absorb about 50 percent of radiation rays that might otherwise hit the back and sides of the eye and cause irreversible damage.

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"Vision loss is a devastating yet common side effect of radiation therapy," vitreoretinal surgeon Dr. Tara McCannel, an assistant professor of ophthalmology and director of the University of California Los Angeles (UCLA) Ophthalmic Oncology Center at the Jules Stein Eye Institute, said in a UCLA news release. "Until recently, physicians focused on killing the tumor and considered vision loss secondary. Our results suggest that silicon oil offers a safe tool for protecting the patient's vision during radiation," she added.

The finding is reported in the July issue of the Archives of Ophthalmology.

Ocular melanoma takes hold under the retina and is the most common adult eye cancer. Standard treatment involves the surgical application, and subsequent removal, of radioactive "seeds" to the white of the eye. Although effective at killing cancer cells, the process can also cause central vision loss by doing irreparable harm to optic nerve fibers and blood vessels.

"If patients survive the cancer, more than half will suffer vision loss in the treated eye six months to three years later," noted McCannel.

However, McCannel's team found that such risk can be significantly minimized by pre-surgical application of FDA-approved silicon oil shields around the interior of the eye. Post-surgery, the silicon is washed away with saline, and ultimately replaced by the patient's natural fluids.

The authors note that such silicon shields are already commonly used in retinal surgery. In addition, they found that the process does not hamper the effective use of radiation to attack tumor cells.

More information

For more on eye cancer, visit the American Cancer Society.

-- Alan Mozes