Study: Tamoxifen affects some visual pathways

Tamoxifen use affects patients’ perception of short-wavelength light, a study has found. Researchers reported that blue-wavelength perimetric tests were affected more than standard perimetric tests in women taking tamoxifen, a drug commonly used in breast cancer treatment. Further, the effects of tamoxifen on short-wavelength visual fields were seen years before completion of the standard 5-year regimen for the drug, researchers said.

Alvin Eisner, PhD, and colleagues at Oregon Health & Science University measured visual fields using two methods in middle-aged women who were being treated with tamoxifen as an adjuvant therapy for early stage breast cancer. Visual fields were assessed using short wavelength automated perimetry (SWAP) and frequency doubling perimetry (FDP). None of the patients had tamoxifen retinopathy or any other eye disease. Mean deviations for each type of visual field measurement were derived as a function of the duration of tamoxifen use.

SWAP sensitivities were found to decrease as a function of the duration of tamoxifen use. Patients who used tamoxifen for less than 2 years were significantly more likely to have high mean deviations than patients treated for longer periods. The difference between the standardized SWAP and FDP mean deviations was significantly related to the duration of tamoxifen use. Duration-of-use effects for FDP were reduced or absent. Duration-of-use effects for SWAP were strongest in the peripheral portion of the visual field, although there was evidence of changes even at the fovea, the researchers said.

The study is published in the January issue of British Journal of Ophthalmology.