Levels of light intensity above what level can cause retinal damage in albino animals?

• A. 25 foot-candles
• B. 50 foot-candles
• C. 65 foot-candles
• D. 75 foot-candles

Answer: (D)

Albino animals are more vulnerable to light because their irises and retina lack pigment that normally helps filter and absorb excess light. This makes photochemical damage to the retina from bright illumination more likely, especially with prolonged exposure.

The level at which this risk becomes evident is about 75 foot-candles. Exposures above this threshold have been associated with retinal changes consistent with phototoxic damage in albino animals, particularly when the light is sustained. Staying at or below this level reduces the chance of retinal injury under typical housing conditions. To put it in perspective, 75 foot-candles is roughly 800 lux, though the exact safety margin also depends on exposure duration and light wavelength, with UV light being more harmful.