Cataracts in bleomycin-treated rats

Bleomycin was administered to 126 normal or human-tumor-bearing baby rats we observed for the development of cataracts. Eighty-four percent of the rats receiving this drug before the age of 10 days developed lens opacities. Bleomycin given to 10-day-old rats or older did not induce cataract formation. The cataracts initially occurred in the nuclear area and later involved most of the lens whether or not bleomycin was later discontinued. The presence of the tunica vasculosa lentis in rats younger than 10 days old may explain why cataracts developed only in these young animals.