Leading Impotence Drugs Warn About Vision (AP)

Federal health officials are examining rare reports of blindness among some men using impotence drugs.

The drugs also may have other rare side effects on vision. Warnings labels for Viagra, Cialis and Levitra currently list such potential side effects, according to the drugs' Web sites.

_Viagra: "Less common side effects that may occur are temporary changes in color vision (such as trouble telling the difference between blue and green objects or having a blue color tinge to them), eyes being more sensitive to light or blurred vision."

_Cialis "may uncommonly cause ... vision changes, such as seeing a blue tinge to objects or having difficulty telling the difference between the colors blue and green."

_Levitra "may uncommonly cause ... vision changes, such as seeing a blue tinge to objects or having difficulty telling the difference between the colors blue and green."