theres always big bright lights during a boxing match and their pointed right at the boxers, so the eyes of a boxer (which sum not all suffer from lack of light sensitivity) are dilated to absorb all the light coming in, its the only way they can see sharp detail, anytime the eye is asked to work a lil bit harder then it normally should, it dilates
i admit, drugs could cause the same thing, but the fact that he tasted clean and he might suffer from lack of light sensitivity tells me hes not a roid head
edit: heres what drugs can cause eye dilation
Tricyclic antidepressants
tumor removal ... see Tumor surgery
Tumor surgery
tumor vaccines ... type of Vaccines
Tylenol® ... see Acetaminophen
typhoid fever vaccine ... type of Vaccines
ultrapotent topical corticosteroid ... type of Topical corticosteroids
Umbilical cord blood transplants ... type of Transplants
Unvaccinated children ... type of Vaccines
UV light exposure ... type of Phototherapy
UVB phototherapy ... type of Phototherapy
Vaccination ... see Vaccines
Vaccination adverse reaction ... type of Vaccines
btw,
http://en.wikipedia.org/wiki/Corticosteroid thats what cortico steroids are, not sumthing a boxer could take advantage of