Joan,
You got my curiosity up on the "Blind Half Hundred" nickname. I did a little searching and found there was an English regiment from Kent (if I remember correctly) that was also designated the "50th". During the Napoleonic wars, they were in Egypt and contracted a disease that blurred their vision and were given the nickname the Blind Half Hundred. I wonder if this is where the 50th IL got the nickname and what the connection is between the regiments.

See:
http://www.napoleonseries.org/reference/military/organization/nickname.cfm