Citigroup upgrades Alcon (ACL

) to buy from hold.

Analyst Peter Bye says his upgrade is based largely on clinical checks that give him increased confidence in two of the company's higher profile products: ReSTOR and RETAANE.

He says, if he's correct, these drugs will lead to upward revenue and earnings per share estimate revisions by the Street, raise long-term top- and bottom-line growth rate, and lead to a higher expected multiple.

Bye maintains his $3.32 2005 earnings per share estimate, and raises his $3.95 2006 earnings per share estimate to $4.00. He lifts his $100 price target up to $106.