I Love Lucy - Season 3 Episode 11
Lucy Has Her Eyes Examined

Lucy finally gets her chance to be in show business, when she tricks Ricky into letting her do the "Jitterbug" in one of his shows. Shes terrific during rehearsals, but problems occur when Lucy accompanies Ricky (whos been suffering from headaches) to the eye doctor just before the show. There, the doctor decides to examine Lucys eyes, as well. He puts some eyedrops in Lucys eyes which "relaxes" them, but Lucys vision is blurry for the next twenty four hours. Naturally, this causes problems since Lucy has to perform that night.