One of the most frequent questions asked of The Young and the Restless' Signy Coleman is ''Are you really blind?'' The answer is no. But so convincing is her portrayal of the sightless farm woman, Hope, that Coleman garnered an Emmy nod last year and a Soap Opera Digest award this year. Cole man, 35, credits the Braille Institute in Los Angeles. ''I took classes; they even let me walk around blindfolded.'' Prior to being cast as Hope, Coleman, a cooking and running enthusiast, was best known as a Huey Lewis-video babe and as a glam hooker on the late Santa Barbara. ''I'm much more interested in playing a character role than a leading lady,'' says the Northern California native. ''I'd rather challenge myself than stand there and just look good.'' In other words, she doesn't hope for a miraculous cure for Hope.