Dr. Jules C. Stein, 85, the ophthalmologist who founded who founded MCA Inc. and became one of the most powerful figures in the entertainment industry in the United States, died of a heart attack Wednesday at UCLA Medical Center in Los Angeles.

He was admitted to the hospital Tuesday and underwent what a hospital spokesman described as "uneventful" gall bladder surgery.

Dr. Stein's career in entertainment began in 1924, when he left medicine to become a promoter and organizer and founded the Music Corporation of America. This later became MCA Inc. At first, the company was primarily a talent agency, booking bands throughout the Midwest. It no longer represents performers. Its principal activities now are producing and distributing films and television programs. It owns Universal Studios, Universal Tours and MCA Records. Other holdings include Columbia Savings and Loan Association, Spencer Gifts and the Sheraton Universal Hotel. Annual revenues have come to exceed $1 billion.

Apart from his business abilities, Dr. Stein was a noted patron of the arts and the founder of the Jules Stein Eye Institute at UCLA.

Dr. Stein was born in South Bend, Ind., the son of a dry goods store owner who named him Julian Caesar Stein. He worked his way through the University of Chicago and Rush Medical College playing the violin and saxophone, did postgraduate study in ophthalmology at the University of Vienna and went into practice in Chicago in 1923.

A year after forming his company, Dr. Stein had signed Guy Lombardo, and by the mid-1930s, MCA represented more than half of the major big bands in the country.

In 1937, Dr. Stein turned to Hollywood and with Lew R. Wasserman, bought up several talent agencies.

Soon MCA represented such stars as Gregory Peck, Myrna Loy, James Stewart, Paulette Goddard, Greta Garbo, Errol Flynn and Jack Benny. By the mid-1940s, according to some industry sources, MCA represented at least a third of the stars in Hollywood -- including the young Ronald Reagan.

Among the honorary pall bearers announced after Dr. Stein's death were President Reagan; actors Jimmy Stewart and Cary Grant; agent Irving Lazar; James C. Petrillo, founder of the American Musicians Union; and film magnates Mervyn Leroy and Hal Wallis.

When television challenged the movies in the late 1940s, Dr. Stein began TV productions that included the shows "Wagon Train," "Alfred Hitchcock Presents," "Leave It to Beaver," "The Jack Benny Show" and "Ozzie and Harriet."

In 1954, he distributed 53 percent of MCA to his associates "at nominal value" before taking the company public in 1959. By then he had entered television production and in 1958 he bought Universal Studios.

In 1962, the Justice Department filed an antitrust suit against MCA on the grounds that the company could not represent actors and actresses and at the same time produce the films and television shows in which they appeared. Dr. Stein reluctantly got out of the talent agency business.

Dr. Stein managed MCA until he retired a decade ago, when he gave up first the presidency and then the board chairmanship to Wasserman. But he remained active in the entertainment industry and in philanthropic affairs until his death.

He never forgot ophthalmology. In 1960, he founded Research to Prevent Blindness Inc., noting that "one-tenth of all patients in American hospitals are eye patients."

Survivors include his wife, Doris, to whom he was married for 52 years, and two daughters, Jean vanden Heuvel and Susan Shiva, both of New York, and four grandchildren