''I decided to talk about it so people would hear it right, and it wouldn't be misinterpeted,'' the 44-year-old Mr. Geiberger said in an interview. ''Before my operation, I had ulcerative colitis and felt miserable. I had recurring diarrhea attacks, and any place I went, the first thing I'd do was locate a bathroom. During tournaments I often had to dash off into the woods. It was embarrassing.'' 'Able to Concentrate on Golf'

Today, he said, ''For the first time in years, I've been able to concentrate on golf.''

Among the other prominent ostomates who have spoken out about their operation and its effects on them include Letitia Baldrige, the New York public relations executive who was head of Jacqueline Kennedy's staff in the White House; Otto Graham, the former Cleveland Browns quarterback who is now athletic director at the United States Coast Guard Academy in New London, Conn.; Jerry Kramer, the former all-pro guard with the Green Bay Packers; and Ann Sothern and Loretta Young, the actresses.

According to Donald Binder, executive director of the United Ostomy Association in Los Angeles, which is celebrating its 20th anniversary this year, about 100,000 people have ostomy surgery annually. Currently, he said, 1.5 million to 2 million people in the United States have had ostomies. He said that about 46,000 belong to the association's 619 affiliated groups in the United States and Canada. Three Kinds of Ostomies

''Ostomate'' is the term applied to a person who has had one of three kinds of ostomies: colostomy, in which a portion of the colon is removed, usually because of cancer; ileostomy, in which the entire colon, rectum and perhaps a part of the small intestine are removed, usually because of inflammatory bowel disease; and urostomy, in which the bladder is removed, usually because of cancer.

In all three cases, a stoma is made in the abdominal wall to allow ongoing drainage into a pouch. Many colostomates, however, do not need to wear a pouch full time. They remove their body waste through a daily or every-other-day irrigation process, similar to an enema, and at other times cover the stoma with a large bandage.