Dr. Frank D. Costenbader, 73, the ophthalmologist who was chairman of the department of ophthalmology of Children's Hospital from 1940 to 1965, and who taught at area medical schools, died Thursday at his home in Washington following a stroke.

Dr. Costenbader came to Washington in 1931 to serve his residency at the old Eiscopal Eye, Ear and Throat Hospital. In 1932 he opened a private practice in general ophthalmology, but from 1944 until he retired in 1970, limited his practice to pediatric ophthalmology.

From 1932 until his retirement, Dr. Costenbader worked at Children's Hospital where he gained a wide reputation as an eye surgeon who instructed a generation of doctors in eye surgery.

In a 1966 interview with The Washington Post, Dr. Costenbader explained that children's eye diseases were best treated at an early age, even if surgery was required, and that he had operated on infants as young as two days old.

The two most common ailments detected in infants that were treated by early surgery were "strabismus," also known as "crossed-eyes," which is an improper alignment of the eyeballs, and tunnel vision produced by congenital glaucoma.

In recognition of his work in surgery and teaching at Children's Hospital, the Ophthalmology Alumni Society of Children's Hospital, most of whose members had trained under Dr. Costenbader, formed the "Costenbader Alumni Society" in 1975. They presented him with a citation that recognized him as "a gentle practitioner, patient teacher, and innovative researcher" and acknowledged that they were showing their "gratitude to the founder of pediatric ophthalmology."

Dr. Costenbader maintained that pediatric ophthalmology was an art that included "trade secrets." He explained that when a child entered the examining room the doctor had to determine if he was spoiled or "tractable and unspoiled."

If the child was "spoiled," the doctor's job was to ignore the young patient during in his first office visit and concentrate on getting a good case history from the parents. Then, "If the child is spoiled he will so resent being ignored that on the second visit he will go all out to cooperate."

If the child is unspoiled, Dr. Costenbader said, he used the first visit as a time to let the child explore his office, so the child would feel more at ease during ensuing visits.

He also maintained that a doctor dealing with the young should wear street clothes and furnish his office with toys and bright colors so the child would not be afraid.

"And you would be surprised how much cooperation you can get with a piece of candy," he added.

His work at Children's Hospital included 25 years as department chairman, surgeon and head of the hospital's eye clinic, which aided blind children in adjusting to their environment. He also taught at the medical schools of Georgetown from 1933 to 1970, and George Washington University from 1942 to 1970, and served on the senior advisory staff of Washington Center from 1958 to 1970.

Dr. Costenbader was a cofounder and president from 1946 to 1951 of the Medical Service of D.C., which later became known as Blue Shield.

He also served as president of the D.C. Medical Society in 1951-52. He was instrumental in the formation of the American Orthoptic Council, service as president from 1960 to 1962.

Dr. Costender helped found the American Association for Pediatric Ophthalmology and the Children's Eye Care Foundation. He was also a member of the editorial board of the American Journal of Pediatric Ophthalmology.

A native of Norfolk, Va., Dr. Costender earned a bachelor's degree at Hampden-Sydney College and a medical degree at the University of Virginia. He interned at the University of Virginia Hospital before moving here in 1931.

He served on the boards of trustees of Hampden-Sydney College, Children's Hospital and the Holton-Arms School.

Dr. Costenbader served as a consultant to numerous agencies, including the National Institutes of Health, and belonged to the American Academy of Pediatrics, the American Academy of Ophthalmology and Otolaryngology, the American and the Pan American ophthalmological societies.

He is survived by his wife, Mary B. of the home; two daughters, Elizabeth C. Cort, of Silver Spring, and [Ann] B. Fox, of Orlando, Fla.; a sister, Elizabeth R. Chandler, of Princeton, N.J.; two brothers, Dr. John H. Jr. and Dr. Benjamin, both of Norfolk, and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Children's Eye Care Foundation in Washington.