MEDICINE : Survey Says Women Are Walking on Thin Ice With Ill-Fitting Shoes : Foot doctors and other experts are told that many females are hurt by sizes they outgrew 20 years ago.

A passion for fashion and avoiding the truth about their shoe sizes are causing many American women a pain in the foot.

A survey of 356 women between 20 and 60 found that 88% wore shoes too small for them and “76% had one or more forefoot deformities,” according to a report issued at the convention here of the American Academy of Orthopaedic Surgeons.

The survey found that most of the women had grown in foot size since the age of 20, but they were ignorant of that fact. “The majority . . . had not had their feet measured in over five years,” the report notes.

The study was done by six doctors who are members of a bone-specialist group called the American Orthopedic Foot and Ankle Society. Their report says that women are flirting with more than temporary pain.

“Shoes have been implicated as being responsible for the majority of foot deformities and problems that physicians encounter in women. The deforming effects of improper shoes on a normal foot can cause hallux vulgus (bunions), . . . hammer toes, calluses, corns, metatarsalgia , and other problems.”

Many women in the survey told the doctors that they suspected that one foot was bigger than the other. That suspicion proved true: 66% of those surveyed had unequal feet.

After ticking off the problems between females and their shoes, the report says: “It is apparent that women need to be instructed in proper shoe fit.”

The report then gives these tips:

* “Women should fit shoes at the end of the day, when their feet are at their largest.”

* “The upper (of the shoe) should not wrinkle with flexion of the foot, and the foot should not bulge over the welt, the strip of leather that joins the insole with the outer sole.”

* “The end of the longest toe of the biggest foot . . . should be 1/2 inch from the end of the toe box.”

* “The forefoot should not be crowded, and the toes should be allowed to extend.”

* “There should be a relatively snug grip of the counter about the heel.”

The report also indirectly recommends that women get their feet measured more often, rather than relying on a shoe size that once fit them. “Sixty per cent of the women felt that their shoe size had increased since they were 20 years old, but 75% had not had their foot measured in more than five years,” the report says.

The survey found that among women between the ages of 30 and 39, 43% needed a bigger shoe size than the one they wore at 20. Among women 40 to 49, 69% needed a bigger shoe than the one they wore at 20. The percentage jumped to 95% among women in the 50 to 60 bracket.

The report also notes one oddity:

“The fact remains that there are many individuals who wear high-fashion shoe wear who do not develop foot pain, as seen in 20% of the women in this study. . . .

“There must be some intrinsic factors which make some women more vulnerable to the deforming effects of shoes.”