Hanging or standing upside-down may cause problems more severe than the possible eye damage recently reported, two doctors write in the Journal of the American Medical Association.

In one case, a 61-year-old man who was using gravity inversion to ease back pain developed severe headaches, fatigue and disorientation. "After the third treatment, his symptoms became more severe," writes Dr. Alfredo A. Sadun of the University of Southern California School of Medicine in Los Angeles. "He also complained of memory loss . . ."

Sadun says the changes in blood flow caused by the practice caused a subdural hematoma, a bruise on the brain underneath the tough tissue covering the brain..

In San Antonio, Tex., a healthy 68-year-old man who had been standing on his head for five minutes a day for several years suffered worsening eyesight and progressive loss of his field of vision.

Examination found that the man, a glaucoma patient, had sharply higher pressure in each eye while standing on his head. "The patient was asked to discontinue these particular exercises," writes Dr. Patrick S. O'Connor of the University of Texas Health Science Center in San Antonio. "Follow-up . . . revealed stable vision, pressures and fields of vision ."