PARADOXICAL RESPONSE TO PHOTOREFRACTIVE TREATMENT FOR POSTKERATOPLASTY ASTIGMATISM

A 42-year-old woman with functionally disabling postkeratoplasty astig matism in her right eye 3 years after corneal transplantation for kera toconus received photorefractive keratectomy for high astigmatism in t hat eye. This did not reduce her astigmatism. The procedure was repeat ed and corneal astigmatism paradoxically increased. The forces within the pseudo-optical ring that cause and maintain astigmatism in corneal transplants may be a significant factor in the unpredictable response of some corneal transplants to excimer photorefractive astigmatism co rrection.