G. Fraenkel et al., PARADOXICAL RESPONSE TO PHOTOREFRACTIVE TREATMENT FOR POSTKERATOPLASTY ASTIGMATISM, Journal of cataract and refractive surgery, 24(6), 1998, pp. 861-865
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.