Early corneal topographic changes need attention before LASIK

Early curvature changes on the corneal surface that are measured by topography need to be heeded in patients undergoing refractive surgery, according to Steven Klyce, PhD.

Dr. Klyce recounted a case in which a patient had mild corneal curvature changes before LASIK. The visual outcome was good after the surgery for 3 months. After 18 months, the patient developed keratectasia and required bilateral corneal transplants. Dr. Klyce is from Louisiana State University Eye Center, New Orleans.

"This case illustrates why it is so important to look for the early signs in the refractive surgery population. In the general population the incidence of keratoconus is about 1 in 2,000 individuals," he said. "In refractive surgery practice, the incidence is 114 in 2,000 individuals. The incidence increases markedly in a refractive surgery population because these patients want to correct their distorted vision and eliminate the use of contact lenses and glasses."

The only detectable changes in the early stages of these corneal pathologies is the warping of the shape of the anterior cornea, Dr. Klyce said.

"With progression, changes can be detected with pachymetry and a diagnosis made," he said.

He described the case of a female patient who initially had mild anterior steepening. She was a keratoconus suspect and had a 7-year progression to clinical keratoconus. Ten years later, she is stable. Had she undergone LASIK, the status of her eyes would be highly questionable now, Dr. Klyce noted.

He pointed out that clinicians need to differentiate between normal variations in the cornea and cases of abnormal steepening and emphasized the attention that should be paid to patients with abnormal anterior steepening to avoid the later vision-threatening consequences in susceptible patients.