PRK TREATMENT

Photorefractive keratectomy (PRK) in eyes with suspected keratoconus appears to be safe and effective in carefully selected patients, according to a long-term study presented at the French Implant and Refractive Surgery Association (SAFIR) annual meeting. Jean-Marc Ancel MD, in private practice at Clinique Lamartine in Paris, presented five-year data from a retrospective study of 29 eyes of 16 patients who were classified as having forme fruste keratoconus.

“Five years is the minimum follow-up time needed to observe whether or not there was a progression in the disease. We found that the refractive results were stable and there was no evidence of any evolution towards ectasia for any of the patients,” he said. Dr Ancel said that the results showed very good long-term refractive stability and topographic integrity for PRK treatment in selected keratoconic eyes and accorded with data presented recently by Damian Gatinel et al.

“In preserving the biomechanical properties of the anterior stroma, PRK allows us to perform a refractive treatment for these selected patients with suspected or confirmed keratoconus without any additional risk as compared to PRK performed on a healthy eye,” he said.

Dr Ancel noted that suspect topography indicative of keratoconus usually constitutes a formal and definitive contraindication for all LASIK refractive surgery owing to the obvious risk of post-operative ectasia.

“On the same basis, patients with advanced or progressive keratoconus may only rarely benefit from a refractive correction by photoablation. However we are now seeing more teams proposing PRK as a possible refractive solution for either suspect or ‘forme fruste’ keratoconus, or confirmed keratoconus in combination with intracorneal rings or crosslinking. At the moment, less than 10 cases of postoperative ectasia have been reported in the scientific literature after PRK without any pre- selection in terms of whether the patients were at risk or not,” he said.

The goal of Dr Ancel’s study was to evaluate the refractive efficacy as well as biomechanical stability of PRK treatments in keratoconus patients over time. “We wanted to see if there was any deterioration of the initial topographical anomalies. All patients in our study had stable preoperative refraction and a best corrected visual acuity close to 10/10,” he said. After one year, the refractive results were in conformity with those known for PKR in myopes in the scientific literature, said Dr Ancel.

“We had the same safety margins with no loss of lines of best-corrected vision and a mean BCVA of 9.7/10. After five years, we see that the refractive results are perfectly stable and there is no trend towards ectasia in any of the patients,” he said. Those results were confirmed over five years.

Summing up, Dr Ancel said that the overall outcomes of these forme fruste or confirmed keratoconus patients were very satisfactory.