Surface ablation no guarantee for avoiding ectasia in FFKC eyes

November 10, 2007

Keratoectasia can develop after surface ablation in eyes with forme fruste keratoconus (FFKC), and there do not appear to be any identifiable features as protecting against that event.

Keratoectasia can develop after surface ablation in eyes with forme fruste keratoconus (FFKC), and there do not appear to be any identifiable features as protecting against that event, said Sheraz M. Daya, MD, at Refractive Surgery Subspecialty Day.

His comments were based on a review of eight eyes of four patients seen on referral for the development of ectasia (frank ectasia, 7 eyes; FFKC progression, 1 eye) after myopic LASEK or PRK. The mean time to presentation after refractive surgery was 32 months; one case developed after 9 years, but all others occurred within 4 to 9 months. Six eyes had preoperative topographic data available and all were identified as having forme fruste keratoconus or pellucid like changes.

Preoperative corneal thickness averaged 519 µm and exceeded 500 µm in 5 of the 6 eyes. At the time of surface ablation, the patients had a mean age of 34 years and two were older than 40. Preoperative keratometry averaged 45.1 D, with a minimum K reading of 42.75/43 D, and mean preoperative SE was about -4 D.

"With the exception of the late onset case, we do not think these eyes would have developed ectasia anyway even if they did not have refractive surgery. This series also suggests a thick or flat cornea and age over 40 do not appear to reduce the risk,- said Dr Daya, director and consultant, corneoplastic unit and eye bank, Queen Victoria Hospital, West Sussex, UK, and medical director, Centre for Sight, London and East Grinstead, UK.

"Therefore, our recommendation would be to avoid surface ablation procedures in these eyes, even for low myopia, and consider other options for refractive correction," Dr. Daya concluded.