Background: Corneal ectasia after photorefractive keratectomy (PRK) has only been occasionally reported, and its incidence has not been assessed.
Methods: In a retrospective, non-comparative case series, incidence of corneal ectasia was evaluated in a personal consecutive 6453-case series of myopic PRK with a minimum follow-up of 18 months. Features and prognosis were evaluated in all patients with ectasia after PRK (in both personal and referred cases).
Results: Ectasia was detected in three eyes of two patients (patients 1 and 2) 3 years and 1 year after PRK performed elsewhere. In addition, in the personal PRK series, two eyes of two patients (patients 3 and 4) developed corneal ectasia 5 months after surgery (incidence: 0.03%). Pre-operatively, forme fruste keratoconus was present in patients 1, 3 and 4; keratoconus in the fellow eye in patient 2; pachymetry <500 micron in patients 2 and 3. In patient 1, rigid contact lenses were prescribed, and in patient 2 deep anterior lamellar keratoplasty was needed; in patients 3 and 4, low induced astigmatism resulted, requiring driving spectacles in patient 3.
Conclusions: PRK induced corneal ectasia in predisposed eyes, even after low myopic ablations. Forme fruste keratoconus and keratoconus in the fellow eye were the main pre-operative findings. Prognosis varies according to severity.