[Iatrogenic Keratectasia: A Review]

Iatrogenic corneal ectasia is a rare complication but also one of the most feared situations that can occur after uneventful corneal laser surgery. Ectatic changes can occur as early as 1 week or can be delayed up to several years after LASIK. The actual incidence of ectasia is undetermined, an incidence rate of 0.04 to almost 2.8 % has been reported. Ectasia is most common following LASIK; however, cases have been reported following PRK and other corneal refractive procedures. Keratectasia shows progressive myopia, irregular astigmatism, ghosting, fluctuating vision and problems with scotopic vision. The progression leads to severe loss of corrected visual acuity. Risk factors are thin corneas < 500 µm, a pathological corneal topography, a residual stromal bed < 300 µm, high myopia > 8 D, young (female) age < 25 years, atopic dermatitis, allergies, family history for keratokonus and collagen diseases and retreatments. Treatment of choice is a cross-linking with riboflavin/UVA light with contact lenses. In severe cases a penetrating or a deep anterior lamellar graft is necessary.