Long-term keratometric changes after penetrating keratoplasty for keratoconus and Fuchs endothelial dystrophy.

PURPOSE To compare long-term keratometric changes after penetrating keratoplasty (PK) for keratoconus and Fuchs endothelial dystrophy. METHODS We retrospectively analyzed 168 corneas after PK for keratoconus (85 eyes of 63 subjects) and Fuchs dystrophy (83 eyes of 60 subjects). Patients were examined after final suture removal at 12 months after PK to 30 years after surgery. Operations were performed by one surgeon using the same suturing technique in all cases. Eyes were excluded from further analysis after regrafting or after relaxing incisions. Mean keratometric corneal power and astigmatism were measured by manual keratometry. Data were assessed by using generalized estimating equation models to determine change over time. RESULTS Mean keratometric corneal power and keratometric astigmatism increased through 30 years after PK for keratoconus (P < .001 and P < .001) but did not change through 20 years after PK for Fuchs dystrophy (P = .55 and P = .55). The change in keratometric corneal power and astigmatism after PK in keratoconus patients differed from the change in Fuchs dystrophy patients only at 10 or more years after PK (P = .002 and P = .003). CONCLUSIONS Corneal curvature and regular astigmatism increase progressively after PK for keratoconus but remain stable after PK for Fuchs dystrophy. This keratometric instability after PK for keratoconus may lead to delayed corneal ectasia.