Long-term changes in corneal surface configuration after penetrating keratoplasty

PURPOSE: To examine the long-term longitudinal changes in corneal surface configuration as determined by Fourier series harmonic analysis of videokeratography data and Of Visual acuity and refraction after penetrating keratoplasty (M). DESIGN: Interventional case series. METHODS: One hundred thirty eyes of 130 consecutive patients who were scheduled for PK using 16 interrupted 10-0 nylon sutures were recruited. Spherical equivalent power, regular astigmatism component, irregular astigmatism (asymmetry and higher,order irregulars ity) component of the central cornea as determined by Fourier analysis of videokeragraphic data, spectacle-corrected visual acuity, and spherical equivalent were examined at I week, and at 1., 3, 6, 9, 12, 18, and 24 months after PK. : RESULTS: Spherical equivalent power increased considerably for tip to I month after PK, but thereafter Showed no further appreciable change up to the final follow-up at 24 months. The regular astigmatism component de, creased markedly for LIP to 6 months after PK, while the total irregular astigmatism (SLIM of the asymmetry and higher-order irregularity) component decreased considerably up to approximately 3 months, and then these showed no further relevant change for up to 24 months. Spectacle-corrected visual acuity also improved markedly until approximately 3 months after PK, after which it was virtually stable. Furthermore, important correlations were found between regular and irregular astigmatism and the spectacle corrected visual acuity. CONCLUSIONS: Corneal surface configuration after PK appears to be stable by approximately 6 months after PK, concurrent with postkeratoplasty stabilization of visual acuity.