Which soft contact lens power is better for piggyback fitting in keratoconus?

PURPOSE: To evaluate the ipact of differente soft contact lens power in the anterior corneal curvature and regulareity in subjects with keratoconus. METHODS: Nineteen subjects (30 eyes) with keratoconus were included in the study. Six corneal topographies were taken with Pentacam Eye System over the naked eye and successively with soft lens (Senofilcon A) powers of -3.00, -1.50, 0.00, +1.50 and +3.00D. Corneal measurements of mean central keratometry (MCK), maximum tangential curvature (TK), maximum front elevation (MFE) and eccentricity (Ecc) at 6 and 8mm diameters as well as anterior corneal surface high order aberrations (i.e. total RMS, spherical- and coma-like and secondary astigmatism) were evaluated. RESULTS: Negative- and plano-powered soft lenses flattened (p0.05 in all cases) in MCK in comparison to the naked eye. The TK power decreased with negative lenses (p0.05 in all cases). Corneal eccentricity increased at 8mm diameter for all lens powers (p0.05). Statistically differences were found in coma-like and secondary astigmatism (both p