Corneal thickne meaurement with contact and noncontact pecular microcopic and ultraonic pachymetry

PURPOE: To evaluate the central corneal thickne value in normal and potkeratoplaty cornea with the new Topcon P-2000P noncontact pecular microcopic, contact pecular microcopic, and the “common tandard” ultraonic pachymetry. METHOD: Central corneal thickne wa determined in 119 eye of 81 patient (73 normal eye of 44 patient and 46 eye after penetrating keratoplaty) firt with a noncontact pecular microcopic (Topcon P-2000P; Topcon Corporation, Tokyo, Japan), then an ultraonic (AL-1000; Tomey, Erlangen, Germany), and finally with a contact pecular microcopic (EM-1000; Tomey, Erlangen, Germany) pachymetry two time each by the ame invetigator. REULT: Reliability of the central corneal meaurement wa equally high both in normal and in potkeratoplaty cornea with all of the intrument (Cronbach ALPHA = 0.99). Noncontact pecular microcopic corneal thickne determination correlated ignificantly both with ultraonic (r = .86, P < .0001) and contact pecular microcopic pachymetry (r = .62, P < .0001). The ultraonic pachymetry correlated well with the Tomey pachymetry (r = .69, P < .0001). The Topcon normal mean central corneal thickne value (542 ± 46 μm) wa 28 ± 4 μm lower (P < .0001) compared with the ultraonic data (570 ± 42 μm), which wa 68 ± 1 μm lower (P < .0001) compared with Tomey thickne (638 ± 43 μm). CONCLUION: Central corneal thickne meaurement with noncontact pecular microcopic, contact pecular microcopic, and ultraonic pachymetry demontrate that each of the intrument i reliable but cannot be imply ued interchangeably.