title: Accuracy and precision of the corneal analysis system and the topographic modeling system.
abstract: Two computer-assisted topographic analysis systems were evaluated with calibrated spherical surfaces and normal human corneas. The Topographic Modeling System-1 (TMS-1) was found to be statistically more accurate in determining the power of calibrated spheres near the apex and at 1 mm from the apex than the Corneal Analysis System (CAS). The CAS, however, was statistically more accurate at 3 mm from the apex with each calibrated sphere. The small differences in accuracy between the two instruments, however, are unlikely to be of clinical significance. The topographic patterns on color-coded maps from 22 normal corneas of 11 subjects were similar with the two instruments. Simulated keratometry values with the CAS more accurately identified the keratometer-determined major cylinder axis compared with the TMS-1. Conversely, the TMS-1 was more accurate than the CAS at determining the level of corneal astigmatism.
authors.affiliation: Department of Ophthalmology, University of Texas, Southwestern Medical Center, Dallas 75235.
authors.forename: S E
authors.initials: SE
authors.lastname: Wilson
authors.forename: S M
authors.initials: SM
authors.lastname: Verity
authors.forename: D L
authors.initials: DL
authors.lastname: Conger
mesh_terms: D001251:Astigmatism / Q000175:diagnosis*; D003315:Cornea / Q000033:anatomy & histology* / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008953:Models, Anatomic; D009885:Ophthalmology / Q000295:instrumentation / Q000379:methods; D015203:Reproducibility of Results