title: Measurements of anterior segment parameters using three different non-contact optical devices in keratoconus patients.
abstract: OBJECTIVE
  To evaluate the measurements of anterior segment parameters using three different non-contact optical devices in keratoconus patients.
  
  
  METHODS
  A hundred and one eyes of 55 keratoconus patients were enrolled in this study. The mean age was 26.2±8.9 years. The inclusion criteria were keratoconus stage I to III according to the Amsler-Krumeich keratoconus classification. All the measurements were done by the same operator, under the mesopic light condition and repeated with three different optical methods; Visante, Orbscan and Pentacam. The evaluated anterior segment parameters were anterior chamber depth (ACD), central and thinnest corneal thickness (CCT and TCT) and pupil diameter (PD).
  
  
  RESULTS
  THE MEAN CCT MEASURED BY VISANTE, ORBSCAN AND PENTACAM WERE AS FOLLOWS: 462.0±48.1µm, 463.9±60.9µm, 476.5±45.3µm, respectively (P=0.873). The mean ACD values were 3.34±0.33mm, 3.26±0.33mm, 3.49±0.40mm, respectively (P=0.118). The mean PD measurements were 5.11±1.14mm, 4.80±0.85mm, 3.80±1.38mm, respectively (P<0.001). The mean TCT measurements of Visante, Orbscan and Pentacam were 437.9±48.2µm, 447.6±60.6µm and 459.9±44.0µm, respectively (P=0.214). The Visante and Orbscan measured CCT similarly, while Pentacam measured CCT thicker than the other two. The Visante measured TCT thinner than the other two devices. In ACD measurements, Orbscan was the one giving the lowest values. PD was measured differently by the devices.
  
  
  CONCLUSIONS
  Although TCT, CCT and ACD measurements acquired by Visante, Orbscan and Pentacam in keratoconus patients are similar, PD measurements show large differences among the devices.
authors.affiliation: Beyoğlu Eye Training and Research Hospital, Istanbul 34000, Turkey.
authors.forename: Ahmet Taylan
authors.initials: AT
authors.lastname: Yazıcı
authors.forename: Gökhan
authors.initials: G
authors.lastname: Pekel
authors.forename: Ercüment
authors.initials: E
authors.lastname: Bozkurt
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Yıldırım
authors.forename: Evre
authors.initials: E
authors.lastname: Pekel
authors.forename: Ahmet
authors.initials: A
authors.lastname: Demirok
authors.forename: Omer Faruk
authors.initials: OF
authors.lastname: Yılmaz
keywords: Orbscan; Pentacam; Visante; anterior chamber depth; corneal pachymetry; pupil diameter