Reliability of Pentacam HR Thickness Maps of the Entire Cornea in Normal, Post–Laser In Situ Keratomileusis, and Keratoconus Eyes

• Published in: American journal of ophthalmology Vol. 162; pp. 74 - 82.e1
• Main Authors: Xu, Zhe, Peng, Mei, Jiang, Jun, Yang, Chun, Zhu, Weigen, Lu, Fan, Shen, Meixiao
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2016; Elsevier Limited
• Subjects: Adult; Cameras; Contact lenses; Cornea; Cornea - anatomy & histology; Cornea - pathology; Corneal Pachymetry - standards; Eyes & eyesight; Female; Glaucoma; Healthy Volunteers; Humans; Keratoconus - pathology; Keratomileusis, Laser In Situ; Male; Observer Variation; Ophthalmology; Reproducibility of Results; Software; Standard deviation; Surgery; Tomography; Topography; Ultrasonic imaging; Visual Acuity - physiology; Womens health; Young Adult
• ISSN: 0002-9394; 1879-1891
• DOI: 10.1016/j.ajo.2015.11.008

Purpose To measure the repeatability and reproducibility of Pentacam HR system thickness maps for the entire cornea in normal, post–laser in situ keratomileusis (post-LASIK), and keratoconus (KC) eyes. Design Reliability study. Methods Sixty normal subjects (60 eyes), 30 post-LASIK subjects (60 eyes), and 14 KC patients (27 eyes) were imaged with the Pentacam HR system by 2 well-trained operators. For pachymetry the cornea was divided into 4 zones: a central zone (2-mm diameter) and concentric pericentral zone (2–5 mm), transitional zone (5–7 mm), and peripheral zone (7–10 mm). The 3 concentric zones were subdivided into 8 sectors. Intraobserver repeatability and interobserver reproducibility of entire corneal thickness maps were tested by the repeatability and reproducibility coefficients, intraclass correlation coefficients, coefficient of variation, and 95% limits of agreement. Results From central to peripheral zones, the precision of corneal thickness measurements became gradually smaller. Central zone repeatability and reproducibility were the best in the normal, post-LASIK, and KC groups. The peripheral superior sectors showed poorer repeatability and reproducibility for all subjects. The intraobserver repeatability and interobserver reproducibility for all zones were ≤19.3 μm, ≤22.1 μm, and ≤20.7 μm, in the normal, post-LASIK, and KC groups, respectively. The intraobserver and interobserver coefficients of variation for all zones were ≤1.3%, ≤1.6%, and ≤1.6% for all 3 groups. Conclusions Pentacam HR system pachymetry of the entire cornea provided good precision in normal, post-LASIK, and KC corneas. Thickness measurements in the peripheral cornea should be interpreted with caution in abnormal corneas after surgery or with diseases.