title: Multimodal Assessment of Corneal Thinning Using Optical Coherence Tomography, Scheimpflug Imaging, Pachymetry, and Slit-Lamp Examination.
abstract: OBJECTIVE
  To assess the relationship between corneal thinning measured by clinician-graded slit-lamp examination compared with ultrasound pachymetry (USP), anterior segment optical coherence tomography (AS-OCT), and the Pentacam.
  
  
  METHODS
  Patients with corneal thinning underwent USP, AS-OCT, Pentacam measurements and standardized clinical grading by 2 cornea specialists estimating thinning on slit-lamp examination. Reproducibility of each testing modality was assessed using the intraclass correlation coefficient. Bland-Altman plots were used to determine precision and limits of agreement (LOA) between imaging modalities and clinical grading.
  
  
  RESULTS
  We included 22 patients with corneal thinning secondary to infectious or inflammatory keratitis. Mean percent stromal thinning estimated by grader 1 was 51% (SD 31) and grader 2 was 49% (SD 33). The intraclass correlation coefficient between the masked examiners was 0.95 (95% confidence interval, 0.88-0.98). Graders were more similar to each other than to any other modality with 2% difference and 4.6% of measurements outside the LOA. When measuring the area of maximum thinning, AS-OCT measured approximately 10% thicker than human graders while the Pentacam measured approximately 10% thinner than human graders with 16.7% outside the LOA. USP measured approximately 20% thinner than human graders with 5.6% outside the LOA.
  
  
  CONCLUSIONS
  Trained corneal specialists have a high degree of agreement in location and degree of corneal thinning when measured in a standardized fashion on the same day. Other testing modalities had acceptable reproducibility and agreement with clinical examination and each other, although Scheimpflug imaging fared worse for corneal thinning, particularly in the periphery, than the other modalities.
authors.affiliation: *Department of Ophthalmology, University of California, San Francisco; San Francisco, CA; and †Francis I. Proctor Foundation, San Francisco, CA.
authors.forename: Julius T
authors.initials: JT
authors.lastname: Oatts
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Keenan
authors.forename: Tova
authors.initials: T
authors.lastname: Mannis
authors.forename: Tom M
authors.initials: TM
authors.lastname: Lietman
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rose-Nussbaumer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003315:Cornea / Q000473:pathology*; D003316:Corneal Diseases / Q000175:diagnosis*; D063171:Corneal Pachymetry / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009929:Organ Size; D010781:Photography / Q000379:methods*; D015203:Reproducibility of Results; D000072776:Slit Lamp Microscopy / Q000379:methods*; D041623:Tomography, Optical Coherence / Q000379:methods*