title: Quantitative Evaluation of the Natural Progression of Keratoconus Using Three-Dimensional Optical Coherence Tomography.
abstract: We quantified the chronologic progression of keratoconus using anterior segment optical coherence tomography (AS-OCT).
  
  
  
  A total of 217 eyes from 113 patients with keratoconus, keratoconus suspect, or forme fruste keratoconus were evaluated by corneal tomography using swept-source OCT. Age-dependent changes in the radius of the posterior best-fit sphere (Rpost), minimum corneal thickness (Tmin), and distance from the thinnest point to the corneal vertex (Dmin) were examined over follow-up periods of up to 5.79 years and were analyzed using generalized estimating equation (GEE) nonlinear regression model.
  
  
  
  Annual changes in Rpost (mean, -0.017 mm) and Tmin (-2.69 μm) were significantly higher in younger patients (P < 0.01, GEE nonlinear regression) and in patients with higher maximal K value (Kmax; P < 0.01, GEE nonlinear regression), whereas no changes were observed in Dmin. Even in patients 30 years or older, 14% of eyes revealed remarkable progression in Rpost. In eyes with acute hydrops, annual changes in Rpost (-0.22 mm) and Tmin (-33.8 μm) before acute corneal hydrops were more than 10 times faster than those in other eyes (P < 0.001, GEE nonlinear regression).
  
  
  
  Chronologic measurements of corneal tomography in keratoconus demonstrated that the progression of steepening at posterior corneal surface was found not only in patients under 30 years but also in older patients, particularly in advanced keratoconus. The rate of progression can be measured by mapping of corneal curvature and thickness using OCT, and the risk of progression was greater in younger patients with steeper Kmax.
authors.affiliation: Department of Ophthalmology Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Hisataka
authors.initials: H
authors.lastname: Fujimoto
authors.affiliation: Department of Ophthalmology Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Maeda
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Shintani
authors.affiliation: Department of Ophthalmology Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: Department of Ophthalmology Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Fuchihata
authors.affiliation: Department of Ophthalmology Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Higashiura
authors.affiliation: Department of Ophthalmology Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Kohji
authors.initials: K
authors.lastname: Nishida
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007640:Keratoconus / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012189:Retrospective Studies; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult