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Application of high resolution OCT to evaluate irregularity of Bowman's layer in asymmetric keratoconus
Author(s) -
Pahuja Natasha,
Shroff Rushad,
Pahanpate Pratik,
Francis Mathew,
Veeboy Leio,
Shetty Rohit,
Nuijts Rudy M. M. A.,
Sinha Roy Abhijit
Publication year - 2017
Publication title -
journal of biophotonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 66
eISSN - 1864-0648
pISSN - 1864-063X
DOI - 10.1002/jbio.201600106
Subject(s) - keratoconus , ophthalmology , corneal topography , medicine , area under curve , area under the curve , cornea , high resolution , nuclear medicine , pharmacokinetics , remote sensing , geology
Irregularity of the Bowman's layer (BL) in keratoconus (KC, sample size ( n ) = 28) and forme fruste keratoconus (FFKC, n = 18) eyes was evaluated. Subjects underwent high resolution OCT imaging (Bioptigen Inc., USA) and corneal tomography (Pentacam v1.20r41, OCULUS Optikgeräte GmbH, Germany). Anterior edge of the BL was segmented. A Bowman's roughness index (BRI) was defined as the sum of the enclosed areas between segmented edge and a smooth 3 rd order polynomial fit to the edge. BRI was compared with corneal aberrations, Keratoconus percentage index (KISA), Cone location magnitude index (CLMI) and Belin–Ambrosio enhanced ectasia display overall deviation index (BAD‐D). Area under the curve (AUC) was determined with logistic regression (LR). Mean BRI (×10 –3 ) was 2.12 mm 2 , 1.81 mm 2 and 1.7 mm 2 in normal ( n = 26), FFKC and KC eyes, respectively ( p < 0.001). BAD‐D (0.79) and BRI (0.74) had the best AUC for FFKC. By combining BAD‐D and BRI, the AUC improved to 0.85 ( p = 0.01). For KC eyes, KISA (0.94), CLMI (0.88), BAD‐D (0.96) and aberrations had comparable AUC ( p > 0.05). However, LR with BRI and other indices didn't improve the AUC in KC eyes ( p > 0.05). BRI was significantly reduced in FFKC and KC eyes. It improved the detection of FFKC but not KC eyes.