title: OCT-Based Quantification and Classification of Optic Disc Structure in Glaucoma Patients.
abstract: OBJECTIVE
  To objectively classify the optic discs of open-angle glaucoma (OAG) patients into Nicolela's four disc types, i.e., focal ischemic (FI), myopic (MY), senile sclerotic (SS), and generalized enlargement (GE), with swept-source optical coherence tomography (SS-OCT).
  
  
  METHODS
  This study enrolled 113 eyes of 113 OAG patients (mean age: 62.5 ± 12.6; Humphrey field analyzer-measured mean deviation: -9.4 ± 7.3 dB). Newly developed software was used to quantify a total of 20 optic disc parameters in SS-OCT (DRI OCT-1, TOPCON) images of the optic disc. The most suitable reference plane (RP) above the plane of Bruch's membrane opening was determined by comparing, at various RP heights, the SS-OCT-measured rim parameters and spectral-domain OCT-measured circumpapillary retinal nerve fiber layer thickness (cpRNFLT), with Pearson's correlation analysis. To obtain a discriminant formula for disc type classification, a training group of 72 eyes of 72 OAG patients and a validation group of 60 eyes of 60 OAG patients were set up.
  
  
  RESULTS
  Correlation with cpRNFLT differed with disc type and RP height, but overall, a height of 120 μm minimized the influence of disc type. Six parameters were most significant for disc type discrimination: disc angle (horizontal), average cup depth, cup/disc ratio, rim-decentering ratio, average rim/disc ratio (upper and lower nasal). Classifying the validation group with these parameters returned an identification rate of 80.0% and a Cohen's Kappa of 0.73.
  
  
  CONCLUSIONS
  Our new, objective SS-OCT-based method enabled us to classify glaucomatous optic discs with high reproducibility and accuracy.
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Takada
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.|Department of Ophthalmic imaging and information analytics, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Omodaka
authors.affiliation: Topcon Corporation, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kikawa
authors.affiliation: Division of Biostatistics, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Airi
authors.initials: A
authors.lastname: Takagi
authors.affiliation: Topcon Corporation, Tokyo, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Matsumoto
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yokoyama
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Shiga
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Maruyama
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Topcon Corporation, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Akiba
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.|Department of Retinal Disease Control, Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.|Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.|Department of Ophthalmic imaging and information analytics, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Nakazawa
mesh_terms: D000368:Aged; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology*; D012372:ROC Curve; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods