title: Comparison of Retinal Thickness Measurements between the Topcon Algorithm and a Graph-Based Algorithm in Normal and Glaucoma Eyes.
abstract: OBJECTIVE
  To assess the correlation and agreement between the Topcon built-in algorithm and our graph-based algorithm in measuring the total and regional macular thickness for normal and glaucoma subjects.
  
  
  METHODS
  A total of 228 normal eyes and 93 glaucomatous eyes were enrolled in our study. All patients underwent comprehensive ophthalmic examination and Topcon 3D-OCT 2000 scan. One eye was randomly selected for each subject. The thickness of each layer and the total and regional macular thickness on an Early Treatment of Diabetic Retinopathy Study (ETDRS) chart were measured using the Topcon algorithm and our three-dimensional graph-based algorithm. Correlation and agreement analyses between these two algorithms were performed.
  
  
  RESULTS
  Our graph search algorithm exhibited a strong correlation with Topcon algorithm. The macular GCC thickness values for normal and glaucoma subjects ranged from 0.86 to 0.91 and from 0.78 to 0.90, and the regional macular thickness values ranged from 0.79 to 0.96 and 0.70 to 0.95, respectively. Small differences were observed between the Topcon algorithm and our graph-based algorithm. The span of 95% limits of agreement of macular GCC thickness was less than 28 μm in both normal and glaucoma subjects, respectively. These limits of total and regional macular thickness were 15.5 μm and 23.1 μm for normal subjects and 29.1 μm and 46.4 μm for glaucoma subjects, respectively.
  
  
  CONCLUSIONS
  Our graph-based algorithm exhibited a high degree of agreement with the Topcon algorithm with respect to thickness measurements in normal and glaucoma subjects. Moreover, our graph-based algorithm can segment the retina into more layers than the Topcon algorithm does.
authors.affiliation: School of Electronic and Information Engineering, Soochow University, Suzhou, China; School of Electronic and Information Engineering, Suzhou University of Science and Technology, Suzhou, China.
authors.forename: Enting
authors.initials: E
authors.lastname: Gao
authors.affiliation: Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China.
authors.forename: Binyao
authors.initials: B
authors.lastname: Chen
authors.affiliation: Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China.
authors.forename: Jianling
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Electronic and Information Engineering, Soochow University, Suzhou, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Shi
authors.affiliation: School of Electronic and Information Engineering, Soochow University, Suzhou, China.
authors.forename: Weifang
authors.initials: W
authors.lastname: Zhu
authors.affiliation: School of Electronic and Information Engineering, Soochow University, Suzhou, China.
authors.forename: Dehui
authors.initials: D
authors.lastname: Xiang
authors.affiliation: Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China.
authors.forename: Haoyu
authors.initials: H
authors.lastname: Chen
authors.affiliation: Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China.
authors.forename: Mingzhi
authors.initials: M
authors.lastname: Zhang
authors.affiliation: School of Electronic and Information Engineering, Soochow University, Suzhou, China.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Chen
mesh_terms: D000465:Algorithms; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D008266:Macula Lutea / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000473:pathology*