title: Reproducibility of Optic Nerve Head Hemoglobin Measures.
abstract: OBJECTIVE
  To evaluate intraobserver, interobserver, within-session and between-session reproducibility of the measurement of optic nerve head (ONH) hemoglobin levels by color analysis using Laguna ONhE [optic nerve hemoglobin (ONH Hb)] program.
  
  
  METHODS
  This was an observational prospective study of 29 eyes (11 glaucomatous; 18 healthy eyes). Two examiners obtained 2 retinal photographs (Canon non-mydriatic retinal camera CD-DGi, Canon Inc.,Tokyo, Japan) in 2 testing sessions 3 weeks apart and analyzed the images using Laguna ONhE. The following parameters were quantified: ONH hemoglobin amounts across the whole disc (ONH Hb) and in the vertical disc diameter (8&20 Hb), cup-disc ratio (C/D), and the Glaucoma Discriminant Function (GDF). Agreement was illustrated using the Bland-Altman plots and reproducibility was assessed comparing the intraclass correlation coefficients (ICC).
  
  
  RESULTS
  In session 1, examiner 1 found mean levels of ONH hemoglobin of 67.94±8.70% in healthy eyes and of 57.90±5.36% in glaucomatous eyes. Corresponding values for examiner 2 were 68.27±8.52% and 57.83±4.88%, respectively. ONH Hb and 8&20 Hb measurements were lower in glaucomatous eyes (P=0.002 and P=0.001 respectively). GDF was also more pathologic in glaucomatous group. C/D ratio estimation was greater in the glaucoma group (P=0.003). ONH Hb and 8&20 Hb showed the highest ICCs (all above 0.9). Variability was greater for GDF (ICC>0.8) and C/D ratio estimation (ICC>0.71).
  
  
  CONCLUSIONS
  Measurement of ONH Hb levels using the Laguna ONhE program shows high reproducibility both in glaucomatous and nonglaucomatous ONHs.
authors.affiliation: *Hospital Clinico San Carlos, Universidad Complutense de Madrid, Madrid, Spain †Hospital Universitario de Canarias, Universidad de La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Mendez-Hernandez
authors.forename: Julian
authors.initials: J
authors.lastname: Garcia-Feijoo
authors.forename: Paula
authors.initials: P
authors.lastname: Arribas-Pardo
authors.forename: Federico
authors.initials: F
authors.lastname: Saenz-Frances
authors.forename: Ignacio
authors.initials: I
authors.lastname: Rodriguez-Uña
authors.forename: Cristina
authors.initials: C
authors.lastname: Fernandez-Perez
authors.forename: Manuel
authors.initials: M
authors.lastname: Gonzalez de la Rosa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003124:Colorimetry; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009898:Optic Disk / Q000098:blood supply*; D009901:Optic Nerve Diseases / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D010108:Oxyhemoglobins / Q000378:metabolism*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012161:Retinal Artery / Q000502:physiology*; D012169:Retinal Vein / Q000502:physiology*; D041623:Tomography, Optical Coherence / Q000379:methods; D014065:Tonometry, Ocular
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen