title: Perimetric progression in open angle glaucoma and the Visual Field Index (VFI).
abstract: OBJECTIVE
  To evaluate the changes in the Visual Field Index (VFI) in eyes with perimetric glaucomatous progression, and to compare these against stable glaucoma patients.
  
  
  METHODS
  Consecutive patients with open angle glaucoma with a minimum of 6 reliable visual fields and 2 years of follow-up were identified. Perimetric progression was assessed by 4 masked glaucoma experts from different units, and classified into 3 categories: "definite progression," "suspected progression," or "no progression." This was compared with the Glaucoma Progression Analysis (GPA) II and VFI linear regression analysis, where progression was defined as a negative slope with significance of <5%.
  
  
  RESULTS
  Three hundred ninety-seven visual fields from 51 eyes of 39 patients were assessed. The mean number of visual fields was 7.8 (SD 1.1) per eye, and the mean follow-up duration was 63.7 (SD 13.4) months. The mean VFI linear regression slope showed an overall statistically significant difference (P<0.001, analysis of variance) for each category of progression. Using expert consensus opinion as the reference standard, both VFI analysis and GPA II had high specificity (0.93 and 0.90, respectively), but relatively low sensitivity (0.45 and 0.41, respectively).
  
  
  CONCLUSIONS
  The mean VFI regression slope in our cohort of eyes without perimetric progression showed a statistically significant difference compared with those with suspected and definite progression. VFI analysis and GPA II both had similarly high specificity but low sensitivity when compared with expert consensus opinion.
authors.affiliation: Department of Ophthalmology, NHS Grampian, Aberdeen Royal Infirmary, La Laguna, Spain.
authors.forename: Ghee Soon
authors.initials: GS
authors.lastname: Ang
authors.forename: Mohammed Sohaib
authors.initials: MS
authors.lastname: Mustafa
authors.forename: Neil
authors.initials: N
authors.lastname: Scott
authors.forename: Valentin Tinguaro
authors.initials: VT
authors.lastname: Diaz-Aleman
authors.forename: Augusto
authors.initials: A
authors.lastname: Azuara-Blanco
mesh_terms: D000368:Aged; D018450:Disease Progression; D005189:False Positive Reactions; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields