title: Estimating the rate of retinal ganglion cell loss in glaucoma.
abstract: OBJECTIVE
  To present and evaluate a new method of estimating rates of retinal ganglion cell (RGC) loss in glaucoma by combining structural and functional measurements.
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  The study included 213 eyes of 213 glaucoma patients followed up for an average of 4.5 ± 0.8 years with standard automated perimetry visual fields and optical coherence tomography. A control group of 33 eyes of 33 glaucoma patients underwent repeated tests over a short period to test the specificity of the method. An additional group of 52 eyes from 52 healthy subjects followed up for an average of 4.0 ± 0.7 years was used to estimate age-related losses of RGCs. Estimates of RGC counts were obtained from standard automated perimetry and optical coherence tomography, and a weighted average was used to obtain a final estimate of the number of RGCs for each eye. The rate of RGC loss was calculated for each eye using linear regression. Progression was defined by a statistically significant slope faster than the age-expected loss of RGCs.
  
  
  RESULTS
  From the 213 eyes, 47 (22.1%) showed rates of RGC loss that were faster than the age-expected decline. A larger proportion of glaucomatous eyes showed progression based on rates of RGC loss rather than based on isolated parameters from standard automated perimetry (8.5%) or optical coherence tomography (14.6%; P < .01), while maintaining similar specificities in the stable group.
  
  
  CONCLUSIONS
  The rate of RGC loss estimated from combining structure and function performed better than either isolated structural or functional measures for detecting progressive glaucomatous damage.
authors: Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, La Jolla, CA 92093, USA. fmedeiros@glaucoma.ucsd.edu
authors: Felipe A
authors: FA
authors: Medeiros
authors: Linda M
authors: LM
authors: Zangwill
authors: Douglas R
authors: DR
authors: Anderson
authors: Jeffrey M
authors: JM
authors: Liebmann
authors: Christopher A
authors: CA
authors: Girkin
authors: Ronald S
authors: RS
authors: Harwerth
authors: Marie-Josée
authors: MJ
authors: Fredette
authors: Robert N
authors: RN
authors: Weinreb
mesh_terms: D002452:Cell Count; D018450:Disease Progression; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000503:physiopathology; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology