title: Relation between macular retinal ganglion cell/inner plexiform layer thickness and multifocal electroretinogram measures in experimental glaucoma.
abstract: OBJECTIVE
  We investigated relations between macular retinal ganglion cell plus inner plexiform layer (RGC+IPL) thickness and macular retinal function revealed by multifocal electroretinonography (mfERG) in a nonhuman primate model of experimental glaucoma.
  
  
  METHODS
  Retinal ganglion cell (RGC) structure and function were followed with spectral-domain optical coherence tomography (SD-OCT) and ERGs in five macaques with unilateral experimental glaucoma. Linear regression was used to study correlations in control (Con) and experimental (Exp) eyes between peripapillary retinal nerve fiber layer (RNFL) thickness, macular RGC+IPL thickness, multifocal photopic negative response (mfPhNR) and high-frequency multifocal oscillatory potentials (mfOP) in slow-sequence mfERG, and low-frequency component (mfLFC) in global-flash mfERG. We used ANOVA and paired t-tests to compare glaucoma-related mfERG changes between superior and inferior hemifields, foveal hexagon, inner three rings, and four quadrants of macula.
  
  
  RESULTS
  Average macular RGC+IPL and temporal RNFL thickness were strongly correlated (r(2) = 0.90, P < 0.001). In hexagon-by-hexagon analysis, all three mfERG measures were correlated (P < 0.001) with RGC+IPL thickness for Con (r(2), 0.33-0.51) and Exp eyes (r(2), 0.17-0.35). The RGC structural and functional metrics decreased as eccentricity increased. The reduction in amplitude of mfERG measures in Exp eyes relative to Con eyes was proportionally greater, in general, than the relative thinning of RGC+IPL at the same location for eyes in which structural loss was not evident, or mild to moderate. Although not statistically significant, percent amplitude reduction of mfERG measures was greatest in the inferior temporal quadrant.
  
  
  CONCLUSIONS
  Macular RGC+IPL thickness and mfERG measures of RGC function can be complementary tools in assessing glaucomatous neuropathy.
authors: University of Houston, College of Optometry, Houston, Texas, United States.
authors: Xunda
authors: X
authors: Luo
authors: University of Houston, College of Optometry, Houston, Texas, United States.
authors: Nimesh B
authors: NB
authors: Patel
authors: University of Houston, College of Optometry, Houston, Texas, United States.
authors: Lakshmi P
authors: LP
authors: Rajagopalan
authors: University of Houston, College of Optometry, Houston, Texas, United States.
authors: Ronald S
authors: RS
authors: Harwerth
authors: University of Houston, College of Optometry, Houston, Texas, United States.
authors: Laura J
authors: LJ
authors: Frishman
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004596:Electroretinography; D005260:Female; D005901:Glaucoma / Q000503:physiopathology*; D007429:Intraocular Pressure; D008253:Macaca mulatta; D008266:Macula Lutea; D008297:Male; D009412:Nerve Fibers / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000503:physiopathology*; D012160:Retina / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D014065:Tonometry, Ocular
keywords: experimental glaucoma; multifocal ERG; photopic negative response; retinal ganglion cell + inner plexiform layer complex