The pattern electroretinogram as a tool to monitor progressive retinal ganglion cell dysfunction in the DBA/2J mouse model of glaucoma.
OBJECTIVE
To determine the baseline characteristics, reliability, and dynamic range of the pattern electroretinogram (PERG) as a tool to monitor progressive RGC dysfunction in the DBA/2J mouse model of glaucoma with spontaneously elevated intraocular pressure (IOP).


METHODS
PERGs were recorded from 56 undilated eyes of 28 anesthetized (ketamine-xylazine-acepromazine) DBA/2J mice of different ages (2-4 months, n = 44 eyes; 12-14 months, n = 12 eyes) in response to contrast reversal of gratings that maximize PERG amplitude (95% contrast, 1-Hz reversal, 0.05 cyc/deg spatial frequency, 50 degrees x 56 degrees field size). Robust averaging (1800 sweeps) was used to isolate PERG from background noise. Cone-driven ERGs in response to diffuse light flashes superimposed on a rod-adapting background (FERG) were also recorded.


RESULTS
PERGs had consistent waveforms and were reproducible across batches of mice and operators. In 2- to 4-month-old mice (prehypertensive stage), the PERG amplitude (mean, 8.15 +/- 0.4 microV [SEM]) was considerably larger than the noise (mean 1.18 +/- 0.1 microV). The test-retest variability (two different sessions 1 week apart) and interocular asymmetry of PERG amplitude was approximately 30%, and that of PERG latency was approximately 17%. In 12- to 14-month-old mice (advanced hypertensive stage) the PERG amplitude (mean, 1.29 +/- 0.12 microV) was close to that of noise. In 12- to 14-month-old mice the FERG was reduced to a lesser extent compared with the PERG.


CONCLUSIONS
The PERG has an adequate signal-to-noise ratio, reproducibility, and dynamic range to monitor the progression of functional changes in the inner retina in DBA/2J mice.
Porciatti
Vittorio
V
Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, USA. vporciatti@med.miami.edu
Saleh
Maher
M
Nagaraju
Mahesh
M
D000818:Animals; D004195:Disease Models, Animal; D004596:Electroretinography; D005260:Female; D005901:Glaucoma / Q000503:physiopathology*; D007429:Intraocular Pressure; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation; D012164:Retinal Diseases / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*; D017948:Retinal Rod Photoreceptor Cells / Q000503:physiopathology; D014065:Tonometry, Ocular