Abstract
Purpose :
Posterior pole asymmetry analysis (PPAA) is a spectral domain optical coherence tomography (SD-OCT) software that compares posterior pole retinal thickness measurements between the superior and inferior hemispheres of each eye. We sought to determine whether these structural abnormalities were correlated with functional retinal ganglion cell (RGC) loss, as quantified by steady state pattern electroretinogram (ssPERG) parameters, in glaucoma suspects (GS).
Methods :
Twenty GS (34 eyes) were enrolled in a prospective single-center study at the Manhattan Eye, Ear, and Throat Hospital in New York City. All subjects underwent comprehensive ophthalmological examination, including Humphrey visual field, Spectralis (Glaucoma Module Premium Edition) SD-OCT PPAA, and ssPERG testing. The ability of ssPERG parameters (Magnitude [Mag, µv], MagnitudeD [MagD, µv], and MagD/Mag ratio) to predict PPAA thickness measurements (total, superior, and inferior thickness, in µm) was tested via multivariate linear regression analysis.
Results :
When total, superior, and inferior PPAA parameters were independently entered as dependent variables, and after controlling for age, spherical equivalent (SE), and central corneal thickness (CCT), Mag explained 8% of variance in total PPAA change (F(1,29)=6.33, B=6.86, 95% CI: 1.29-12.44, p=0.018), 8% in superior PPAA change (F(1,29)=5.57, B=6.92, 95% CI: 0.92-12.92, p=0.025), and 7.1% in inferior PPAA change (F(1,29)=5.83, B=6.80, 95% CI: 1.04-12.56, p=0.022). In the same analysis, MagD explained 9.7% of variance in total PPAA change (F(1,29)=8.09, B=6.47, 95% CI: 1.82-11.13, p=0.008), 10% in superior PPAA change (F(1,29)=7.33, B=6.63, 95% CI: 1.62-11.63, p=0.011), and 8.5% in inferior PPAA change (F(1,29)=7.25, B=6.36, 95% CI: 1.53-11.18, p=0.012). No significant associations between MagD/Mag ratio and PPAA measures were found.
Conclusions :
To the best of our knowledge, this is the first report describing the positive relationship between RGC dysfunction and structural retinal changes in the posterior pole. These findings demonstrate possible morphological changes in RGCs prior to cell death, including shrinkage, reductions in the dendritic tree, and thinning of the retinal nerve fiber layer. The detection of asymmetrical structural RGC loss, combined with RGC function assessment using PERG, may be a more informative tool for glaucoma diagnosis in GS.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.