Abstract
Purpose :
Posterior pole asymmetry analysis (PPAA), an optical coherence tomography (OCT) software that compares the thickness of the superior versus inferior hemifields of the posterior pole, has been shown to improve the diagnostic accuracy of glaucoma. We sought to assess the relationship between changes in PPAA and papillary vessel density (VD) measured by OCT angiography (OCT-A) in glaucoma suspects (GS).
Methods :
Thirteen GS (16 eyes) were enrolled in a prospective research study at the Manhattan Eye, Ear, and Throat Hospital (MEETH) in New York City. VD was measured on an OCT-A 3x3 scan using ImageJ software and major vessels were subtracted from the VD measurements. PPAA was measured by Spectralis (Glaucoma Module Premium Edition) OCT. Partial correlation was used to assess the relationship between optic nerve head (ONH) whole image vessel density (WIVD) and PPAA variables (total, superior, and inferior thickness in μm). Additionally, we tested the relationship between VD and PPAA using a linear regression model where in step 1, intraocular pressure (IOP), spherical equivalent (SE), patient ethnicity, and Q-score were entered as covariates, and in step 2, ONH WIVD was entered.
Results :
Partial correlation revealed significant positive relationships between ONH WIVD and PPAA total thickness (r=0.59, p=0.045) as well as with PPAA inferior thickness (r=0.68, p=0.015), but not PPAA superior thickness (r=0.47, p=0.125). In the linear regression model, after adjusting for IOP, SE, patient ethnicity, and Q-score ONH WIVD explained 11% of variance in total PPAA thickness (F(1,10)=6.27, B=1.41, 95% CI: 0.15-2.66, p=0.031), 13.3% of variance in inferior PPAA thickness (F(1,10)=9.20, B=1.57, 95% CI: 0.42-2.72, p=0.013), and 7.9% of variance in superior PPAA thickness (F(1,10)=3.72, B=1.22, 95% CI: -0.19-2.63, p=0.082).
Conclusions :
To our knowledge, this is the first report characterizing the significant positive relationships between ONH WIVD and the total and inferior thickness of the posterior pole measured by PPAA. These findings are suggestive of hemiretinal microvascular damage to the ONH that coincides with asymmetrical morphological changes in retinal ganglion cells, resulting in thinning of the inferior retina. Therefore, both vessel density and posterior pole assessments used in conjunction may improve diagnostic accuracy in GS.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.