As imaging technology allows deeper and deeper evaluation of the eye’s anatomy, more connections can be made between physical changes and disease pathogenesis. Clinicians are now noticing that, in glaucoma suspects with myopia, the width of β-zone parapapillary atrophy (PPA) without Bruch’s membrane can affect the macular intraretinal layer thickness. The findings suggest that clinicians should use OCT to evaluate a patient’s PPA when examining for glaucomatous damage.
The South Korea–based researchers looked at 113 eyes of healthy subjects with myopia. They gathered SD-OCT images of each subject’s macula, subfoveal choroid and optic nerve head. They then segmented the macular images into seven intraretinal layers. In particular, they were interested in PPA widths, measured with and without Bruch’s membrane. They also evaluated the association between macular intraretinal thickness and axial length and the microstructure of PPA.
Results showed an increase in axial length associated with a decrease in whole macular thickness of the peripheral region and an increase in whole macular thickness of the central region. Thickness alterations of the macular intraretinal layers were most apparent in the peripheral region. The team said they uncovered a significant correlation between PPA without Bruch’s membrane width and macular intraretinal layer thickness, whereas no significant correlation was found between PPA with Bruch’s membrane width and macular intraretinal layer thickness. Both widths also correlated with subfoveal choroidal thickness.
“SD-OCT provides high-resolution images and enables the visualization of detailed morphological changes in each macular intraretinal layer and optic nerve head,” the report reads. “With an increase in axial length, whole macular thickness in the peripheral region decreased, while whole macular thickness in the central region increased.”
Piao H, Guo Y, Ha J, et al. Association of macular thickness with parapapillary atrophy in myopic eyes. BMC Ophthalmol. March 6, 2020. [Epub ahead of print].