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Grace Marie Richter, Andrew Nelson, Zhongdi Chu, Ryuna Chang, Bruce Burkemper, Benjamin Xu, Amir Kashani, Rohit Varma, Ruikang Wang; Relationship between intraocular pressure and peripapillary vessel density in treatment-naïve glaucoma patients from the African American Eye Disease Study. Invest. Ophthalmol. Vis. Sci. 2019;60(11):PB050.
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Perfused radial peripapillary capillaries (RPCs), as measured by optical coherence tomography angiography (OCTA), are reduced in glaucoma, and this relationship is proportional to the extent of nerve damage. We studied a group of treatment-naïve glaucoma patients from the African American Eye Study to determine the ocular factors associated with OCTA parameters. We hypothesized that higher intraocular pressure would be independently associated with reduction of the perfused RPCs.
6x6mm spectral domain OCTA scans centered on the optic nerve were obtained on participants 40 years and older from the African American Eye Disease Study (AFEDS). RPC vessel density (VD) was determined using custom software with exclusion of large vessels. Multivariate linear regression was used to identify ocular factors associated with RPC VD and flux. Candidate variables included: intraocular pressure (IOP), age, signal strength (SS), visual field mean deviation (MD), central corneal thickness (CCT), ocular perfusion pressure (2/3 mean arterial pressure minus intraocular pressure; OPP), mean retinal nerve fiber layer thickness (mRNFL), and axial length (AL).
3840 eyes from 2025 participants received OCTA imaging. Of these, 1473 eyes from 1042 subjects had SS ≥ 7 out of 10 and good quality images based on a standardized image quality grading algorithm. Of these, 45 eyes from 36 patients were diagnosed with glaucoma and had never received treatment. 31 eyes from 31 patients were studied due to some missing data and inclusion of only 1 eye per participant. In this group, average RPC VD was 0.26 ± 0.079. The factors independently associated with RPC VD were: IOP (β=-.0026, p=.035), mRNFL (β=.0043, p<.0001), and SS (β=.02; p=.043), with a model R2 of 0.83.
From this group of treatment-naïve glaucoma patients from a population-based cohort, higher IOP was associated with reduced RPC VD, controlling for SS and mRNFL. These results support the idea that elevated IOP reduces the peripapillary microcirculation in glaucomatous eyes, and that this phenomenon may result from reduced autoregulation in glaucomatous eyes.
This abstract was presented at the 2019 ARVO Imaging in the Eye Conference, held in Vancouver, Canada, April 26-27, 2019.
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