June 2022
Volume 63, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2022
In vivo measurement of plexus-specific retinal erythrocyte velocity and acceleration in human subjects and NHPs
Author Affiliations & Notes
  • Shih-En Chen
    University of Maryland School of Medicine, Baltimore, Maryland, United States
  • Victoria Chen
    University of Maryland School of Medicine, Baltimore, Maryland, United States
  • Jessica Pottenburgh
    University of Maryland School of Medicine, Baltimore, Maryland, United States
  • Osamah Saeedi
    University of Maryland School of Medicine, Baltimore, Maryland, United States
  • Footnotes
    Commercial Relationships   Shih-En Chen None; Victoria Chen None; Jessica Pottenburgh None; Osamah Saeedi Aerie Pharmaceuticals, Code F (Financial Support), Heidelberg Engineering, Code F (Financial Support), Vasoptic Medical Inc., Code F (Financial Support)
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2022, Vol.63, 3502. doi:
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    • Get Citation

      Shih-En Chen, Victoria Chen, Jessica Pottenburgh, Osamah Saeedi; In vivo measurement of plexus-specific retinal erythrocyte velocity and acceleration in human subjects and NHPs. Invest. Ophthalmol. Vis. Sci. 2022;63(7):3502.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : We utilized multimodal imaging with Erythrocyte Mediated Angiography (EMA) and Optical Coherence Tomography Angiography (OCTA) to precisely quantify erythrocyte velocity and acceleration in perifoveal retinal arterioles, capillaries, and venules of humans and nonhuman primates (NHPs) at baseline and high intraocular pressure (IOP).

Methods : 15 eyes of 9 healthy human subjects and 4 eyes of NHPs underwent sequential EMA and OCTA. High intraocular pressure (IOP), defined as 18mmHg or higher, was induced in NHPs using a tight lid speculum. Systolic blood pressure, diastolic blood pressure, and IOP were measured to calculate mean ocular perfusion pressure (MOPP). Erythrocytes in capillaries were tracked using a semiautomated approach. To identify the corresponding vascular plexus, overlays were made using a time-lapse stack of EMA frames and OCTA images of the superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP) (Figure 1). We compared erythrocyte velocity and acceleration in each plexus using generalized estimating equations for statistical analysis.

Results : In human subjects, overall mean capillary velocity was 1.7±1.6mm/s. Differences between capillary velocities were noted between SVP, ICP, and DCP (p<0.01 for all comparisons) (Table 1). Overall mean human capillary acceleration was 4.0±2.5x10-3mm/s2, which did not differ significantly between plexuses. In NHPs, overall mean capillary velocity (0.69±0.31mm/s) at baseline IOP was significantly higher than that of high IOP (0.39±0.18mm/s, p<0.01). Overall NHP mean capillary acceleration was significantly higher at baseline as compared to high IOP (p<0.001). While there were no significant differences between plexus velocities in NHPs at baseline, mean capillary velocities at high IOP varied significantly between DCP and ICP (p<0.01) and DCP and SVP (p<0.01). Mean capillary accelerations in NHPs at baseline IOP varied significantly between DCP and ICP (p=0.015). At high IOP, mean NHP capillary accelerations were significantly lower for SVP and ICP as compared to DCP.

Conclusions : In humans and NHPs, erythrocyte decelerate in arterioles then accelerate in venules as expected. We have shown that blood flow in the SVP, ICP, and DCP can be precisely quantified and can differ between plexuses. Furthermore, elevated IOP results in decreased erythrocyte velocity and acceleration.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

 

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