title: Aqueous Angiography in Living Nonhuman Primates Shows Segmental, Pulsatile, and Dynamic Angiographic Aqueous Humor Outflow.
abstract: To evaluate the feasibility of safely performing aqueous angiography in intact eyes of living nonhuman primates (NHPs) for evaluating aqueous humor outflow and segmental patterns.
  
  
  
  Cross-sectional, observational study.
  
  
  
  Six nonhuman primates.
  
  
  
  Aqueous angiography was performed in 6 nonhuman primates. After anesthesia, an anterior chamber (AC) maintainer was placed through a temporal 1-mm side-port wound. Indocyanine green (ICG; 0.4%) or 2.5% fluorescein was introduced (individually or in sequence) into the eye with a gravity-driven constant-pressure system. Aqueous angiography images were obtained with a Spectralis HRA+OCT (Heidelberg Engineering GmbH, Heidelberg, Germany) suspended over the NHP eye using a custom-designed surgical boom arm. Concurrent anterior segment optical coherence tomography (OCT) was performed on distally angiographically positive and negative regions.
  
  
  
  Angiographic patterns described by location, time-course, choice of tracer, and anterior-segment OCT.
  
  
  
  Aqueous angiography in the living NHP eye demonstrated mostly stable angiographic patterns. With multimodal imaging, angiographically positive signal co-localized with episcleral veins as identified by infrared imaging and intrascleral lumens, as demonstrated by anterior segment OCT. Sequential aqueous angiography in individual eyes with ICG followed by fluorescein showed similar angiographic patterns. A pulsatile nature of aqueous angiographic outflow was sometimes observed. Aqueous angiographic patterns could also dynamically change. In some instances, positive angiographic flow suddenly arose in regions previously without an angiographic signal. Alternatively, an angiographic signal could suddenly disappear from regions in which an angiographic signal was initially documented.
  
  
  
  Aqueous angiography in living NHPs demonstrated segmental and pulsatile patterns with a newly described ability to dynamically shift. These characteristics further the understanding of live aqueous humor outflow biology and may be useful in improving glaucoma surgeries aimed at trabecular meshwork bypass.
authors.affiliation: Doheny Eye Institute, Los Angeles, California, and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California. Electronic address: Ahuang@Doheny.org.
authors.forename: Alex S
authors.initials: AS
authors.lastname: Huang
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Diya
authors.initials: D
authors.lastname: Yang
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Huaizhou
authors.initials: H
authors.lastname: Wang
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China. Electronic address: wningli@vip.163.com.
authors.forename: Ningli
authors.initials: N
authors.lastname: Wang
authors.affiliation: Hamilton Glaucoma Center and Shiley Eye Institute, University of California, San Diego, California.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
mesh_terms: D000818:Animals; D000869:Anterior Eye Segment / Q000000981:diagnostic imaging / Q000378:metabolism*; D001082:Aqueous Humor / Q000378:metabolism*; D004396:Coloring Agents / Q000008:administration & dosage; D003430:Cross-Sectional Studies; D005240:Feasibility Studies; D005260:Female; D019793:Fluorescein / Q000008:administration & dosage; D005451:Fluorescein Angiography / Q000379:methods*; D005456:Fluorescent Dyes / Q000008:administration & dosage; D007208:Indocyanine Green / Q000008:administration & dosage; D007429:Intraocular Pressure; D008253:Macaca mulatta; D008297:Male; D011673:Pulsatile Flow; D012590:Sclera / Q000098:blood supply; D041623:Tomography, Optical Coherence
chemical_list: D004396:Coloring Agents; D005456:Fluorescent Dyes; D007208:Indocyanine Green; D019793:Fluorescein