title: Aqueous Angiography: Real-Time and Physiologic Aqueous Humor Outflow Imaging.
abstract: OBJECTIVE
  Trabecular meshwork (TM) bypass surgeries attempt to enhance aqueous humor outflow (AHO) to lower intraocular pressure (IOP). While TM bypass results are promising, inconsistent success is seen. One hypothesis for this variability rests upon segmental (non-360 degrees uniform) AHO. We describe aqueous angiography as a real-time and physiologic AHO imaging technique in model eyes as a way to simulate live AHO imaging.
  
  
  METHODS
  Pig (n = 46) and human (n = 6) enucleated eyes were obtained, orientated based upon inferior oblique insertion, and pre-perfused with balanced salt solution via a Lewicky AC maintainer through a 1mm side-port. Fluorescein (2.5%) was introduced intracamerally at 10 or 30 mm Hg. With an angiographer, infrared and fluorescent (486 nm) images were acquired. Image processing allowed for collection of pixel information based on intensity or location for statistical analyses. Concurrent OCT was performed, and fixable fluorescent dextrans were introduced into the eye for histological analysis of angiographically active areas.
  
  
  RESULTS
  Aqueous angiography yielded high quality images with segmental patterns (p<0.0001; Kruskal-Wallis test). No single quadrant was consistently identified as the primary quadrant of angiographic signal (p = 0.06-0.86; Kruskal-Wallis test). Regions of high proximal signal did not necessarily correlate with regions of high distal signal. Angiographically positive but not negative areas demonstrated intrascleral lumens on OCT images. Aqueous angiography with fluorescent dextrans led to their trapping in AHO pathways.
  
  
  CONCLUSIONS
  Aqueous angiography is a real-time and physiologic AHO imaging technique in model eyes.
authors.affiliation: Doheny Eye Institute, Los Angeles, California, United States of America.
authors.forename: Sindhu
authors.initials: S
authors.lastname: Saraswathy
authors.affiliation: Doheny Eye Institute, Los Angeles, California, United States of America.|Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
authors.forename: James C H
authors.initials: JC
authors.lastname: Tan
authors.affiliation: Department of Biostatistics, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.affiliation: Doheny Eye Institute, Los Angeles, California, United States of America.|Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Francis
authors.affiliation: Department of Ophthalmology and Pathology, University of Southern California, Los Angeles, California, United States of America.
authors.forename: David R
authors.initials: DR
authors.lastname: Hinton
authors.affiliation: Hamilton Glaucoma Center and Shiley Eye Institute, University of California San Diego, San Diego, California, United States of America.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Weinreb
authors.affiliation: Doheny Eye Institute, Los Angeles, California, United States of America.|Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
authors.forename: Alex S
authors.initials: AS
authors.lastname: Huang
mesh_terms: D000818:Animals; D001082:Aqueous Humor / Q000502:physiology*; D003199:Computer Systems; D003911:Dextrans; D005451:Fluorescein Angiography / Q000379:methods*; D005456:Fluorescent Dyes; D006801:Humans; D007091:Image Processing, Computer-Assisted; D012212:Rheology / Q000379:methods*; D034421:Sus scrofa; D013552:Swine; D041623:Tomography, Optical Coherence
chemical_list: D003911:Dextrans; D005456:Fluorescent Dyes