Aqueous humor dynamics in inbred rhesus monkeys with naturally occurring ocular hypertension

Carol B. Toris, Justin M. Risma, Janis Gonzales-Martinez, Marsha A. McLaughlin, William W. Dawson

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


This study evaluates aqueous humor dynamics in rhesus monkeys from the University of Florida inbred colony with ocular normotension and naturally occurring ocular hypertension. Eight monkeys with untreated intraocular pressures (IOPs) of less than 18 mmHg in one eye (ONT group) and seven with untreated IOPs of greater than or equal to 18 mmHg in one eye (OHT group) were included in the study. Assessments included central cornea thickness by ultrasound pachymetry, IOP by tonometry, aqueous flow and outflow facility by fluorophotometry, and uveoscleral outflow by mathematical calculation. Animals were sedated with ketamine for all measurements. Values from the two eyes of each animal were averaged, with the exception of one animal that had only one good eye. Comparisons between groups were made by Student's two-tailed unpaired t-tests. Compared to the ONT group, the OHT group had higher IOPs at all times measured (4:00 PM the day before the study, 21.2 ± 6.5 versus 14.4 ± 1.5 mmHg, p = 0.01; 9:00 AM the day of the study, 20.7 ± 6.6 versus 14.8 ± 1.2 mmHg, p = 0.03; 11:00 AM the day of the study, 16.0 ± 1.6 versus 13.3 ± 2.9 mmHg, p = 0.05) and lower aqueous flow (2.12 ± 0.40 versus 4.54 ± 1.11 μl/min, p = 0.0001), outflow facility (0.17 ± 0.10 versus 0.33 ± 0.07 μl/min/mmHg, p = 0.01) and uveoscleral outflow (p < 0.05). The elevated IOP in inbred Florida rhesus monkeys is a result of significantly reduced outflow facility and uveoscleral outflow. These animals also have slower aqueous flow than the ONT animals which does not contribute to the higher IOP.

Original languageEnglish (US)
Pages (from-to)860-865
Number of pages6
JournalExperimental Eye Research
Issue number6
StatePublished - Dec 2010


  • Aqueous humor dynamics
  • Glaucoma
  • Intraocular pressure
  • Rhesus monkey

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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