Abstract
Purpose:
Clinical trials require assessment of patients to confirm suitability for study enrollment. Similar considerations have to be made preclinically for efficacy and safety studies, particularly in large animal models where smaller cohort sizes are often employed. Defining the normal range of a test species, whether ophthalmic parameters or otherwise, can facilitate study recruitment and support evaluation of adverse or therapeutic responses to treatment. We conducted ophthalmic examinations in a population of healthy African green monkeys to define the normal range of these parameters in this species.
Methods:
Ophthalmic examinations were performed on healthy adult male and female African green monkeys. Animals were sedated with ketamine and xylazine and endpoints including laser flare photometry, pachymetry, tear film break up, corneal staining and anatomic dimensions were evaluated. The normal range was defined as mean values plus (upper value) or minus (lower values) the standard deviation multiplied by two. All studies were conducted in compliance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research.
Results:
The normal range of laser flare in healthy eyes was 1.5 to 10.9 photons/msec, with an average of 5.4 photons/msec. No significant differences in laser flare were observed between male and female eyes. Central corneal thickness measures were significantly higher in males (471±4.7 μm) than females (453±4.5 μm, p<0.05). The normal pachymetry range was 406 to 535 μm in males and 393 to 514 μm in females. No sex differences were evident from tear film break up time, fluorescein or lissamine corneal staining or from (TFBUT) or Schirmer’s test analyses. Additional measures, including tonometry and various anatomical dimensions, have also been examined and normal ranges defined.
Conclusions:
Our studies have established normal limits for a range of ophthalmic measures and supported use of rigorous animal enrollment and exclusion criteria for nonhuman primate studies, which has the potential of reducing inter-animal variability and increasing the opportunity for statistically significant responses to therapeutic intervention. Assessments of other ophthalmic parameters in the African green monkey are underway and will further enhance the value of this species for ophthalmic disease modelling.
Keywords: 419 anatomy •
480 cornea: basic science •
568 intraocular pressure