Abstract
Purpose :
Aging remains a critical contributor to the manifestation of a number of debilitating ocular diseases including age-related macular degeneration, cataracts and other reversible and irreversible causes of vision loss. The goals of this study were to compare ocular anatomical and electrophysiological differences between young and geriatric African green monkeys (Chlorocebus sabaeus; St. Kitts origin) and to evaluate the potential utility of this species as a model for investigating aging-associated ocular diseases.
Methods :
Ophthalmic data were collected from 30 geriatric (19 – 26 years old) and 30 young (4 – 12 years old) green monkeys. Ophthalmic examinations including color fundus photography (CFP), slit lamp biomicroscopy, intraocular pressure (IOP), optical coherence tomography (OCT) and full-field electroretinography (ffERG) were conducted while monkeys were under ketamine/xylazine sedation.
Results :
Cataracts were present in over 50% of geriatric monkeys, but absent in all young monkeys evaluated. Dilated pupil diameter was significantly reduced and general ocular health, as assessed through slit lamp biomicroscopy, revealed a higher incidence of findings outside of the normal limits of general population in geriatric monkeys. Significant reductions in retinal thickness and volume, and retinal nerve fiber layer thickness in geriatric monkeys were observed as assessed by OCT. No significant overall age-associated differences in IOP were observed. Electrophysiological evaluation of differences in photoreceptor responses by ffERG showed that geriatric monkeys had reduced scotopic a-wave and b-wave amplitude and increased latencies at light intensities of 5 cd*sec/m2. When considering only rod responses, a-wave and b-wave latencies were significantly elevated in geriatric monkeys. The photopic flicker response was significantly reduced in geriatric compared to young monkeys. These data indicate shifts in retinal function in geriatric monkeys.
Conclusions :
The current study identified a number of ocular anatomical and functional differences between young and geriatric green monkeys similar to those associated with aging in humans. These data provide a basis for further investigation of the green monkey as a test system for evaluating the etiology and treatment of age-associated ocular diseases.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.