Ocular wavefront aberrations in the common marmoset Callithrix jacchus: Effects of age and refractive error

Abstract

The common marmoset, Callithrix jacchus, is a primate model for emmetropization studies. The refractive development of the marmoset eye depends on visual experience, so knowledge of the optical quality of the eye is valuable. We report on the wavefront aberrations of the marmoset eye, measured with a clinical Hartmann-Shack aberrometer (COAS, AMO Wavefront Sciences). Aberrations were measured on both eyes of 23 marmosets whose ages ranged from 18 to 452 days. Twenty-one of the subjects were members of studies of emmetropization and accommodation, and two were untreated normal subjects. Eleven of the 21 experimental subjects had worn monocular diffusers or occluders and ten had worn binocular spectacle lenses of equal power. Monocular deprivation or lens rearing began at about 45 days of age and ended at about 108 days of age. All refractions and aberration measures were performed while the eyes were cyclopleged; most aberration measures were made while subjects were awake, but some control measurements were performed under anesthesia. Wavefront error was expressed as a seventh-order Zernike polynomial expansion, using the Optical Society of America’s naming convention. Aberrations in young marmosets decreased up to about 100 days of age, after which the higher-order RMS aberration leveled off to about 0.10 micron over a 3 mm diameter pupil. Higher-order aberrations were 1.8 times greater when the subjects were under general anesthesia than when they were awake. Young marmoset eyes were characterized by negative spherical aberration. Visually deprived eyes of the monocular deprivation animals had greater wavefront aberrations than their fellow untreated eyes, particularly for asymmetric aberrations in the odd-numbered Zernike orders. Both lens-treated and deprived eyes showed similar significant increases in Z3-3 trefoil aberration, suggesting the increase in trefoil may be related to factors that do not involve visual feedback.

Higher order aberrations, refractive error development and myopia control: a review

“…During normal visual development, chick, marmoset and rhesus monkey eyes display a decrease in HOAs over time, similar to the reduction in neonatal refractive error. A myopigenic stimulus such as imposed hyperopic defocus or form deprivation results in significantly greater ocular HOAs associated with the development of significant ametropia compared to untreated eyes (Figure A); however, both the treated and untreated eyes show a reduction in HOAs over time (Figure B). The increase in ocular HOAs observed in chicks reared with monocularly imposed negative lenses and diffusers are predominantly due to changes in third order RMS (root mean square wavefront error), while fourth order and spherical aberration RMS were minimally affected.…”

“…Similarly, the magnitude of coma and trefoil RMS (both third order terms) increased in monkeys who developed refractive errors from imposed defocus and form deprivation . Coletta et al also showed strong interocular correlations for each radial order of HOAs, except third order RMS, in monocularly form‐deprived marmosets.…”

“…Higher order aberrations (HOAs) associated with animal models of experimental myopia showing A: the greater level of HOAs during or immediately following form deprivation compared to untreated fellow eyes in marmosets (reproduced from Coletta et al), B: the change in HOAs in chick eyes during treatment with form deprivation compared to untreated control eyes (reproduced from Garcia de la Cera et al), and C: the change in HOAs in treated rhesus monkey eyes that developed form deprivation or lens‐induced ametropia compared to an untreated control group (reproduced from Ramamirtham et al), where the three time points represent pre‐treatment, immediately post‐treatment and following a period of recovery in rhesus monkeys. Note that the eyes that did not recover from their experimental ametropia showed increased HOAs compared to untreated eyes and treated eyes that exhibited recovery from induced ametropia.…”

“…The findings of experimentally induced ametropia in animal models suggest that the changes in HOAs associated with refractive error development are predominated by an increase in the asymmetric aberrations of the third radial order . Eyes with experimentally acquired ametropia show increased magnitudes of coma and trefoil, therefore such asymmetric HOAs may provide a signal that influences ocular growth, which has been hypothesised based on longitudinal data from human studies .…”

Three-dimensional OCT based guinea pig eye model: relating morphology and optics

“…It is a mammal, shows a rapid ocular development, responds to lens-induced blur, is easy to raise and handle, and optical measurements are feasible. We have previously reported optical aberration measurements (using Hartmann Shack wavefront sensors) in other animal models, such as chickens [5,6], marmosets [7], macaques [8] and mice [9]. However, despite the increasing use of the guinea pig model, and extensive research on the regulation of its eye growth (in terms of axial length and refractive error) [4,10,11], there is scarce information on its optical properties in vivo.…”