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Reynolds Ablordeppey, Xiaoying Zhu, David Troilo, Alexandra Benavente-Perez; Development of a protocol to perform behavioural measurements of accommodative response in naïve marmosets. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2154.
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© ARVO (1962-2015); The Authors (2016-present)
To develop a behavioral protocol to measure accommodation dynamics in naïve marmosets with no training using pediatric fixation toys as targets
The accommodative response of 10 non-cyclopleged marmosets to a moving and a fixed target was measured as changes in refraction using an infrared video photorefractor (PowerRefractor; MultiChannel Systems). Three toys used in pediatric clinics with both light and auditory stimuli served as fixation targets: a phone, robot and microphone (Fisher-Price®). Under oscillatory moving conditions (OT), the target was moved in 2.5 cycles from near (accommodative demand, AD, 13D) to far (AD, 0.56D) at a steady rate of 6cm/sec. The fixed target protocol (FT) measured accommodation at 3 fixed distances: 25cm (AD 4D), 100cm (AD 0.98D) and 180cm (0.56D). The photorefractor was set in continuous mode to measure refraction, pupil size and horizontal gaze in both eyes to track fixation and to filter data outside ±5deg. Accommodative amplitude, variability (±SD), dynamics and fixation were used to select the toy of preference.
Marmosets (176.7±106.61 days old) had an average refraction of OD: 0.48±1.30D and OS: 0.38±1.40D. When we compared the oscillatory vs the fixed accommodative protocol, the average variability in the accommodative response was similar between protocols [OT: ±0.49D, FT: ±0.46D, p=0.27]. For both protocols, the microphone provided the largest range of accommodative amplitude (6D OT, 1.52D FT), least variability (±0.40D OT, ±0.48D FT), and best dynamics and fixation patterns. Marmosets used their effectively less hyperopic eye to follow their preferred toy and kept it clear at distance (OT lag: 0.42±1.20D, FT lag: 0.22±1.44D; p=0.48); with a moderate lag at near (OT: 3.49±1.30D, FT: 3.08±1.47D; p=0.16).
The accommodative response can be measured non-invasively in awake marmosets with no previous training using either an oscillatory or a fixed pediatric toys as a target. Animals tended to focus with their effective myopic eye and experienced significant lag with demands greater than 2D. The development of this protocol will allow us to measure the dynamics of the marmoset accommodative response under monocular and binocular conditions with or without correction in an effort to understand the pathogenesis of myopia.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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