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Mateusz Tomasz Jaskulski, Rita Nieu, Xiaoying Zhu, Alexandra Benavente-Perez; Applying Retinal Image Simulations to the Marmoset Eye for Emmetropization Studies. Invest. Ophthalmol. Vis. Sci. 2019;60(9):611.
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© ARVO (1962-2015); The Authors (2016-present)
Image quality is an important factor to help understand visual performance and it can be one of the cues used by the visual system during emmetropization. In this study, we evaluated the feasibility of applying wavefront aberrometry, objective refraction, and image-plane metrics in studies of emmetropization using the marmoset model.
The wavefront aberrations of nine marmosets (N=9) treated with positive or negative contact lenses (-5D or +5D) were measured under cyclopegia (1% cyclopentolate) approx. every 3 weeks for 7 months in awake animals using a COAS aberrometer.The aberrometry data expressed as Zernike coefficients was used to compute paraxial objective refraction, image-plane metrics of image quality (VSX), point-spread-functions (PSF) and retinal image simulations. Prior to computing the image-plane quality metrics, the defocus was corrected in the data in C(2,0) and C(4,0) Zernike terms, leaving only the Seidel spherical aberration, which corresponded to imaging an object situated at the far point of each marmoset.
The wavefront objective refraction of the animals treated with -5D lenses shifted towards varying degrees of myopia as they grew older and compensated for the imposed defocus (average paraxial Rx change ±SD: -3.8 ± 1.4 D). The repeatability of the measurements was affected by blinking and fixation errors, with standard errors of 0.45 ± 0.22 D where 3 or more measurements were available. The pupil diameter of all animals increased with age by 0.5 ± 0.2 mm. When the defocus was corrected in the data (Fig. 2a.) the average Visual Strehl Ratio (Fig. 2b.) of the animals ranged between 0.1 and 0.25. Simulated retinal images of a 20/20 optotype and PSF's exhibited a range in visual acuities that from approx. 1.3 to -0.1 logMAR.
Measurements of wavefront aberrations are feasible to perform in awake marmosets in a safe and repeatable manner and can provide derived image-plane metrics including retinal simulations. These derived metrics of image quality and objective refraction open new avenues to study visual performance and how it interacts with the mechanisms of emmetropization.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Objective refraction, pupil diameter and visual strehl ratio.
Retinal image simulations and point-spread-functions
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