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M. C. Campbell, J. J. Hunter, M. L. Kisilak, E. L. Irving; Retinal Image Quality During Ocular Development in Chick, Monkey and Human. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3715. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
We analyzed previously published data to describe the components of retinal blur in the chick, monkey and human during development. We compared the longitudinal changes in optical quality to predictions of uniformly and non-uniformly scaled models of eye growth. We wished to better understand normal development of the different components of retinal blur in human and in animal models of myopia.
We used published rates of ocular component growth of chick and monkey eyes (Irving et al., 1996; Qiao-Grider et al., 2007) and infant versus adult human ocular parameters (Wang and Candy, 2005) to develop our models. The models predict changes in optical quality and its components on the retina with age. The predictions were compared to experimental observations in the growing eye (Kisilak et al., 2006; Ramamirtham et al., 2006; Qiao-Grider et al., 2007; Wang and Candy, 2005) of higher-order aberrations (HOA), defocus, retinal image quality and in chick, its metrics. Using the comparisons, we estimate the actual changes in the components of linear and angular retinal blurs.
In chick, monkey and human, the observed improvement in angular blur on the retina due to HOA is more rapid than predicted by anatomically-based, uniformly scaled eye growth. In human, improvement in HOA between the infant and adult eye implies a small change in linear retinal blur. Overall, in chick and monkey, the observed exponential decrease in angular blur occurs at a rate that is faster than that predicted by our model which holds linear retinal blur constant. Thus, in chick and monkey, linear retinal blur due to HOA decreases with age. However, in chick, blur due to 3rd order aberrations decreased at a rate predicted by our model, consistent with this order giving constant linear retinal blur. In chick, human and monkey respectively, retinal blur due to HOA appears to decrease with age more slowly, similarly and more rapidly than that due to defocus.
In all three species, the results imply that more than simple ocular scaling has occurred. Relative time courses for blur from defocus and HOA are species dependent. Improvement in HOA in the chick eye, specifically that due to 3rd order aberrations, is consistent with active emmetropization at a slower rate than emmetropization of defocus blur. Image quality predictions given by the new, simpler model are superior to those of schematic eye models with spherical surfaces. These methods could predict developmental changes in retinal image quality for any species for which the differential scaling with age of wavefront aberration, pupil size and focal length is known.
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