Abstract
The chicken is the most commonly used animal model for the study of refractive error development and myopia. In vivo imaging the photoreceptors in this model may provide new insight into the effect of myopic eye growth on cone photoreceptor distribution. To achieve this goal, we developed a chicken retina-imaging module on an adaptive optics scanning laser ophthalmoscope (AOSLO), originally designed for imaging the human eye. The unit included a confocal scanning laser imaging system, a low coherence light source, and a MEMS deformable mirror-based adaptive optics (AO) system. We modified the scanning optics to accommodate the smaller pupil size of the chicken, and made a platform with multiple degrees of freedom for positioning the chicken and appropriately aligning the chicken eye for sequential scanning across a selected retinal location. With AO compensation for the ocular aberration of the chicken eye, their cone photoreceptors were clearly visible. After in vivo imaging, the retinas from the same animals were whole-mounted, photoreceptors uppermost, and their mosaic photographed with a Zeiss deconvolution microscope, and cones counted to obtain comparative cone density data. As cone density maps can be constructed from in vivo images, the AOSLO is an effective tool for the longitudinal study of refractive error-induced changes in cone density.