Abstract
The chick is commonly used as an animal model for human myopia and emmetropization. However one criticism of this model has been the very large refractive errors that are usually induced, either by visual deprivation or through the use of lenses to first impose focussing errors. This study sought to determine the threshold for compensatory responses to imposed defocus. We observed compensation in chick eyes fitted at hatching with + 1 D and − 1 D lenses (one over each eye). Consistent with the 2 D interocular difference in refraction imposed, an average of 2.13 D (SD 1.0 D) of anisometropia and a 0.09mm (SD 0.05mm) interocular difference in vitreous chamber depth were recorded after five days of lens wear. The 1 D focusing errors imposed on individual eyes are not much greater in magnitude than the estimated depth of focus of the chick eye. The significance of these results for emmetropization are discussed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
