Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Changes in corneal curvature during accommodation in chicks.

D Troilo, J Wallman

    Vision Research
    |January 1, 1987
    PubMed
    Summary

    Chicks exhibit active corneal accommodation, with increased corneal curvature observed during stimulated accommodation. The cornea plays a larger role in lower ranges of accommodation, with its power change leveling off around 6 D.

    Related Concept Videos

    You might also read

    Related Articles

    Articles linked to this work by shared authors, journal, and citation graph.

    Sort by
    Same author

    AAV-mediated transduction and targeting of retinal bipolar cells with improved mGluR6 promoters in rodents and primates.

    Gene therapy·2016
    Same author

    Novel, continuous visual motion induces c-fos expression in the avian optokinetic nuclei and optic tectum.

    Neuroscience·2009
    Same author

    Differences in time course and visual requirements of ocular responses to lenses and diffusers.

    Investigative ophthalmology & visual science·2001
    Same author

    Endogenous rhythms in axial length and choroidal thickness in chicks: implications for ocular growth regulation.

    Investigative ophthalmology & visual science·2001
    Same author

    Diurnal illumination patterns affect the development of the chick eye.

    Vision research·2000
    Same author

    Form deprivation myopia in mature common marmosets (Callithrix jacchus).

    Investigative ophthalmology & visual science·2000

    Area of Science:

    • Ophthalmology
    • Animal Models
    • Vision Science

    Background:

    • Accommodation is the eye's ability to adjust focus for different distances.
    • The role of the cornea in avian accommodation is not fully understood.
    • Previous research primarily focused on lenticular accommodation.

    Purpose of the Study:

    • To investigate the presence and extent of corneal accommodation in chicks.
    • To quantify the contribution of corneal curvature changes to overall accommodation amplitude.

    Main Methods:

    • Anesthetized chicks were used to measure accommodative responses.
    • Accommodation was induced via electrical stimulation of the Edinger-Westphal nucleus.
    • Nicotine sulfate (0.4%) was topically applied to the cornea to induce accommodation.
    • Corneal curvature and refractive power changes were measured using specialized optical techniques.

    Main Results:

    • Electrical stimulation resulted in 9.2 diopters (D) of accommodation with a 3.9 D change in corneal power.
    • Nicotine treatment induced 15.1 D of accommodation and a 6.1 D change in corneal power.
    • Corneal power change increased with accommodation amplitude, plateauing around 6 D at approximately 10 D of total accommodation.

    Conclusions:

    • Evidence supports an active corneal component in chick accommodation.
    • The cornea contributes significantly to accommodation, particularly at lower amplitudes.
    • A limit exists for corneal curvature change, suggesting a greater proportional role for the lens in higher accommodation demands.

    Related Experiment Videos