These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Is the spectacle lens jack-in-the-box phenomenon really due to the lenses?
    Author: Walsh G, Pearce EI.
    Journal: Ophthalmic Physiol Opt; 2006 Jan; 26(1):116-9. PubMed ID: 16390491.
    Abstract:
    The calculation of the extent of the ring scotoma around positive lenses, as conventionally taught to students of clinical optics, indicates that the scotoma is of a significant size. Using knife-edge lenses this study shows that the calculations are invalid due to the finite size of the eye's entrance pupil and in many instances the scotoma is shown not to exist. The effect noticed in clinical practice is probably largely due to the frame and the edging techniques used which add to the refractive scotoma which is present with high powered lenses, large apertures and/or small pupil sizes.
    [Abstract] [Full Text] [Related] [New Search]