HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Vera-Diaz, F. A. Articles by Whitaker, D. Search for Related Content PubMed PubMed Citation Articles by Vera-Diaz, F. A. Articles by Whitaker, D.

A Psychophysical Investigation of Ocular Expansion in Human Eyes

¹From the New England College of Optometry, Boston, Massachusetts; ²School of Psychology, University Park, Nottingham, United Kingdom; the ³Department of Vision Sciences, Glasgow Caledonian University, Glasgow, Scotland, United Kingdom; and the ⁴Department of Optometry, University of Bradford, Bradford, United Kingdom.

PURPOSE. To investigate spatial anisotropies in the peripheral visual field of axially myopic eyes, in an attempt to distinguish between models of isotropic and anisotropic ocular stretching.

METHODS. Stimuli consisted of two high-contrast Gaussian patches presented in one of four orientations (90°, 180°, 45°, or 135°). For each orientation, perceived separation was established relative to that for all other orientations. The experiment was conducted with central fixation and at 15° in the nasal and inferior visual fields. Eleven myopes and nine emmetropes participated in the study. Biometric data were collected from all subjects.

RESULTS. For foveal fixation, the magnitude of the spatial anisotropy (5%) was consistent with the well-documented horizontal-vertical illusion (HVI), and unrelated to axial length. In the nasal visual field, much larger misperceptions were found (19%), the magnitude of which increased significantly with increasing axial length. Inferiorly, a reversal of the traditional HVI is found in most subjects (7%), with a tendency for a larger reversed illusion with increasing axial length. Differences between nasal and inferior misperceptions were significantly correlated with axial length.

CONCLUSIONS. Isotropic stretching, such as globe expansion, should preserve the aspect ratios of receptive fields, predicting a separation misperception which is independent of axial length. In contrast, the magnitude of the misperception is significantly correlated with axial length, supporting anisotropic stretching models of myopic growth.

This article has been cited by other articles:

				A. Jaworski, A. Gentle, A. J. Zele, A. J. Vingrys, and N. A. McBrien Altered visual sensitivity in axial high myopia: a local postreceptoral phenomenon? Invest. Ophthalmol. Vis. Sci., August 1, 2006; 47(8): 3695 - 3702. [Abstract] [Full Text] [PDF]

				K. D. Singh, N. S. Logan, and B. Gilmartin Three-dimensional modeling of the human eye based on magnetic resonance imaging. Invest. Ophthalmol. Vis. Sci., June 1, 2006; 47(6): 2272 - 2279. [Abstract] [Full Text] [PDF]