J Korean Ophthalmol Soc.  1999 Dec;40(12):3450-3459.

Comparison of Activation in the Primary Visual Cortex between Anisometropic and Strabismic Amblyopias using Functional MRI

• Choi MY
• Lee KM
• Hwang JM
• Choi DG
• Park KH
• Yu YS

Abstract

The purpose of the present study is to examine neural responses of the primary visual cortex[V1] in patients with anisometropic and strabismic amblyopias, using functional MRI[fMRI]. Fourteen amblyopias[8 anisometropic and 6 strabismic] with best corrected visual acuity in amblyopic eye of 20/60 or less were studied with fMRI using checkerboards of various checker sizes and temporal frequencies. While T2*-weighted MR images were obtained, patients viewed the stimuli monocularly with amblyopic eye and sound eye. Amblyopic eyes showed reduced V1 responses when compared to intact eyes in all amblyopias. V1 response via amblyopic eyes in anisometropic amblyopias was more suppressed at higher spatial frequency, while that of via amblyopic eyes in straismic amblyopias was more suppressed at lower spatial frequencies, when compared to that of via sound eyes of the same patients. V1 activation via amblyopic eyes was significantly suppressed at 4 and 8 Hz in anisometropic amblyopias. These results suggest that amblyopia is a visual disorder manifested by functional abnormalities in visual cortex and may suggest differences in neurophysiological mechanism that underlies the development of the two types.

Keyword

Amblyopia; Anisometropia; Functional MRI; Strabismus; Visual cortex

MeSH Terms

Amblyopia*
Anisometropia
Humans
Magnetic Resonance Imaging*
Strabismus
Vision Disorders
Visual Acuity
Visual Cortex*