Physiological Basis of Anisometropic Amblyopia

Abstract

In the visual cortex of kittens that have received their only visual experience while wearing a high-power lens before one eye, most neurons are dominated by input from the normal eye. Moreover, contrast sensitivity and resolving power are lower for stimulation through the originally defocused eye, mimicking psychophysical results from human anisometropic amblyopes.

The visual system of the cat

“…A somewhat similar effect has been reported for unilateral induced astigmatism (Cynader & Mitchell, 1977). If, in front of one eye, the kitten wears a lens that defocuses the entire image, in all meridians, the number of cortical neurons driven by that eye is reduced and those which can be activated through the originally defocused eye exhibit an overall depression in contrast sensitivity (Eggers & Blakemore, 1978). This latter finding may represent the neural basis of anisometropic amblyopia.…”

Influence of Amblyopia on High-Pass Resolution Perimetry

“…In amblyopia evidence has been given phys iologic abnormalities in the retina [20,21], lat eral geniculate nucleus [21], and visual cortex [22], The perimetric abnormalities, observed in the current study, could not discriminate between damage at these different levels of the visual system.…”

Equivalent intrinsic blur in amblyopia

“…In this section we briefly review anatomical and physiological studies of experimental amblyopia. Eggers and Blakemore (1978) have studied the contrast sensitivity of neurons in kittens reared with experimental anisometropia. They discovered that neurons driven through the amblyopic eye showed reduced contrast sensitivity, particularly at high spatial frequencies.…”