Amblyopia Essay examples

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Amblyopia

This paper provides a brief description of amblyopia and discusses current research regarding the motion pathway in individuals with amblyopia.

Amblyopia is a condition in which visual acuity in one eye is greatly reduced. It is caused by lack of stimulation or disuse during visual development (Rose, 1998). Because the eye is not fully developed at birth (Jarvis, 1992, as cited in Rose, 1998), infants need stimulation to complete the visual neural pathway. When one or both eyes are inhibited, for example due to misalignment of one eye (strabismus) or a large difference in refractive power between two eyes (anisometropia), the neural pathway for the inhibited eye develops abnormally, or does not develop at all. At
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This information is important because it could provide meaningful insight into the nature of the underlying problems involved (Hess & Anderson, 1993).

There is a general consensus that amblyopes have reduced contrast sensitivity, grating acuity, and spatial resolution in one eye and a loss of binocular vision (Levi, 1991; Sireteanu et al., 1977, as cited in Fahle & Bachmann, 1996). Amblyopes also suffer from "crowding" (Levi & Klein, 1985, as cited in Fahle & Bachmann, 1996) which causes difficulty, for example, in comprehending a letter found in text rather than an isolated letter. The mechanisms delegating positional information are also disabled in amblyopes (Rentschler & Hilz, 1985, as cited in Fahle & Bachmann, 1996).

Even though amblyopia results in a profusion of visual obstacles, there is one area for which amblyopia may actually provide beneficial. Arguments have been made that while fine spatial detail has been affected in amblyopes, the motion pathway has not been affected (Chung & Levi, 1997; Kubova, Kuba, Juran, & Blakemore, 1996), and may even be more acute (Fahle & Bachmann, 1996). It has been proposed that in amblyopes the parvocellular pathway is impaired resulting in loss of fine spatial detail (Kubova, et al., 1996). On the other hand, parasol cells that lie in the magnocellular layers
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