Astigmatism

Life in a blurred world

Overview

A person's eye is naturally shaped like a sphere "Under normal circumstances, when light enters the eye, it refracts, or bends evenly, creating a clear view of the object" (WebMD, 2014). When a person is suffering from an astigmatism their lens or cornea has an irregular curve; which can change the way light is refracted or passes to your retina. Objects at any distance can appear as blurry due to the light being refracted more in one direction than the other allowing only part of an object to be in complete focus at a time.

What the brain sees

Refraction can be defined as the bending of light as it passes through one object to the next. As light rays are refracted through the cornea and lens visions occurs. The light is focused into the retina, which in returns sends these images to the brain through the optic nerve. The brain interrupts these messages into what we are looking at, but when a cornea has an astigmatism the image is not seen clearly so the brain can not interrupt the message correctly.

How we perceive objects and scenes

The proximal stimuli is the optical image on the retina. Normally we are able to recognize an object regardless of the viewpoint, this is known as the viewpoint invariance. The Gestalt Approach suggests that we do not focus on every component of an object. Our mind rather perceives objects as a whole that are made up of elements of much more complex systems. The Gestalt Approach played a major role in the development of sensation and perception in humans. (Goldstein, 2014).

Treatments

Although astigmatism is usually associated with other vision impairments such as nearsightedness and farsightedness. This vision impairment can usually be corrected with eyeglasses or contact lenses. In extreme cases surgery may be used to correct the irregular cornea. "Refractive surgeries require healthy eyes that are free from retinal problems, corneal scars, and any eye disease" (WebMD, 2014). Eyeglasses is the safest way to treat an astigmatism.

References

Goldstein, E.B. (2014). Sensation and Perception. 9th Edition. Cengage: Belmont, CA.


WebMD. (2014, August). Astigmatism: Causes, Symptoms, Diagnosis, and Treatment. Retrieved from http://www.webmd.com/eye-health/astigmatism-eyes