Diagnosing A Refractive Error Essay Example | Topics and Well Written Essays - 3250 words

Diagnosing A Refractive Error - Essay Example Being myopic, you would be able to see better at near, while objects become progressively blurrier with distance. "Hyperopia, the hyperopic eye is deficient in refractive power. The rays from infinity are not refracted enough; thus the point of focus is behind the retina. The eye lacks plus power." (Handbook of Refraction, George E. Garcia, M.D., Pg 23) This is caused either by the cornea being too flatly curved, the axial length of the eye being too short, or a combination of both. 'Astigmatism is a condition in which rays of light are not refracted equally in all meridians. For the purpose of classification, an astigmatic eye is assumed to have two principle meridians that are usually at right angles to each other. (Handbook of Refraction, George E. Garcia, M.D., Pg 35) Astigmatism is caused by the abnormal shape of the eye. Like a football, distorted in shape, being flatter along one meridian and steeper along the other. The clarity of vision would be affected at all distances. If your astigmatism is oriented vertically, there will be selective blurring of vertical lines. "Presbyopia is a normal condition associated with age. ... "Hyperopia, the hyperopic eye is deficient in refractive power. The rays from infinity are not refracted enough; thus the point of focus is behind the retina. The eye lacks plus power." (Handbook of Refraction, George E. Garcia, M.D., Pg 23) This is caused either by the cornea being too flatly curved, the axial length of the eye being too short, or a combination of both. If you were Hyperopic, you would see both distance and near blurred. But the distance is clearer compared to the near objects. 'Astigmatism is a condition in which rays of light are not refracted equally in all meridians. For the purpose of classification, an astigmatic eye is assumed to have two principle meridians that are usually at right angles to each other. (Handbook of Refraction, George E. Garcia, M.D., Pg 35) Astigmatism is caused by the abnormal shape of the eye. Like a football, distorted in shape, being flatter along one meridian and steeper along the other. The clarity of vision would be affected at all distances. If your astigmatism is oriented vertically, there will be selective blurring of vertical lines. "Presbyopia is a normal condition associated with age. Accommodation available falls short of the demand made upon it for the usual reading range. It is due to a physiological decrease in the amplitude of accommodation. Its appearance varies with the individual, particularly his or her occupation and refractive error." (Handbook of Refraction, George E. Garcia, M.D., Pg 78) 2. PROCESS OF REFRACTION The overall process of refraction can be divided into three parts. Part one is called the "starting point." The refractionist collects basic information about the visual conditions of the patient. This includes a technique called static retinoscopy. This determines the refractive