Friday, December 9, 2011

What is Refraction?

Refractometry is defined as the measurement of refractive error and it should not be confused with the term refraction. Refraction is defined as the sum of steps performed in arriving at a decision as to what lens or lenses (if any) will most benefit the patient. These steps include, in addition to Refractometry, measurements of visual acuity, measurement of accommodative ability and the exercise of clinical judgment. Refractometry, on the other hand, is strictly limited to clinical application of optical principles. This measurement function can be performed at the highest level of precision by technicians and, in some cases, even by sophisticated instruments and computers.

The exercise of clinical judgment included in the foregoing definition of refraction refers to a consideration of such factors as the patient's occupational requirements, muscle balance, impairment of vision by other than refractive error (such as cataract, macular degeneration or amblyopia), the extent and type of refractive error present and even the emotional "set" of the patient with respect to wearing glasses. For some patients, even though there may be a significant error, the maximum benefit will be achieved by prescribing no lenses at all.

If you have any questions regarding refraction or measurement of refractive error please schedule an appointment for an examination at Doctor & Associates by calling 203-227-4113.