Apples, Honey, and Visual Acuity
You've surely already heard of the concept of 20/20 vision. It seems to me that most people, including myself until very recently, associate a value of 20/20 with perfect vision. The reality is that this value is an expression of visual acuity which is only one of the many components of good vision.
One of my favorite courses this semester presents to us the responsibilities of other professionals in our field, specifically those of the optometrist.
In this course, I was surprised to learn that visual acuity-- the degree with which the eye can perceive the finest details of an object, is a measure completely independent of the refractive power of the eye.
This means that it is possible for an individual with no need for corrective lenses to have a visual acuity inferior to 20/20. How can this be? Today, I sought clarification from Agnes, one of our optometrists.
Agnes explained to me that an eye able to form a sharp image on the retina can have a poor visual acuity if it is afflicted by an underlying, non-refractive, problem. There you have it: you really do learn something new every day.
It seems as though the subject of visual acuity somehow got me thinking about Rosh Hashanah, the Jewish new year: apples dipped in honey are traditionally eaten during the first Rosh Hashanah meal to assure a sweet year to come.
Shana Tova! (Happy New Year!)