VISION TESTING

Over the past few decades, we vision specialists have been noting a disturbing trend. The studies show that the number of people who are nearsighted has been increasing and those who are already nearsighted have shown an increase in their prescription as well. It has been postulated that the cause is the increased sustained near work demands on individuals. From in-office computer use to constant cell phone use, the focusing and aiming demands are constant and show no signs of letting up. So, how can the visual strain on the individual be decreased? One method is to follow the guidelines on this website to increase ergonomic efficiency. However, while the guidelines are extremely important, they cannot undo problems of an old, improper, ill-fitting or ill-designed prescription, whether it be in the form of glasses, contact lenses or both. 

Unlike your hands that can do different tasks at the same time, your eyes have to do identical tasks. That is, they have to focus the same amount and have to turn in, to view a close object, such as a cell phone, the same amount. They cannot work independently. As a result, should the eyes not be balanced as to clarity and coordination, strain ensues. This results in eyestrain, loss of focus, lack of efficiency, and just plain blur, just to name a few. 

So we need to differentiate visual acuity from visual function. Visual acuity is the ability to see and recognize something. Visual function is the ability to have the eyes work efficiently for depth, accuracy and coordination. And there are separate specific optometric testing to examine each. The fact that a user can say “I see fine” usually refers to their visual acuity but not their visual function.

In a complete eye and visual examination, tests are performed to determine the health, vision acuity and function. 

Let’s start with the health of the eyes. Tests are performed to check for eye pressure, color perception, and the health of the structures of the eyes. These include tests that can detect glaucoma, macular degeneration, tumors, diabetes, hypertension, high cholesterol and cataract to name but a few of the conditions recognizable through the eyes. Any health shortcoming will certainly affect how the eye see and how they coordinate. 

Next comes visual acuity. The majority of the testing here is to determine if and what prescription the patient may need in order to see clearly. Nearsightedness (myopia), farsightedness (hyperopia) and problems with seeing clearly at near (presbyopia) are all determined at this stage with numbers used to indicate the power of the lenses that are needed by the individual. This insures that the patient is seeing as equally clear as possible out of both eyes. But that’s not the whole visual picture.

How the eyes function is one of the most important aspects of the examination. These tests check to see, for distance and near, how the eyes are coordinating, as well as their focusing, or accommodative, ability. If it is determined that there is excessive strain on the eyes in order for them to function properly, there are methods to try to correct this. These include the use of what is termed prism in the prescription, the use of visual therapy to train the eyes to increase their efficiency and response, and the use of specialized glasses to allow for greater coordination and to relieve the effort it takes for them to work together properly.