Defects in Focus

The eye is said to have a power of accommodation which permits it to focus on objects at varying distances from it. This ability to focus depends on the action of its small ciliary muscles. In near vision, they contract and make the crystalline lens of the eye thicker. For distant vision, the opposite process occurs and the lens become flatter. There is a limit, however, to the power of accommodation. When the ciliary muscles are constantly overworked, the effect is eyestrain or eye fatigue, which may be reflected in other parts of the body.

In order for a clear image to be seen, the rays of light proceeding from the visible ob­ject must pass through the cornea and crys­talline lens and must be focused more or less exactly on the retina. Defects in focusing of­ten occur as a result of weakness or strain on the ciliary muscles, abnormalities in the shape of the cornea and lens, rigidity of the lens and too-great or too-little depth (or length) of the eyeball.

The four common defects in focusing are myopia (nearsightedness), hyperopia (far­sightedness), presbyopia ("oldsightedness") and astigmatism. These conditions account for most cases of poor eyesight. The correc­tion of these defects is made by fitting and wearing the proper kinds of glasses, which compensate for refractive errors of the eye itself.

Professional Eye Care

Here are the "danger signals" from the eyes that should prompt you to see a doctor: seeing double, seeing blurred outlines around objects that you formerly saw sharply, seeing rain­bows or halos around lights, or seeing poorly in the dark.

In some cases your doctor will further rec­ommend that you see an eye specialist. The ophthalmologist, formerly called oculist, is a physician (M.D.) licensed to treat all diseases and disorders of the eye and, of course, to use all diagnostic methods. In addition to his reg­ular medical training, the eye specialist has taken postgraduate courses of study in his specialty His competency is in many in­stances certified by the American Board of Ophthalmology, first of the specialty examin­ing boards in American medicine.

The optometrist is also a licensed, profes­sional person, who has taken special college and graduate courses in optometry. Optome­trists are licensed in all fifty states to exam­ine the eyes for errors of refraction in the lens system, to prescribe lenses (glasses) to correct these errors, and to prescribe eye exercises and other non-medical measures in eye care. The optometrist, however, is not a physician. Perhaps three-fourths of all prescriptions for glasses in the United States are written by optometrists.

The optician is a technician; he grinds lenses to the prescription of the oculist or op­tometrist and fits them to the eye in a prop­erly adjusted frame. The adjustment of the glasses to the eye must be accurate, and this requires proper fitting of frames.