<< back to Article Index
<< back to home

Just the Facts About... Why Have Regular Eye Exams?

What is a refraction?

A refraction is one of the essential steps in evaluating the health status of the eyes. The information gained from a refraction of the eye goes beyond the determination of any lenses that may be needed to correct nearsightedness, farsightedness or astigmatism. Failure to accurately determine the cause of blurred vision may result in irreparable harm to the eyes and a partial loss of vision or blindness.

The eye, as an optical system, allows for the precise sectioning of images of the world around us. The eye, as an organ of the body, can provide evidence of and be affected by disease processes such as diabetes that occur throughout the body. The presence of an optical system defect, an eye disease, or a systemic health problem may cause the image formed by the eye to be out of section. It is not possible for a lay person or the patient to know whether the blurred vision is caused by underlying disease or the need for a new spectacle correction.

I am told that I don't need a complete eye exam to deal with blurred vision. Is this true? Those who may advocate providing a refraction in isolation from a complete eye examination are overlooking the fact that the source of blurred vision is not always a refractive error. The presence of undetected diseases, such as GLAUCOMA, DIABETES MELLITUS, MACULAR DEGENERATION, RETINAL DETACHMENT, CATARACT, ARTHRITIS, and AIDS may result in blurred vision. Patients with these diseases may still be correctable to 20/20 visual acuity with new lenses. However, it cannot be presumed that good ocular health is present if the patient achieves 20/20 visual acuity (with or without glasses). Certain drugs taken for the treatment of general health problems may also result in a transient change in refraction. Environmental and occupational factors, trauma to the eye, or dietary deficiencies may also contribute to refractive changes. Proper diagnosis is necessary to determine the true cause.

What else is done in a complete exam besides a refraction? Although objective means are available for measuring the refractive state of the eye, this information cannot automatically be translated into a prescription for eyeglasses or contact lenses. The components of a refraction must include a thorough patient history and an evaluation of the refractive state of the eye in relation to its accommodative (sectioning) and vergence (eye muscle coordination) status, as well as eye health. This information is needed to adequately prescribe glasses. Improper or inadequate eyeglass prescriptions based only on refractive information may alter eye coordination and sectioning ability, create visual distortion, eyestrain, headaches, dizziness or double vision, and mask symptoms of eye disease.

Who provides eye examination services? A refraction to determine a prescription for eyeglasses or contact lenses should not be performed independently of an eye health and vision examination. Only eye care professionals (optometrists and ophthalmologists) with the education and training to evaluate the entire eye and vision system should make the appropriate diagnosis regarding whether a lens prescription is all that is needed to restore clear, comfortable vision and to safeguard the health of the patient. EARLY DETECTION OF DISEASE IS EQUATED WITH LONG TERM SAVINGS IN HEALTH CARE COSTS.



Dr. Steve Briggs - Dr. Liane Pitre 1701 3rd Ave. East,
Owen Sound, Ont. N4K 2M3 (519) 376-3937
Other Articles by Dr. Steve Briggs

The Truth About Laser Pointers
Just the Facts About Glaucoma