Personalized Eye Exam
What does 20/20 mean?
This is a measure of normal visual acuity related to an ability to identify letters on a Snellen eye chart. You may know it as the eye chart topped with a giant E. The patient stands 20 feet away. A person with normal visual acuity can identify block letters that are slightly less than ½ inch high (8.87mm). A person with below normal acuity will only be able to identify larger letters. If you can identify smaller letters, your visual acuity is better than 20/20. The single E that tops the Snellen chart is 20 times the size of the 20/20 letters. If the E is all you can see, you have 20/400 vision. If the E is all you can see using your best corrective lenses, you are considered legally blind.
I’m always asked to read letters from a projector, not a chart on a wall. The letters are closer than twenty feet. Is there a new number for normal vision?
No. The distance from the patient position, usually an examination chair, to the projector screen is precisely measured. The size of the letters, numbers or symbols you’re asked to identify are adjusted accordingly. Identifying the 20/20 line of letters or symbols from an examination chair at twelve feet requires the same visual acuity as identifying them on a traditional Snellen wall chart at 20 feet.
What if some of the letters are blurred?
This is considered a refractive condition. Light enters the eye through a natural lens that directs light to a specific area of your retina. If the light is not precisely directed, images will not be perfectly focused nor appear with exacting detail. The most common refractive errors are nearsightedness, farsightedness and astigmatism.
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What does a farsighted person see?
A farsighted person can clearly see objects in the distance but cannot focus on closer objects. Light rays reach the retina before coming into sharp focus. This condition is termed hyperopia. A corrective lens is created by an optician to produce clear, near vision.
A nearsighted person sees close objects but distant objects are blurry?
Yes. Light rays from distant objects come into focus in front of the retina. This condition is termed myopia. Based upon a prescription written by an ophthalmologist or an optometrist, an optician produces a corrective lens that provides the patient with clear, distance vision.
Can you outgrow myopia and hyperopia?
In a certain sense, yes you can. Abnormal, natural lenses change shape as they age just like a natural, normal lens. A normal lens loses focus as it becomes presbyopic. It is possible a refractive error can be naturally corrected as parts of the eye change shape as a result of aging.
What is astigmatism?
Light rays entering the eye through the cornea and lens are directed toward the retina. If refraction angles are not precise, light waves will not perfectly converge on the retina’s macula cells to produce a sharply focused image. Slight astigmatism frequently goes unnoticed. As the severity of astigmatism increases, blurring occurs.
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What is presbyopia?
Your natural lens loses its elasticity as it ages. Its ability to quickly and accurately focus on every object at every distance becomes diminished; usually between the ages of 45 and 50. The eye loses its ability to focus on small objects and symbols like details and fine print. People with presbyopia wear corrective lenses commonly referred to as reading glasses.
How often should eyes be examined?
That depends upon a person’s age and, more importantly, if a disease or disorder has been diagnosed. The most important eye examination is the first one – at birth. A family physician, pediatrician, physician’s assistant or nurse should examine a newborn’s eyes. A second examination should occur 6 to 12 months later to ensure the infant’s eyes and eyesight are developing normally. By the age of 5, all children should be examined for crossed eyes (strabismus), lazy eye (amblyopia) as well as the refractive problems of hyperopia (farsightedness), myopia (nearsightedness) and astigmatism.
After the age of 5, how often should eyes be examined?
Even if no vision problems occur or any of the physical symptoms we have identified appear, a comprehensive eye examination is essential to rule out serious eye diseases and disorders that have no initial stage symptoms. This should occur at or before the age of 20.
What can I expect from an eye examination by an ophthalmologist?
Patients receive a comfortable, comprehensive, painless eye examination. Does the patient have perfect vision? Are there any imperfections in the anatomy of the eye? Has the patient observed or experienced any abnormality like sudden changes in vision, eye pain, light sensitivity, light flashes, floaters, excessive tearing, unusual dryness or redness? To answer these questions, a patient’s pupils may be dilated with eye drops possibly requiring arrangements for a driver.
Following the examination, the ophthalmologist will discuss the patient’s condition and review all treatment options. Most importantly, the ophthalmologist should take whatever time is needed to answer all of the patient’s questions and for the patient to feel comfortable with the treatment plan.
That is the essence of personalized eye care.
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