In the 'Symptoms - Head - Eyes/Ocular' section of our in-depth questionnaire we ask the following question about nearsightedness and farsightedness:
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Are you nearsighted or farsighted? For additional information see optical prescription.
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Your answer |
...indicates |
...and suggests |
| 1. |
"No, my vision is fine / don't know" |
Having normal uncorrected vision |
A risk factor |
| 2. |
"I'm very nearsighted / -7.0 diopters or over" |
Being very nearsighted |
A symptom |
| 3. |
"I'm somewhat nearsighted / up to -7.0 diopters" |
Being somewhat nearsighted |
A symptom |
| 4. |
"I'm somewhat farsighted / up to +7.0 diopters" |
Being somewhat farsighted |
A symptom |
| 5. |
"I'm very farsighted / +7.0 diopters or over" |
Being very farsighted |
A symptom |
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Your answer will affect the likelihoods of the conditions below.
Any answers in green reduce the likelihood of the condition.
GLOSSARY
Acute
An illness or symptom of sudden onset, which generally has a short duration.
Farsightedness (Farsighted, Hypermetropia, Hyperopia, Hyperopic)
Trouble seeing objects that are close to your eyes.
Glaucoma
A disease of the eye characterized by vision loss due to an increase in the pressure of fluid within the eye. This rise in pressure results from a build-up of aqueous fluid and leads to progressive damage to the optic nerve that transmits visual signals to the brain. Over time, glaucoma can lead to a gradual loss in peripheral vision. There are usually no signs that you're developing glaucoma until vision loss occurs.
Nearsightedness (Myopia, Myopic, Nearsighted, Short Sighted)
Trouble seeing at a distance.
Optical Prescription
The units used to represent the amount of correction needed in order to normalize vision for distance are called 'diopters'. The more nearsighted or farsighted you are, the higher your prescription is in diopters. Your prescription is usually written as three numbers, for example:
OD -4.25 -1.75 X 180
OS -5.50 -1.25 X 175
+2.25 Add OU
OD (referring to the Latin "Ocular Dexter") stands for right eye, and OS ("Ocular Sinister") is for the left eye. The first number (-4.25 and -5.50 in this example) is the degree of spherical nearsightedness or farsightedness. The sign identifies whether you are nearsighted (minus sign) or farsighted (plus sign). The second number (-1.75 and -1.25) is the degree of astigmatism. The number can be written either with a + sign or a - sign. The last and 3rd number (180 and 175) is the axis, or the direction of your astigmatism. An axis of 180 degrees, for example, means the astigmatism is horizontal. Therefore, this prescription means that the patient is moderately nearsighted, with a moderate degree of astigmatism in a horizontal direction. The "add" at the bottom of the prescription is for the reading part of a bifocal glass. It might be unusual for anyone under the age of 40 to need this. Some people only have one number written for each eye. This is when there is no astigmatism.
Last updated: May 10, 2007
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