What do the numbers on a sight test mean?
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What do the numbers on a sight test mean?
In general, the further away from zero the number on your prescription, the worse your eyesight and the more vision correction (stronger prescription) you need. A “plus” (+) sign in front of the number means you are farsighted, and a “minus” (-) sign means you are nearsighted.
What does 0.75 mean on an eye test?
This second number, -0.75, indicates the person has an astigmatism, which is a distortion in the shape of the cornea that causes blurred vision. Not everyone has astigmatism, of course, so if the number wasn’t there, you’d see some letters – DS or SPH – to indicate that there is no astigmatism.
What is a normal eye axis number?
The axis number helps your eye care provider to know the direction in which they should position a cylindrical power in the lenses of your glass. The number may be between 1 to 180, where 90 represents the vertical position while 180 represents the horizontal position.
What is spherical number of eye?
Sphere (SPH) – The term “sphere” means that the correction for nearsightedness or farsightedness is spherical, equal in all meridians of the eye. This indicates the amount of lens power, measured in diopters (D), prescribed to correct nearsightedness or farsightedness.
How do I read my PD for eyeglass prescription?
Your PD is the distance between the center of one pupil (the central black dot of your eye) to the center of the other pupil. It is measured in millimeters and is an important part of your prescription….It is indicated as follows:
- BO (base out)
- BU (base up)
- BI (base in)
- BD (Base-down)
How do you read Snellen chart results?
Recording Snellen Results Top number equates to the distance (in metres) at which the test chart was presented (usually 6m), Bottom number identifies the position on the chart of the smallest line read by the ‘patient’. Eg; 6/60 means the subject can only see the top letter when viewed at 6m.
What is normal SPH vision?
An SPH number indicates if you are farsighted or nearsighted. If the SPH value is 0.00, or noted by Plano, Pl, or an infinity sign, you do not have a vision distance problem. Typical SPH numbers range between 0.00 and +/- 20.00.
What do the numbers mean on my eye test results?
Understanding your eye test results: the numbers explained. The numbers on your spectacle prescription are shown for your right eye (indicated as RE or sometimes OD – the Latin for oculus dexter, meaning right eye) and your left eye (LE or OS – oculus sinister).
What do the numbers on an eyeglass prescription mean?
On an eyeglass or contact lens prescription a “sphere” with a “plus” value describes hyperopia or farsightedness and a “minus” indicates myopia or nearsightedness. Astigmatism is another critical factor that determines a corrective prescription and is defined by two values: “axis” and cylinder or “cyl.”
What do the numbers on my astigmatism axis mean?
If there is a low number it means your eyes are slightly out of shape whereas a high number indicates that your eyes are very oval in shape and therefore more affected by astigmatism. What does Axis denote? Axis shows the Cyl described above by measuring the astigmatism in degrees. This is used by your opticians when angling your lenses.
What do the numerical tests measure?
The numerical tests measure how you think numerically and how advanced your calculation aptitude is. Although the calculations require basic mathematical skills, you do need to know how to interpret the given information from charts, tables, number sequences, texts, and graphs.