What is the number on your reading glasses mean ? (such as 1.0 or 1.5, etc...)?!
Question: A typical prescription looks like this:
OD -1.25 -1.00 x 90
OS -2.00 -1.25 x 94
+2.00 ADD PD 64/61
OD is a Latin abbreviation meaning oculus dexter, or right eye. OS, oculus sinister, signifies the left eye. The prescription for the right eye is always written first. In the above example, the prescription signifies that the person is near-sighted with a fair amount of astigmatism, and needs bifocals reading glasses.
The first number written, -1.25, is the sphere power. This sphere power can be written for near or far-sighted powers, and measures how much near or distance power a person needs to see clearly.
The second and third numbers, -1.00 x 90, measure astigmatism, and are read in combination. The second number, called the cylinder, measures how many diopters of astigmatism a person has, and the third number is the axis. The axis tells the optician where in the lens to place the cylindrical power. The axis is measured in degrees, and can be any number between 1 and 180. Astigmatism means that the eye is not perfectly rounded, but shaped more like a football, and causes blurred vision. Most people have both sphere and astigmatism correction.
The next number, +2.00 Add, signifies that the person also needs correction to see close up, or needs reading glasses. The Add power is almost always the same in each eye. Everyone will eventually need glasses for reading or close work. As the eye ages, the elasticity of the eye
Answers: A typical prescription looks like this:
OD -1.25 -1.00 x 90
OS -2.00 -1.25 x 94
+2.00 ADD PD 64/61
OD is a Latin abbreviation meaning oculus dexter, or right eye. OS, oculus sinister, signifies the left eye. The prescription for the right eye is always written first. In the above example, the prescription signifies that the person is near-sighted with a fair amount of astigmatism, and needs bifocals reading glasses.
The first number written, -1.25, is the sphere power. This sphere power can be written for near or far-sighted powers, and measures how much near or distance power a person needs to see clearly.
The second and third numbers, -1.00 x 90, measure astigmatism, and are read in combination. The second number, called the cylinder, measures how many diopters of astigmatism a person has, and the third number is the axis. The axis tells the optician where in the lens to place the cylindrical power. The axis is measured in degrees, and can be any number between 1 and 180. Astigmatism means that the eye is not perfectly rounded, but shaped more like a football, and causes blurred vision. Most people have both sphere and astigmatism correction.
The next number, +2.00 Add, signifies that the person also needs correction to see close up, or needs reading glasses. The Add power is almost always the same in each eye. Everyone will eventually need glasses for reading or close work. As the eye ages, the elasticity of the eye