SPH/CYL/AXIS/ADD
O.D. +1.75/-0.50/x017/+2.00
O.S. -3.00/DS +2.00
PD 65
Prism: OD 1/2 BO 1/4 BD and OS 1/2 BO

There are some basic optometric terms. The top row (O.D.) is the information for your right eye, and the second row (O.S.) is the information for your left eye. Sometimes, OE also means left eye. PD or Pupil Distance is the distance between pupil centers in millimeters. Important for fitting the optical centers of the lenses in front of the customers pupils.

SPH or SPHERE: The amount of long or short sightedness. This value specifies the optical power of a lens in diopters. It always has a plus (+) or a minus (-) sign in front or above it. The lens power for the distance correction will be minus while the correction for near distance and reading will be plus power. There will always be a value for sphere, even if it is just zero (written as 0.00, Plano or P). As you can see in the example, the right eye needs a power of +1.75 and left eye needs a power of -3.00.

CYL or CYLINDER: This is the measure for astigmatism. The symbols like SPH. As you can see in the example, the right eye has a CYCLINDER NUMBER -0.50, the left eye does not have, the eye doctor may leave it blank or put down placeholder like “SPH (sphere)” or “DS” (diopters sphere, it means that you have sphere power only), in that case, you just leave this field blank when ordering.

AXIS: This will only appear if there is a value for cylinder, as it relates to the cylindrical lens and denotes a reference point that indicates the direction of the power of the cylindrical lens. It will be a number between 1 and 180. It is without a degree ‘o’ symbol after the number. As you can see in the example, a number “017″ for the right eye since it has CYCLINDER NUMBER, and he leaves it blank for the left eye or “000″ when ordering.

Prism is a box on the rx prescription form that is not normally filled in. Occasionally, when the two eyes are not properly aligned and looking directly at the same thing, PRISM can be ground into the lenses in order to re-align them. This can occur with strabismus (ie – an eye turn) or in situations where the eyes are properly aligned but are under a tremendous amount of strain in order to keep them aligned. As the example, “OD 1/2 BO 1/4 BD and OS 1/2 BO” means that your right eye has 0.5 base out prism and 0.25 base down, and left eye has 0.5 base out prism.

Actually, the prism of eyeglasses prescription is too difficult to process with lenses. Especially the progressive (no-line bifocals) lenses are not workable. PrescriptionGlassesOnline.net could process prisms to glasses lenses, which charge just between $20 to $50 for single vision or bifocal eyeglasses. At this example, only $35 for prism fee based on the eyeglasses prescription information.

The downfall to the eyeglass lens is the weight of a pair of prescription glasses made of glass. They are also very breakable and have to undergo a heat-treated process to ensure durability.

I think resin plastic is another type of material used in manufacturing the prescription eyeglass lens. They are the lightest of all lenses, but do not offer the high level of protection against ultra violet light that the other lenses offer.

There is still another material used to manufacture prescription glasses is the High-Index plastic lens. It also absorbs ultra violet light well. This type of lens is much lighter in weight than the eyeglass lens; however, they are also very expensive and can be scratched very easily.

Some prescription glasses are tinted with a wide variety of colors and shades. The purpose of the tint is to reduce the glare from certain situations: such as bright lights, computers television sets, etc. Another reason for the tinting of the lenses are to offer comfort to the eyes. Also, people order tints on their eyeglasses for the fashion.

Eyeglass and most plastic lenses are coated with a UV protection coating. Ultra violet rays can cause severe damage to the eyes. It is very important to protect your eyes while out in the sun.

Another coating that is added to a pair of prescription eyeglasses is the scratch-resistant coating. Sometimes this coating is applied at the manufacturer and other times it can be added right there at the eye doctors office.

It must be said, however, that even while this coating can aid in the durability of the lens, it does not make the lens scratch proof