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How to Read Your Eyeglasses Prescription

Making sense of your eye prescription nautical chart

The numbers on your eyeglass prescription relate to the shape of your eyes and strength of your vision. They can aid you effigy out whether you have nearsightedness, farsightedness or astigmatism — and to what degree.

If you know what to look for, you can brand sense of the numbers and abbreviations on your prescription nautical chart.

OD vs. OS: One for each eye

Middle doctors employ the abbreviations "OD" and "Bone" to denote your right and left optics.

Your eye physician may give yous a paper prescription that looks something like this.

• OD is your right center. OD is short for oculus dexter, the Latin phrase for "right centre."

• OS is your left eye. Bone is short for oculus sinister, Latin for "left eye."

Your vision prescription may as well have a column labeled "OU." This is the abridgement for oculus uterque, which means "both eyes" in Latin.

These abbreviated terms are common on prescriptions for glasses, contact lenses and eye medicines, but some doctors and clinics take opted to modernize their eye prescriptions by using RE (right eye) and LE (left eye) instead of OD and Os.

The information for your correct eye (OD) always comes before the data for your left center (OS). Eye doctors write prescriptions this way because, when they face you, they see your correct eye on their left (first) and your left center on their right (second).

Sphere (SPH)

Sphere indicates the amount of lens power prescribed to correct nearsightedness or farsightedness. Lens power is measured in diopters (D).

• If the number nether this heading comes with a minus sign (–), yous are nearsighted.

• If the number under this heading has a plus sign (+), you are farsighted.

The term "sphere" means that the correction for nearsightedness or farsightedness is "spherical," or equal in all meridians of the eye.

Cylinder (CYL)

Cylinder indicates the amount of lens ability needed for astigmatism. Information technology always follows the sphere ability on an eyeglass prescription.

The number in the cylinder column may accept a minus sign (for correction of nearsighted astigmatism) or a plus sign (for farsighted astigmatism).

If goose egg appears in this column, y'all either don't have astigmatism, or your caste of astigmatism is so small that it doesn't demand to exist corrected.

The term "cylinder" means that this lens power added to correct astigmatism is not spherical, but instead is shaped so one meridian has no added curvature, and the summit perpendicular to this "no added power" meridian contains the maximum power and lens curvature to right astigmatism.

Meridians of the centre are determined by superimposing a protractor calibration on the heart's front surface. The 90-caste tiptop is the vertical meridian of the eye, and the 180-degree summit is the horizontal acme.

Meridians of the eye are adamant by superimposing a protractor calibration on the eye's forepart surface. The ninety-degree meridian is the vertical meridian of the eye, and the 180-degree top is the horizontal meridian.

Axis

Centrality describes the lens meridian that contains no cylinder power to correct astigmatism.

If an eyeglass prescription includes cylinder power, it also needs to include an axis value, which follows the cylinder power.

The centrality is defined with a number from i to 180.

• The number 90 corresponds to the vertical meridian of the eye.

• The number 180 corresponds to the horizontal top of the eye.

The centrality is the lens height that is 90 degrees abroad from the meridian that contains the cylinder power for astigmatism correction.

Add

"Add together" is the added magnifying power practical to the bottom function of multifocal lenses to correct presbyopia — the natural farsightedness that happens with age.

The number appearing in this department of the prescription is always a "plus" power, even when y'all don't see a plus sign. Generally, it will range from +0.75 to +iii.00 D and will be the same power for both eyes.

Prism

This is the corporeality of prismatic ability, measured in prism diopters ("p.d." or a triangle when written freehand), prescribed to compensate for eye alignment issues.

Only a minor percentage of eyeglass prescriptions include a prism measurement.

When present, the amount of prism is indicated in either metric or fractional English units (0.five or ½, for instance), and the direction of the prism is indicated by noting the relative position of its "base of operations" (thickest edge).

4 abbreviations are used for prism management: BU = base up; BD = base downwards; BI = base in (toward the wearer'southward olfactory organ); BO = base out (toward the wearer's ear).

How they're measured

Sphere ability, cylinder power and add together power always appear in diopters. They are in decimal form and generally are written in quarter-diopter (0.25 D) increments.

Centrality values are whole numbers from 1 to 180 and signify only a meridional location, not a power.

When prism diopters are indicated in decimal form, typically only one digit appears after the period (east.g., 0.5).

An example eye prescription nautical chart

Withal confused? Permit's look at an example prescription chart:

	SPH	CYL	Axis	Add	Prism
OD	-2.00	SPH		+2.00	0.5 BD
OS	-1.00	-0.fifty	180	+2.00	0.5 BU

In the right eye (OD), the heart physician prescribed:

• -two.00 D sphere for the correction of nearsightedness.

• No cylinder power or axis, which means no astigmatism is present. This medico chose to write "SPH," to confirm the right heart is existence prescribed only spherical power. Some doctors will add "DS" for "diopters sphere" and others volition leave it blank.

The left heart (OS) was prescribed:

• -i.00 D sphere for nearsightedness correction.

• -0.50 D cylinder for the correction of astigmatism.

• A cylinder power with an centrality at the 180 acme. This means that the horizontal (180-caste) meridian of the center has no added power for astigmatism and the vertical (90-degree) elevation gets the added -0.fifty D from the cylinder column.

Both eyes were prescribed:

• An "add power" of +two.00 D for the correction of presbyopia.

• Prismatic correction of 0.5 prism diopter in each centre. In the right center, the prism is base down (BD); in the left eye, it's base of operations up (BU).

Your heart physician may besides write specific lens recommendations on your eyeglass prescription. They might suggest anti-reflective blanket, photochromic lenses and/or progressive lenses to give you the nearly comfortable vision correction possible.

SEE RELATED: How "bad" is my prescription?

Can eyeglass prescriptions be used to buy contact lenses?

No, yous cannot use your spectacles prescription to purchase contact lenses.

An eyeglass prescription only works for the purchase of eyeglasses. Information technology does not contain certain information that is crucial to a contact lens prescription.

That information can merely be obtained through a contact lens plumbing fixtures, an additional process that can be performed during your eye doctor visit.

Eyeglass lenses are positioned at a altitude from the eyes, while contacts rest directly on the eyes. That distance affects the lens power required for eyes to focus properly.

In addition to the information in an eyeglass prescription, a contact lens prescription must specify the base of operations (primal) curve of the back surface of the contact lens, the lens bore, and the specific manufacturer and brand proper name of the lens.

Also, the ability of an eyeglass prescription frequently is modified when determining the all-time contact lens ability. This is considering eyeglass lenses are worn some distance (unremarkably well-nigh 12 millimeters) from the surface of the eye, whereas contact lenses residual directly on the cornea of the eye.

An authentic contact lens prescription can be written only later on a contact lens fitting has been performed and the prescribing doctor has evaluated your optics' response to the lenses and to contact lens wear in general.

Encounter As well: Contact lens vs. eyeglasses prescriptions

Your eyeglass prescription is yours to go along

The Federal Trade Commission (FTC) is the U.S. regime's consumer protection agency. Their Prescription Release Rule requires that heart doctors give patients a re-create of their eyeglass prescription at the cease of an centre examination that includes a refraction.

The Prescription Release Dominion is intended to let the "portability" of your eyeglass prescription, giving you lot the freedom to buy glasses from any vendor of your option.

Your eye md must give you a copy of the prescription whether or not yous ask for it. Eye doctors may not status the release of your prescription on your understanding to purchase eyeglasses from them, nor may they charge you lot an extra fee to release your prescription.

If y'all think your eye md has violated this rule, you can written report the problem to the FTC.

Page published in Feb 2019

Page updated in February 2022

Brown With Silver Polka Dot 1.0 Reading Glasses

Source: https://www.allaboutvision.com/eyeglasses/eyeglass-prescription.htm

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