How Do You Read an Eye Glass Perscription

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 optics and strength of your vision. They can help you figure out whether you have nearsightedness, farsightedness or astigmatism — and to what caste.

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

OD vs. Bone: One for each eye

Eye doctors use the abbreviations "OD" and "OS" to announce your right and left eyes.

Your middle doctor may give you a newspaper prescription that looks something similar this.

• OD is your right eye. OD is brusk for oculus dexter, the Latin phrase for "correct eye."

• Os is your left eye. Os is short for oculus sinister, Latin for "left middle."

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

These abbreviated terms are common on prescriptions for glasses, contact lenses and eye medicines, merely some doctors and clinics have opted to modernize their heart prescriptions by using RE (correct eye) and LE (left centre) instead of OD and OS.

The information for your right eye (OD) ever comes before the information for your left centre (Os). Middle doctors write prescriptions this manner considering, when they face you lot, they see your right center on their left (start) and your left centre 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 under this heading comes with a minus sign (–), y'all are nearsighted.

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

The term "sphere" ways 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 power needed for astigmatism. It always follows the sphere power on an eyeglass prescription.

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

If nothing appears in this column, you either don't have astigmatism, or your degree of astigmatism is and then small that it doesn't need to be corrected.

The term "cylinder" ways that this lens power added to right astigmatism is not spherical, just instead is shaped then one meridian has no added curvature, and the top perpendicular to this "no added power" meridian contains the maximum ability and lens curvature to correct astigmatism.

Meridians of the center are adamant by superimposing a protractor calibration on the eye's front surface. The xc-degree meridian is the vertical meridian of the eye, and the 180-degree peak is the horizontal meridian.

Meridians of the eye are adamant by superimposing a protractor scale on the eye's front surface. The 90-degree meridian is the vertical meridian of the heart, and the 180-caste height is the horizontal meridian.

Axis

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

If an eyeglass prescription includes cylinder power, information technology also needs to include an centrality value, which follows the cylinder power.

The axis is defined with a number from one 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 axis is the lens peak that is 90 degrees away from the acme that contains the cylinder power for astigmatism correction.

Add

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

The number appearing in this section of the prescription is ever a "plus" power, even when yous don't see a plus sign. More often than not, information technology will range from +0.75 to +3.00 D and will be the aforementioned power for both eyes.

Prism

This is the amount of prismatic power, measured in prism diopters ("p.d." or a triangle when written freehand), prescribed to recoup for eye alignment problems.

Only a small-scale percentage of eyeglass prescriptions include a prism measurement.

When present, the corporeality of prism is indicated in either metric or fractional English language units (0.5 or ½, for instance), and the direction of the prism is indicated by noting the relative position of its "base" (thickest border).

Four abbreviations are used for prism direction: BU = base upwardly; BD = base down; BI = base in (toward the wearer's nose); BO = base out (toward the wearer's ear).

How they're measured

Sphere power, cylinder power and add power ever appear in diopters. They are in decimal form and mostly are written in quarter-diopter (0.25 D) increments.

Axis values are whole numbers from one to 180 and signify but a meridional location, not a power.

When prism diopters are indicated in decimal form, typically but one digit appears afterwards the period (e.thousand., 0.v).

An instance eye prescription chart

However confused? Let's expect at an example prescription nautical chart:

	SPH	CYL	Axis	Add	Prism
OD	-2.00	SPH		+2.00	0.5 BD
Bone	-1.00	-0.50	180	+ii.00	0.5 BU

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

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

• No cylinder power or axis, which ways no astigmatism is present. This doctor chose to write "SPH," to confirm the correct eye is being prescribed but spherical power. Some doctors will add "DS" for "diopters sphere" and others will leave information technology blank.

The left eye (Os) was prescribed:

• -1.00 D sphere for nearsightedness correction.

• -0.fifty D cylinder for the correction of astigmatism.

• A cylinder power with an axis at the 180 meridian. This ways that the horizontal (180-degree) acme of the eye has no added power for astigmatism and the vertical (90-caste) meridian gets the added -0.50 D from the cylinder column.

Both optics were prescribed:

• An "add power" of +2.00 D for the correction of presbyopia.

• Prismatic correction of 0.5 prism diopter in each middle. In the correct centre, the prism is base of operations downwardly (BD); in the left eye, it's base upwardly (BU).

Your eye medico may too write specific lens recommendations on your eyeglass prescription. They might suggest anti-reflective blanket, photochromic lenses and/or progressive lenses to give you the well-nigh comfy vision correction possible.

Run across RELATED: How "bad" is my prescription?

Can eyeglass prescriptions exist used to buy contact lenses?

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

An eyeglass prescription only works for the purchase of eyeglasses. It does non contain sure information that is crucial to a contact lens prescription.

That information can only exist obtained through a contact lens fitting, an additional procedure that tin be performed during your eye doctor visit.

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

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

As well, the power of an eyeglass prescription frequently is modified when determining the best contact lens power. This is because eyeglass lenses are worn some distance (ordinarily nigh 12 millimeters) from the surface of the middle, whereas contact lenses rest straight on the cornea of the centre.

An accurate contact lens prescription can be written simply after a contact lens fitting has been performed and the prescribing doctor has evaluated your eyes' response to the lenses and to contact lens vesture in general.

SEE ALSO: Contact lens vs. eyeglasses prescriptions

Your eyeglass prescription is yours to keep

The Federal Trade Committee (FTC) is the U.S. government's consumer protection agency. Their Prescription Release Rule requires that center doctors requite patients a re-create of their eyeglass prescription at the stop of an eye examination that includes a refraction.

The Prescription Release Dominion is intended to allow the "portability" of your eyeglass prescription, giving you the freedom to buy glasses from whatsoever vendor of your choice.

Your eye doctor must give yous a copy of the prescription whether or not y'all enquire for it. Eye doctors may non status the release of your prescription on your agreement to buy eyeglasses from them, nor may they charge y'all an extra fee to release your prescription.

If y'all think your eye doctor has violated this dominion, you lot can report the problem to the FTC.

Folio published in February 2019

Page updated in February 2022

How Do You Read an Eye Glass Perscription

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