What does D mean on contacts?

Sphere (SPH): The amount of lens power, measured in diopters (D), which corrects nearsightedness or farsightedness. If the number under this heading features a minus sign (–), this means you're nearsighted; if it has a plus sign (+), this means you're farsighted.

What does D mean in eye prescription?

Diopter is often abbreviated "D." For example, if your prescription says -1.00, you have one diopter of nearsightedness. This is a fairly mild amount of nearsightedness. If you are -4.25, that means you have 4 and 1/4 diopters of nearsightedness.

What is D and BC contacts?

BC - Base Curve (usually a number between 8 and 10) DIA - Diameter (usually a number between 13 and 15) Brand - The brand/type of contact lens that your doctor has fitted you for.

Is Power D on contact lenses?

Extended-range contact lenses are available in spherical powers up to -20.00D for short-sightedness and +15.00D for long-sightedness, as well as up to cylinder power -5.75D for astigmatism. However, it's important to know that soft contact lenses with high powers have thicker edges compared to low-power ones.

What does 0.0 for contacts mean?

The Numbers. The numbers you see represent diopters, the units used to measure the correction of the lens (the focusing power) required by each of your eyes. Sometimes diopter is abbreviated to “D.” On a glasses prescription, 0.00 (zero focusing power needed) represents good vision.

The numbers on your contact lens (what do they mean) | Lens Parameters

What is 0.1 vision?

1 Moderate visual impairment. Visual acuity <= 0.3 > 0.1. 2 Severe visual impairment. Visual acuity <= 0.1 > 0.05.

What does PWR mean on contacts?

Read the power (PWR) of the lens strength (it may be different for each eye), measured in diopters. The higher the power number, the stronger the prescription is. Look for a minus sign to indicate nearsightedness (myopia) and a plus sign that indicates farsightedness (hyperopia).

How do I know my base curve for contacts?

Figuring out the proper base curve based upon Rx is fairly simple: Plus Power – Use the Spherical Equivalent (Sphere power plus half the cylinder power) and add 4.00 diopter to that. Example – Rx of +2.50, the base curve will be approximately 6.50.

How do I know my contact lense power?

If a GP lens is selected with a base curve radius that's one-half diopter flatter (less curved) than the cornea, a contact lens power of -2.75D would be predicted. If the base curve radius is a half diopter steeper (more curved) than the cornea, a contact lens power of -3.75D would be predicted.

What is the strongest contact prescription?

What is the strongest contact lens prescription? Contact lenses can be prescribed for extreme degrees of myopia, even for those who need correction of more than -20 Dioptres. Some lenses can go over -30 Dioptres. For monthly soft contact lenses, the highest level of corrective power is about -12 Dioptres.

Does the BC and DIA matter?

The diameter and base curve are important factors in determining what the optimum fit is for you. A proper fit ensures full coverage of the cornea, optimum edge alignment, and adequate movement of the lens for tear exchange.

How do I know which contact is for which eye?

On your eyeglasses prescription, the information for your right eye (OD) comes before the information for your left eye (OS). This is because eye doctors see your right eye on their left (first) and your left eye on their right (second).

Is SPH the same as D?

The values under the column “Sphere (SPH)” indicate the amount of lens power, measured in diopters (D), prescribed to correct your nearsightedness or farsightedness.

What astigmatism means?

Astigmatism (uh-STIG-muh-tiz-um) is a common and generally treatable imperfection in the curvature of the eye that causes blurred distance and near vision. Astigmatism occurs when either the front surface of the eye (cornea) or the lens inside the eye has mismatched curves.

What eye prescription is legally blind?

Visual acuity less than 20/200 is considered legally blind, but to actually fit the definition, the person must not be able to attain 20/200 vision even with prescription eyewear.

What do the numbers on my contacts mean?

One number that remains the same will be the sphere power (like a spherical lens). The second number is the amount of astigmatism, sometimes listed as cylinder or CYL. The third number is meridian or where the astigmatism lies. This is called the axis.

What is the maximum negative eye power?

It can be corrected by giving concave ( minus) lens in front of eye. In Simple Myopia power does not progress after adolescence. (power of 5 or 6 dioptres may be the maximum).

How can I check my eye power at home?

What is the best base curve for a lens?

The most basic rule is that you always want the base curve to be as close to +6.00 as you can get and still have the Rx work. In theory +6.00 should always give you the best possible combination of curves for weight, optics, etc.

Does base curve affect vision?

The base curve of a lens may affect certain aspects of vision, such as distortion and magnification, and wearers may notice perceptual differences between lenses with different base curves.

Can my base curve change?

Base curve can also change as you wear a contact lens based on environmental factors like the lens drying out, temperature changes, and exposure to makeup or soaps. As a doctor, selecting a contact lens for best fit is also challenging because the sagittal depth of any contact lens is not notated on the packaging.

What does ax mean on contacts?

Prescription Figures for Astigmatism

Axis (AX): Astigmatism is caused by the irregular curvature of the eye; the axis is a figure which determines the angle of the correction needed in order to see clearly. The Axis is always a number between 0 and 180 degrees.

What does SPH mean for contacts?

Notable terms include: 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.

What is a good eye test score?

Visual acuity of 20/20 is considered “perfect vision” because no aids are required to see better, but people can have better than 20/20 vision. Many young people are able to see letters smaller than the general “20/20” size.