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How do you read numbers on a contact lens box?

Author

Mia Moss

Published Mar 02, 2026

How do you read numbers on a contact lens box?

Regular Prescription
  1. Eye - Which eyes the prescription line item is for.
  2. SPH - Sphere (this can also be referred to as Power or PWR)
  3. BC - Base Curve (usually a number between 8 and 10)
  4. DIA - Diameter (usually a number between 13 and 15)
  5. Brand - The brand/type of contact lens that your doctor has fitted you for.

Keeping this in consideration, what do the 3 numbers on contacts mean?

astigmatism lens

Subsequently, question is, how do you read the power on a contact lens prescription? Power (pwr) / Sphere (sph) / Dioptre (D): This value is the power of the lens needed to correct your long or short-sightedness and is measured in Dioptres (D). A minus (-) sign indicates that you are short-sighted, whereas a plus (+) sign shows that you are long-sighted.

Also, what does the negative numbers mean on contacts?

myopia

What do the numbers mean in contacts?

The further the number is from zero, the stronger your prescription. It is common to have a different prescription in each eye. BC: Base Curve - this refers to the back curvature of the contact lens, measured in millimeters. This number is usually between 8 and 10.

What is high add for contacts?

Reading Your Multifocal Contact Lens Prescription
Multifocal contact lenses bundle ADD amounts into three groups: low, medium or high. Low add is a number up to + 1.25, medium is an add between +1.50 and +2.0, and high is an add of +2.25 up to +2.50.

Is minus 3.5 eyesight bad?

If your number is between -0.25 and -2.00, you have mild nearsightedness. If your number is between -2.25 and -5.00, you have moderate nearsightedness. If your number is lower than -5.00, you have high nearsightedness.

What prescription is legally blind?

It depends. A contact prescription of -6.50 does not mean you are legally blind if your vision improves from 20/200 with them in. However, if you still have 20/200 eyesight or worse after putting contacts in, you are considered legally blind.

What happens if you wear contacts with the wrong base curve?

If your lenses have the wrong diameter or base curve, you'll likely feel that something is always in your eye. If the lenses are too flat, your eyelids will tend to dislodge them when you blink. The wrong size lenses can even cause an abrasion of your cornea.

What is the difference between 14.0 and 14.2 diameter contacts?

In fact, there is not much difference between these two. Some manufacturers only make 14.2mm diameter contacts, and some others produce 14.0mm diameter contacts. However, there is no manufacturer that makes both 14.0mm and 14.2mm diameter contacts. This is because they only choose one of these two small size contacts.

How do you read a left and right contact prescription?

OD is short for oculus dexter, which is Latin for 'right eye. ' OS is the abbreviation for oculus sinister, which sounds like your eye's evil twin — but means 'left eye. ' OD always comes first on a contact lens prescription because that's the eye your eye doctor examines first when facing you, looking left to right.

How do I figure out my contact lens base curve?

Base curve = 0.95 * 34.82 D = 33.07 D and then round up or down to the nearest whole diopter to arrive at the following final base curve to use for a contact lens over-refraction: Base curve = 33.00 D (actual measured base curve is 32.95 D)

What is a contact lens blister?

The blister packs your contact lenses come in can be recycled in a way that requires very little time and effort. These are made from PP (polypropylene) plastic and are accepted for recycling. You should be sure the blister packs are free of liquid, then you can drop them into the plastic bin.

What liquid are contacts packaged in?

Because Saline Solution (the liquid that comes with the lens) doesn't disinfect Contact Lenses. So it's recommended to soak the contact lenses for 6-8 hours in multi-purpose solution or in disinfectant before the first use. This is done to neutralize them before letting them come in contact with your eyes.

What does add high or low mean on contact lenses?

The higher the number, the stronger the visual correction needed. The Addition figure is a positive number between 0.50 and 3.00. Some contact lens brands refer to this as a high, medium, or low.

How are contacts packaged?

Lenses are generally either packaged in a glass vial, or plastic and foil vacuumed blister pack. The vial or blister will be filled with saline solution, a similar consistency to human tears. The hydrophilic material of the contact lens soaks up the saline solution.

What is the power range for contact lenses?

All Contact Lenses contact lenses
Contact Lens NamePower RangeDiameters
1 Day Acuvue TruEye+6.00 to -12.0014.2
Acuvue 2+8.00 to -12.0014.0
Acuvue Advance+8.00 to -12.0014.0
Acuvue Advance For Astigmatism+6.00 to -9.0014.5

What is the smallest size of contact lenses?

appeared first on Advanced Eye Care Center. Lenses that are 18 mm or smaller are subcategorized as mini-sclerals. The average human cornea is approximately 11.8 mm in diameter so even the smallest scleral contact lens is designed to cover the entire corneal surface.

Does base curve matter in contact lenses?

You should never order contact lenses with a base curve that is different from your prescription. This can damage your eyes and cause problems with vision. This is especially important for people who purchase cosmetic coloured contact lenses, which are often of a standardised size.

How do you turn a 20/20 into a diopter?

To convert to 20/20-based, you divide 20 by the distance you read from and then multiply that to the second number of the line you read. In this example, you divide 20 by 10, which is 2. Now you multiply 2 by 40 which gives you 20/80 as your current vision level.

Is a bad prescription for contacts?

One of the most common effects of wearing the wrong contact lens prescription is blurry vision. Since contacts are meant to improve vision, the wrong prescription will typically cause impairment in a person's vision, says the U.S. Food and Drug Administration.

Is contact lens prescription stronger than glasses?

No, this is a misunderstanding of how contacts and glasses work. The 'strength' of the prescription is dependent on the eye's ability to focus an image on the retina. Contact lenses sit on the eye, closer by about 12mm to the retina than a pair of glasses.

Why are my multifocal contact lenses blurry?

Many presbyopes experience a hyperopic shift due to decreasing index of refraction in the lens, exacerbating their presbyopic symptoms. Multifocal contact lenses are designed to supplement one another to offer the wearer a range of clear vision without the need for reading glasses.

What is the meaning of 20 100 Vision?

If you have 20/100 vision, it means that you must be as close as 20 feet to see what a person with normal vision can see at 100 feet. Having 20/20 vision does not necessarily mean you have perfect vision. 20/20 vision only indicates the sharpness or clarity of vision at a distance.

What number is bad astigmatism?

If you have less than 0.6 diopters of astigmatism, your eyes are considered normal. Between this level and 2 diopters, you have a small degree of astigmatism. Between 2 and 4 is moderate astigmatism, and above 4 is considered significant astigmatism.

How do I know which eye is for contacts?

The right eye is always listed first on the prescription. This is just a sample prescription. Yours will likely look different but should contain the same information.

What does PWR mean on my contacts?

left eye. Power (PWR): Strength of your contact lens (e.g., -1.00, -1.25, +1.50, +3.00, etc.)

What if PD is off by 2mm?

If the PD measured was 2mm off initially, by using a millimeter rule, the net cumulative error might be 4.5mm or more.

Is 5 eyesight bad?

A -5 eye and a -7 eye are not much differently at risk, but both are significantly more at risk of retinal problems than a more normal, non-myopic eye. These are rare, though, so no cause for alarm. Just know in advance the signs and symptoms of a retinal tear or detachment if you are very myopic.

Is your prescription the same for glasses and contacts?

The answer is no. While they both have the same objective — to correct what eye doctors call “refractive errors†that prevent you from seeing correctly — prescriptions for eyeglasses and contact lenses are distinctly different.

What is the highest prescription for contact lenses?

If not, what is the maximum number of diopters for which a person would be able to wear contacts? A: Actually, almost all nearsighted people can wear contact lenses, no matter how high their prescription. In fact, there are contact lens laboratories that make custom lenses up to -30.00 diopters!

Does 0.00 power contacts mean?

zero focusing power needed

What's the average PD for a woman?

about 62mm for

Can I wear my left contact in my right eye?

Using a single contact lens won't hurt your eyes if that's what your prescription calls for. However, if you're not wearing both contacts because you lost one of them, you may experience vision loss symptoms in the unprotected eye. Blurry, distorted vision and other side effects of uncorrected vision can return.

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