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How to Choose Prescription Swim Goggles


If you require corrective lenses to see clearly, you may also want to purchase goggles with prescription lenses for the pool. Luckily, there are several companies that manufacture prescription goggles in a variety of styles. This guide walks you how to choose the prescription goggles that are best for you.

The Lens

Prescription goggles come with ready-made spherical lenses of varying strengths known as diopters, or step diopters. This type of lens production is similar to the generic reading glasses found in pharmacies: The prescription will be a close match to your own, but may not be as precise as that in the glasses or contact lenses you use every day. For use in the water (an already-blurry environment), step diopter prescription glasses are perfectly adequate. They are also more widely available and affordable than custom-made prescription goggles from a doctor's office.

Negative diopter lenses are the most commonly available goggles, and are intended for those with nearsighted or myopic vision. Lenses range in diopters from -1.5 to -10.0 and come in increments of 0.5. Positive diopter lenses are for farsighted swimmers, and are less common.

Finding Your Diopter Strength

The first step to choosing prescription goggles is determining the diopter strength that most closely matches your current prescription. Follow the below steps, or ask your doctor to help you choose the best ones for you.

  1. Get your most current prescription numbers.
  2. Calculate the strength of the diopter you need using this formula:

             1/2 of the cylinder + sphere = diopter strength

    Sphere is the degree of weakness in diopters. This is always a negative number for nearsighted people, and a positive number for farsighted. Cylinder is the degree of astigmatism in your eye. Add half of this number to the sphere to determine diopter strength.

  3. To choose a diopter lens, simply find the one that has a prescription closest to your own. A general rule of thumb when choosing a diopter lens is to round down — rather than up — to the prescription that most closely matches your own. This places less strain on your eyes.

For example, if your prescription is a sphere of -5.0 and a cylinder of +2.0, then (1/2 x +2.0) + -5.0 = -4.0 step diopter lens. Or if your prescription is a sphere: -2.0 and a cylinder: -1.0, then (1/2 x -1.0) + -2.0 = -2.0 (rounded up from -2.5) step diopter lens.

Choose the Goggle Model

Prescription goggles have come a long way in recent years. Prescription goggle users can now choose from lenses and goggle frames that are just as sleek and hydrodynamic as non-prescription goggles.

  • There are both recreational and racing styles of prescription goggles. Serious swimmers and lap swimmers will want to buy a racing style and should look for low profile frames, or those with "racing" in the model name.
  • Swimmers who rarely do lap swimming and just want an alternative to going without glasses in the water — such as masks or goggles with larger lenses — should look at recreational models. These have more generously padded frames and offer wider peripheral vision.
  • Some brands (such as Aqua Sphere™) offer separate prescription lenses that can be inserted into specific goggle models. Make doubly sure that the lenses you order are compatible with your goggle frames. This may be a good option for swimmers whose eyes have significantly different prescriptions.
  • There are a few brands (such as Sporti™) that design bifocal goggles, with just the lower half of the lens set to a certain prescription.
  • One of the few brands that offer positive diopter lenses is Hilco™, with their Z Leader goggle model.

Prescription goggles may be a bit more expensive than non-prescription goggles, but they are still very affordable (and getting more so every year). If you are having trouble deciding which goggles to buy, consider asking your optometrist. Once you have your goggles, it may take a few minutes for your eyes to adjust to new lens, but after a short adjustment period, you should be able to use them adequately in the pool.

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Ary
6 days ago.
Would you please let me know the proper goggle strength for this prescription? Thank you.

Right: -5.0 (sphere) -3.0 (cylinder) 20 (axis) Left: -5.0(sphere) -3.0 (cylinder) 150 (axis)
PD 65
Swimoutlet.com
4 days ago.
Hi Ary,

Sure! Your diopter strength is -6.5 for both eyes. Let us know if you have any other questions. Have a wonderful day!
Yassy
2 weeks ago.
My brothers prescription says
Right: -3.25 with a cyl of -0.50 and axis of 145
Left: -3.50 and it just says sph under cyl and no axis provided and it does mentioned prism. How can I do these calculations since mine were off
swimoutlet.com
1 week ago.
Hi Yassy,

I would recommend that you contact your optometrist for the correct diopter strength. It may be just -3.5 for your left eye, but you should confirm that with your optometrist first. Let us know if you have any other questions. Thank you!
Sophie
2 weeks ago.
My prescription does not include the cylinder, it just says SPH. If my sphere is -3.00 would I just order Negative 3.0 prescription goggles?
Swimoutlet.com
1 week ago.
Hi Sophie,

Please contact your optometrist to get your diopter strength. Most likely it will be -3 but just to be on the save side I would recommend that you contact your optometrist to confirm. Please let us know if you have any other questions. Have a great day!
Victor
2 weeks ago.
My prescription reads:
-4.25 -1.50 x 25
-3.50 -1.25 x 165

I'm not sure what diopter strength I should purchase
swimoutlet.com
1 week ago.
Hi Victor,

If Im reading your prescription correctly, your diopter would be -5 & -4.1. Please let us know if you have any other questions. Have a great day!
Katie
2 weeks ago.
I need help figuring out what strength lenses I need.

OD Sphere -7.00 Cylinder -0.75 Axis 175
OS Sphere -7.00 Cylinder -1.00 Axis 165

Thank you.
Swimoutlet.com
1 week ago.
Hi Katie,

Your diopter strength would be -7.3 and -7.5. So you would either get a -7.0 pair or get 2 pairs (one in -7.0 and one in -7.5) and interchange the eye pieces for 2 pairs of custom goggles. I hope this information is helpful. Please let us know if you have any other questions. Have a wonderful day!
Lamar
2 weeks ago.
So if my sphere is -5.25 (OD) and -5.25 (Cylinder) (well my prescription says in the cylinder box (SPH.) and the -5.00 (OS) and -0.75 (Cylinder).

My numbers would be OD: -7.875 and OS: -5.375 if that is correct.
swimoutlet.com
1 week ago.
Hi Lamar,

Thats correct! You would probably then want to go with -7.5 and -5.0 since the increments go by 0.5. Let us know if you have any questions. Have a wonderful day!
Kayla
3 weeks ago.
Hi my Rx reads as the following:

OD -6.75 (SPH), -0.25 (CYL), 95 (Axis)
OS -5.75 (SPH), -0.75 (CYL), 85 (Axis)

Which googles should I purchase?

Thank you
Swimoutlet.com
2 weeks ago.
Hi Kayla,

Your diopter strength would be -6.8 & -6.1. So you can either get one pair in -6 or you can get 2 pairs (one in -6 and one in -6.5) and interchange the eye pieces for 2 custom goggles. I hope this information is helpful. Please let us know if you have any other questions. Have a wonderful day!
Angela
3 weeks ago.
Hello, My son' numbers are:
R -2.5, -.50
L -2.25, -.25

If I;m doing this right, I am doing a strenth of -2.75 in the right and -2.37 in the left. Which goggle should I get -2.5 or -2?

Read more at: http://www.swimoutlet.com/guides/how-to-choose-prescription-goggles
Swimoutlet.com
3 weeks ago.
Hi Angela,

Im assuming his cylinder values are -.50 & -.25 and sphere are -2.5 & -2.25. then your calculations are absolutely correct. You have a choice of either getting one pair at -2.0 or 2 pairs (one in -2.0 & one in -2.5) and interchanging the eye pieces for 2 custom pairs. I hope this information is helpful. Please let us know if you have any other questions. Have a wonderful day!
Susan
3 weeks ago.
What diopter strength would I order for my prescription.
O.D. -2.50 spherical, -0.50 cylindrical, axis 173
O.S. -2.00 spherical, -0.75 cylindrical, axis 2
Thank you
SwimOutlet.com
3 weeks ago.
Hi Susan,

Your diopter strength would be -2.7 & -2.3. Since our prescription goggles increase by increments of 0.5, you would want to get either a -2.0 pair or 2 pairs (one in -2.0 and one in -2.5) and interchange the eye pieces for 2 custom pairs. I hope this information is helpful. Please let us know if you have any other questions. Have a wonderful day!
Steven
3 weeks ago.
Please help

Right eye: Sphere -5.50 Cylinder -1.25
Left eye: Sphere -4.75 Cylinder -0.75
Swimoutlet.com
3 weeks ago.
HI Steven,

Your diopter strength would be Right: -6.1 Left: -5.1. Please let us know if you have any other questions. Have a wonderful day!
Reddy
3 weeks ago.
Hello, I bought recently 2 goggles of different diopter strength as suggested as I have different strength in each eye. Also I was told I could exchange the diopters. Could you provide some instructions on how to do it as i was unable to change the lens. I bought Sport Optical Pro II.
Thank you
Swimoutlet.com
3 weeks ago.
Hi Reddy,

You should be able to just pop off the nose piece and weave the whole eye piece through the strap to take it off and then just weave in the correct eye piece. I hope this information is helpful. Please let us know if you have any other questions. Have a wonderful day!
Anita
3 weeks ago.
please help me find the correct prescription for swimming goggles sphere. -3.50 Cylind +0.75 on both eyes Axis 120 085
Thank you
Anita
Swimoutlet.com
3 weeks ago.
HI Anita,

Your diopter would be -3.1. So you would want to get a pair in -3.0. Let us know if you have any questions or concerns. Have a great day!
joan
4 weeks ago.
Can you help me with this Rx for 12 yr old
R)-1.75-1.75x15
L)-2.00-1.50x160
Thankyou
Swimoutlet.com
3 weeks ago.
Hi Joan,

We would be happy to help you! Can you please specify which is the sphere and cylinder values since its not clearly stated please? Thank you!
Emily
4 weeks ago.
Please help.
left -6.5, -1 cylinder
right -6, -1.25 cylinder
I calculated diopter to be -6.625 and -7. Should I go with -6.5 or -7 for goggles?
Swimoutlet.com
4 weeks ago.
Hi Emily,

You would want to got with -6.5. You do not want to go with anything stronger because that can hurt your eyes. Please let us know if you have any questions. Have a wonderful day!
Morgan
4 weeks ago.
Hello. Would you please let me know the proper goggle strength for this prescription?

Right: -3.00 (sphere) -1.25 (cylinder) 090 (axis)
Left: -2.75 (sphere) -1.75 (cylinder) 080 (axis)
Swimoutlet.com
4 weeks ago.
Hi Morgan,

The diopter strength would be Right: -3.6 Left: -3.6. I hope this information is helpful. Please let us know if you have any other questions or concerns. Have a great day!
Lee
4 weeks ago.
Hi I am trying to make sure I order the correct goggles for my son. His prescription isRight -4.25-2.00 axis 10 and Left -4.75 -3.25 axis 1.75.Which diopter would he need? Thank you!
SwimOutlet.com
4 weeks ago.
Hi Lee,

Im assuming his cylinder values are -2 and -3.25 and his sphere is -4.25 and -4.75. Based off that assumption his diopter strength would be Right -5.25 and Left -6.37. Please let us know if you have any questions. Have a great day!
Fay
4 weeks ago.
how do I interpret this as my prescription?:
OD -5.50-10x090
OS -5.00-125x105-/+2.00
Swimoutlet.com
4 weeks ago.
HI Fay,

Since your prescription doesnt clearly state the cylinder and sphere values, I suggest that you contact your optometrist to get those values and then we would be happy to calculate the diopter for you. Have a wonderful day!
Robin
4 weeks ago.
Hello. Would you please let me know the proper goggle strength for this prescription? Thank you.

Right: -1.25 (sphere) -.25 (cylinder) 105 (axis)
Left: -1.25 (sphere) -.50 (cylinder) 75 (axis)
Swimoutlet.com
4 weeks ago.
Hi Robin,

The diopter strength would be Right: -1.4 & Left: -1.5. Since your diopter strength is low, you may be able to get away with just regular goggles. The prescription goggles that we carry start off at -2 and that would be too strong for your eyes. I hope this information is helpful. Please let us know if you have any other questions. Have a great day!
Joe
4 weeks ago.
The site does not allow me to select the diopter strength for each eye but only 1 selection.
SwimOutlet.com
4 weeks ago.
Hi Joe,

Since our prescription goggles come premade, you are unable to select different strengths for each eye. If you do have 2 different strengths we suggest that you either get one pair in the lower of the prescription or get 2 pairs (one in each strength) and interchange the eye pieces. I hope this information is helpful. Please let us know if you have any other questions. Have a wonderful day!
Kevin
5 weeks ago.
Hi my 14 yr old son has Esotropia (convergent squint), with each eye switching to the intended focal point randomly--one time, one eye does the work; the next time the other eye does the work. His prescription is:
Right eye: +8.50 (SpH), -0.50 (Cyl), 90 (Axis)
Left eye: +8.50 (Sph), -0.50 (cyl), 80 (Axis)
1] Does this mean that the bert goggle prescription for him would be +8.25 in each eye, irrespective of the differences in the Axis measurement?
2] Won't goggles like thee be very thick? Is there a way to make them thinner and lighter?
Thanks!!
Kevin
Swimoutlet.com
4 weeks ago.
HI Kevin,

You are correct, his diopter strength is +8.25. When calculating the diopter, the Axis is not needed. The lenses will not be thick. They are all one thickness. I hope this information is helpful. Please let us know if you have any other questions. Have a wonderful day!
Suzanne
1 month ago.
Need help with ordering my son's goggles.
right: sphere +1.5 Cylinder +.50 Axis 90 Add +3
left : sphere +2.25 cylinder +.50 Axis 90

My calculations for them is but I don't know what to do with +3 for bifocals.
Right eye is +1.75
Left eye is +2.5
SwimOutlet.com
4 weeks ago.
Hi Suzanne,

The prescription goggles that we have are standard so the bifocal number will not matter. And I dont think he will be reading under water so it should be okay =). Please let us know if you have any other questions or concerns. Have a great day!
Shirin
1 month ago.
Hi:

My son does not have a cylinder measurement, and his sphere in both eyes is -3.25. Does this mean that his measurement is -3.25 (so we round down to -3.0)?
Thanks for the help.
Stephanie
1 month ago.
Hi,
Please help me calculate what strength goggle I would need for an RX of:

OD -425 -050 @ 010
OS -475 - 100 @180

I do have a reading adjustment of +250, but I don't think I will need it.

Thanks for your help on advance.

Stephanie
Swimoutlet.com
1 month ago.
Hi Stephanie,

Since your prescription doesnt clearly state which one are the sphere and cylinder values, I would suggest contacting your optometrist for that information. I do not want to give you the wrong diopter strength as that can hurt your eyes. Let us know if you have any other questions. Have a great day!
jenny
1 month ago.
okay I am so confused!

Right -6.5/-2.00
Left -5.5/-2.5
Swimoutlet.com
1 month ago.
Hi Jenny,

No worries Jenny! If I read your prescription correctly and the first numbers are spheres and the last set are the cylinder values then your diopter strength would be -7.5 and -6.7. Feel free to contact us if you have any other questions. Have a great day!
Missy
1 month ago.
Please let me know proper goggle strength with this prescription:

OD sphere -6.75 wih cylinder -1.75 and axis 026
OS sphere -6.75 with cylinder -2.00 and axis 153.

Thanks!
Swimoutlet.com
1 month ago.
Hi Missy,

Your diopter strength would be -7.6 & -7.8. Please let us know if you have any other questions. Have a wonderful day!
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