Underwater Lens Calculator

Enter your prescription to find your recommended underwater lens strength

Have your prescription handy?

Tips for a clear prescription photo

For the clearest read:

  • Show the full prescription, not just a cropped number.
  • Keep OD/right, OS/left, Sphere, Cylinder, and Axis sharp and well lit.
  • Avoid glare, blur, tiny text, and handwritten notes.
Good photoAll values and labels are visible and in focus.
Clear prescription example showing OD, OS, Sphere, Cylinder, and Axis
AvoidValues are cropped without eye or column labels.
Cropped prescription example missing eye and column labels

or enter your prescription below

Right Eye (OD)
Enter the SPH value exactly as shown on your prescription, including the + or - sign.
Enter the CYL value exactly as shown on your prescription, including the + or - sign. If your prescription has no CYL value, leave this at 0.00.
Enter the AXIS number shown with your CYL, from 001 to 180. AXIS is only required when CYL is not 0.00.
Left Eye (OS)

How RX lenses help overall?

Whether your correction is “minus” or “plus,” the lens is simply bending light in the direction your eyes need so the focal point lands on the retina. That brings the whole scene into focus across common dive and snorkel distances. The nearsighted/farsighted labels just indicate which way we’re bending the light, not a limit on what you’ll see clearly.

Man wearing a prescription snorkeling mask with a beach and ocean in the background

Why you need a

Prescription Snorkel and Dive Mask!

See the reef the way it was meant to be seen. Our prescription dive masks and prescription snorkeling masks (RX masks) put your exact diopter into a comfortable, well-sealing frame.

So you can skip contacts, skip renting a gross mask that won’t have your prescription, and avoid missing that turtle or puffer fish cruising by. Contacts can dry out in saltwater and trap sand; an RX mask gives you crisp vision the moment you hit the water.

Nearsighted vs. farsighted.

Nearsighted (Myopia)

If you’re nearsighted, distant detail goes blurry. Negative-diopter lenses bend incoming light outward before it reaches your eyes, so far-away subjects like reefs, fish, and boats snap into focus. About 1 in 3 Americans are nearsighted. Correcting myopia also improves overall clarity across typical dive distances, not just “far away.”

Farsighted (Hyperopia/Presbyopia)

If you’re farsighted, plus-diopter lenses aren’t only for close-up. They shift the focal point forward so the eye doesn’t have to work as hard. That small change in the angle of convergence helps your retina receive a sharp image across a wide range of distances: gauges at arm’s length, your buddy a few meters away, and the reef beyond. In short, farsighted RX masks improve overall clarity, not just close-up vision.

Rx Lens Strength + Face Fit

Find Your Prescription Mask Quiz

Built specifically for prescription snorkel and dive masks, this quiz helps match your lens strength, face fit, and intended use in one simple flow.

Answer up to 6 quick questions in about 2 minutes.

Start the quiz →

Have your prescription nearby if you know your numbers. If not, no problem, we can still guide you.

Lens strength Face fit Snorkel or dive
4.94 / 5 based on 1251 verified reviews

Your prescription image is only used to read your values. It is never stored.

Choose your style:

All our lenses are made form HD Tempered glass. Safe for Snorkeling, Freediving & Scuba diving

MORE THAN JUST A MASK

Your Free Snorkeling Learning Hub

MORE THAN JUST A MASK

Your Free Snorkeling Learning Hub

At Oceans Optics, we believe the right gear is only part of the experience. Knowing how to use it, what to look out for, and how to feel confident in the water matters just as much.

Built by Professional Instructors
Explore lessons on:
Gear & Vision
Safety & Conditions
In-Water Skills
Underwater Science & Your Body
Marine Life & Conservation

Free to explore. Easy to follow. Built to help you snorkel with more confidence.

EXPLORE THE LEARNING HUB

Let customers speak for us

from 1251 reviews
Customer care

My son has a unique prescription, so I was unsure of what i should order. I emailed oceanoptics and received a quick response which steered me in the right direction! We couldnt be happier with the customer care!

Sean R.
Excellent company and customer service!

I really didn’t think I would be satisfied with this mask but after reading the reviews I figured I try it. I asked questions in my order and they were answered almost immediately. I received the mask and snorkel set very quickly. I’m thrilled I found this company and took a chance with them. You will be too.

Michele
OBSESSED it’s so nice to be able to see underwater

OBSESSED it’s so nice to be able to see underwater. Thank you guys for making an excellent and affordable product! Can’t wait for future vacations

Deanna R.

The fit is awesome I'm looking forward when trying to use them out later when I have an opportunity.

Christopher
Great mask

Great mask. Extra material underneath nose ensures no links. Glass was clean and the prescription was accurate.

Anonymous
I saw the fish!!!

I love, love, love these goggles! I can finally see all the fish when I go snorkeling. The goggles were made to my exact prescription. I could see all things underwater perfectly. The goggles didn’t leak or fog. Best snorkel gear ever!

Joan M.
I can Sea!

I can Sea! I am so excited to use these! I can see through them and feel excited more than ever now to go snorkeling! Thank you for giving me my sight under water :)

Amber

I cannot reccomend this enough for people who need perscription lenses. Makes snorkleing/ diving much more enjoyable and I prefer the lens quality compared to a non RX regular mask. Its very clear and fits well! No complaints or issues. If youre hesitant about what perscription to get, include your RX and someone will reach out to you with reccomendations (i went with their rec). Pretty fast shipping too.

Ashley

I bought it because other friends said it was good quality, and the skirt part is also soft so it gently fits against the face and it's really nice.
The design is pretty and the price is reasonable, so there's no reason not to use it.
I will use it well and order again~^^*

Isaiah V.
All around a great mask!!!

Excellent mask! I used this for a trip to Roatán. I've never worn a prescription mask before so I didn't know what to expect. On our dive down to 55ft it sealed great, no leaks!! I followed the instructions about how to fog-proof the mask and it worked, no fogging! Best of all, I could actually see!! Great customer service as well. All in all a fantastic experience.

Joseph
I can't believe these weren't expensive

I can't believe I let some years go by thinking that prescription masks must be super expensive. These aren't. I haven't used them yet, but just wearing them in the house and looking at objects that I know would be a little fuzzy at a distance, were incredibly sharp. Mask made of silicon is a plus.

ROBERT L.
This worked beautifully

This was my first time snorkeling. I never went before because I can't see well without my glasses. Honestly, I was nervous about it. But, I didn't need to be. Everything worked really well. I could see. I could breathe. In the end, I had a blast.
Even the boat captain commented that it was a really nice set.

Denise B.

The glasses are great. Good quality, lens correction perfect.

Maurine S.

Worked great!

Kathy T.
Allowed my daughter to snorkel and see everything!

My daughter has bad eyesight, -7.5 prescription. She doesnt do well with contacts so wears glasses all the time. Without them she cannot see 3 feet in front of herself. These were so easy to order, arrived quickly and allowed her to really enjoy our snorkel trip to St. Croix. They worked great, no issues with using them. Thank you so much for this!!

Brenda

What customers think about the store

Store specializing in prescription snorkeling/diving masks and swimming goggles. Customers praise accurate prescriptions, excellent quality, reasonable prices, fast shipping, and responsive customer service. Products enable clear underwater vision for those wi...

AI-generated from customer reviews.

Goggles Mask Prescription Quality