A Guide to Prescription Goggles

If you rely on corrective lenses to see clearly, swimming without vision support isn’t just frustrating—it can impact your performance and comfort in the pool. That’s where prescription goggles come in. At Team Aquatic Supplies, we stock the Speedo Optical Prescription Goggle—available in clear and smoke lens options—designed specifically for swimmers who are nearsighted and require negative diopters. Here's what you need to know to choose the right pair.

Understanding Diopters: How Prescription Goggles Work

Prescription swim goggles are available with pre-set spherical lenses, called diopters. These step diopter lenses work much like over-the-counter reading glasses: not tailored down to the decimal, but accurate enough to improve vision for lap swimming, water fitness, or competition.

Most goggles use negative diopters, which support nearsighted swimmers (myopia). The Speedo Optical Goggle is available in diopter strengths from -1.5 to -8, in 0.5 increments.

If you're farsighted and need positive diopters, note that our current in-stock option does not include those.

How to Calculate Your Diopter Strength

If you’re unsure which strength to order, follow this simple method using your most recent glasses prescription:

1. Find your Sphere (SPH) and Cylinder (CYL) values.

2. Use the formula:
   ½ Cylinder + Sphere = Diopter Strength

✳️ Example 1: SPH = -5.0, CYL = +2.0 → ½ of 2.0 is 1.0 → -5.0 + 1.0 = -4.0 diopter

✳️ Example 2: SPH = -2.0, CYL = -1.0 → ½ of -1.0 is -0.5 → -2.0 + (-0.75) = -2.75 → round down to -2.5

🔍 SwimExpert Tip: Always round down to avoid visual strain.

For the most accurate selection, consult your optometrist or bring your prescription to one of our SwimExpert staff members for guidance.

Why We Recommend the Speedo Prescription Optical Goggle

This goggle isn’t just a quick fix—it’s a proven performer. It offers:

• Negative diopters from -1.5 to -8

• A choice of clear or smoke lenses (great for indoor or outdoor use)

• Comfortable gasket seal for a secure fit

• Universal fit

• Anti-fog lenses with UV protection

• Easy adjust straps for a customized fit

It's the ideal option for swimmers looking for simplicity, affordability, and reliable correction in the water.

What If You Have Two Different Prescriptions?

Here’s a SwimExpert trick: purchase two pairs in different diopters and build a custom set!

How to swap lenses:

1. Start with both pairs of goggles.

2. Gently pop the lens from the nose bridge using your thumbs.

3. Remove and set aside the straps.

4. Label left and right lenses to avoid mixing them up.

5. Insert the correct diopter lens into each side of one pair.

6. Reattach straps and adjust for fit.

Voilà! You now have a tailored prescription set—and an extra backup pair to spare.

Final Thoughts

Prescription swim goggles are a game-changer for athletes, lap swimmers, and water lovers who want clear vision in the pool. At Team Aquatic Supplies, we’re here to make sure you choose the right fit, lens, and style.

🎯 Need help picking the right strength? Ask a SwimExpert in-store or reach out to us online. We’ll walk you through your options and make sure you hit the water with confidence.