How to Read a Prescription Scuba Mask

Wikimedia Commons

While objects underwater do appear larger than they really are due to the refractive effects of water, those who need eyeglasses or contacts should still look into getting a prescription scuba mask if they intend to dive frequently. After all, the point of diving in the first place is to see things, and the best way to do that is by getting a prescription dive mask.

Instructions

Difficulty: Easy

Things You’ll Need:

Existing eyeglasses or contacts prescription
Existing eyeglasses or contacts prescription

Step 1

Look at your existing eyeglasses prescription and note the numbers for OD and OS. These are diopter measurements, with OD being for the right eye and OS for the left eye. Diopter refers to focal distance, with the number serving as the denominator of a fraction of a meter. So, for example, a diopter of -5 means a focal distance of 1/5 of a meter, while a diopter of -3 means 1/3 of a meter.

Step 2

Apply those numbers to shopping for a prescription scuba mask. Most manufacturers make standardized masks where the OD and OS are the same, ranging between -1 and -5, with a few manufacturers going -8.

Step 3

Compare those numbers and decide if they are right for your needs. Most people, for example, rarely have ODs and OSs that are the same, but the standardized masks are all made that way. If you want a mask with two different corrective lenses, you will need to get that specially made at the factory. Likewise, very specialized lenses, such as bifocals or those beyond -8, will need to be ordered from the factory.

Tips & Warnings

Keep in mind that water refraction makes everything underwater look bigger, and that even the clearest waters rarely exceed a visibility of 100 feet. Under circumstances like that, most eyeglass or contact wearers really only need a mask that approximates their prescription. It does not need to exactly match it. Water refraction also counters any and all problems with astigmatisms, so do not worry about that when reading a prescription dive mask.

Water refraction also counters any and all problems with astigmatisms, so do not worry about that when reading a prescription dive mask.

Article Written By Edwin Thomas

Edwin Thomas has been writing since 1997. His work has appeared in various online publications, including The Black Table, Proboxing-Fans and others. A travel blogger, editor and writer, Thomas has traveled from Argentina to Vietnam in pursuit of stories. He holds a Master of Arts in international affairs from American University.

Editor's Pick

Backcountry Camping Tips

You've already tried car and RV camping. You've camped at commercial campsites that had a convenient restroom and water supply. Now, you want to explore the road less traveled. Backcountry camping, also known as primitive camping, is a wonderful way to explore the remote...
More Backcountry Camping...
Popular Article

Beach Camping Near Pismo Beach, California

Pismo State Beach, California, has many attractions and activities including camping, swimming, hiking and wildlife viewing. Birdwatching is one of the primary activities in the area. The park also has the largest over-wintering colony of monarch butterflies in the natio...
More Beach Camping...
Featured Video

Common Sense Hiking Tips

The first and most fundamental thing is never hike alone. There are too many situations, especially as an unexperienced hiker, where you may find yourself without anyone to help you. So the buddy system works and applies very much in hiking.
More Camping Basics...