What to Look for in Prescription Snorkel Masks
The Mask Itself
Although the key things you're after are corrective lenses, don't forget that the mask itself is just as important as always. The best prescription snorkel masks should still come with low internal volume, tempered glass, silicone skirt features.
Read the mid-level reviews. People tend to write reviews on products that they feel strongly about for whatever reason. Check out the mid-range reviews that list both pros and cons. Usually these people are more detailed and can provide input on all aspects of the mask, not just a particular feature.
First, make sure the snorkel mask INCLUDES corrective lenses. Some companies offer the exact same mask either with or without corrective lenses. If the default is without corrective lenses, just make sure you specify in your order.
Don't expect that your lenses will match your prescription exactly. For example, if you have a nearsighted prescription of -2.25, there is a good chance you will have to choose between -2.0 and -2.5. Most people don't find this a problem though, as it's still a huge improvement on the standard lenses.
If you have a strong prescription, make sure the snorkel mask you are interested in is able to fit and/or offer those lenses. Many companies do not offer lenses more negative than -8.5, or more positive than +4.0. If you need something closer to -10.0, this should be specified in the product description. For more information on how to interpret your prescription, please click here.
If you are replacing your lenses, make sure your mask is capable of this and that you have a good idea of how to do so before you begin. Check out the video below for a nice tutorial on how to change your lenses.
Your Skill Level and Intended Use
This may seem obvious, but it can be easy to overlook simple things like your skill level and intended use. If you are a beginner to snorkeling, but know you want a prescription snorkeling mask, it could be a good idea to look for something a little cheaper. Just because they are prescription, doesn't mean they have to be expensive.
On the other hand, if you are becoming more experienced and are looking for an upgrade, then you will likely want to spend a little more in order to receive the long term benefits that a top prescription snorkeling mask can provide. Corrective lenses in snorkeling masks don't vary too much, so most of what you will be looking for is quality in the mask itself.
Intended use is a big one. If you live in, or are moving to a tropical destination, or this is an activity you have been able to maintain, then higher grade and/or more specialized equipment could be worth it for you.
If you are heading out for a vacation and know you will be snorkeling more than once, it could even be worth buying a full set, even if it's cheap, so you can avoid rental fees and hassle. Corrective lenses shouldn't add too much to the cost, so don't immediately rule out this option.