Flip-Up Vs. Through-The-Lens: Most loupes come fixed into the lens of the glasses. This is known as Through-The Lens or TTL. The convenience here is that it will always be in the right position, but this set up requires you to look over the top of the loupes for a non-magnified peek at things. If you plan on going back and forth regularly, flip up loupes are available and this set up allows your to move the loupes out of your way.
Galilean Vs. Prismatic Loupes: Galilean loupes are fixed at one focus level in the lens, and are usually lower in magnification power. Prismatic loupes allow for higher magnification, and greater clarity.
Field of View: Choose a loupe that allows you to see everything in the view necessary for the procedure. Each pair of loupes comes with a unique setting of field of view and magnification.
Depth of Field: This is another area to carefully consider the procedures you perform when choosing your loupes. You may be able to see 4-5 teeth, but how many teeth are in focus? Improved depth of field helps to have more of what you are looking at to be in focus.
Working Length: The manufacturer will help you set up the proper working length for your loupes. This will ensure that the teeth are in perfect focus when your head is in the right position.
Frames: There are many types of materials and styles available when it comes to the frame itself. These options can range from plastics to titanium to carbon fiber and more. Keep in mind that the most important feature is not necessarily how you look, but how light and comfortable the frame feels when you wear it.
Lens Construction: Simply put, a nicer lens with give you a magnified view that provides a more concise image with better contrast.
Lighting Options: Most loupe manufacturers have a lighting option for their loupes. You also can find third party manufacturers of lighting. Most loupe lights mount in the bridge of the frames between the eyes, and have multiple points of adjustment. Most commonly, there is a cord that either connects to a battery, or plugs into a wall. There are some that have the battery integrated into the frame of the glasses, providing a “wireless” experience at the cost of additional weight on your face.