Choosing the right eyewear can become surprisingly complicated when you need vision correction and protection from bright sunlight at the same time. You may already have prescription glasses that you rely on every day, but carrying a second pair of prescription sunglasses can be inconvenient. Switching between frames every time you step outdoors is another small task that can quickly become annoying. There is a simpler approach for many glasses wearers: a clip-on lens that attaches directly to an existing frame. Magnetic clip glasses are designed around this basic idea. Instead of replacing your everyday spectacles, a separate tinted lens can be attached to the front of the frame when extra protection from bright visible light is wanted. When the sunlight fades, the clip can be removed and the regular glasses can be used again. The concept is straightforward, but there are several things worth understanding before choosing this type of eyewear. From how magnetic attachment works...