Using a flashlight or similar, shining it on the lens allows you to see two apertures on the discount prescription glasses lens. Then adjust the angle of the lower flashlight until the two circles coincide and make a mark (the position of the mark is the optical center of the lens).

The same goes for the other lens, then take a ruler to measure and record the data. Compare the data of pupil distance when you go for a mirror examination. (This method is only suitable for rough measurements and is more accurate in actual measurements.)

The frame of this mirror is much larger than before, so it is normal for you to feel uncomfortable while wearing it. If your degree has increased significantly, it is normal to experience discomfort when wearing new glasses.

If the tilt angle of the frame is incorrect, it can cause the light to deviate from the path it should take when passing through the lens and entering the eyes, causing discomfort to the eyes (which is why when you go to get glasses, they keep adjusting the frame for you. It is also why some people buy lenses/frames eyeglasses online cheap but choose to buy them from physical stores).

After ruling out these simple situations, how do you roughly measure the refractive index of the lens at home? First, draw the size of the frame on a piece of white paper. Click on the optical center point of the lens that was previously found. Record the distance between any point connecting the optical center point to the edge.

Measure the thickness of the lens at the same position as the cheap eyeglasses near me and record the data. The value obtained by dividing the thickness by the length is only a rough estimate of the refractive index of the lens.