Glossary
Prescription lenses
Corrective lenses fitted to a frame in place of the standard ones, within a stated range of prescription strengths.
Prescription lenses are corrective lenses made to an optical prescription and fitted into the frame instead of the plain or tinted lenses it ships with. Most AI glasses support them, either as a factory option or through an optician.
Reading the range
Manufacturers publish the range they can fit, written as two numbers such as -6.00 to +6.00. Those are dioptres: negative values correct short sight, positive values long sight, and a prescription outside the stated range cannot be fitted to that frame. Astigmatism, progressive lenses and coatings are quoted separately and are not always available. Because the electronics sit in the frame rather than the lens, a prescription fit is usually possible, but it is worth confirming the range before buying rather than after.