According to manufacturers such as Trayner, pinhole glasses can permanently improve eyesight and relieve eyestrain, fatigues and headaches. However, the College of Optometrists warns that such claims are unsubstantiated and are best viewed with caution.
While pinhole glasses are being worn, they make for a clearer image for those with vision defects. This is done by making the pupils smaller and reducing the amount of light getting through. They are normally used when prescription glasses cannot be used. The reason they are not used more frequently is because they cut down on the amount of light reaching the eye. According to the College of Optometrists, wearing pinhole glasses while walking and especially while driving can be dangerous.