A lensmeter or lensometer, also known as a focimeter or vertometer, is an ophthalmic instrument. O jẹ lilo nipasẹ awọn otTometrists ati awọn igbeyawo lati mọ daju ilana ilana ti o tọ ni bata awọn gilaasi ti awọn lẹnsi ti o peye ni awọn fireemu ti awọn fireemu ni awọn fireemu.