1) This is a very convenient type of lens that allows the wearer to focus on objects both at close range and far range through a single lens. -top" (FT) or "straight-top" (ST) bifocals.
1) ນີ້ແມ່ນເລນປະເພດທີ່ສະດວກທີ່ສຸດເຊິ່ງຊ່ວຍໃຫ້ຜູ້ທີ່ເອົາໃຈໃສ່ວັດຖຸທັງໃນລະດັບໃກ້ແລະໄກຜ່ານເລນດຽວ. -top " (FT) ຫຼື" ທາງເທິງຊື່ " (ST) bifocals.