Presbyopia is also known as "visual acuity dysfunction". It is most directly manifested as blurred reading at close range, fatigue, soreness, tears, photophobia, dryness, and associated headaches. Middle-aged and elderly people often say "forty-seven-eight, dazzled eyes", "a lot of poor eyesight", and "lost eyesight" are all typical symptoms of presbyopia. Nowadays, many elderly people are also controlled by mobile phones. They often guard their mobile phones to grab red envelopes in various groups, which to a large extent increases the burden of using their eyes.