Question

what is the main reason presbyopia? ​

Answer 1

Presbyopia is caused by hardening of lens which occurs generally through ageing.

Answer 2

Presbyopia is caused by an age-related process. ... Presbyopia generally is believed to stem from a gradual thickening and loss of flexibility of the natural lens inside your eye. These age-related changes occur within the proteins in the lens, making the lens harder and less elastic over time