Unlike other conditions that affect your vision, presbyopia is unrelated to the shape of the eye. This condition, quite simply, comes as a result of aging. Anyone can develop presbyopia, regardless of whether they have ever had any other vision problems. Presbyopia typically begins to manifest during middle age, causing blurred vision when engaging in activities such as reading or using the computer.
Normally, when focusing on a close object, the muscles around the eye lens contract, changing the curve of the lens. As we age, the proteins in the lens thicken and lose flexibility. Thus, the lens becomes harder and less elastic. With this decrease in the flexibility of the lens, muscles cannot change its shape as easily, causing a loss of ability to focus on nearby objects.