Presbyopia (the need for bifocals) occurs as a natural aging process of the crystalline lens inside the eye (located behind the pupil). After age 40, the ability of the crystalline lens to instantly change shape in order to focus light rays on the retina for near vision tasks starts to decline. This decline is gradual through age 50 at which time there is generally a total dependence on bifocals or reading glasses. Refractive surgery changes the cornea curvature, and thus does not affect the natural aging process of the eye’s crystalline lens. Therefore, you will more than likely still need to use reading glasses as you get older. If you are approaching or are in the presbyopic age range (above age 40), you and your doctor may decide to “tailor” the surgery (leave some residual near-sighted ability in your non-dominant eye) to allow some independence from reading glasses. This is called monovision. You may be familiar with this arrangement if you are over age 40 and have worn contact lenses set up for monovision.

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