See Chapter 3 for a discussion of the terminology and mechanisms of accommodation.
Presbyopia is the gradual loss of accommodative response resulting from reduced elasticity of the crystalline lens. Accommodative amplitude diminishes with age. It becomes a clinical problem when the remaining accommodative amplitude is insufficient for the patient to read and carry out near-vision tasks comfortably. Fortunately, appropriate convex lenses can compensate for the waning of accommodative power.
Symptoms of presbyopia usually begin to appear in patients after 40 years of age. The age of onset depends on preexisting refractive error, depth of focus (pupil size), the patient’s visual tasks, and other variables. Table 4-3 presents a simplified overview of age norms. The KAMRA corneal Inlay (AcuFocus Inc, Irvine, CA) has been approved by the United States Food and Drug Administration (FDA) for the correction of presbyopia through the use of pinhole optics. The inlay is 3.8 mm in diameter and has a 1.6-mm aperture.
Table 4-3 Average Accommodative Amplitudes for Different Ages
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.