Detecting Human Posterior Lens Surface Topographical Changes During Accommodation

Accommodation is the eye's ability to focus up close by changing the shape of the lens. Accommodation affects the development of myopia and glaucoma and its age-related decline results in presbyopia. Presbyopia affects 100% of the population in the fifth decade of life. An understanding of accommodation is required to develop the best treatments for these maladies, but how the lens changes shape is still in dispute after more than 165 years. The fundamental issue is whether the change in lens shape results from all zonules (circumferential suspensory ligaments that connect the lens of the eye to the ciliary body) relaxing, which causes central and peripheral lens surface steepening, or whether instead just the anterior and posterior zonules relax while the equatorial zonules are under increased tension, which causes the lens surface to peripherally flatten and centrally steepen. The alternatives are illustrated in Figure 1.