Presbyopia is the gradual loss of the eye's ability to change focus (accommodation) for seeing near objects. The long-term goal of this research is to understand the physiological mechanism in presbyopia progression. In this study we will test whether a method of accommodative training can keep the ciliary muscle and the lens flexible, and therefore delay the progression of presbyopia.
During training, the subject will be asked to view a moving target through an optical device which will exercise each eye slowly and rhythmically over its full range of accommodation. We will use both subjective and objective measurements to assess the subject's accommodative amplitude before and after training. The subject will exercise each eye for 5 minutes per day for two weeks. We are going to compare:
Presbyopia progression is associated with aging and occurs in essentially every person over age 45. The result of this study may lead to a new strategy for delaying the onset and progression of presbyopia among pre-presbyopic subjects. In addition, the result will also help to assess two existing theories related to the mechanism of presbyopia, i.e. the Donders-Duane-Fincham theory and Helmholtz-Hess-Gullstrand theory.