Optical coherence tomography equipped wavefront system for studying accommodation In the human eye a clear vision over a range of viewing distances is achieved through a biological process called accommodation, by which refractive power is varied due to a deformation of the shape of the crystalline lens, brought about by a contraction of the ciliary muscle. The study of accommodation is interesting to public health because age-related loss of the accommodation leads to presbyopia in almost every eye and meanwhile inaccurate accommodation increases the risk to develop myopia in schoolchildren. But, due to the technical limitations, geometric changes in both the ciliary muscle and the lens have not been accurately measured in vivo. No technique is currently available to simultaneously assess the behavior of all accommodative components and to test interactions between each others. So far, we know very little about the contribution from each component, quantitatively by itself or by its interaction with the others, to a normal, abnormal or even loss of accommodation. As such, it is still difficult to make effective intervention to control presbyopia and myopia development or to plan presbyopia surgeries, such as accommodative IOL and lens refilling, with a predictable success. The overall goal of this proposed project is to develop a novel optical system to be used for simultaneously measuring ciliary muscle contraction, lens deformation and optical performance of the human eye during accommodation in vivo. Three techniques including the wavefront aberrometry, the anterior chamber optical coherence tomography (AC-OCT) and the anterior sclera optical coherence tomography (AS-OCT) will be employed and integrated into the new system. Use of the wavefront technique will allow us to estimate accommodative changes in refractive power and higher order aberrations. The AC-OCT will provide a unique instrumentation to image the entire anterior segment and the whole lens. The AS-OCT will allow us to assess ciliary muscle contraction with unprecedented accuracy. Promised advantages by using the new system include (1) more accurate measurement of accommodative change in each of the key components;and (2) simultaneous assessment of their performances together. In addition, this proposal is aimed to derive quantitative relationships between optical performance and the ciliary muscle contraction and/or the lens shape deformation for adults at different ages. Successful accomplishment of our goals will make us the first to simultaneously and accurately measure accommodation system in vivo. This method will help us to better understand the functional role of each accommodative component, and thus to find effective interventions to control the development of presbyopia and myopia. It will also present a substantial breakthrough in the methodology to evaluate current presbyopia treatments. The technology developed in this project can be shared through publications and holds the potential to produce significant tangible applications that enhance quality of life and therefore have a significant positive impact on public health.
Accommodation study is interesting to public health since age-related loss of the accommodative ability leads to presbyopia in almost every one while inaccurate accommodation is a risk factor for myopia development in school children. But, due to a lack of fully understanding of the accommodative mechanism, it is still difficult to make effective intervention to control development of the presbyopia and myopia or to plan presbyopic surgeries, such as accommodative IOL and lens refilling, with a predictable success. The overall goal of this proposal is to develop a novel optical system to be used in both basic eye research and clinical eye care for simultaneously measuring ciliary muscle contraction, lens shape deformation and optical performance of the accommodative eye in the human eye in vivo with unprecedented accuracy.
