Research SummaryDr. Leo T. Chylack directs the Center for Ophthalmic Research (COR), a group of laboratories dedicated to the study of mechanisms of normal vision and blinding diseases. Its primary disease-related focus is the study age-related and other forms of lens opacification and cataract. Areas of research within COR include: 1. The NASA Study of Cataract in Astronauts (NASCA) In Dr. Chylack’s research group the present primary focus is the study of lens opacification in astronauts, particularly the relationship between radiation in deep space and the prevalence, incidence, and progression rates of cataracts in the entire population of American astronauts and control groups of military pilots and ground-based controls in the Longitudinal Study of Astronaut Health (LSAH). He is the Principal Investigator of this five-year 3.2 million dollar project involving the BWH, Baylor College of Medicine (BCM), National Aeronautics and Space Administration (NASA), Johnson Space Center (JSC), Wyle Laboratories (WL), and Space Center Eye Associates (SCEA). The NASCA Study is a cross-sectional and longitudinal five-year epidemiological study of the risk factors associated with cataract incidence and progression in the whole population of American astronauts and two control populations – pilots with military aviation experience and participants in the Longitudinal Study of Astronaut Health (LSAH). The study of risk factors focuses on the types and doses of radiation exposure in space flight, measures of nutrition, and general health. The assessment of cataract will use digital images of the lens and validated measures of severity. The study will measure the prevalence, incidence, and progression rates of cortical, nuclear, posterior subcapsular, and mixed cataracts, and it will relate these measures to measures of radiation, nutrition, and general health. A secondary goal of this project will be to improve the routine annual clinical assessment of the ocular lens by including Nidek EAS 1000 digital imaging of the lens in the annual ocular examination. The objectives the NASCA project are: 1. NASCA contains an initial cross-sectional assessment of prevalence, and a follow-on assessment of progression rates of lens opacification in the populations of astronauts, military pilots, and ground based comparison participants in the Longitudinal Study of Astronaut Health (LSAH). 2. Main goal of cross-sectional study: To determine the prevalence of the three main classes of age-related lens opacification in the complete sample of astronauts and in two control populations: military pilots and ground-based subjects in the LSAH. We will determine the risk of each class of cataract associated with exposure to various components and dosages of radiation during space flight. 3. A secondary goal of the cross-sectional study is to estimate the prevalence of the three main classes of age-related lens opacification and determine the risk of each class of cataract associated with various factors (nutrition, general health, UV radiation, and others) encountered non-space flight. 4. A tertiary goal of the cross-sectional study is to modify the ocular assessment protocol in the astronauts’ regular annual medical examination to improve the assessment of the status of the crystalline lens. 5. The main goal of the five-year longitudinal study is to determine the progression rates of the three main types of lens opacification in the complete sample of astronauts, the control populations of pilots and ground-based subjects in the LSAH, and then determine the risk factors associated with cataract progression with a specific focus on the components and doses of radiation exposure during space flight. Specifically, total radiation lens dose, space radiation lens dose, and individual contributions from space galactic cosmic ray and trapped proton lens dose will be assessed. Dr. Chylack’s collaborators at the BWH on this project are Mr. William Tung, B.S. (Image Analyst) and Ms. Sherlaine Holliday, M.P.H. (Project Coordinator). 2. Developing Methods of Teaching the "LOCS" Methods of Classifying Age-Related Opacification of the Ocular Lens Dr. Chylack was the first author of a publication describing novel methods of classifying they type and severity of opacification in the crystalline lens. The two systems developed here at the BWH, Lens Opacities Classification System II (so-called “LOCS II”) and Lens Opacities Classification System III (so-called “LOCS III”) are widely used worldwide by clinical researchers and pharmaceutical companies needing to accurately classify age-related or drug-related opacification of the crystalline lens. Dr. Chylack has developed face-to-face, interactive web-based, and self-administered web-based courses for training and certifying physicians and scientists in these classification systems. He works closely with Dr. Wendi Yajnik in the Office of Corporate Sponsored Research and Licensing (OSCRL) in this effort. 3. Massachusetts Lions Eye Research Fund-Sponsored Projects For many years the Massachusetts Lions Eye Research Fund (MLERF) has awarded Dr. Chylack a substantial grant for the support of research at the BWH on blinding eye disease. These projects have included studies of the mechanisms of protein aggregation in the lens (Dr. Liang), means by which Alzheimer’s disease (AD) protein A-beta causes increased aggregation of proteins in the lens of patients with AD (Dr. Goldstein), studies of the transcription factor LEDGF in the lens and central nervous system (Drs. Fu and Goldstein). Dr. Chylack collaborates with the investigators in these laboratories. 4. Alcon-Sponsored European Clinical Study of the Acrysof Angle-Supported Phakic Intraocular Lens Alcon is studying a new treatment for myopia – the implantations into the eye of a synthetic intraocular lens. Since the natural lens of the eye is clear and present in the eye with the implant the implant is called a “phakic” intraocular lens. Dr. Chylack is assessing the effect of a synthetic phakic intraocular lens on the transparency of the natural lens of the eye. He and his colleagues are using digital images from the Nidek EAS 1000 Lens Imaging System to image the lens and any changes in its clarity. Dr. Chylack and Mr. William Tung then subject these digital images to image analysis to derive continuous measures of lens clarity or lens opacity. Since this is a longitudinal study these measures can be used to assess the incidence and progression rates of any opacities that appear during the course of this trial. Back to the top | 
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