Purchase this article with an account.
L. T. Chylack, Jr., A. H. Feiveson, L. Peterson, F. K. Manuel, M. Wear, W. H. Tung, D. Hardy, L. Marak, C. Bell, F. A. Cucinotta; The NASCA Study - Report 3: Cross-Sectional Analysis of Exposure to Radiation in Space and Risk of Lens Opacification. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5454.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The NASA Study of Cataract in Astronauts (NASCA) will assess risk of lens opacification from exposure to radiation in space in US astronauts. This is Progress Report #3.
This 5-yr study follows populations of US astronauts, military aircrew, and ground-based subjects with annual eye exams, assessment of space radiation exposure (SRE), solar ocular exposure (SOE), and nutrition. Nidek EAS 1000 digital lens images, demographic and nutritional data were gathered. Statistical analysis consisted of fitting customized non-normal regression models to six measures of opacity (3 nuclear (N), 1 cortical (C), and 2 PSC).We tested effects of subject group, SRE, and other variables on each of the 6 measures. We identified variables that are possibly confounded with subject group and used a free step-down resampling method to account for multiple testing with a family-wise error rate of 0.05.
Age is most important predictor of size and spread of C opacity. Astronauts who have flown in space have significantly greater C mean area opaque than those who have not. For astronauts who have flown in space, there is no relationship between total lens dose of space radiation and mean or variance of age-adjusted C. For all gps increased SOE was weakly associated with higher C opacity. We found also some evidence that larger intake of Vitamin A was associated with reduced C opacity. Neither SRE, nor SOE, nor any nutritional variable, was associated with increased or decreased N opacification. Age was slightly associated with increased area of P opacification and the number of isolated PSC centers of opacity. Only for ground based controls was there a gender effect of area of P opacification (males:greater area opaque). Identified confounders are as follows: indicators of hypertension (p=0.006) and asthma (p<0.001) are associated with greater C area opaque, and max. logMAR acuity (p=0.001) associated with greater P area opaque.
SRE is a risk factor for greater C opacification. SOE, and the identified cofounders are associated with greater C opacification, and higher vitamin A intake may be associated with lower C area opaque. Other than age, no study variables were associated with N opacification.
This PDF is available to Subscribers Only