May 2007
Volume 48, Issue 13
ARVO Annual Meeting Abstract  |   May 2007
The NASCA Study - Report 3: Cross-Sectional Analysis of Exposure to Radiation in Space and Risk of Lens Opacification
Author Affiliations & Notes
  • L. T. Chylack, Jr.
    Surgery / Center for Ophthalmic Research, Brigham & Womens Hosp/Harvard, Boston, Massachusetts
  • A. H. Feiveson
    Lyndon B. Johnson Space Center, NASA, Houston, Texas
  • L. Peterson
    Public Health, The Methodist Hospital, Houston, Texas
  • F. K. Manuel
    Space Center Eye Associates, Houston, Texas
  • M. Wear
    Wyle Laboratories, Houston, Texas
  • W. H. Tung
    Surgery / Center for Ophthalmic Research, Brigham & Womens Hosp/Harvard, Boston, Massachusetts
  • D. Hardy
    Medicine, Baylor College of Medicine, Houston, Texas
  • L. Marak
    Wyle Laboratories, Houston, Texas
  • C. Bell
    Division of Space Life Sciences, USRA, Houston, Texas
  • F. A. Cucinotta
    Lyndon B. Johnson Space Center, NASA, Houston, Texas
  • Footnotes
    Commercial Relationships L.T. Chylack, None; A.H. Feiveson, None; L. Peterson, None; F.K. Manuel, None; M. Wear, None; W.H. Tung, None; D. Hardy, None; L. Marak, None; C. Bell, None; F.A. Cucinotta, None.
  • Footnotes
    Support NASA Cooperative Agreement Number: NAG9-1491
Investigative Ophthalmology & Visual Science May 2007, Vol.48, 5454. doi:
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      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.

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      © ARVO (1962-2015); The Authors (2016-present)

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Purpose:: 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.

Methods:: 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.

Results:: 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.

Conclusions:: 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.

Keywords: cataract • radiation damage: light/UV • clinical (human) or epidemiologic studies: risk factor assessment 

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