Dark adaptation status of pregnant Nepali and nonpregnant US women

N. G. Congdon, R. Nivitsky, M. Dreyfuss, D. Haselwood, J. H. Humphrey, K. P. West, A. M. Sanchez, A. Sommer

Research output: Contribution to journalArticlepeer-review


Purpose: We have reported a new, non-invasive technology for the assessment of population Vitamin A status among young children (AJCN 61:1076-1082; IOVS 36:8863 abstr.) We wished to determine if our device would detect impaired dark adaptation among pregnant women in an area where vitamin A deficient nightblindness is common. Methods: 102 pregnant Nepali and 100 nonpregnant American women of similar (23.6 vs 24.6 yrs, p = 0.3) ages underwent testing of dark-adapted visual and pupillary thresholds according to a previously reported protocol. Half of the Nepali women were randomized to vitamin A supplementation and half placebo. Results: More than 97% of subjects in both groups completed all testing. Mean pupillary (-1.31 ± 0.38 vs -1.84 ± 0.51 log candela/m2, P < 0.0001) and visual (-4.41 ± 0.46 vs -4.84 ± 0.35 log candela/m2, P < 0.0001) dark adaptation thresholds were significantly higher (less sensitive dark vision) for the Nepali women. Post-partum follow-up testing and results of non-intervened pregnant women will also be presented. Conclusion: Pupillary and visual dark adaptation testing are further validated as a non-invasive, practical and highly effective technology for population assessment of vitamin A status.

Original languageEnglish (US)
Pages (from-to)S309
JournalInvestigative Ophthalmology and Visual Science
Issue number3
StatePublished - Feb 15 1996

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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