A new, simple, inexpensive means of testing functional vitamin A status: the night vision threshold test (NVTT). A preliminary field-test report.
Shrestha AK, Duncan B, Taren D, Canfield LM, Greivenkamp JE, Shrestha N, Shrestha KK. A new, simple, inexpensive means of testing functional vitamin A status: the night vision threshold test (NVTT). A preliminary field-test report. J Trop Pediatr. 2000 12; 46(6):352-6.