Sanchez A M, Congdon N G, Sommer A, Rahmathullah L, Venkataswamy P G, Chandravathi P S, Clement L
Johns Hopkins University School of Medicine, Baltimore, USA.
Am J Clin Nutr. 1997 Jan;65(1):61-6. doi: 10.1093/ajcn/65.1.61.
Two hundred seven vitamin A-deficient southern Indian children aged 1-7 y (mean age: 56.9 mo) underwent testing of dark-adapted visual and pupillary thresholds in their village setting according to a previously reported protocol. One hundred thirty (62.8%) of the children also underwent serum retinol testing, and 178 (86.0%) participated in a randomized, placebo-controlled vitamin A dosing trial with pre- and postdose testing of dark-adaptation threshold. Most subjects (184 of 207, 88.9%) were able to complete pupillary testing, an objective sign requiring minimal cooperation, including a high proportion of the youngest children (72.2% of subjects aged 2 y). The proportion of children completing visual threshold testing, which requires greater understanding and cooperation, was significantly smaller than that able to complete pupillary testing (131 of 207, 63.3%; P < 0.0001, chi square). At baseline (predosing), the mean serum retinol concentration declined in linear fashion with a higher pupillary threshold (0.73 mumol/L with a score < or = 4; 0.47 mumol/L with a score > or = 8; P < 0.01). The mean pupillary threshold for these highly vitamin A-deficient Indian children (-0.622 log cd/m2) was significantly higher than that for 136 more moderately deficient Indonesian children (-0.985 log cd/m2; P < 0.001, two-sample t test) and 56 normal American children (-1.335 log cd/m2; P < 0.0001, two-sample t test). The improvement in pupillary dark-adaptation testing was not significant for children receiving vitamin A or placebo, though there was a nonsignificant trend toward greater improvement in children receiving vitamin A (P = 0.2, two-sample t test). Pupillary threshold testing represents a new, noninvasive, practical, and seemingly valid approach to assessing the vitamin A status of a moderately to severely deficient preschool population.
207名年龄在1至7岁（平均年龄：56.9个月）的印度南部维生素A缺乏儿童，按照先前报道的方案在其村庄环境中接受了暗适应视觉和瞳孔阈值测试。其中130名（62.8%）儿童还接受了血清视黄醇检测，178名（86.0%）儿童参与了一项随机、安慰剂对照的维生素A给药试验，并在给药前和给药后进行了暗适应阈值测试。大多数受试者（207名中的184名，88.9%）能够完成瞳孔测试，这是一项所需合作最少的客观指标，包括很大比例的最小儿童（2岁儿童中的72.2%）。完成需要更多理解和合作的视觉阈值测试的儿童比例，显著低于能够完成瞳孔测试的儿童比例（207名中的131名，63.3%；P<0.0001，卡方检验）。在基线（给药前）时，平均血清视黄醇浓度随瞳孔阈值升高呈线性下降（得分≤4时为0.73μmol/L；得分≥8时为0.47μmol/L；P<0.01）。这些维生素A严重缺乏的印度儿童的平均瞳孔阈值（-0.622 log cd/m2），显著高于136名维生素A缺乏程度较轻的印度尼西亚儿童（-0.985 log cd/m2；P<0.001，两样本t检验）和56名美国正常儿童（-1.335 log cd/m2；P<0.0001，两样本t检验）。接受维生素A或安慰剂的儿童在瞳孔暗适应测试中的改善并不显著，尽管接受维生素A的儿童有改善趋势但不显著（P = 0.2，两样本t检验）。瞳孔阈值测试代表了一种新的、非侵入性的、实用的且看似有效的方法，用于评估中度至重度缺乏维生素A的学龄前人群的维生素A状况。
