The Effects of Prematurity on Visual Development

在美国，几乎每八个孩子中就有一个是早产儿，但对这一大群孩子的视力发育或视力损伤模式知之甚少。在美国，儿童双侧低视力的主要原因是脑视觉障碍（CVI），通常由早产儿的神经损伤引起。这种情况在不久的将来可能是可以预防或治疗的，因为新的治疗方法出现，用于预防和治疗由极端早产引起的神经系统疾病。显然，需要更好的方法来测试和分析视力。否则，就没有准确的方法来判断医疗或康复干预的效果。在这项研究中，我们将测量小于32周胎龄的健康早产儿的视觉发育，并将其与足月婴儿进行比较。在早产儿组中，将在6、9和12个月的实际年龄时以及在足月儿组中，在3、6、9和12个月的实际年龄时获得扫描VEP光栅敏锐度、游标敏锐度和对比敏感度测量值。在第二个目标中，我们将在6个月、9个月和12个月时测量作为早产并发症的脑室内出血（IVH）婴儿的这三种视觉功能。这项研究的结果将提供有关正常早产儿视觉发育的重要信息，以及这种视觉发育受到极端早产和神经损伤（IVH）干扰的方式。在第三个目标中，我们将评估扩散张量成像（DTI）在识别视力异常婴儿中的作用。DTI在婴儿生命的早期进行，此时干预最有可能预防或治疗神经损伤。通过进行结构-功能分析，将儿童的视力变化谱与扫描的变化谱进行比较，我们希望能够识别出那些视觉系统受损的儿童。这将有助于及早发现视力异常，并为早期医疗和康复工作铺平道路。头部超声和DTI结果的比较将证明DTI是否应该取代超声诊断新生儿托儿所的神经损伤。

DESCRIPTION (provided by applicant): Nearly one in every eight children is born prematurely in the US, yet very little is known about visual development or patterns of vision damage in this large group of children. The leading cause of bilateral low vision in children in the US is cerebral visual impairment (CVI), usually caused by neurological injury in premature infants. This condition will be potentially preventable or amenable to treatment in the near future as new therapies emerge for the prevention and treatment of neurological disease that result from extreme prematurity. Clearly, better methods to test and assay vision are needed. Otherwise, there will be no accurate way to judge the effects of medical or rehabilitative intervention. In this study, we will measure visual development in healthy, premature infants less than 32 weeks gestational age, and compare this to full term infants. Sweep VEP grating acuity, vernier acuity, and contrast sensitivity measures will be obtained at 6, 9, and 12 months chronological age in the premature group, and at 3, 6, 9, and 12 months chronological age in the fullterm group. In a second aim, we will measure these same three visual functions at 6, 9, and 12 months in infants who suffer an intraventricular hemorrhage (IVH) as a complication of prematurity. Results from this study will provide important information about visual development in normal premature infants, and the manner in which such visual development is perturbed by extreme prematurity and neurological damage (IVH). In a third aim, we will evaluate the role of diffusion tensor imaging (DTI) in identifying infants with vision abnormalities. DTI is performed early in the infant's life, at a time when intervention is most likely to prevent or treat neurological damage. By performing a structure-function analysis, comparing the spectrum of acuity changes in children with the spectrum of changes on their scans, we expect to be able to identify those children who have suffered damage to their visual system. This will allow early detection of vision abnormalities and pave the way for early medical and rehabilitation efforts. A comparison of head ultrasound and DTI findings will demonstrate whether DTI should replace ultrasound for the diagnosis of neurological injury in the newborn nursery.