The Effects of Prematurity on Visual Development

描述（由申请人提供）：在美国，每8个儿童中就有1个是早产儿，然而，人们对这一大批儿童的视力发育或视力损害模式知之甚少。美国儿童双侧低视力的主要原因是脑性视觉障碍（CVI），通常由早产儿的神经损伤引起。在不久的将来，随着预防和治疗极端早产导致的神经系统疾病的新疗法的出现，这种情况将有可能得到预防或治疗。显然，需要更好的方法来测试和分析视力。否则，将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，我们将测量健康早产儿的视觉发育，小于32周胎龄，并将其与足月婴儿进行比较。早产儿组在6、9、12个月龄时，足月组在3、6、9、12个月龄时，分别测量扫描VEP光栅、游标视力和对比灵敏度。在第二个目标中，我们将在6、9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。本研究的结果将提供关于正常早产儿视觉发育的重要信息，以及这种视觉发育如何受到极端早产和神经损伤（IVH）的干扰。在第三个目标中，我们将评估弥散张量成像（DTI）在识别视力异常婴儿中的作用。DTI在婴儿生命早期进行，这是干预最有可能预防或治疗神经损伤的时期。通过进行结构-功能分析，将儿童的视力变化光谱与扫描结果的变化光谱进行比较，我们希望能够识别出那些视觉系统受损的儿童。这将有助于早期发现视力异常，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.