Wensveen Janice M, Harwerth Ronald S, Hung Li-Fang, Ramamirtham Ramkumar, Kee Chea-su, Smith Earl L
College of Optometry, University of Houston, Houston, Texas 77204-2020, USA.
Invest Ophthalmol Vis Sci. 2006 Jun;47(6):2468-77. doi: 10.1167/iovs.05-0885.
To characterize how the mechanisms that produce unilateral form-deprivation amblyopia integrate the effects of normal and abnormal vision over time, the effects of brief daily periods of unrestricted vision on the spatial vision losses produced by monocular form deprivation were investigated in infant monkeys.
Beginning at 3 weeks of age, unilateral form deprivation was initiated in 18 infant monkeys by securing a diffuser spectacle lens in front of one eye and a clear plano lens in front of the fellow eye. During the treatment period (18 weeks), three infants wore the diffusers continuously. For the other experimental infants, the diffusers were removed daily and replaced with clear, zero-powered lenses for 1 (n=5), 2 (n=6), or 4 (n=4) hours. Four infants reared with binocular zero-powered lenses and four normally reared monkeys provided control data.
The degree of amblyopia varied significantly with the daily duration of unrestricted vision. Continuous form deprivation caused severe amblyopia. However, 1 hour of unrestricted vision reduced the degree of amblyopia by 65%, 2 hours reduced the deficits by 90%, and 4 hours preserved near-normal spatial contrast sensitivity.
The severely amblyogenic effects of form deprivation in infant primates are substantially reduced by relatively short daily periods of unrestricted vision. The manner in which the mechanisms responsible for amblyopia integrate the effects of normal and abnormal vision over time promotes normal visual development and has important implications for the management of human infants with conditions that potentially cause amblyopia.
为了描述产生单侧形觉剥夺性弱视的机制如何随时间整合正常和异常视觉的影响，研究了在幼年猴子中，每日短时间的无限制视觉对单眼形觉剥夺所导致的空间视觉损失的影响。
从3周龄开始，对18只幼年猴子进行单侧形觉剥夺，方法是在一只眼前固定一个漫射眼镜片，在另一只眼前固定一个透明平光镜。在治疗期（18周）内，3只幼猴持续佩戴漫射镜。对于其他实验幼猴，漫射镜每天取下，换上透明的零屈光度镜片1小时（n = 5）、2小时（n = 6）或4小时（n = 4）。4只佩戴双眼零屈光度镜片饲养的幼猴和4只正常饲养的猴子提供对照数据。
弱视程度随每日无限制视觉的时长而显著变化。持续的形觉剥夺导致严重弱视。然而，1小时的无限制视觉可使弱视程度降低65%，2小时可使缺陷降低90%，4小时可使空间对比敏感度保持在接近正常的水平。
相对较短的每日无限制视觉时间可显著减轻幼年灵长类动物中形觉剥夺的严重致弱视作用。导致弱视的机制随时间整合正常和异常视觉影响的方式促进了正常视觉发育，并且对患有可能导致弱视疾病的人类婴儿的治疗具有重要意义。
