单卵双胎儿表型不一致性共同性斜视

①目的通过分析单卵双胎儿表型不一致性共同性斜视发病因素,探讨其发病机制。②方法回顾性分析在我院就诊的表型不一致性斜视单卵双胎儿7对14例,记录出生后体质量、产期,有无家族发病史、外伤史或神经系统疾病史。检查屈光、斜视角、眼球运动等以确定斜视类型。③结果外斜视与正位视结合5对,内斜视与正位视结合2对。7对单卵双胎儿中6对早产,13例体质量低于2 500 g。斜视表型病儿体质量明显低于非斜视病儿(P=0.039 1)。7例弱视中的5例见于斜视表型,另2例见于非斜视表型。所有伴斜肌异常、分离性垂直斜视或眼球震颤者均见于斜视表型。④结论发生于单卵双胎儿的不一致性斜视揭示了环境因素在斜视发生中所起的作用。出生时低体质量、早产可能与不一致性共同性斜视的发生有关。

DISCORDANCE OF CONCOMITANT STRABISMIC PHENOTYPES IN MONOZYGOTIC TWINS

Objective To analyze environmental factors of the discordance of concomitant strabismus phenotypes in monozygotic twins. Methods Seven pairs of monozygotic twins demonstrating discordance of concomitant strabismic phenotypes were studied. A history of pregnancy, delivery, birth weight, trauma, systemic abnormalities, and the familial history of strabismus were taken. Reflection, angle of strabismus and ocular movement were measured to determine the type of strabismus. Results The discordance of strabismic phenotypes were found in all pairs of twins, five of them showing a combination of exotropia and straight alignment and two showing a combination of esotropia and straight alignment. Six of seven cases were pre-matured and 13 of 14 members had birth weight less than 2 500 g. The birth weight of strabismic members were less than that of non-strabismic members (P=0.039 1). Seven amblyopia subjects were identified and five of them were patients with strabismus and two were subjects without strabismus. DVD, abnormal oblique muscle function and nystagmus were all observed in patients with strabismus. (Conclusion The) discordant strabismic phenotypes in monozygotic twins indicate that environmental factors contribute to the deve-(lopment) of strabismus. Pre-maturity and low birth weight are likely to be the most important factors.