正常和间歇性外斜视儿童立体视的研究

目的 研究正常和分开过强型间歇性外斜视儿童手术前,后不同距离立体视的变化。方法 对4－12岁正常组儿童844例和患儿组因分开过强型间歇性外斜视行手术治疗的患儿35例,采用TNO立体视检查法和新立体视检查法（new stereo tests,NST)检测近距离立体视,采用自制的中,远距离立体视检查法检查1－5m立体视;比较不同年龄和间歇性外斜视手术前,后不同距离平均立体视锐度的差异。结果 （1）正常组：4－8岁儿童约98％TNO检查近距离立体视锐度≤60“,立体视锐度与年龄的增长呈直线相关性;10－11岁时立体视锐度最小;4－8岁儿童与9－12岁儿童比较,立体视锐度分布差异有非常显著意义（P＜0．01）;约97％儿童NST检查近距离立体视锐度≥40“,各年龄段平均立体视锐度为40“-42“。中,远距离立体视锐度4岁时最大,随年龄的增长逐渐减小,9－10岁时最小;（2）患儿组;TNO和NST检查,手术前,后近距离立体视锐度接近,差异均无显著意义（P＞0．05）;术前中,远距离立体视锐度大于正常组,差异有显著意义（P＜0．05）;术后中距离立体视锐度较术前明显改善并接近政党,远距离立体视锐度有轻微改善。结论 （1）正常组4岁儿童不同距离立体视开始发育,随年龄的增长继续发育,8岁后明显提高,9－11岁完善。（2）分开过强型间歇性外斜视儿童术前近距离立体视良好,中,远距离立体视不良,术后中距离立体视改善明显,间歇性外斜视手术应以中距离立体视的恢复程度作为疗效指标。

Study on the near,middle and long distance stereopsis of normal and children with intermittent exotropia

OBJECTIVE: To study the pre- and post-operative changes of stereopsis at different distances in normal and children with divergence in excess type of intermittent exotropia. METHODS: TNO and new stereo tests (NST) and the middle and long distance stereotest were used for the evaluation of stereoacuity at 40 cm - 5 m in 844 normal and 35 children aged 4 - 12 years with divergence excess type of intermittent exotropia undergoing operative correction of strabismus. RESULT: (1) Normal subjects: The TNO test showed that the near distance stereoacuity /= 40" was in 97% subjects. The mean stereoacuity was 40" - 42" in children various in age. The middle and far distance stereoacuity was the greatest in children aged 4 years, along with the increase of age, it was gradually declined and at 9 - 10 years it was the lowest. (2) Divergence excess type of intermittent extropia: There was no significant difference between the pre- and post-operative near stereoacuity examined by TNO and NST (P > 0.05) The pre-operative middle and long distance stereoacuities were greater than that in the normal children, the difference being significant (P < 0.05). The post-operative middle distance stereoacuity was improved and approximately normal in comparison with that before the surgery, and the far distance stereoacuity was improved mildly. CONCLUSIONS: (1) In the normal group, the development of stereopsis at different distances begins at 4 years, keeping on developing with the increase of age, and the stereoacuity is elevated after 8 years and in 9 - 11 years well developed. (2) In the group of divergence excess type of intermittent exotropia, the pre-operative near stereoacuity is well, but the middle and far distance stereoacuities are poor and the middle stereoacuity improves significantly after the surgery. The recovery of middle distance stereoacuity seems to be an objective criterion of the operative therapeutic effect.