闭路式强化优先注视法用于早产儿早期视力发育的观察

目的用闭路式强化优先注视（COPL）法检测早产儿6月龄前的条栅视力，探讨其发育情况。方法前瞻性病例对照研究。符合筛选标准且能完成条栅视力检查，随访1〉6个月的早产儿48名，用COPL法检测条栅视力，年龄7d～8个月，体重（2233．4±448．0）g，分组段定期测试每一名早产儿单、双眼视力。另外筛选正常足月儿34名作为对照组，体重（3443．3_＋553．0）g，定期作检测。视力结果以5分法记录。数据采用独立样本t检验、配对t检验、单因素方差分析、Pearson相关、直线回归及Mann—Whitney检测进行分析。结果早产儿出生2周内、校正孕周满38周、出生后14周、校正孕周满52周、出生后6个月、校正孕周满63周的右眼和左眼条栅视力分别为2．48±0．02和2．49±0．02，2．70±0．01和2．70±0．01，3．54±0．03和3．51±0．03。3．70±0．03和3．69±0．03，3．98±0．03和3．95±0．03，4．10±0．02和4．09±0．02，同一个体左右眼视力差异无统计学意义；各组段双眼条栅视力分别为2．51±0．02、2．70±0．01、3．55±0．03、3．69±0．03、3．96±0．03、4．18±0．02。早产儿的视力与月龄之间存在高度正相关关系（r=0．928，P〈0．01），视力（V）与月龄（X）之间的直线回归方程为Y=0．248X＋2．457（R。=0．861，F=1769．743，P〈0．01）；视力与孕周呈高度正相关（r=0．725，P〈0．01），视力（Y）与孕周（X）之间的直线回归方程为Y=0．017X＋1．457（R。=O．261，F=11．743，P〈0．01）。与出生体重、性别的相关性无统计学意义。足月儿出生后2周、出生后3个月、出生后6个月右眼和左眼视力分别为2．60±0．02和2．63±0．02，3．71±0．02和3．72±0．02，4．06±0．02和4．05±0．02，同一个体左右眼间视力差异无统计学意义；足月儿各组段双眼视力分别为2．60±0．02、3．72±0．02、4．14±0．02。比较同组段平均单双眼条栅视力，各月龄早产儿平均单双眼条栅视力与同组段正常足月儿相比，均较低，差异均有统计学意义（t=0．81、0．79、0．87，P〈0．05）。结论无眼底病变早产儿的单眼条栅视力与眼别无关，单、双眼条栅视力均低于同龄正常足月儿，条栅视力发育与月龄、孕周呈高度正相关，与性别、体重和屈光状态无相关性。电脑控制强化优先注视检测系统是检测0～6月龄早产儿视力的有效手段。

Report on the early development of grating acuity in preterm infants determined by the Closed-Circuit Operant Preferential Looking System

Objective To determine the grating acuity of healthy preterm infants by using the Closed-Circuit Operant Preferential Looking System （COPL） and to investigate visual development during the early 6-month period after birth. Methods In this prospective case-control study, the COPL was used to determine the monocular and binocular grating acuity of 48 preterm infants （25 males, 23 females）, who met the eligibility criteria of 7 days-8 months old, with birth weight from 1415 g to 2770 g （2233.4±448.0）g. The infants were measured periodically. The grating acuity of another 34 full-term infants, who were the controls, were measured periodically for six months at the same time points after birth. The data were analyzed statistically by independent samples t test, paired t test, ANOVA, Pearson correlation, linear regression and Mann-Whitney test. Results The mean values of monocular acuity （right and left） for the preterm infants were： 2.48±0.02 and 2.49±0.02 （2 weeks after birth）, 2.70±0.01 and 2.70±0.0l （gestational age, 38 weeks）, 3.54±0.03 and 3.51-20.03 （14 weeks after birth）, 3.70±0.03 and 3.69±0.03 （gestational age, 52 weeks）, 3.98±0.03 and 3.95±0.03（6 months after birth）, 4.10±0.02 and 4.09±0.02 （gestational age, 63 weeks）. There were positive correlation between visual acuity and months in the preterm infants r=0.928, P〈0.01; R^2=0.248X＋ 2.457 （R2=0.861, F=1769.743, P〈0.01）]. Also between visual acuity and weeks of gestational age r=0.725, P〈0.01; Y=0.017±l.457 （R2=0.261, F=11.743, P〈0.O1）]. Nor the weight or gender. The mean values of binocular acuity for the preterm infants at corresponding time points were 2.51±0.02, 2.70±0.01, 3.55±0.03, 3.69＋0.03, 3.96＋0.03, 4.18±0.02. Mean values of monocular acuity for the full-term infants were 2.60±0.02 and 2.63±0.02 （2 weeks after birth）, 3.71±0.02 and 3.72±0.02 （3 months after birth）, 4.06±0.02, and 4.05±0.02 （6 months after birth）. There was no statistically significant difference between the two eyes. The binocular aeuities of the full-term infants at corresponding time points were 2.60±0.02, 3.72±0.02, 4.14±0.02. Within the same age group, the acuities of the preterm infants was lower than those of the full-term infants （t=0.81, 0.79, 0.87, P〈 0.05）. Conclusion The grating acuities of the preterm infants are lower than those of full-term infants. Visual acuity of the preterm infant progressively increases with age and improves at a faster rate during 1 to 5 months after birth. There is no correlation between visual acuity and gender. This study shows that the early retinopathy of premature is present. The t of visual acuity in preterm infants is necessary even if no COPL system is useful for assessing grating acuity in infants.