光照度对豚鼠屈光发育的影响

Influence of illuminance on the refractive development of the guinea pig eyes

目的探讨豚鼠在不同光照度照明条件下(10 000,500,5 lx,白色光,色温6000 K)的屈光发育状况,以比较光照度对豚鼠屈光发育的影响。方法 30只3周龄的豚鼠(英国种三色豚鼠),随机分为强光组10只、对照组10只和弱光组10只,分别置于10 000、500、5 lx三种光照度环境下,光照周期为12/12 h(早6:00～晚6:00)。于实验前及光照12周末分别用带状检影计、A超测定仪、角膜曲率计对豚鼠右眼重复进行眼球的生物学测量(包括屈光度、眼轴、角膜曲率)。光照12周结束后处死豚鼠取右眼球行高效液相色谱分析,对不同时间点的组间测量数据采用单因素方差分析,以P<0.05为差异有统计学意义。结果光照前不同组间生物学测量参数差异无显著性(P>0.05)。光照12周后,强光组屈光度为(4.03±1.59)D,同光照前相比发生(0.45±1.65)D的变化,对照组屈光度为(2.15±2.01)D,发生(2.28±0.66)D的变化,强光组同对照组相比远视度数偏高约1.50 D,两者差异有显著性(P<0.05);强光组眼轴增长(0.54±0.10)mm,对照组为(0.76±0.05)mm,强光组较对照组眼轴长度延长较慢,差异有显著性(P<0.05);光照后不同组角膜曲率半径均增加,但组间变化差异无显著性(P>0.05);强光组视网膜多巴胺含量平均为(148.70±22.44)nmol/g,对照组为(44.50±12.45)nmol/g,两者差异有显著性(P<0.001)。光照12周后弱光组较对照组相比,无论是屈光度、曲率、眼轴以及视网膜多巴胺含量均无统计学差异(P>0.05)。结论强光可以引起豚鼠眼球眼轴增长减缓,正视化进展减慢,屈光度数偏远视,弱光对豚鼠的屈光发育没有影响。强光照射后可以引起豚鼠视网膜多巴胺含量增加,可能为强光引起豚鼠正视化进展减缓的机制之一。

Objective To investigate the refractive development of guinea pig eyes under conditions of varying illuminance（10000,500,5 lx,white light,color temperature 6000 K）.Methods Thirty 3 weeks old guinea pigs were randomly assigned into three groups： high illuminance group（n=10）,normal control group（n=10）,and low illuminance group（n=10）,which were raised under the light illumination of 10000,500 and 5 lx,with color temperature 6000 K,respectively,from 6：00 am to 6：00 pm.The refractive power,the radius of corneal curvature and axial length（AL） of the right eye were measured by a streak retinoscope,keratometer（Topcon OM-4,Japan） and A-scan ultrasonagraphy（Opticon Hiscan A/B）,respectively,before and 12 weeks after treatment.One-way ANOVA analysis of variance was used in all comparisons between the three groups of eyes with a statistical analysis software SPSS 10.0.Results There were no significant differences among groups before the experiment（P0.05）.At 12 weeks after treatment,the variation of refraction in the high illuminance group was 0.45±1.65 D,and 2.28±0.66 D in the control group.The refraction of the high illuminance group became more hyperopic compared with that of the control group（4.03±1.59 D versus 2.15±2.01 D,P0.0001）.There was about 1.50 D hyperopia shift in the high illuminance group compared with that of the the control group.Axial length increased 0.54±0.10 mm in the high illuminance group and 0.76±0.05 mm in the control group.The high illuminance group was accompanied with a less accelerated speed of axial growth compared with that of the control group（P0.0001）.The radius of corneal curvature increased in all groups among the the three groups at the end of the experiment,but there were no significant differences（P0.05）.The level of retinal dopamine in the high illuminance group was much significantly higher than that in the control group（148.70±22.44 nmol/g versus 44.50±12.45 nmol/g,P0.0001）.There was no significant difference between the low illuminance group and control group in refraction,radius of corneal curvature and levels of retinal dopamine after 12 weeks of light exposure（P0.05）.Conclusions High ambient illuminance can slow the growth of the axial length and emmetropization process in guinea pigs,while low ambient illuminance makes no difference to the normal eye development of the guinea pigs.The levels of retinal dopamine can be increased under the condition of high illuminance,which may partly explain the changes of the eye development.