透镜诱导条件下混合性近视和真性近视豚鼠屈光度和眼轴长度变化

Changes in diopter and axial length of guinea pigs with mixed myopia and true myopia under lens-induced conditions

目的探讨-6.0 D透镜诱导条件下混合性近视和真性近视豚鼠屈光度和眼轴长度变化。方法选取2周龄睫状肌麻痹前和麻痹后屈光度均在1.00~3.00 D之间的健康英国三色短毛豚鼠20只。将20只豚鼠适应性饲养3 d后,右眼配戴-6.0 D透镜,进行近视模型构建。依据透镜诱导2周后豚鼠睫状肌麻痹前后屈光度差值≥0.5 D且同时存在真性近视作为混合性近视的判断标准,将豚鼠分为混合性近视组和真性近视组,继续诱导至第8周,最终两组均为10只豚鼠。测量透镜诱导不同时间两组豚鼠屈光度和眼轴长度,并进行统计学分析。结果透镜诱导2周、4周时混合性近视组与真性近视组豚鼠屈光度比较,差异均无统计学意义(均为P>0.05)。透镜诱导6周、8周时混合性近视组与真性近视组相比,睫状肌麻痹前、睫状肌麻痹后豚鼠屈光度均明显降低(均为P<0.05)。且透镜诱导8周时两组之间睫状肌麻痹前和睫状肌麻痹后豚鼠屈光度差值明显大于0周时(P<0.05)。透镜诱导2周、4周、6周时混合性近视组与真性近视组豚鼠眼轴长度比较,差异均无统计学意义(均为P>0.05)。透镜诱导8周时混合性近视组豚鼠眼轴长度明显长于真性近视组(P<0.05)。且透镜诱导8周时混合性近视组与真性近视组豚鼠眼轴长度差值明显大于0周时(P<0.05)。结论混合性近视比真性近视豚鼠屈光度增加和眼轴增长更快,混合性近视中的假性近视成分应作为高度近视发展的预警指标。

Objective To investigate the changes in diopter and axial length of mixed myopia and true myopia in guinea pigs induced by-6.0 D lens.Methods Twenty healthy British tricolor short-haired guinea pigs with diopter between 1.00 D and 3.00 D before and after mydriasis at 2 weeks of age were selected.Twenty guinea pigs were adaptively fed for 3 days,and the right eyes worn-6.0 D lens to induce myopia.After 2 weeks of lens induction,mixed myopia was defined as the after-mydriasis diopter minus the before-mydriasis diopter≥0.5 D,and there was true myopia at the same time,which was defined as mixed myopia.According to the criteria mentioned above,these guinea pigs were divided into mixed myopia group and true myopia group with 10 per group,and the induction was continued to the 8th week.The diopter and axial length of the two groups were measured and analyzed at different induction time.Results There were no significant differences in diopter between mixed myopia group and true myopia group at 2 weeks and 4 weeks(both P>0.05).Compared with the true myopia group,the after-mydriasis diopter and pre-mydriasis diopter were significantly reduced in the mixed myopia group at 6 weeks and 8 weeks(all P<0.05).At 8 weeks,the difference of diopter between the two groups after-mydriasis diopter and pre-mydriasis diopter was significantly greater than that at 0 week(P<0.05).The axial length of the guinea pigs in the mixed myopia group was significantly longer than that in the true myopia group at 8 weeks(P<0.05),whereas no significant difference at 2 weeks,4 weeks and 6 weeks(all P>0.05).At 8 weeks,the difference of axial length between mixed myopia group and true myopia group was significantly greater than that of 0 week(P<0.05).Conclusion The diopter and axial length increase faster in mixed myopia guinea pigs than that in true myopia.The pseudomyopia in mixed myopia should be used as an early diagnosis parameter for high myopia.