Abstract:

Objective

The aim of this study is to observe the effect of dynamic full spectrum light onmyopia progression of lens-induced guinea pigs.

Methods

Fifty seven one week old British trichrome guinea pigs weighing≤100 g were randomly divided into continuous illumination group（18 guinea pigs），low-frequency change group（20 guinea pigs）and high-frequency change group（19 guinea pigs）.The full spectrum SoLux light source was used to simulate outdoor lighting，and the light intensity was dynamically fluctuated in a cosine manner through electronic control equipment.The continuous illumination group received light intensity of 8000 lux，and the low-frequency change group received light intensity of 500 to 8000 lux，with a change frequency of 10 min/0.05 Hz.The high-frequency change group was exposed to 500 to8000 luxwith a frequency of20 s/0.002 Hz.All guinea pigswere equipped with－6.00 D lenses in both eyes.The changes of ocular biological parameters such as diopter，anterior chamber depth，lens thickness，vitreous cavity length，and axial length were measured before and 3 weeks after the experiment.Diopter，anterior chamber depth，lens thickness，vitreous depth and axial length were all in linewith normal distribution，and described by（¯x±s），and performed with analysis of variance between groups.The changes of eye parameters before and after the experimentwere detected by paired t-test，and the changes of eye parameters between groups with different light modes or dynamic light sources with different change frequencies were compared by t test.

Results

Before the experiment，refractive error of the constant lighting group was（3.55±0.53）D.The low frequency dynamic light group was（3.66±0.58）D and the high frequency dynamic light group was（3.49±0.49）D.There was no difference in refractive error among all groups.After3 weeks treatment，all the groups of guinea pigs developedmyopia.The low frequency dynamic light group developed tomyopia by（－2.43±0.68）D，followed by constant lighting group（－1.62±0.95）D.Before the experiment，the visual acuity of guinea pigs in the continuous illumination group，lowfrequency variation group，and high-frequency variation group were（3.55±0.53）D，（3.66±0.58）D，and（3.49±0.49）D，respectively.There was no statistically significant difference between the groups（F＝0.69，P＞0.05）.Before the experiment，the anterior chamber depth，lens thickness，vitreous cavity length，and axial length of the guinea pigs in the continuous lighting group were（1.09±0.05）mm，（2.46±0.14）mm，（3.40±0.18）mm，and（7.23±0.09）mm，respectively.The low-frequency variation groups were（1.08±0.05）mm，（2.47±0.15）mm，（3.41±0.19）mm，and（7.18±0.08）mm，respectively.The high-frequency change groups were（1.11±0.04）mm，（2.49±0.15）mm，（3.44±0.16）mm，and（7.23±0.09）mm，respectively.There was no statistically significant difference in the biological parameters of guinea pig eyeballs between groups（F＝1.22，0.36，0.19，2.10；P＞0.05）.After 3 weeks of experimental treatment，the refractive power of guinea pigs in the low-frequency change group increased by（－2.43±0.68）D compared to before the experiment，the highfrequency illumination group increased by（－1.34±0.91）D，and the continuous illumination group increased by（－1.62±0.95）D.The high-frequency variation group showed the least increase compared to before the experiment，followed by the continuous illumination group and the low-frequency variation group.Compared with the low-frequency change group，the high-frequency change group of guinea pigs showed a relative hyperopia state in terms of refractive power，and the difference in refractive power changes between the two groups of guinea pigs was statistically significant（t＝－4.35，P＜0.05）.There was no statistically significant difference in the changes of lens thickness，axial length，anterior chamber depth，and vitreous cavity length among the groups of guinea pigs（F＝0.32，2.10，1.05，1.10；P＞0.05）.

Conclusions

High frequency dynamic illumination can effectively slow down the progression of lens-induced myopia in guinea pigs.However，compared with constant lighting，high frequency dynamic lighting did not show greater protective effect againstmyopia.The results of this experiment need further research and exploration.

Key words: Guinea pig, Full spectrum light, Myopia