关键词: 近视模型, 照度, 形觉剥夺性近视

Abstract: Objective To study the effect of different illumination on the development of axial length in chicks with visual distance restriction. Design Experiment study.  Participants Sixty 10-day-old chicks.  Methods Chicks were randomly divided into 5 groups with 12 chicks in each group. One group was the control group and the others were the experimental groups. Using the greedy and phototaxis of the chicken to food, the visual distance of the chicken was more naturally restricted. Four groups of chickens were raised in four sets of self-made myopia induction devices, which could keep the visual distance within about 5 cm with the growth of chicks. The illuminances of the experimental groups were set at 0.5 Lx, 5 Lx, 50 Lx, and 500 Lx, respectively. The control group was reared in the natural light environment near the window without restricting the visual distance. When the chickens were 50 days old, the axial length of the eyes was measured by A-scan. The refraction was measured by retinoscope in the dark room and under non-local anesthesia. The weight was measured by electronic scale and the abnormal growth of axial length was calculated. The relationship between this value and diopter was analyzed. Main Outcome Measured Axial length, axial increase, diopter. Results There was a linear relationship between axial length and body weight in the control group (R2=0.89). When the chicken were 50 days old, the abnormal axial growth of 0.5 Lx, 5 Lx, 50 Lx and 500 Lx groups were 0.60 mm, 0.30 mm, 0.75 mm and 0.80 mm, respectively. There were significant differences in the increase of axial length among 5 Lx group and 0.5 Lx group, 50 Lx group, 500 Lx group (P=0.033, 0.001, 0.003). There was a linear proportional relationship between diopter and abnormal axial growth (R2=0.74). Conclusion The model can significantly induce axial myopia in chicks. Illumination had a significant effect on the increase of abnormal axial growth. The increase of abnormal axial growth was the smallest at 5 Lx and the largest at 500 Lx.  (Ophthalmol CHN, 2023, 32: 294-298)

Key words: myopia model, intensity of illumination, form deprivation myopia