Effects of the long wavelength-filtered continuousspectrum on natural refractive development in juvenile guinea pigs

摘要

AIM: To investigate the effects of spectral composition and light intensity on natural refractive development in guinea pigs.METHODS: A total of 124 pigmented guinea pigs(2-week-old) were randomly assigned to three groups at high(Hi;4000 lx), medium(Me;400 lx) and low(Lo;50 lx) light intensities under a 12:12 light/dark cycle for 6 wk. Each group was subdivided into subgroups with the following spectra: broad spectrum Solux halogen light(BS), 600 nm above-filtered continuous spectrum(600F), 530 nm above-filtered continuous spectrum(530F), and 480 nm above-filtered continuous spectrum(480F;HiBS: n=10, Hi600F: n=10, Hi530F: n=10, Hi480F: n=10, MeBS: n=10, Me600F: n=10, Me530F: n=10, Me480F: n=10, LoBS: n=11, Lo600F: n=12, Lo530F: n=10, Lo480F: n=11). Refractive error, corneal curvature radius, and axial dimensions were determined by cycloplegic retinoscopy, photokeratometry, and A-scan ultrasonography before and after 2, 4, and 6 wk of treatment. Average changes from both eyes in the ocular parameters and refractive error were compared among different subgroups.RESULTS: After 6 wk of exposure, high-intensity lighting enhanced hyperopic shift;medium-and low-intensity lighting enhanced myopic shift(P<0.05). Under the same spectrum, axial increase was larger in the low light intensity group than in the medium and high light intensity groups(HiBS: 0.65±0.02 mm, MeBS: 0.67±0.01 mm, LoBS:0.82±0.02 mm;Hi600 F: 0.64±0.02 mm, Me600F: 0.67±0.01 mm, Lo600F: 0.81±0.01 mm;Hi530F: 0.64±0.02 mm, Me530F: 0.67±0.01 mm, Lo530F: 0.73±0.02 mm;Hi480F: 0.64±0.01 mm, Me480F: 0.66±0.01 mm, Lo480F: 0.72±0.02 mm;P<0.05). Under 400 lx, there was a faster axial increase in the MeBS group than in the Me480F group(P<0.05). Under 50 lx, axial length changes were significantly larger in LoBS and Lo600F than in Lo530F and Lo480F(P<0.01).CONCLUSION: Under high-intensity lighting, high light intensity rather than spectrum distributions that inhibits axial increase. Under medium-and low-intensity lighting, filtering out the long wavelength inhibits axial growth in juvenile guinea pigs.