Long-Wavelength–Filtered Light Transiently Inhibits Negative Lens-Induced Axial Eye Growth in the Chick Myopia Model

Purpose Eye growth and myopia development in chicks, and some other animal models, can be suppressed by rearing under near-monochromatic, short-wavelength blue light. We aimed to determine whether similar effects could be achieved using glass filters that transmit a broader range of short and middle wavelengths. Methods On day 6 or 7 post-hatch, 169 chicks were assigned to one of three monocular lens conditions (-10 D, +10 D, plano) and reared for 7 or 10 days under one of four 201-lux lighting conditions: (1) B410 long-wavelength-filtered light, (2) B460 long-wavelength-filtered light, (3) Y48 short-wavelength-filtered light, or (4) HA50 broadband light. Results At 7 days, B410 (but not B460) long-wavelength-filtered light had significantly inhibited negative lens induced axial growth relative to Y48 short-wavelength-filtered light (mean difference in experimental eye = -0.249 mm; P = 0.006) and HA50 broadband light (mean difference = -0.139 mm; P = 0.038). B410 filters also inhibited the negative lens-induced increase in vitreous chamber depth relative to all other filter conditions. Corresponding changes in refraction did not occur, and biometric measurements in a separate cohort of chicks suggested that the axial dimension changes were transient and not maintained at 10 days. Conclusions Chromatic effects on eye growth can be achieved using filters that transmit a broad range of wavelengths even in the presence of strong cues for myopia development. Translational Relevance Broad-wavelength filters that provide a more "naturalistic" visual experience relative to monochromatic light have potential to alter myopia development, although the effects shown here were modest and transient and require exploration in further species.