title: The effect of spectral property and intensity of light on natural refractive development and compensation to negative lenses in guinea pigs.
abstract: OBJECTIVE
  To investigate the effect of spectral composition and light intensity on refractive development in guinea pigs.
  
  
  METHODS
  One-week-old guinea pigs were randomly assigned to groups exposed to broad-spectrum Solux halogen light (BS) or spiked-spectrum fluorescent light (FL) at both high (Hi, 10,000 lux) and low (Lo, 500 lux) intensities under a 12:12 light/dark cycle. Half of the animals in each group were used as controls (n = 24, 20, 22, and 20, respectively), and half were fitted with binocular -4-diopter (D) lenses (L, lenses; n = 22, 20, 24, and 22, respectively). Refractive error, corneal curvature, and axial dimensions were determined by cycloplegic retinoscopy, photokeratometry, and A-scan ultrasonography, respectively.
  
  
  RESULTS
  Guinea pigs exposed to FL and BS showed similar changes in refraction under both high (HiFL: 2.26 ± 0.55 D versus HiBS: 2.17 ± 0.65 D, P > 0.05)- and low-intensity lighting (LoFL: 1.39 ± 0.88 D versus LoBS: 1.40 ± 0.93 D, P > 0.05). This was also true for the groups wearing lenses (HiFL-L: -1.81 ± 0.73 D versus HiBS-L: -1.45 ± 0.99 D, P > 0.05; LoFL-L: -2.58 ± 0.65 D versus LoBS-L: -2.29 ± 0.50 D, P > 0.05). Nevertheless, animals under high-intensity lighting exhibited a significantly larger hyperopic shift compared with those under low-intensity lighting (HiFL versus LoFL: P < 0.01; HiBS versus LoBS: P < 0.05). Similarly, a significantly smaller myopic shift was observed with brighter light in the lens condition (HiFL-L versus LoFL-L: P < 0.05; HiBS-L versus LoBS-L: P < 0.05).
  
  
  CONCLUSIONS
  In guinea pigs, spectrally spiked light and broad-spectrum light have similar effects on natural refractive development and negative lens compensation. As found in other species, effects of light intensity on refractive development were also observed in guinea pigs in both illuminants.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Li
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Weizhong
authors.initials: W
authors.lastname: Lan
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Shiqi
authors.initials: S
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Yunru
authors.initials: Y
authors.lastname: Liao
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China Aier Eye Hospital Group, Changsha, China.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Lixia
authors.initials: L
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China Aier Eye Hospital Group, Changsha, China.
authors.forename: Zhikuan
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004195:Disease Models, Animal; D018450:Disease Progression; D005123:Eye / Q000254:growth & development*; D006168:Guinea Pigs; D007909:Lenses / Q000009:adverse effects*; D017440:Photoperiod; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000209:etiology / Q000503:physiopathology*
keywords: guinea pigs; lens-induced myopia; light intensity; spectral property