title: Effects of Long-Wavelength Lighting on Refractive Development in Infant Rhesus Monkeys.
abstract: OBJECTIVE
  Differences in the spectral composition of lighting between indoor and outdoor scenes may contribute to the higher prevalence of myopia in children who spend low amounts of time outdoors. Our goal was to determine whether environments dominated by long-wavelength light promote the development of myopia.
  
  
  METHODS
  Beginning at 25 ± 2 days of age, infant monkeys were reared with long-wavelength-pass (red) filters in front of one (MRL, n = 6) or both eyes (BRL, n = 7). The filters were worn continuously until 146 ± 7 days of age. Refractive development, corneal power, and vitreous chamber depth were assessed by retinoscopy, keratometry, and ultrasonography, respectively. Control data were obtained from 6 monkeys reared with binocular neutral density (ND) filters and 33 normal monkeys reared with unrestricted vision under typical indoor lighting.
  
  
  RESULTS
  At the end of the filter-rearing period, the median refractive error for the BRL monkeys (+4.25 diopters [D]) was significantly more hyperopic than that for the ND (+2.22 D; P = 0.003) and normal monkeys (+2.38 D; P = 0.0001). Similarly, the MRL monkeys exhibited hyperopic anisometropias that were larger than those in normal monkeys (+1.70 ± 1.55 vs. -0.013 ± 0.33 D, P < 0.0001). The relative hyperopia in the treated eyes was associated with shorter vitreous chambers. Following filter removal, the filter-reared monkeys recovered from the induced hyperopic errors.
  
  
  CONCLUSIONS
  The observed hyperopic shifts indicate that emmetropization does not necessarily target the focal plane that maximizes luminance contrast and that reducing potential chromatic cues can interfere with emmetropization. There was no evidence that environments dominated by long wavelengths necessarily promote myopia development.
authors.affiliation: College of Optometry University of Houston, Houston, Texas, United States 2Vision Cooperative Research Centre, Sydney, New South Wales, Australia.
authors.forename: Earl L
authors.initials: EL
authors.lastname: Smith
authors.affiliation: College of Optometry University of Houston, Houston, Texas, United States 2Vision Cooperative Research Centre, Sydney, New South Wales, Australia.
authors.forename: Li-Fang
authors.initials: LF
authors.lastname: Hung
authors.affiliation: College of Optometry University of Houston, Houston, Texas, United States 2Vision Cooperative Research Centre, Sydney, New South Wales, Australia.
authors.forename: Baskar
authors.initials: B
authors.lastname: Arumugam
authors.affiliation: Vision Cooperative Research Centre, Sydney, New South Wales, Australia.
authors.forename: Brien A
authors.initials: BA
authors.lastname: Holden
authors.affiliation: Department of Ophthalmology, University of Washington Medical School, Seattle, Washington, United States.
authors.forename: Maureen
authors.initials: M
authors.lastname: Neitz
authors.affiliation: Department of Ophthalmology, University of Washington Medical School, Seattle, Washington, United States.
authors.forename: Jay
authors.initials: J
authors.lastname: Neitz
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003315:Cornea / Q000528:radiation effects*; D004195:Disease Models, Animal; D008029:Lighting; D008253:Macaca mulatta; D010775:Photic Stimulation; D012029:Refraction, Ocular / Q000528:radiation effects*; D012030:Refractive Errors / Q000175:diagnosis / Q000503:physiopathology*