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Myopic defocus in the evening is more effective at inhibiting eye growth than defocus in the morning: Effects on rhythms in axial length and choroid thickness in chicks
- Source :
- Experimental Eye Research. 154:104-115
- Publication Year :
- 2017
- Publisher :
- Elsevier BV, 2017.
-
Abstract
- Animal models have shown that myopic defocus is a potent inhibitor of ocular growth: brief (1-2 h) daily periods of defocus are sufficient to counter the effects of much longer periods of hyperopic defocus, or emmetropic vision. While the variables of duration and frequency have been well-documented with regard to effect, we ask whether the efficacy of the exposures might also depend on the time of day that they are given. We also ask whether there are differential effects on the rhythms in axial length or choroidal thickness. 2-week-old chickens were divided into 2 groups: (1) "2-hr lens-wear". Chicks wore monocular +10D lenses for 2 h per day for 5 days at one of 3 times of day: 5:30 a.m. (n = 11), 12 p.m. (n = 8) or 7:30 p.m. (n = 11). (2) "2-hr minus lens-removal". Chicks wore monocular -10D lenses continually for 7 days, except for a 2-hr period when lenses were removed; the removal occurred at one of 2 times: 5:30 a.m. (n = 8) or 7:30 p.m. (n = 8). Both paradigms exposed eyes to brief myopic defocus that differed in its magnitude, and in the visual experience for the rest of the day. High frequency A-scan ultrasonography was done at the start of the experiment; on the last day, it was done at 6-hr intervals, starting at noon, over 24-hr, to assess rhythm parameters. Refractive errors were measured using a Hartinger's refractometer at the end. In both paradigms, myopic defocus in the evening was significantly more effective at inhibiting eye growth than in the morning ("2-hr lens-wear": X-C: -149 vs -83 μm/5d; "2-hr lens-removal": X-C: 91 vs 245 μm/7d; post-hoc Bonferroni test, p
- Subjects :
- 0301 basic medicine
medicine.medical_specialty
Evening
genetic structures
Emmetropia
Noon
Eye
Refraction, Ocular
Article
03 medical and health sciences
Cellular and Molecular Neuroscience
0302 clinical medicine
Optics
Rhythm
Ophthalmology
Myopia
medicine
Animals
Circadian rhythm
Morning
Rest (physics)
Choroid
business.industry
eye diseases
Sensory Systems
Circadian Rhythm
Axial Length, Eye
Disease Models, Animal
Eyeglasses
030104 developmental biology
Duration (music)
030221 ophthalmology & optometry
sense organs
Sensory Deprivation
business
Chickens
Subjects
Details
- ISSN :
- 00144835
- Volume :
- 154
- Database :
- OpenAIRE
- Journal :
- Experimental Eye Research
- Accession number :
- edsair.doi.dedup.....0779e5f93f60d27b7e58ce9fd9d68cd5