Effects of brief periods of clear vision on the defocus‐mediated changes in axial length and choroidal thickness of human eyes

Delshad, Samaneh; Collins, Michael J.; Read, Scott A.; Vincent, Stephen J.

doi:10.1111/opo.12833

Cited by 13 publications

(14 citation statements)

References 51 publications

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“…Although recovery from light induced changes has not been documented previously in human subjects, studies have shown that young human eyes recover quickly from other optical stimuli (such as induced defocus). 65,66 Whether ocular changes quickly revert back to normal for higher intensity illumination levels and/or longer durations of light exposure (>2 h) warrants further research.…”

Section: Mean Change At 120 Min Of Light Exposure (Sem) (Mm)mentioning

confidence: 99%

Effects of mild‐ and moderate‐intensity illumination on short‐term axial length and choroidal thickness changes in young adults

Chakraborty

Baranton

Spiegel

et al. 2022

Ophthalmic Physiologic Optic

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Previous studies have shown that time spent outdoors is protective against myopia development in children. In this study, we examined the effects of 500 and 1000 lux of illumination to the eye on axial length (AL) and choroidal thickness (CT) changes in young adults.Methods: Fifteen participants (mean age, 21.60 years [2.16]) with a mean refraction of −0.34 D (0.37) were exposed to 500 and 1000 lux of illumination for 120 min in a dark room on two different days, using a pair of light-emitting glasses. Ocular measurements were repeated on an additional day in darkness (~5 lux). Ocular biometrics and CT were measured and analysed in the right eye before the light exposure (0 min), after 30, 60 and 120 min of exposure and 30 min after light offset to measure recovery using the Lenstar biometer and the Cirrus optical coherence tomographer, respectively.

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Section: Mean Change At 120 Min Of Light Exposure (Sem) (Mm)mentioning

confidence: 99%

Effects of mild‐ and moderate‐intensity illumination on short‐term axial length and choroidal thickness changes in young adults

Chakraborty

Baranton

Spiegel

et al. 2022

Ophthalmic Physiologic Optic

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“…The literature demonstrates the ability both to accelerate and retard axial growth in a range of species by imposing single vision, full‐field, relative hyperopic and myopic defocus 11–15 . In addition, several studies have demonstrated short‐term changes in axial length and choroidal thickness in response to hyperopic defocus in humans 16–20 . It seems plausible that these principles could be applied to children with hyperopia.…”

Section: Introductionmentioning

confidence: 99%

“… 11 , 12 , 13 , 14 , 15 In addition, several studies have demonstrated short‐term changes in axial length and choroidal thickness in response to hyperopic defocus in humans. 16 , 17 , 18 , 19 , 20 It seems plausible that these principles could be applied to children with hyperopia.…”

Section: Introductionmentioning

confidence: 99%

The effect of peripheral defocus on axial growth and modulation of refractive error in hyperopes

Beasley

Davies

Logan

2022

Ophthalmic Physiologic Optic

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To establish whether axial growth and refractive error can be modulated in hyperopic children by imposing relative peripheral hyperopic defocus using multifocal soft contact lenses. Methods:A prospective controlled study with hyperopic participants allocated to a control or test group. Control group participants were corrected with single vision spectacles and changes to axial length and refractive error were followed for 3 years. For the test group, axial growth and post-cycloplegic refractive error were observed with participants wearing single vision spectacles for the first 6 months of the trial and then corrected with centre-near multifocal soft contact lenses with a 2.00 D add for 2 years. The central 'near' portion of the contact lens corrected distance refractive error while the 'distance' portion imposed hyperopic defocus.Participants reverted to single vision spectacles for the final 6 months of the study.Results: Twenty-two participants, mean age 11.13 years (SD 1.72) (range 8.33-13.92), completed the trial. Axial length did not change during the first 6 months in either group (p = 1.00). Axial growth across the 2-year intervention period was 0.17 mm (SEM 0.04) (p < 0.0005) in the test group versus 0.06 mm (SEM 0.07) (p = 0.68) in the control group. Axial length was invariant during the final 6 months in either group (p = 1.00). Refractive error was stable during the first 6 months in both groups (p = 1.00). Refractive error change across the 2-year intervention period was −0.26 D (SEM 0.14) (p = 0.38) in the test group versus −0.01 D (SEM 0.09) (p = 1.00) in the control group. Neither the test (p = 1.00) nor control (p = 0.63) group demonstrated a change in refractive error during the final 6 months. Conclusions: The rate of axial growth can be accelerated in children with hyperopia using centre-near multifocal soft contact lenses. K E Y W O R D S axial growth, contact lenses, hyperopia, peripheral defocus, refractive error | 535 EFFECT OF DEFOCUS ON AXIAL GROWTH IN HYPEROPES F I G U R E 1 Schematic to demonstrate the concept of relative peripheral hyperopic defocus (RPHD) imposed with a centre-near bifocal contact lens (CL), while full refractive error is corrected centrally

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“…Interrupting hyperopic defocus has also shown to prevent or decrease myopia development in chickens 35 , guinea pigs 36 , tree shrews 37 , and rhesus monkeys 30 . Brief periods of clear vision can also diminish axial elongation induced by hyperopic defocus in human eyes 38 .…”

Section: Introductionmentioning

confidence: 99%

Temporal properties of positive and negative defocus on emmetropization

Zhu

Kang

Troilo

et al. 2022

Sci Rep

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Studying the temporal integration of visual signals is crucial to understand how time spent on different visual tasks can affect emmetropization and refractive error development. In this study we assessed the effect of interrupting positive and negative lens-imposed defocus with brief periods of unrestricted vision or darkness. A total of forty-six marmosets were treated monocularly with soft contact lenses for 4 weeks from 10 weeks of age (OD: + 5D or − 5D; OS: plano). Two control groups wore + 5D (n = 5) or − 5D (n = 13) lenses continuously for 9 h/day. Two experimental groups had lens-wear interrupted for 30 min twice/day at noon and mid-afternoon by removing lenses and monitoring vision while marmosets sat at the center of a viewing cylinder (normal vision interruption, + 5D: n = 7; − 5D: n = 8) or while they were in the dark (dark interruption, + 5D: n = 7; − 5D: n = 6). The interruption period (30 min/day) represented approx. 10% of the total stimulation time (9 h/day). On-axis refractive error (RE) and vitreous chamber depth (VCD) were measured using an autorefractor and high frequency A-scan ultrasound at baseline and after treatment. Wearing + 5D lenses continuously 9 h/day for 4 weeks induced slowed eye growth and hyperopic shifts in RE in treated relative to contralateral control eyes (relative change, VCD: − 25 ± 11 μm, p > 0.05; RE: + 1.24 ± 0.58 D, p > 0.05), whereas − 5D lens wear resulted in larger and myopic eyes (relative change, VCD: + 109 ± 24 μm, p < 0.001; RE: − 2.03 ± 0.56 D, p < 0.05), significantly different from those in the + 5D lens-treated animals (p < 0.01 for both). Interrupting lens induced defocus with periods of normal vision or darkness for approx. 10% of the treatment time affected the resulting compensation differently for myopic and hyperopic defocus. Interrupting defocus with unrestricted vision reduced − 5D defocus compensation but enhanced + 5D defocus compensation (− 5D, VCD: + 18 ± 33 μm; RE: − 0.93 ± 0.50 D, both p > 0.05; + 5D, VCD: − 86 ± 30 μm; RE: + 1.93 ± 0.50 D, both p < 0.05). Interrupting defocus with darkness also decreased − 5D defocus compensation, but had little effect on + 5D defocus compensation (− 5D, VCD: + 73 ± 34 μm, RE: − 1.13 ± 0.77 D, p > 0.05 for both; + 5D, VCD: − 10 ± 28 μm, RE: + 1.22 ± 0.50 D, p > 0.05 for both). These findings in a non-human primate model of emmetropization are similar to those described in other species and confirm a non-linear model of visual signal integration over time. This suggests a mechanism that is conserved across species and may have clinical implications for myopia management in school-aged children.

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Effects of brief periods of clear vision on the defocus‐mediated changes in axial length and choroidal thickness of human eyes

Abstract: Citation information: Delshad S, Collins MJ, Read SA, & Vincent SJ. Effects of brief periods of clear vision on the defocus-mediated changes in axial length and choroidal thickness of human eyes.

Cited by 13 publications

References 51 publications

Effects of mild‐ and moderate‐intensity illumination on short‐term axial length and choroidal thickness changes in young adults

Effects of mild‐ and moderate‐intensity illumination on short‐term axial length and choroidal thickness changes in young adults

The effect of peripheral defocus on axial growth and modulation of refractive error in hyperopes

Temporal properties of positive and negative defocus on emmetropization

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