Influence of the time of day on axial length and choroidal thickness changes to hyperopic and myopic defocus in human eyes

dc.contributor.author Moderiano, Daniel en_US
dc.contributor.author Do, Michelle en_US
dc.contributor.author Hobbs, Sam en_US
dc.contributor.author Lam, Vy en_US
dc.contributor.author Sarin, Simran en_US
dc.contributor.author Alonso-Caneiro, David A en_US
dc.contributor.author Chakraborty, Ranjay en_US
dc.date.accessioned 2019-04-26T03:01:32Z
dc.date.available 2019-04-26T03:01:32Z
dc.date.issued 2019-03-26
dc.description © 2019 Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 12 month embargo from date of publication (March 2019) in accordance with the publisher’s archiving policy en_US
dc.description.abstract Research in animal models have shown that exposing the eye to positive or negative spectacle lenses can lead to predictable changes in eye growth. Recent research indicates that brief periods (1–2 h) of monocular defocus results in small, but significant changes in axial length and choroidal thickness of human subjects. However, the effects of the time of day on these ocular changes with defocus are not known. In this study, we examined the effects of monocular myopic and hyperopic defocus on axial length and choroidal thickness when applied in the morning (change between 10 a.m. and 12 p.m.) vs the evening (change between 5 and 7 p.m.) in young adult human participants (mean age, 23.44 ± 4.52 years). A series of axial length (using an IOL Master) and choroidal thickness (using an optical coherence tomographer) measurements were obtained over three consecutive days in both eyes. Day 1 (no defocus) examined the baseline ocular measurements in the morning (10 a.m. and 12 p.m.) and in the evening (5 and 7 p.m.), day 2 investigated the effects of hyperopic and myopic defocus on ocular parameters in the morning (subjects wore a spectacle lens with +3 or −3 DS over the right eye and a plano lens over the left eye between 10 a.m. and 12 p.m.), and day 3 examined the effects of defocus in the evening (+3 or −3 DS spectacle lens over the right eye between 5 and 7 p.m.). Exposure to myopic defocus caused a significant reduction in axial length and thickening of the subfoveal choroid at both times; but, compared to baseline data from day 1, the relative change in axial length (−0.021 ± 0.009 vs +0.004 ± 0.003 mm, p = 0.009) and choroidal thickness (+0.027 ± 0.006 vs +0.007 ± 0.006 mm, p = 0.011) with defocus were significantly greater for evening exposure to defocus than for the morning session. On the contrary, introduction of hyperopic defocus resulted in a significant increase in axial length when given in the morning (+0.026 ± 0.006 mm), but not in the evening (+0.001 ± 0.003 mm) (p = 0.047). Furthermore, hyperopic defocus resulted in a significant thinning of the choroid (p = 0.005), but there was no significant influence of the time of day on choroidal changes associated with hyperopic defocus (p = 0.672). Exposure to hyperopic and myopic defocus at different times of the day was also associated with changes in the parafoveal regions of the choroid (measured across 1.5 mm nasal and temporal choroidal regions on either side of the fovea). Our results show that ocular response to optical defocus varies significantly depending on the time of day in human subjects. These findings represent a potential interaction between the signal associated with the eye's natural diurnal rhythm and the visual signal associated with the optical defocus, making the eye perhaps more responsive to hyperopic defocus (or ‘go’ signal) in the morning, and to myopic defocus (or ‘stop’ signal) in the latter half of the day. en_US
dc.identifier.citation Moderiano, D., Do, M., Hobbs, S., Lam, V., Sarin, S., Alonso-Caneiro, D., & Chakraborty, R. (2019). Influence of the time of day on axial length and choroidal thickness changes to hyperopic and myopic defocus in human eyes. Experimental Eye Research, 182, 125–136. https://doi.org/10.1016/j.exer.2019.03.019 en_US
dc.identifier.doi https://doi.org/10.1016/j.exer.2019.03.019 en_US
dc.identifier.issn 0014-4835
dc.identifier.uri http://hdl.handle.net/2328/39153
dc.language.iso en en_US
dc.publisher Elsevier en_US
dc.rights © 2019 Elsevier Ltd. en_US
dc.rights.holder Elsevier Ltd. en_US
dc.rights.license CC-BY-NC-ND
dc.subject Hyperopic defocus en_US
dc.subject Myopic defocus en_US
dc.subject Time of day en_US
dc.subject Axial length en_US
dc.subject Choroidal thickness en_US
dc.subject Myopia en_US
dc.title Influence of the time of day on axial length and choroidal thickness changes to hyperopic and myopic defocus in human eyes en_US
dc.type Article en_US
local.contributor.authorOrcidLookup Chakraborty, Ranjay: https://orcid.org/0000-0001-8850-1907 en_US
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