July 2019
Volume 60, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2019
Effects of short-term imposed optical defocus on central and peripheral eye length and choroidal thickness in healthy subjects.
Author Affiliations & Notes
  • Ingrid Ornella Mekountchou Koumbo
    The Brien Holden Vision Institute, Sydney, New South Wales, Australia
    School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
  • Fabian Conrad
    The Brien Holden Vision Institute, Sydney, New South Wales, Australia
    School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
  • Padmaja Sankaridurg
    The Brien Holden Vision Institute, Sydney, New South Wales, Australia
    School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
  • Klaus Ehrmann
    The Brien Holden Vision Institute, Sydney, New South Wales, Australia
    School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
  • Footnotes
    Commercial Relationships   Ingrid Mekountchou Koumbo, None; Fabian Conrad, None; Padmaja Sankaridurg, None; Klaus Ehrmann, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 4339. doi:https://doi.org/
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      Ingrid Ornella Mekountchou Koumbo, Fabian Conrad, Padmaja Sankaridurg, Klaus Ehrmann; Effects of short-term imposed optical defocus on central and peripheral eye length and choroidal thickness in healthy subjects.. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4339. doi: https://doi.org/.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Changes in human choroidal thickness, eye length and accommodative responses have been reported in response to short-term exposure to optical defocus. This study presents preliminary data on the effects of monocular short-term optical defocus on central and peripheral eye length, choroidal thickness and accommodative responses.

Methods : Over 3 separate occasions, the right eyes of 10 healthy young subjects were exposed to 30 min of continuous optical defocus (+3.00D and -3.00D) and a multifocal centre distance lens (Plano/+2.50D addition) over their optimal correction (worn bilaterally). Eye length (HS Lenstar LS900) and choroidal thickness (DRI Triton OCT, Topcon) were measured at central and peripheral locations upto 20° field angles. The three visits were scheduled at the same time of the day. At each visit, measurements were taken before (two baselines (BL1, BL2); 30 minutes apart) and after exposure (EXP). The defocus lens was inserted after BL2. Accommodative response to a 4.00D stimulus was determined following each measurement session. Between measurements, subjects watched a movie at a 4m distance under normal indoor lighting conditions.

Results : With the exception of central eye length with -3.00D defocus (12µm ±12.3µm increase, p = 0.013) none of the defocus conditions caused a statistically significant change in EL (all p > 0.05). Choroidal thickness exhibited a small increase with +3.00D in the inferior fields (p= 0.039 for 10° and p=0.032 for 20°) and with the multifocal lens in the superior field at 20° (p=0.013). There were no changes in the accommodative responses before and after optical defocus. In addition, we evaluated the changes between the two baselines sessions and we found no significant changes, except at 10° inferior and 20° superior/temporal in eye length and at 10° temporal in choroidal thickness values.

Conclusions : Overall, the observed changes in central and peripheral eye length and choroidal thickness following imposed optical defocus were small and not consistent. There were no changes in accommodative response following imposed defocus. Moreover, the changes observed between the 2 baselines suggest that there may also be short-term fluctuations in physiological conditions that need to be accounted for when considering the effect of optical defocus.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

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