Monocular hyperopic defocus and diurnal variations in axial length and choroidal thickness

Ranjay Chakraborty, S Read, Michael Collins

Research output: Contribution to conferenceAbstractpeer-review

Abstract

Purpose: To investigate the influence of monocular hyperopic defocus on the normal diurnal rhythms in axial length and choroidal thickness. Methods: Axial length and choroidal thickness measurements were collected approximately every 3 hours for 15 emmetropic young adults over three consecutive days, with the first measurement at ~9am and final measurement at ~9pm on each day. The natural diurnal rhythms with no defocus (Day 1 and 3) and with monocular hyperopic defocus (Day 2, -2.00 DS spectacle lens over the right eye) were examined. Results: Both axial length and choroidal thickness underwent significant diurnal changes on each of the three days (p<0.0001). The introduction of monocular hyperopic defocus on day 2, resulted in significant changes in the diurnal rhythms of both parameters (p<0.05). A significant increase in the amplitude (peak to trough) of change in axial length (mean increase, 0.016±0.004 mm) and choroidal thickness (mean increase, 0.012±0.003 mm) was observed with hyperopic defocus compared to the two ‘no defocus’ days. At the second measurement (mean time 12:10 pm) on the defocus day, the eye was significantly longer by 0.013±0.002 mm compared to the other two days (p<0.05). No significant difference was observed in the average timing of the peaks of diurnal rhythms in axial length (peak at 12:12 pm) and choroidal thickness (21:02 pm) over the three days. Conclusion: Diurnal changes in axial length and choroidal thickness in human eyes were significantly altered by monocular hyperopic defocus, but returned to normal upon removal of the defocus.
Original languageEnglish
Publication statusPublished - Sep 2012
Externally publishedYes
Event14th Scientific Meeting in Optometry and 8th Optometric Educators Meeting - University of Melbourne, Melbourne, Australia
Duration: 22 Sep 201224 Sep 2012

Conference

Conference14th Scientific Meeting in Optometry and 8th Optometric Educators Meeting
Abbreviated titleSEMO 2012
CountryAustralia
CityMelbourne
Period22/09/1224/09/12

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