Centre for Vision and Eye Research, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Queensland, Australia.
Ophthalmic Physiol Opt. 2021 Jul;41(4):932-940. doi: 10.1111/opo.12833. Epub 2021 May 10.
To investigate the influence of brief, repeated periods of clear vision on the changes in axial length and choroidal thickness in response to short-term imposed defocus.
The right eye of 16 young adults was exposed to 60 min episodes of continuous and interrupted defocus conditions (+3 DS and -3 DS) over five separate sessions, with the left eye optimally corrected for distance. For interrupted defocus, 2 min episodes of clear vision were imposed before each 15 min episode of myopic or hyperopic defocus (2/15 min). For hyperopic defocus, the effect of frequency of clear vision exposure was also assessed by imposing 1 min of clear vision before each 7.5 min of defocus (1/7.5 min). The right eye axial length and choroidal thickness were measured before, during and after each defocus condition.
After 60 min of continuous hyperopic defocus the eye elongated significantly by +9 ± 9 μm (p = 0.02). When exposed to interrupted (2/15 min) hyperopic defocus, axial elongation was significantly reduced by 77% compared to continuous hyperopic defocus (p = 0.03), with a final change of only +2 ± 10 μm relative to baseline. During interrupted (1/7.5 min) hyperopic defocus, axial elongation reduced slightly compared to continuous hyperopic defocus (+6 ± 8 μm relative to baseline, p = 0.12). For continuous myopic defocus, a reduction in axial length occurred but was not statistically significant (p > 0.05). A similar pattern of response was observed for choroidal thickness changes with continuous and interrupted (1/7.5 min) hyperopic defocus conditions.
Brief periods of clear vision can diminish axial elongation and choroidal thinning induced by hyperopic defocus exposure in human eyes. If hyperopic defocus contributes to myopia progression in humans, then interruption with brief periods of clear vision could reduce its myopiagenic effects.
研究短暂、重复的清晰视觉期对短期离焦诱导的眼轴长度和脉络膜厚度变化的影响。
16 名年轻成年人的右眼在 5 个不同的时间段内分别暴露于连续和间断性离焦条件（+3DS 和-3DS）60 分钟，左眼经优化以矫正远距离视力。对于间断性离焦，在每个 15 分钟的近视或远视离焦（2/15 分钟）时段之前施加 2 分钟的清晰视觉期。对于远视离焦，还通过在每个 7.5 分钟的离焦（1/7.5 分钟）之前施加 1 分钟的清晰视觉来评估清晰视觉暴露频率的影响。在每个离焦条件之前、期间和之后测量右眼眼轴长度和脉络膜厚度。
连续 60 分钟的远视性离焦后，眼轴显著延长了+9±9μm（p=0.02）。当暴露于间断性（2/15 分钟）远视性离焦时，与连续远视性离焦相比，眼轴延长显著减少了 77%（p=0.03），与基线相比最终变化仅为+2±10μm。在间断性（1/7.5 分钟）远视性离焦期间，与连续远视性离焦相比，眼轴延长略有减少（相对于基线增加+6±8μm，p=0.12）。对于连续近视性离焦，眼轴长度减小，但无统计学意义（p>0.05）。对于脉络膜厚度的变化，也观察到了与连续和间断性（1/7.5 分钟）远视性离焦条件相似的反应模式。
短暂的清晰视觉期可以减少远视性离焦诱导的眼轴伸长和脉络膜变薄。如果远视性离焦对人类近视进展有贡献，那么通过短暂的清晰视觉期中断可能会降低其近视诱导作用。
