Purpose

Accommodative micro-fluctuations (AMF) are small dioptric changes during accommodation. The aim of this study was to evaluate and compare changes in AMF when wearing silicone hydrogel contact lenses of two different optical designs.

Methods

A multi-centre, randomised, cross-over, non-dispensing study was conducted on 68 adapted contact lens wearers aged 25–35 years to compare AMF responses to a spherical and aspheric silicone hydrogel (comfilcon A) lens designs. A Righton Speedy “i” series Auto Refractometer in accommodation analyser mode was utilized before and after reading a standard text in font size 8 on an iPhone 5 for 20 min at a 25 cm viewing distance. Phone screen brightness was set by automatic adjustment mode and ambient illumination was controlled at all sites.

Results

Mean ± SD AMF change from before to after the reading task was 2.25 ± 5.6 and 0.13 ± 5.7 (relative values) for the spherical and aspheric lens designs, respectively. The difference was statistically significant (P = 0.017, Paired t-test).

Conclusions

The smaller change in AMF when using an aspheric lens design suggests reduced ciliary muscle stress when reading print on a smart phone at a close distance for short periods (20 min). Contact lens wearers who frequently use digital devices and are experiencing eye strain may benefit from switching from a spherical design to one that incorporates aspheric optics.

中文翻译：

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佩戴不同光学设计的隐形眼镜后调节性微波动的变化。

目的

调节微波动 (AMF) 是调节过程中的小的屈光度变化。本研究的目的是评估和比较佩戴两种不同光学设计的硅水凝胶隐形眼镜时 AMF 的变化。

方法

一项多中心、随机、交叉、非配药研究对 68 名 25-35 岁的隐形眼镜佩戴者进行了比较，以比较 AMF 对球形和非球形硅水凝胶 (comfilcon A) 镜片设计的反应。在 iPhone 5 上阅读字体大小为 8 的标准文本之前和之后，在 25 厘米的观看距离下使用 Righton Speedy “i”系列自动折光仪在适应分析仪模式下阅读 20 分钟。手机屏幕亮度由自动调节模式设置，所有站点的环境照明都受到控制。

结果

对于球面和非球面透镜设计，阅读任务前后的平均 ± SD AMF 变化分别为 2.25 ± 5.6 和 0.13 ± 5.7（相对值）。差异具有统计学意义（P  = 0.017，配对t检验）。

结论

使用非球面镜片设计时 AMF 的较小变化表明，在短时间（20 分钟）近距离阅读智能手机上的印刷品时，睫状肌压力降低。经常使用数字设备并且眼睛疲劳的隐形眼镜佩戴者可能会受益于从球面设计切换到包含非球面光学元件的设计。