Mordi John A, Ciuffreda Kenneth J
School of Optometry, Inter-American University, Hato Rey, Puerto Rico 00918, USA.
Vision Res. 2004 Mar;44(6):591-601. doi: 10.1016/j.visres.2003.07.014.
There has been no comprehensive study involving each of the primary dynamic components of accommodation in the same cohort as related to age and presbyopic onset; furthermore, the current findings are equivocal. Dynamic monocular components of accommodation (latency, time constant, peak velocity/amplitude relationship, and microfluctuations) were assessed objectively using an infrared optometer within the linear region of accommodation in 30 visually-normal human subjects aged 21-50 years. The time constant and the peak velocity/amplitude relationship did not change with age. However, latency progressively increased, and microfluctuation amplitude and frequency progressively decreased, with increasing age. The invariance in time constant suggests that the gross biomechanical aspects of the lens and related structures in the remaining linear region are relatively unaffected by age. In contrast, the decrease in microfluctuation activity with age suggests more subtle alterations in the biomechanical aspects of the lens to these very small perturbations, such as a response amplitude non-linearity. With respect to neurologic control, the progressive latency increase suggests a processing delay of the blur input, and this is consistent with age-related changes in reaction time measures. The lack of any age-related changes in the peak velocity/amplitude relationship implies normalcy of central and peripheral neuromotor control, as well as grossly normal first-order lens biomechanics, in this linear response region. The results are consistent with the Hess-Gullstrand theory of presbyopia.
尚未有研究在同一队列中全面涉及与年龄和老花眼发病相关的调节主要动态成分；此外，目前的研究结果并不明确。使用红外验光仪在30名年龄在21至50岁的视力正常的人类受试者的调节线性区域内客观评估调节的动态单眼成分（潜伏期、时间常数、峰值速度/幅度关系和微波动）。时间常数和峰值速度/幅度关系不随年龄变化。然而，随着年龄的增加，潜伏期逐渐增加，微波动幅度和频率逐渐降低。时间常数的不变性表明，晶状体和其余线性区域相关结构的总体生物力学方面相对不受年龄影响。相比之下，微波动活动随年龄的降低表明晶状体生物力学方面对这些非常小的扰动存在更细微的改变，例如反应幅度的非线性。关于神经控制，潜伏期的逐渐增加表明模糊输入的处理延迟，这与反应时间测量中与年龄相关的变化一致。峰值速度/幅度关系缺乏任何与年龄相关的变化意味着在这个线性反应区域中，中枢和外周神经运动控制正常，以及一级晶状体生物力学基本正常。这些结果与老花眼的赫斯 - 古尔斯特兰德理论一致。
