Microfluctuations in accommodation: an update on their characteristics and possible role

Area of Science:

• Ophthalmology
• Vision Science
• Physiological Optics

Background:

• Ocular accommodation is known to fluctuate, with microfluctuations (MFs) occurring at frequencies up to a few Hz.
• Research since 1988 has focused on understanding the characteristics and control mechanisms of these accommodative MFs.

Purpose of the Study:

• To review advancements in understanding the characteristics of ocular microfluctuations (MFs) since 1988.
• To explore the potential role of MFs in the control of the eye's accommodation.

Main Methods:

• Review of studies investigating the influence of stimulus form, luminance, vergence, pupil diameter, age, and ametropia on MFs.
• Analysis of research linking MFs to cardiopulmonary system, higher-order aberrations, and depth-of-focus.

Main Results:

• Understanding of MFs' dependence on observing conditions has improved.
• Links between MFs and factors like aberrations and depth-of-focus have been identified.
• Limited progress has been made in defining the role of MFs in accommodation control.

Conclusions:

• The influence of viewing conditions on MFs is well-understood, but their role in accommodation control requires further clarification.
• MFs may be more involved in maintaining accommodative responses than initiating them.
• Low-frequency MFs (<0.6 Hz) likely play a role in accommodation control, potentially by modulating retinal image contrast and spatial frequency.