The effect of image resolution of display types on accommodative microfluctuations.

Purpose: To determine whether accommodative microfluctuations (AMFs) are affected by the image resolution of the display type being observed. The effect of refractive error is also examined.

Methods: Twenty participants, (10 myopes and 10 emmetropes) observed a target on four different displays: paper, smartphone, e-reader and visual display unit screen (VDU), whilst their accommodative responses were measured using a continuous recording infrared autorefractor.

Blur adaptation: clinical and refractive considerations.

The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.

Cognitive Demand and Accommodative Microfluctuations.

Previous studies have shown cognition to have an influence on accommodation. Temporal variation in the accommodative response occurs during the fixation on a stationary target. This constantly shifting response has been called accommodative micro-fluctuations (AMFs).

Sensitivity of Chaos Measures in Detecting Stress in the Focusing Control Mechanism of the Short-Sighted Eye.

When fixating on a stationary object, the power of the eye's lens fluctuates. Studies have suggested that changes in these so-called microfluctuations in accommodation may be a factor in the onset and progression of short-sightedness. Like many physiological signals, the fluctuations in the power of the lens exhibit chaotic behaviour.

The effect of interrupted defocus on blur adaptation.

Purpose: Blur adaptation occurs when an observer is exposed to continuous defocus. However, it is unclear whether adaptation requires constant defocus, or whether the effect can still be achieved when the adaptation period is interrupted by short periods of clear vision.

Methods: The study included 12 emmetropes and 12 myopes.

Effect of correction of aberration dynamics on chaos in human ocular accommodation.

We used adaptive optics to determine the effect of monochromatic aberration dynamics on the level of chaos in the accommodation control system. Four participants viewed a stationary target while the dynamics of their aberrations were either left uncorrected, defocus was corrected, or all aberrations except defocus were corrected. Chaos theory analysis was used to discern changes in the accommodative microfluctuations.

The time course of blur adaptation in emmetropes and myopes.

Purpose/background: This study examined the effect of myopic defocus on visual acuity (VA) over time, with attention being paid to the first point at which blur adaptation had a significant and measurable effect on defocused VA. Visual acuity was sampled at a higher rate than previous studies in order to assess the time course of blur adaptation processes in myopic and emmetropic observers.

Methods: Participants were 24 normally-sighted observers (12 emmetropes and 12 myopes, median age: 22.

Effect of blur adaptation on human parafoveal vision.

Purpose: This study was conducted to investigate whether neural compensation for induced defocus can alter visual resolution in other areas of the human retina beyond the fovea. In certain circumstances, the blur adaptation response may be influenced by refractive status.

Methods: The effect of blur adaptation on the central 10° of the retina was investigated in 20 normally sighted observers (10 emmetropes and 10 myopes; median age, 21 years).

Simultaneous measurement of objective refraction, accommodation response and axial length of the human eye.

Purpose: Accurate measurements of ocular biometry and objective refraction are of vital importance to research laboratories working in the area of refractive error development and oculomotor function. A number of commercially available instruments can provide these measurements, and are used in both their intended modes, and with modifications to increase their research utility. A limitation that exists currently is the inability to conduct simultaneous measurements of refractive error or accommodation response, and the axial length of the same eye.

Dynamic accommodation responses following adaptation to defocus.

Purpose: Adaptation to defocus is known to influence the subjective sensitivity to blur in both emmetropes and myopes. Blur is a major contributing factor in the closed-loop dynamic accommodation response. Previous investigations have examined the magnitude of the accommodation response following blur adaptation.

Static accommodative responses following adaptation to differential levels of blur.

Purpose: To investigate the effects of two levels of blur adaptation on visual resolution and steady-state accommodation responses in emmetropes and myopes.

Methods: Eleven emmetropes (mean refractive error +0.01 +/- 0.

Effect of blur adaptation on blur sensitivity and discrimination in emmetropes and myopes.

Purpose: To determine whether blur adaptation influences blur sensitivity and blur discrimination thresholds in young adult myopes and emmetropes. In addition, to determine whether there is a differential effect of blur adaptation on blur sensitivity and discrimination between refractive error groups.

Methods: Proximal and distal blur sensitivity thresholds and blur discrimination thresholds were measured under cycloplegia with a Badal optometer in 24 young adult subjects (8 emmetropes [EMM], 8 early-onset myopes [EOM], and 8 late-onset myopes [LOM]).