Fluctuations in pupil size and lens accommodation are measured concurrently under open loop conditions, constant illumination and far fixation. In 12/17 trials no correlation was measured between the fluctuations in pupil size and lens accommodation. For the remaining 5/17 trials no lag was observed between the changes in pupil size and lens accommodation indicating that this correlation does n...

We determined the foveal Stiles-Crawford Effect as a function of up to 8 D accommodation stimulus in 6 young emmetropes and 6 young myopes using a psychophysical two-channel Maxwellian system in which the threshold luminance increment of a 1mm spot entering through variable positions in the pupil was determined against a background formed by a 4 mm spot entering the pupil centrally. The SCE bec...

Purpose: To determine the relationship between the high-frequency component of accommodative microfluctuation (HFC) and accommodative lag in presbyopic eyes and how they affect the subjective accommodation power with other ophthalmic factors, such as pupil diameter and corneal multifocality. Methods: Forty subjects (80 eyes) were included in this study, and the non-corrected distance and near v...

The aim of this study was to evaluate the accommodation response under both monoand polychromatic light while varying the amount of spherical aberration. It is thought that chromatic and spherical aberrations are directional cues for the accommodative system and could affect response time, velocity or lag. Spherical aberration is often eliminated in modern contact lenses in order to enhance ima...

We assessed the extent to which different accommodative functions are correlated and whether accommodative functions predict the refractive error or the progression of myopia over a 12 month period in 64 young adults (30 myopes and 34 non-myopes). The functions were: amplitude of accommodation; monocular and binocular accommodative facility (6 m and 40 cm); monocular and binocular accommodative...

PURPOSE To test the efficacy of a novel dual treatment for improving accommodative accuracy and dynamics in young persons with myopia. METHODS Ninety-three young persons with myopia (mean spherical equivalent, -3.0 +/- 1.8 D; age 16.8 +/- 2.1 years; spherical aberration +0.06 +/- 0.04 microm) participated in the study. Custom-designed soft contact lenses were used to alter ocular SA to -0.10 ...

AIMS To clarify the cerebellar control of accommodation in humans, the frequency characteristics of accommodation were studied in a patient with agenesis of the posterior cerebellar vermis and four age matched normal subjects. METHODS Magnetic resonance imaging of the brain of the 29 year old patient showed agenesis of the vermis and paravermis of lobules VIII-X and hypoplasia of the vermis a...

High order aberrations have been suggested to play a role in determining the direction of accommodation. We have explored the effect of retinal blur induced by high order aberrations on dynamic accommodation by measuring the accommodative response to sinusoidal variations in accommodative demand (1-3D). The targets were blurred with 0.3 and 1mum (for a 3-mm pupil) of defocus, coma, trefoil and ...

Dynamic correction of monochromatic aberrations of the eye is known to affect the accommodation response to a step change in stimulus vergence. We used an adaptive optics system to determine how the temporal location of the correction affects the response. The system consists of a Shack-Hartmann sensor sampling at 20 Hz and a 37-actuator piezoelectric deformable mirror. An extra sensing channel...