Objective Verification of Physiologic Changes During Accommodation Under Binocular, Monocular, and Pinhole Conditions

Study Overview
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Brief Summary
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The investigators believe that this simple, clear, and objective study may be a great help in understanding the accommodative response during various accommodative stimulation conditions.

Detailed Description
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The purpose in this study was to investigate physiological changes in accommodative power, pupil diameter, astigmatic value, and axis when visual stimuli were applied under binocular, monocular (dominant eye, non-dominant eye, ipsilateral, and contralateral), and pinhole conditions using the WAM-5500 binocular autorefractor/keratometer (Grand Seiko Co. Ltd., Hiroshima, Japan).

Official Title
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Objective Verification of Physiologic Changes During Accommodation Under Binocular, Monocular, and Pinhole Conditions

Conditions
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Accommodation

Intervention / Treatment
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* Device: the WAM-5500 binocular autorefractor/keratometer (Grand Seiko Co. Ltd., Hiroshima, Japan)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age between 20 and 40 years spherical equivalent (SE) within ± 4.0 diopters (D) correctable distant and near visual acuity by glasses to 20/20 normal ocular alignment. Exclusion Criteria: disturbance of accommodation (e.g., Adie's pupil, Parkinson's disease, accommodative esotropia, accommodative spasm, presbyopia) disorders that can affect accommodation (e.g., history of ocular trauma, previous ocular surgery) disorders that might limit testing accuracy (e.g., corneal pathological features, cataract, glaucoma, vitreous opacity, and retinal abnormalities).

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: the WAM-5500 binocular autorefractor/keratometer (Grand Seiko Co. Ltd., Hiroshima, Japan)|: Subjects underwent a basic ophthalmic examination and the accommodative response to refractive stimuli was measured. Refractive stimuli were given at 0.25 diopters (D) (4 m distance), 2D (50 cm), 3D (33 cm), and 4D (25 cm) and stimulation was applied with the eyes in binocular, monocular (dominant eye, non-dominant eye, ipsilateral, and contralateral), and pinhole conditions. In addition, changes in the astigmatic value and direction of the astigmatism axis under binocular stimulus were evaluated.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Accommodative power | Accommodative powers in diopters were measured using WAM-5500 binocular autorefractor/keratometer | Subjects performed this examination while being under binocular, monocular, and pinhole conditions with one week apart in random order after baseline study | 
| Pupil diameter | Pupil diameters in millimeters were measured using WAM-5500 binocular autorefractor/keratometer | Subjects performed this examination while being under binocular, monocular, and pinhole conditions with one week apart in random order after baseline study | 
| Astigmatic value and axis change | Astigamtic value in diopters and axis change in degrees were measured using WAM-5500 binocular autorefractor/keratometer The spherical equivalent (sphere + 1/2 cylinder) was used to assess the response to refractive stimuli. The principal meridian of the cylinder for 0.25D refractive stimulus was set to the baseline axis. For 2D, 3D, and 4D refractive stimuli, vertical movement was determined when the baseline meridian moved to the 90' axis, and it was considered horizontal movement when it moved to the 0' or 180' axis. | Subjects performed this examination while being under binocular, monocular, and pinhole conditions with one week apart in random order after baseline study |