J Korean Med Sci.  2019 Jan;34(4):e32. 10.3346/jkms.2019.34.e32.

Objective Verification of Physiologic Changes during Accommodation under Binocular, Monocular, and Pinhole Conditions

• Park H
• Park IK
• Shin JH
• Chun YS

• KMID: 2432109
• DOI: http://doi.org/10.3346/jkms.2019.34.e32

Abstract

BACKGROUND
To objectively investigate accommodative response to various refractive stimuli in subjects with normal accommodation.
METHODS
This prospective, non-randomized clinical trial included 64 eyes of 32 subjects with a mean spherical equivalent −1.4 diopters (D). We evaluated changes in accommodative power, pupil diameter, astigmatic value, and axis when visual stimuli were applied to binocular, monocular (dominant eye, non-dominant eye, ipsilateral, and contralateral), and pinhole conditions. Visual stimuli were given at 0.25 D (4 m), 2 D (50 cm), 3 D (33 cm), and 4 D (25 cm) and accommodative response was evaluated using open view binocular autorefractor/keratometer.
RESULTS
The accommodative response to binocular stimulus was 90.9% of the actual refractive stimulus, while that of the monocular stimulus was 84.6%. The binocular stimulus induced a smaller pupil diameter than did the monocular stimulus. There was no difference in accommodative response between the dominant eye and non-dominant eye or between ipsilateral and contralateral stimuli. As the refractive stimuli became stronger, the absolute astigmatic value increased and the direction of the astigmatism axis became more horizontal. Pinhole glasses required 10%-15% less accommodative power compared with the monocular condition.
CONCLUSION
Binocular stimuli enable more precise and effective accommodation than do monocular stimuli. Accommodative response is composed of 90% true accommodation and 10% pseudo-accommodation, and the refractive stimulus in one eye affects the contralateral eye to the same extent. This should be taken into account when developing guidelines for wearing smart glasses while driving, as visual stimulation is applied to only one eye, but far distance attention is constantly needed. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03557346

Keyword

Accommodation; Astigmatism; Pinhole; Pupil Diameter

MeSH Terms

Astigmatism
Eyeglasses
Glass
Non-Randomized Controlled Trials as Topic
Photic Stimulation
Prospective Studies
Pupil
Telescopes*