Accommodation and visual discomfort: a laboratory, optometric and subjective analysis.

Area of Science:

• Ophthalmology and Vision Science
• Human Physiology
• Experimental Psychology

Background:

• Near-vision activities are linked to visual discomfort and potential accommodative dysfunction.
• Existing research on the relationship between visual discomfort and accommodation shows inconsistent findings.

Purpose of the Study:

• To investigate changes in the accommodative response before and after visual tasks designed to induce visual discomfort.
• To analyze objective and subjective measures of accommodation and discomfort.

Main Methods:

• Twelve healthy young adults (26 ± 3 years) performed five visual tasks with varying parameters (duration, viewing distance, vergence demand).
• Objective accommodation metrics (static and dynamic) were recorded before and after tasks.
• Subjective visual discomfort and optometric accommodation tests were also conducted.

Main Results:

• A two-hour task at 3.00 D accommodative demand (NV33) induced the most significant changes.
• Following NV33, accommodative response variability and time constant increased, while peak velocity decreased.
• Subjective visual discomfort scores significantly increased after the NV33 task, while optometric tests remained unchanged.

Conclusions:

• The NV33 task significantly altered objective measures of accommodation and subjective visual discomfort.
• Changes in accommodative response variability, time constant, and peak velocity may be linked to visual discomfort.
• The NV33 task serves as a valuable experimental model for studying visual discomfort.