Objective concurrent measures of open-loop accommodation and vergence under photopic conditions

Area of Science:

• Ophthalmology
• Vision Science
• Neuroscience

Background:

• Accommodation and vergence are crucial for clear and single binocular vision.
• Understanding their interplay, especially under open-loop conditions, is vital for visual function.
• The influence of cognitive factors like mental effort on these systems is not fully elucidated.

Purpose of the Study:

• To examine the relationship between photopic open-loop accommodation and vergence.
• To investigate how mental effort affects these visual parameters.

Main Methods:

• Twenty participants viewed a Maltese cross target under photopic conditions through a pinhole.
• Objective measurements of accommodation and vergence were recorded using infrared optometry and eye tracking.
• Mental effort was imposed to assess its impact on passive and active visual states.

Main Results:

• A significant correlation was found between photopic open-loop accommodation and vergence under passive viewing (R = 0.671, P = 0.0012).
• Mental effort unsystematically shifted accommodation and vergence levels, with no significant correlation between these shifts (R = 0.259, P = 0.270).
• Active open-loop accommodation and vergence positions were also significantly correlated (R = 0.692, P = 0.0007).

Conclusions:

• Correlations between photopic open-loop accommodation and vergence are likely influenced by proximal stimuli.
• The uncoordinated response to mental effort suggests complex interactions with spatiotopic stimuli and perceived proximity.
• These findings highlight the distinct neural control mechanisms for passive and active visual states.