Optimisation of dark adaptation time required for mesopic microperimetry

Area of Science:

• Ophthalmology
• Visual Neuroscience

Background:

• Macular Integrity Assessment (MAIA) microperimetry assesses retinal sensitivity and fixation stability.
• Testing is typically performed under mesopic conditions following dark adaptation.

Purpose of the Study:

• Determine the minimum adaptation time for optimal MAIA microperimetry performance.
• Investigate the necessity of dark adaptation before mesopic microperimetry.

Main Methods:

• MAIA microperimetry (10-2 grid) was conducted on healthy participants and those with choroideremia.
• Adaptation times tested included 0, 5, 10, 15, 20, and 30 minutes after ambient or bright light exposure.
• Changes in threshold sensitivity and fixation stability were compared across adaptation durations.

Main Results:

• Microperimetry performance did not improve with adaptation time after ambient light exposure in either group.
• Following bright light exposure, threshold sensitivity improved after 10 minutes but showed no further gains at 20 minutes.
• No significant differences were observed in adaptation requirements between healthy individuals and those with choroideremia.

Conclusions:

• Mesopic adaptation is unnecessary before MAIA microperimetry post-ambient light exposure.
• Ten minutes of adaptation is adequate after bright light stimuli (e.g., ophthalmoscopy) for improved microperimetry.
• Findings support cone-mediated retinal function under mesopic conditions and suggest brief adaptation periods are sufficient.