Mesopic microperimetry in Stargardt disease: Application and reliability.

Area of Science:

• Ophthalmology
• Clinical Trials
• Visual Electrophysiology

Background:

• Mesopic microperimetry (mMP) is a key functional outcome measure for Stargardt disease type 1 (STGD1) clinical trials.
• Assessing the test-retest variability of mMP is crucial for ensuring the reliability of trial results.

Purpose of the Study:

• To evaluate the test-retest variability of mesopic microperimetry (mMP) in patients with STGD1.
• To identify factors influencing mMP variability, including fixation stability and exam duration.

Main Methods:

• 115 eyes from 68 STGD1 patients in the STARTT trial underwent mMP testing using the MAIA microperimeter at two visits.
• Test-retest variability was assessed using Bland-Altman analyses and coefficients of repeatability (CoR).
• Mean sensitivity (MS) and pointwise sensitivity (PWS) were analyzed, along with fixation stability and exam duration.

Main Results:

• Mean sensitivity (MS) demonstrated lower variability (CoR: 3.53 dB) compared to pointwise sensitivity (PWS) (CoR: 12.69 dB).
• Increased variability was associated with longer test durations and higher fixation losses.
• Variability was lower in central regions and specific sensitivity ranges; no learning effect was observed.

Conclusions:

• Pointwise sensitivity (PWS) should be used cautiously due to high variability in STGD1 trials.
• Mean sensitivity (MS) offers better reliability but may obscure localized functional deficits.
• Optimizing test duration (≤450 seconds) and operator training are recommended to enhance mMP reliability.