Evaluation of fixation characteristics in amblyopia using microperimetry

Area of Science:

• Ophthalmology
• Neuroscience
• Vision Science

Background:

• Amblyopia, or lazy eye, is a developmental disorder affecting visual acuity.
• Fixation stability, crucial for clear vision, is often impaired in amblyopic individuals.
• Macular integrity assessment (MAIA) microperimetry offers a detailed evaluation of visual function.

Purpose of the Study:

• To assess fixation characteristics in amblyopic eyes using MAIA microperimetry.
• To identify factors influencing fixation stability in amblyopia.
• To compare fixation patterns between amblyopic and non-amblyopic eyes.

Main Methods:

• A prospective, cross-sectional study involving 58 amblyopic patients (ages 8-55).
• Evaluation of average threshold macular sensitivity (AT) and fixation stability using MAIA microperimetry.
• Quantification of fixation stability via bivariate contour ellipse area (BCEA) indices and percentage of fixation points (P1, P2) near the fovea.

Main Results:

• Amblyopic eyes exhibited significantly worse AT and fixation stability indices compared to fellow eyes (p < 0.05).
• Moderate positive correlations were found between best-corrected visual acuity (BCVA) and AT/P2, and moderate negative correlations with BCEA indices.
• 48% of amblyopic eyes showed eccentric fixation, with higher rates in strabismic and combined groups; a negative correlation existed between fixation eccentricity and BCVA (r = -0.327, p = 0.012).

Conclusions:

• Amblyopic eyes demonstrate reduced fixation stability and increased eccentric fixation.
• Fixation stability and BCVA are positively correlated, while eccentric fixation is negatively correlated with BCVA.
• MAIA microperimetry is valuable for quantifying fixation deficits in amblyopia.