Which type of amblyopia is caused by uncorrected astigmatism and persists even after the correction of that astigmatism?

• A. Meridional amblyopia
• B. Refractive amblyopia
• C. Strabismic amblyopia
• D. Anisometropic amblyopia

Answer: (A)

Meridional amblyopia arises when uncorrected astigmatism during development blurs input along a specific meridian. That persistent orientation-specific blur means the brain’s orientation-tuned neurons receive poorer stimulation for lines at that axis, so the visual system learns to process that orientation less effectively. Even after you correct the astigmatism later, those neural connections for that meridian may remain weakened, leaving a lasting reduction in acuity for lines oriented along that axis. Early correction helps prevent this by giving clear input across all orientations, whereas the other forms of amblyopia involve different causes—strabismus-related suppression or general refractive blur—without the same lasting, axis-specific neural deficits.