What is a common cause of visual distortion in multifocal lenses?

Misalignment of the optical center relative to the pupil is a common cause of visual distortion in multifocal lenses. Multifocal lenses have multiple areas of vision correction—typically for distance, intermediate, and near vision—each positioned in specific segments of the lens. If the optical center does not align properly with the wearer's pupil, it results in a misalignment that can lead to visual distortions, blurriness, or an inability to focus properly when switching between different viewing areas.

This misalignment can occur due to improper fitting of the lenses, where the positioning of the frame does not correspond correctly to the individual eye measurements. As a result, when the wearer looks through a part of the lens that isn't aligned with their pupil, they experience distortion, leading to discomfort or difficulty seeing clearly. Correct alignment is crucial for the effectiveness of multifocal lenses, ensuring that the wearer can transition seamlessly between different visual zones without distortion.