Provide a valuable resource to your clients or customers by linking to this resource page. Just place the following link on your website.
Image jump is the abrupt displacement of an image when the line of sight moves across the distinct dividing line in a bifocal lens. This optical effect makes objects appear to suddenly shift or "jump" as the eye moves from the distance segment to the near segment of the lens.
read more about an image jump ...Image jump occurs because the optical center of the near-vision segment is not aligned with the dividing line. When the pupil crosses this line, the eye encounters a sudden change in both magnification and prismatic power. This abrupt power shift causes the image to appear to move vertically.
Image jump is specific to lenses with a hard segment line that separates the power zones.
This effect is present in older-style lined bifocal and trifocal lenses. It is most noticeable when the wearer looks down at a curb, a step, or when shifting quickly from a far object to a nearby one. It can create momentary disorientation.
Modern multifocal lenses, such as progressive lenses, have no visible line. The vision correction changes gradually across the lens surface. This design eliminates the sudden power change at the segment line, resulting in a smooth transition between focus distances.
No, but it can cause disorientation or affect balance until the wearer adapts.
No, the smooth, line-free design of progressive lenses removes the cause of image jump.
Some people prefer the full, clear width of the reading area provided by a lined bifocal segment.
If you feel dizzy or lose your balance when looking down through your bifocals, ask your optician about lowering the bifocal line or switching to a "flat-top" design. This can minimize the sudden displacement of images as your eye crosses the segment line.
The Vision Council. Bifocal and Trifocal Lenses (thevisioncouncil.org). 2024.
Review of Optometry. Management of the Presbyope (reviewofoptometry.com). 2023.
ABDO. Image Jump in Multifocal Lenses (abdo.org.uk). 2024.
College of Optometrists. Ophthalmic Lens Design (college-optometrists.org). 2024.