As a follow-up to the previous report, #99-1: comparison of distance and near vision with PanOptix and PanOptix Pro in the same patient, we performed another important test, "contrast sensitivity," at 1 month after surgery, and report the results here.
What is contrast sensitivity?
A visual acuity test checks "how small a letter you can see," but in daily life it also matters how well you see in low-contrast situations, such as "faint print," "outlines in dark places," or "hazy scenery." The contrast sensitivity test puts this into numbers and allows an objective assessment of how well you see when driving at night or in dim rooms.
*The structure and design features of the PanOptix Pro are explained in detail in this article (Japanese).
This time, both eyes were measured with distance vision fully corrected by glasses. This removes the effect of postoperative power deviation (refractive error) so that the lenses' own performance can be compared fairly.
The graph below shows the results for both eyes under photopic (bright) conditions. The light green band shows the range of normal contrast sensitivity for people of the same age, and both eyes fall well within this normal range.
Contrast sensitivity is summarized in a single number, the AULCSF, shown at the bottom of the figure above. The larger this number, the better the contrast sensitivity, meaning better vision for faint print and in dark places. The AULCSF values were right eye PanOptix: 1.59 and left eye PanOptix Pro: 1.65, so the PanOptix Pro came out slightly ahead. In this graph, stripes become finer (harder to distinguish) toward the right, and points higher up mean fainter contrast (paler stripes) could be distinguished. In other words, the higher the blue line in the graph, the better the contrast sensitivity.
How should this be interpreted?
There is one important point here. To focus at several distances, "far, intermediate and near," multifocal lenses work by dividing the incoming light. As a result, they have a weakness: contrast sensitivity tends to be lower than with monofocal lenses, which focus at only one distance.
In this case, however, the left eye with the PanOptix Pro:
- stayed well within the normal range for people of the same age
- had higher contrast sensitivity than the right eye with the conventional PanOptix
We believe this objectively supports what we described in #99-1: the PanOptix Pro's "design that uses light without waste (94% light utilization)" and "design that halves the scattered light that causes flicker" improve near vision without sacrificing contrast sensitivity.
The patient herself felt that "the PanOptix Pro in my left eye is easier to see with at all distances," and these test results also support that.
Summary
- A comparison within the same patient, with the conventional PanOptix in the right eye and the PanOptix Pro in the left eye.
- Both eyes remained within the normal range for their age, with the PanOptix Pro slightly better.
Multifocal lenses involve a trade-off: the wider the range of focus (the easier near vision becomes), the more contrast sensitivity tends to fall. I consider the PanOptix Pro to be one of the multifocal lenses that can reduce dependence on glasses the most at present, as it achieves two things that have been hard to combine: better near vision and preserved contrast sensitivity.
Next time, we plan to report on contrast sensitivity under mesopic (twilight) and dark conditions and a comparison of intermediate vision.
2026.04.29