Visualising vision correction

I’ve been trying out contact lenses for the first time. Multi-focal lenses provide different focal lengths to the eye at once, and you can have different prescription lenses in each eye (as long as they don’t differ by too much).

This means the brain is getting signals from the eyes, each providing potentially multiple focal lengths, and learns to combine them to reduce blur. It’s interesting and I wanted to be able to visualise how that works, so I made this interactive simulator. It shows a heatmap (green is sharp, red is blurry) over distance, comparing uncorrected vision with modern multi-focal lenses. Try it out! All the calculations happen locally within your browser.