iPhone’s Grayscale filter switches the display to black and white and may ease eye strain, help people with some types of colorblindness or reduce distractions. Enable it in Settings > Accessibility > Display & Text Size > Color Filters, then select Grayscale.
For quicker access, add Color Filter to Control Center: open Control Center, tap Add a Control (or press and hold first if needed), search for “Color Filter” and select it. The Display & Text Size menu also offers text-size, contrast, color-inversion and bright-color intensity adjustments; some accessibility features can be set per app.
The article also suggests checking how close you are to the screen and following the 20-20-20 rule: after every 20 minutes of screen viewing, focus on an object 20 feet away for 20 seconds.
