Why small print gets blurry with age

The lens stops flexing

To focus on something close, the ciliary muscle in your eye squeezes the crystalline lens into a rounder shape. From your 20s onward that lens slowly hardens. By your 40s it can no longer round up enough for close work, and the near point retreats. This is presbyopia.

Why you hold things further away

Moving an object away reduces the focusing power required. Stretching your arms out is an unconscious workaround for a lens that cannot flex — and it stops working when your arms run out of length.

Why light makes such a difference

Bright light constricts the pupil, which increases depth of focus in the same way a small camera aperture does. That is why the same menu is readable by a window and hopeless in a dim restaurant. It is also why readers feel more necessary in the evening.

What does and does not help

• Helps: correct magnification for the distance you actually read at
• Helps: bright, even light on the page
• Helps: increasing text size on phones and e-readers
• Does not help: eye exercises, supplements, or waiting it out
• Does not help: squinting, which just fatigues the muscles

The fix, and the limit

Reading glasses restore the missing focusing power. If you switch between print, a screen and a room, graduated multifocal readers handle all three in one lens. But blur that arrives suddenly, affects one eye, or comes with pain or flashes is not presbyopia — that needs an eye exam, not glasses from a website.