An optic-nerve tumor is a growth that forms right on or around the cable sending pictures from eye to brain. Because the space is tight, even a small bump can blur or blot out sight before any pain shows up.

The first warning is slow vision fade in one eye. Colors look washed-out, like someone turned down the saturation, and reading fine print takes longer than it used to.

Side chunks of sight disappear next. You miss cars on the left when pulling out, or the top shelf seems to vanish unless you tilt your head.

Straight lines may start to warp. Door frames look pinched in the center, or a phone screen appears bent like a fun-house mirror.

Flickers or flashes can pop up. Brief sparkles show at the corner of sight, often mistaken for migraine until they last for hours.

The eye may bulge slightly forward. Family notices one lid looks “bigger,” or you feel the eye is drier because it no longer closes fully at night.

Pain is usually mild or absent, but a dull ache behind the eye can grow when you move it to look far left or right.