Solved cryptogram
Each eye has a blind spot where the optic nerve leaves, and your brain paints over the gap.
Biology Facts, sourced to National Eye Institute.
What it means
The nerve fibers gather and pass out through the back of the retina, and at that point there are no light sensitive cells at all. You never notice, partly because the two eyes cover different regions and partly because the visual system simply fills in the missing patch with whatever surrounds it. You can find your own with a pencil and a piece of paper in about a minute.
The claim comes from National Eye Institute, and the page it comes from was read on 2026-08-27 to confirm it still says this.
This is not the kind of claim that goes out of date, which is why it was set as a puzzle rather than a fact with a shelf life.
Solve it yourself
This fact is a cryptogram here: 72 letters over 19 different ones, graded medium.
- SourceNational Eye Institute
- CollectionBiology Facts
- Difficultymedium
- Length72 letters, 19 of them different
Nearby in the collection
The facts either side of this one.
- U.S. Geological Surveyhard, 66 letters
- National Eye Institutemedium, 73 letters
- NIDCDmedium, 68 letters
- NIDCDhard, 74 letters
About as hard as this one
Scored closest to it by the model behind our guide to solving cryptograms.
- MedlinePlusmedium, 69 letters
- MedlinePlusmedium, 68 letters
- NCBI Bookshelfmedium, 79 letters
- NHLBImedium, 74 letters