Anatomy of sight
Take the eye apart. Then borrow someone else’s.
Explode a 3D model of the human eye into its layers, then see this whole page the way people with cataracts, glaucoma, color blindness and a dozen other conditions see it.
If you can read this line easily at arm’s length, your near vision is doing fine today.
Part 1 · Anatomy
Take the eye apart
Drag to rotate. Pull the slider to separate the layers. Click any part, or its label, to learn what it does and which conditions affect it.
Parallel light meets at a single point on the retina.
Drag to rotate · Ctrl + scroll or pinch to zoom
The 3D model needs WebGL, which this browser has turned off. The parts list and the rest of the page still work.
Try it
Find your own blind spot
Close your left eye and stare at the cross with your right eye. Slowly move toward or away from the screen, somewhere around 30 to 50 cm. At one distance the dot vanishes: its image has landed on the optic disc, where there are no light sensors. Your brain fills the gap so smoothly you never notice it.
Part 2 · Conditions
Borrow someone else’s eyes
Pick a condition and this whole page, 3D eye included, is redrawn through it. Adjust severity in the bar at the bottom, hold Space to compare with normal vision, and press Esc to clear.
Part 3 · Test images
See the difference
Choose an image below and a condition on the right. Drag the divider to compare with normal vision, and move your pointer over the image to shift your gaze.