As light waves enter the eye, which three structures do they pass through first?

As light enters to the eye, it would pass first through three (3) structures or main layers/tunics:

1. Fibrous tunic - outermost layer of the eye. Consists of cornea and sclera which gives the eye white color and protect the inner parts of the eye.

2. Vascular tunic - middle layer of the eye. Consists of iris and choroid which gives the dark color of the eye and inhibits disorderly reflections inside the eye.

3. Nervous tunic - inner layer of the eye. Consist of retina which is responsible for vision