What kind of wave is in the retina eye detect light and send signals to brain?

Electromagnetic waves.

The retina is a thin, light-sensitive layer of tissue that lines the back of the eye. It contains millions of photoreceptor cells called rods and cones, which convert light into electrical signals that are then sent to the brain through the optic nerve.

Electromagnetic waves are a type of energy that can travel through space and matter. They include light waves, radio waves, and microwaves.

Visible light is the part of the electromagnetic spectrum that humans can see. The retina detects light waves and sends signals to the brain that are interpreted as images.