The translucent structure where the light enters eye is called the Aqueous Humour. The entire Eyeball it's self is covered by a thin clear layer called the Sclera.
The iris has an opening, called the pupil, through which light enters the eye.
The biconcave structure is the "lens, but his focuses the light, it does not adjust for the amount of light. The structure that adjusts for the amount of light entering the eye is the "iris"
Pupil.
Lens
As light enters the eye, it passes through the cornea and the lens and is eventually focused onto the retina.
Light rays enter the eye through the cornea.
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The retina
That is the correct spelling of translucent, meaning allowing a diffuse passage of light.
As light enters the eye, it strikes the receptor cells of the retina, called the rods and cones.
the retina! where else, it burns it and riuns your eye
lens