Light enters the eye through a thin membrane called

Light enters the human eye through a thin, transparent membrane known as the cornea [1]. The cornea forms a clear, dome-shaped bulge on the front surface of the eyeball [1][3]. Its primary function is to act as the eye's outermost lens, where most of the refraction (bending) of light rays occurs before they pass through the pupil [1]. While the iris is a muscular diaphragm that regulates the amount of light by adjusting the pupil's size, and the retina is the light-sensitive layer at the back that converts light into electrical signals, the cornea is the specific membrane through which light first enters [1][2]. The eyeball itself is approximately spherical with a diameter of about 2.3 cm, and the cornea serves as the initial 'window' for the visual system [1].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 10: The Human Eye and the Colourful World > 10.1 THE HUMAN EYE > p. 161
2. [3] https://www.nei.nih.gov/eye-health-information/healthy-vision/how-eyes-work
3. [2] Science , class X (NCERT 2025 ed.) > Chapter 10: The Human Eye and the Colourful World > 10.1 THE HUMAN EYE > p. 162