The cornea possesses remarkable optical properties, primarily characterized by its high transparency and specific refractive index, which are crucial for focusing light onto the retina.
Key Optical Characteristics of the Cornea
Based on the provided reference, the main optical properties of the cornea include:
- High Transparency: The cornea is described as highly transparent. This essential property allows light to pass through unobstructed, enabling vision.
- High Transmission Rate: It exhibits a transmission rate above 95% in the spectral range of 400-900 nm. This covers the visible light spectrum and a portion of the near-infrared, ensuring most incoming light reaches the interior of the eye.
- Structural Basis for Transparency: This high transparency is attributed to the orderly arrangement of collagen fibrils within the corneal tissue.
- Refractive Index: The refractive index of the cornea is approximately n ≈ 1.3765 ± 0.0005. This precise index is vital for bending light rays as they enter the eye, contributing significantly to the eye's overall refractive power.
While the reference also mentions that the amount of light reaching the retina is regulated by the pupil size (varying between 1.5 mm and 8 mm), this refers to the function of the iris and pupil, not an intrinsic optical property of the cornea itself. However, it highlights how the light transmitted through the cornea is subsequently controlled before reaching the light-sensitive cells of the retina.
These specific optical properties make the cornea the primary refractive surface of the eye, playing a critical role in clear vision.
