The cornea is an important refractive interstice of the eye, and under normal conditions, its refractive index is around 1.376. The cornea is located in the front part of the eye and is transparent and avascular. It is able to deflect incident light by refraction at a certain angle, which is called the angle of refraction, and the ratio of the sine of the angle of incidence to the sine of the angle of refraction is called the refractive index. The refractive index of the cornea is roughly 1.376, and the back surface is in contact with the aqueous humor, which has a refractive index of about 1.336. The refractive index of the cornea has a great impact on the refractive ability of the eye. When the cornea becomes cloudy due to inflammation, the refractive ability of the cornea decreases, and it will block the path of incoming light, resulting in a decrease in the patient’s vision, and the patient should seek medical treatment in a timely manner. It is recommended that patients with corneal anomalies seek prompt medical attention to evaluate their condition and follow the doctor’s instructions for treatment.