Various refractive eye surgery techniques change the shape of the cornea in order to reduce the need for corrective lenses or otherwise improve the refractive state of the eye.

In many of the techniques used today, reshaping of the cornea is performed by photoablation using the excimer laser.

Orthokeratology is a method using specialized hard or rigid gas-permeable contact lenses to transiently reshape the cornea in order to improve the refractive state of the eye or reduce the need for eyeglasses and contact lenses.

Upon death or removal of an eye the cornea absorbs the aqueous humor, thickens, and becomes hazy. Transparency can be restored by putting it in a warm, well-ventilated chamber at 31 °C (88 °F, the normal temperature), allowing the fluid to leave the cornea and become transparent.

Transitions lenses are photochromic lenses that are clear until dangerous ultraviolet radiation (UV) is present. Once outdoors, the brighter the sun, the darker Transitions lenses become. They turn as dark as sunglasses by automatically reacting to the intensity of UV radiation.

In most instances, the person will meet with their ophthalmologist for an examination in the weeks or months preceding the surgery. During the exam, the ophthalmologist will examine the eye and diagnose the condition.

The doctor will then discuss the condition with the patient, including the different treatment options available.

The cornea is one of the most sensitive tissues of the body, as it is densely innervated with sensory nerve fibres via the ophthalmic division of the trigeminal nerve by way of 70–80 long ciliary nerves and short ciliary nerves. Research suggests the density of pain receptors in the cornea is 300-600 times greater than skin and 20-40 times greater than dental pulp, making any injury to the structure excruciatingly painful

The optical component is concerned with producing a reduced inverted image on the retina. The eye's optical system consists of not only two but four surfaces—two on the cornea, two on the lens.

Rays are refracted toward the midline. Distant rays, due to their parallel nature, converge to a point on the retina.

On 25 August 2010 investigators from Canada and Sweden reported results from the first 10 people in the world treated with the biosynthetic corneas. Two years after having the corneas implanted, six of the 10 patients had improved vision.

Nine of the 10 experienced cell and nerve regeneration, meaning that corneal cells and nerves grew into the implant.

In most instances, the person will meet with their ophthalmologist for an examination in the weeks or months preceding the surgery. During the exam, the ophthalmologist will examine the eye and diagnose the condition.

The doctor will then discuss the condition with the patient, including the different treatment options available.

The cornea is one of the most sensitive tissues of the body, as it is densely innervated with sensory nerve fibres via the ophthalmic division of the trigeminal nerve by way of 70–80 long ciliary nerves and short ciliary nerves. Research suggests the density of pain receptors in the cornea is 300-600 times greater than skin and 20-40 times greater than dental pulp, making any injury to the structure excruciatingly painful

The optical component is concerned with producing a reduced inverted image on the retina. The eye's optical system consists of not only two but four surfaces—two on the cornea, two on the lens.

Rays are refracted toward the midline. Distant rays, due to their parallel nature, converge to a point on the retina.

On 25 August 2010 investigators from Canada and Sweden reported results from the first 10 people in the world treated with the biosynthetic corneas. Two years after having the corneas implanted, six of the 10 patients had improved vision.

Nine of the 10 experienced cell and nerve regeneration, meaning that corneal cells and nerves grew into the implant.