Exploring the Cornea: Understanding Its Function and Common Problems

Exploring the Cornea

What is Cornea?

The cornea is the foremost layer of the eye. It is the thin and transparent layer that reflects or bends light. It covers all the delicate parts of the eyes such as the pupil, iris, and anterior chamber. The cornea reflects the UV rays and saves the eye from other harmful particles such as dust and germs. However, the importance of the cornea in maintaining a clear vision cannot be forgotten.


Functions of Cornea

The outermost layer of our eye, the cornea has the following functions:

  • Refractive Function:

    The cornea is the eye’s primary refractive surface, bending and concentrating light rays as they enter the eye. This aids in the initial focus of light onto the retina, which is necessary for clear and crisp vision.

  • Protection:

    It serves as a shield, keeping dust, foreign particles, and bacteria out of the sensitive interior tissues of the eye. It also aids in the prevention of UV radiation damage.

  • Giving Shape to the Eyes:

    The curvature of the cornea contributes greatly to the formation of eye structure and offers structural support, which aids in the preservation of the eye’s spherical shape.

  • Transparency:

    Because of corneal transparency, light can pass through it unhindered. Transparency is important for clear eyesight because it allows light to reach the retina without distortion.

  • Obstruct UV Rays:

    The cornea can filter out some of the sun’s damaging ultraviolet (UV) radiations, giving an extra layer of protection to the eye.


Common Corneal Disorders

A corneal disorder or disease occurs when the cornea is affected or experiences any abnormalities. These problems can impact your vision and eye health. Some of the common corneal diseases are as follows:

  • Keratitis:

    Keratitis is the inflammation of the cornea that can be infectious (microbial) or noninfectious. A corneal ulcer is the medical term for infectious keratitis. Bacteria are the most common cause of infectious keratitis. Viruses, fungi, and parasites may also result in corneal infection. Noninfectious keratitis is caused by a variety of factors, including dry eye, exposure to irritants, or contact lens misuse.

  • Corneal Dystrophy:

    It is a group of genetic disorders that occurs due to the deposition of protein or fluids in the cornea. The adults are usually affected after the age of 40. The condition can worsen when the corneal dystrophy becomes progressive. It can also result in visual impairment. Fuchs’ dystrophy, lattice dystrophy, epithelial dystrophy, and granular corneal dystrophy are some of the corneal dystrophy.

  • Corneal Erosion:

    It refers to the condition when the outer layer of the cornea detaches from the underlying tissues. The condition is highly painful and recurrent and mostly impacts after waking up.

  • Corneal ectasia:

    It refers to a group of conditions that alter the shape of the cornea either by thinning or bulging it outward. Sometimes the condition arises after the eye surgery including the LASIK treatment or corneal transplant. In most cases, no symptoms are found. The extreme version of corneal ectasia can lead to the rise of corneal hydrops.

  • Corneal Abrasions:

    These are superficial corneal scratches or injuries produced by foreign objects, contact lenses, or trauma. They can be uncomfortable and cause impaired vision.

  • Keratoconjunctivitis:

    It is the condition where both the cornea and conjunctiva are affected. The condition is painful and requires immediate action.

  • Pterygium:

    It refers to the condition where there is a growth on the white part of the eye and it extends to the cornea.


Symptoms to look for corneal diseases

The symptoms of the different types of corneal disorders vary and depend on the specific eye condition. Some of the most common symptoms are as follows:

  • Eye pain (mild to severe)

  • Light Sensitivity

  • The sensation of something in the eyes.

  • Blurred vision.

  • Diminished vision over time

  • Red or bloodshot eyes.

  • Watery or teary eyes.

  • Increased pus discharge from your eyes.

These symptoms can indicate a variety of illnesses. That is why, if you are experiencing these symptoms, you should consult an eye care specialist.


What factors can cause corneal disease?

Some of the underlying factors that can cause the corneal infection are:

  • Bacterial, viral, or fungal infection can lead to damage to the cornea.

  • Improper usage of the contact lens including poor hygiene and extended wear.

  • Allergic reactions in the eye.

  • Genetic or heredity.

  • Refractive and complicated eye surgeries.

  • Exposure to chemicals.

  • Improper diet or lack of nutrition.


Treatments for Corneal Disorders

We specialize in evaluating and treating a wide range of eye conditions, including corneal ulcers, keratoconus, ocular trauma, chemical injuries, surface disorders such as dry eye, and ocular surface squamous neoplasia (OSSN), which includes tumors on both the conjunctival and corneal surfaces. Our primary goal is to provide complete examination and management for various vision-related disorders.

In addition to the corneal examination, we also provide major surgery to rectify corneal disorders such as

Refractive Surgeries

  • Bladeless LASIK (FEMTO LASIK)

  • Traditional (blade) LASIK

  • Trans PRK (No Touch Advanced Surface Ablation)

  • Phakic IOLS (ICL, IPCL)

  • Phototherapeutic Keratectomy

Corneal Transplantation

  • Full-thickness (PK)

  • Partial-thickness (DALK, DSEK, DMEK)

Ocular Surface Reconstruction

  • Mucous Membrane grafting (MMG)

  • Amniotic Membrane Transplantation (AMT)

  • Simple Limbal Epithelial Transplant (SLET)

  • Treatment for Symblepharon

  • Excision and surface reconstruction for OSSN (Ocular Surface Squamous Neoplasia)

  • Corneoscleral Tear Repairs


How to Prevent Corneal Disease?

Certain types of genetic disorders cannot be prevented but they can be constrained to a certain amount by following the underlying guidelines:

  • Use protective eye gear while working with chemicals or other hazardous products.

  • Follow proper guidelines and hygiene while wearing the contact lens.

  • Avoid sleeping with contact lenses, even though it is labelled with extended wear.

  • Do not share your eye makeup to combat the infection.

  • Be gentle while rubbing your eyes, as excessive rubbing can lead to corneal abrasions or irritation.

  • Stay hydrated to produce a proper amount of tear to get better corneal health.

  • Cultivate a good sleeping habit to give your eye proper rest.

The cornea is an important part of our eye. Any problem generated in the cornea can cause trouble to eye health. MM Joshi Eye Institute, Hubli is one of the best eye care hospitals that provides the best healthcare and helps to maintain a healthy eye for clear vision.


  • What are the common diseases of the cornea?

    Keratitis is one of the common diseases of the cornea. Some more corneal disorders include Corneal Dystrophies, Corneal Abrasions, Keratoconus, and Keratoconjunctivitis.

  • Where is the cornea located?

    The cornea is located at the front of the eye and covers the pupil and iris. It functions as a transparent, protective “window” that enables light into the eye, assisting in the focus of incoming light onto the retina at the back of the eye.

  • What is the size of the cornea?

    When viewed from the front, the cornea is typically 12 millimeters (mm) wide horizontally and 11 mm wide vertically. When viewed from behind, however, it appears spherical with a continuous diameter of approximately 11.7 mm. In comparison, the cornea is roughly two-thirds the size of a dime.

  • Can you see without a cornea?

    The cornea plays a crucial role in vision. Though it is a transparent structure covering the eye two-thirds of the eye focussing is done with the help of cornea. Therefore, it would not be possible for one to see without a cornea.