About Corneal Diseases

What Is The Cornea?

The cornea is the inclined transparent layer, which is located at the front of the eye. It has the task of focusing the light and protecting the eye from external factors and plays a major role in the function of vision.

What are the cornea examination methods?

A person who is not an ophthalmologist can evaluate corneal transparency, surface brightness, corneal injuries, and corneal sensitivity with the help of a cotton swab with local light. Ophthalmologists use some devices to evaluate corneal morphology and function:

• Biomicroscopy: It is useful for binocular examination of the cornea and other structures of the anterior segment. Light beams of different thicknesses are sent from different angles, allowing the slit-lamp to be magnified and the cornea can be examined. It is the most commonly used examination method.
• Keratometry: It is the measurement of the refractive power of the cornea. It is used before contact lens and intraocular lens implantation.
• Topography: It is used in the topographic analysis of the anterior surface of the cornea.
• Pachymetry: It is the measurement of corneal thickness.
• Specular microscopy: It shows the endothelial cell number and structure.
• Estesiometry: It is useful for the evaluation of corneal sensitivity.
• Examination of the cornea by staining: Defects on the corneal surface can be seen with a "fluorescein and rose bengal" solution.

Corneal scratches

The cornea is the oblique, transparent layer of the eye that is located in front of the eye. Its task is to focus light and protect the eyes from external factors, and it also plays an important role in the function of vision. Corneal scratches can occur for many reasons. Factors such as impact, prolonged wearing of contact lenses, not removing the lens during sleep, and excessive pressure on the eye negatively affect the stratum corneum. These effects are manifested by symptoms such as burning, stinging, and increased sensitivity of the eyes. If these symptoms appear, an eye examination is recommended.

Corneal scratch symptoms

• Increased eye sensitivity
• Intense pain and burning in the eye
• Hemorrhage and tearing in the eyes
• Blurred vision

In case of injuries, scratches, and hemorrhages of the cornea, a detailed microscopic examination of the eye should be performed. If these symptoms appear, it is recommended to consult an ophthalmologist.

Symptoms of corneal thinning

Corneal thinning is a condition in which the normal thickness of the cornea is reduced. This condition is often associated with an eye disease known as keratoconus.

Keratoconus is a condition in which there is thinning of the cornea, mainly in the upper central part. In this case, the cornea loses its ball shape and acquires a more pointed shape. The thinning of the cornea prevents light from focusing on the eye and causes blurred vision.

Keratoconus usually occurs in people between the ages of 10 and 25 and is associated with various factors such as genetic factors or allergies. Symptoms of corneal thinning include blurred vision, increased sensitivity to light, scratchy sensations in the eyes, and ill-fitting glasses or lenses.

Corneal thinning is an eye disease that often goes unnoticed. However, in advanced cases, the following symptoms may occur:

• Blurred or altered vision: thinning of the cornea causes light to not focus properly on the eye, which can lead to poor vision.
• Sensitivity to light: Increased sensitivity to light or eye pain is another sign of corneal thinning.
• Scratching sensation in the eye: A scratching or cutting sensation in the eye is another symptom of corneal thinning.
• Headache: People with corneal thinning may have headaches.
• Changes in glasses or contact lenses: As corneal thinning progresses, glasses or contact lenses may not fit properly.

Symptoms of corneal thinning can vary depending on the rate of progression and the severity of the disease. In the case of corneal thinning, early diagnosis is very important for successful treatment.

Corneal rupture symptoms

A corneal tear is a damage to the eye caused by a tear or cut in the surface of the cornea. Corneal rupture symptoms:

• Pain: A corneal tear usually causes pain. Eye pain can be severe and worse with eye movements.
• Lachrymation: A tear in the cornea can cause lacrimation. Lachrymation in the eye is a defense mechanism to clear objects that damage the surface of the eye.
• Eye redness: A corneal tear can cause redness in the eyes. Redness is a sign of inflammation in the eye.
• Sensitivity to light: People with corneal tears may be sensitive to light. This means that light entering the eye can cause more pain.
• Blurred vision: People with a corneal tear may have blurred vision. This means that the cornea cannot focus correctly.

If you suspect a corneal rupture, you should immediately contact an ophthalmologist.

About corneal surgery

Corneal surgery is performed to restore the clarity of vision, impaired for various reasons. These causes may include conditions such as corneal lesions, corneal spots, corneal ulcers, corneal protrusion, and keratoconus.

Corneal surgery can be performed using various methods. These include methods such as LASIK, PRK, LASEK, femtosecond laser corneal surgery, and intraocular lens implantation. Which method will be used is decided depending on the structure of the patient's cornea and the goals of the operation.

After the corneal surgery, the patient is bandaged over the eye for several days. The recovery period after surgery can vary from person to person but usually ranges from a few days to a few weeks. Postoperative symptoms such as pain, discomfort, sensitivity to light, and blurred vision are normal.

Corneal surgery can be a risky procedure and, like any surgical procedure, comes with some risks. These risks include infections, loss of vision, changes in the shape of the cornea, and reduced visual acuity. However, when performed correctly, corneal surgery can be a very effective method of correcting vision problems in patients.

Frequently Asked Questions

Is the cornea renewed?

Unlike many other tissues, the cornea is a tissue capable of self-renewal. Corneal cells are formed by a layer of tissue called the corneal stroma, which is located under the epithelial layer, which, in turn, is constantly renewed.

The corneal stroma is composed of collagen fibrils and cells. This structure helps the corneal cells to regenerate naturally. When corneal cells are damaged or diseased, they are stimulated by proteins produced by the corneal stroma and growth factors, and cell regeneration begins.

However, when the cornea becomes damaged or ill, it cannot fully recover. In some cases, depending on the extent and type of damage to the cornea, the self-renewal process may not be sufficient. Therefore, surgery may be required for certain diseases and injuries of the cornea.

Thus, the cornea can regenerate, but this ability may be limited depending on the degree and type of damage to the cornea.

What is the corneal reflex?

The corneal reflex is a test used by ophthalmologists and neurologists. This test is done to evaluate the sensitivity of a person's cornea (the outer layer of the eye). The cornea is the outermost transparent layer of the eye and the protective layer that surrounds the eye.

A corneal reflex test is performed by a doctor by touching the cornea under the eyelid with a cotton swab or sterile swab. This touch causes the eye muscles to contract for a short time. This contraction is called the "corneal reflex".

The corneal reflex should normally be present in both eyes. This test can also be used to evaluate a person's brain function and the health of their nervous system. The corneal reflex can also be used in particular in people with neurological disorders and traumatic brain injuries.

How thick should the cornea be?

The thickness of the cornea can vary from person to person and is usually between 0.5 and 0.6 mm. However, in some people, the thickness of the cornea may be thinner or thicker. The thickness of the cornea is important when measuring intraocular pressure because the thickness of the cornea can affect the measurement of intraocular pressure.

Intraocular pressure is the fluid pressure inside the eye and is important for eye health. High intraocular pressure can damage the optic nerves and cause vision loss. Measurement of intraocular pressure is made taking into account the thickness of the cornea. Therefore, corneal thickness is important for accurate measurement of intraocular pressure.

Corneal thickness is usually measured by an ophthalmologist using a micrometer. This measurement is important information for eye health, and ophthalmologists can make important decisions for diagnosing and treating diseases by assessing the thickness of the cornea.

What happens when the cornea is damaged?

If the cornea is damaged, vision loss and other eye problems can occur. The cornea is one of the most important parts of the eye and forms the outer shell of the eye. Since the cornea is a transparent layer, light from an important part of the eye passes through it and provides clear vision. If the cornea is damaged, light transmission may be impaired and vision loss may occur.

Corneal damage can be caused by many reasons. These include infections, injuries, burns, diseases, or postoperative complications. Signs of corneal damage may include eye redness, pain, blurred vision, sensitivity to light, foreign body sensation in the eye, tearing, eyelid swelling, and headache.

When the cornea is damaged, treatment options may vary depending on the extent and cause of the damage to the cornea. In some cases, the cornea can regenerate and the wound heals on its own. However, in some other cases, treatment is necessary. Treatment options may include medication, eyeglasses, contact lenses, corneal transplant, or corneal surgery. Early diagnosis and treatment can prevent the progression of corneal damage and are important for eye health.

Prepared by the Dünyagöz Hospital Editorial Board.

*The content of this page is for informational purposes only. See your doctor for diagnosis and treatment.