# Cornea

Source page: https://www.kudretgozistanbul.com/en/treatments/cornea

**Author:** Kudret Eye İstanbul | **Medical Approval:** Op. Dr. Deniz Oygar Baylançiçek | **Date:** 2026-09-13

> **Summary:** The cornea is the transparent, dome-shaped front layer of the eye that lets light in and focuses it on the retina, maintains the eye's shape and protects it from infection; it is transparent because it has no blood vessels and a regular cellular structure. Microcornea, keratitis, keratoconus, corneal dystrophies, corneal ulcer and pterygium can cloud it and affect vision; treatment ranges from drops, glasses and contact lenses to crosslinking, corneal rings and corneal transplantation.

## Quick Facts
- **Common corneal diseases:** Microcornea, keratitis, keratoconus, corneal dystrophies, corneal ulcer, pterygium (conjunctivitis is covered separately: it is not a corneal disease but can affect the eye surface together with the cornea)
- **Diagnosis:** Slit lamp examination, keratometry, pachymetry, corneal topography, fluorescein staining, tear testing
- **Typical symptoms:** Blurred vision, eye pain, light sensitivity, redness, foreign body sensation, watery eyes
- **Emergency:** Corneal ulcer needs urgent care; untreated it can lead to blindness

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## What is the Cornea?
A transparent dome-shaped organ at the front of the eye. It allows light to enter and focus on the retina, helps maintain the shape of the eye and protects it from infections. Diseases that impair its transparency affect vision.

## How are Corneal Diseases Diagnosed?
- Slit lamp: detailed examination of the cornea and other parts of the eye
- Keratometry: measures the curvature of the cornea
- Pachymetry: measures the thickness of the cornea
- Corneal topography: maps the shape of the cornea
- Fluorescein staining: reveals wounds or ulcers
- Tear testing: checks for dryness or other tear abnormalities

## Corneal Diseases and Treatment
- **Microcornea:** the cornea is smaller than normal, usually congenital and can run in families; mostly accompanied by refractive errors such as hyperopia. Microcornea itself cannot be corrected; glasses or contact lenses improve visual acuity and associated problems such as glaucoma, cataract or refractive errors are treated.
- **Keratitis:** inflammation of the cornea from infection, injury, autoimmune disease or allergy; symptoms are eye pain, redness, light sensitivity, watering and blurred vision. Treated with antibiotics, antiviral or antifungal drugs, steroids or painkillers depending on the cause.
- **Keratoconus:** thinning of the cornea, which takes a cone shape and bulges forward; blurred vision, double vision, light sensitivity and astigmatism. Depending on the stage: contact lenses, corneal cross-linking or corneal transplantation.
- **Corneal dystrophies:** a group of inherited diseases impairing corneal transparency and function, with mild to severe symptoms; treated with glasses, contact lenses, laser surgery or corneal transplantation.
- **Corneal ulcer:** an open wound on the corneal surface from infection, injury or chemical burns; severe eye pain, redness, blurred vision, light sensitivity and discharge. A serious condition needing urgent attention; untreated it can lead to blindness. Treated with antibiotics, antiviral or antifungal drugs, steroid drops for pain and inflammation, and surgery in some cases.
- **Conjunctivitis:** inflammation of the conjunctiva; not a corneal disease, but covered because it can affect the eye surface together with the cornea. Causes include bacterial or viral infection and allergy. Bacterial: antibiotic drops or ointments; viral: usually resolves on its own, over-the-counter medication for symptoms; allergic: avoiding the trigger plus antihistamine drops or ointments.
- **Pterygium:** abnormal growth of the conjunctiva towards the cornea, usually from sunlight exposure; redness, irritation and blurred vision. Drops and ointments relieve symptoms but do not stop growth; surgery removes it and prevents regrowth.

## Cornea Transplant
A damaged or diseased cornea is replaced with a cornea from a healthy donor; an effective method for restoring or significantly improving lost vision in keratoconus, corneal injuries, infections and dystrophies.

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## Frequently Asked Questions

**Q: What are the symptoms of corneal diseases?**
A: Blurred vision, eye pain, sensitivity to light, redness, foreign body sensation and watery eyes.

**Q: What are the treatment methods for corneal diseases?**
A: Depending on the disease: medications, eye drops, contact lenses, crosslinking, corneal ring implantation or corneal transplantation.

**Q: Why is the cornea transparent?**
A: It has no blood vessels and a regular cellular structure, so light passes through and focuses properly.

**Q: What should be done to maintain corneal health?**
A: Hygiene, sunglasses against UV rays, correct contact lens use, regular eye examinations, avoiding eye injuries, and seeing a doctor when the eye feels uncomfortable.