lee eye institute

The cornea is the clear tissue at front of the eye. The cornea serves two main purposes.  Firstly, as the eye's outermost later, the cornea protects the inner eye.  Secondly, as a clear curved tissue, the cornea refracts (bends) light.  The curved shaped of the cornea functions in much the same way a camera lens focuses images on film by bending light rays so that they land on the retina correctly.  Refraction of light is performed by both the cornea and the eye's crystalline lens.  The lens of the eye can change shape to focus at different points, but the cornea's shape remains constant.

If the cornea is damaged or becomes weakened by injury or disease, you may need a cornea transplant. Trauma, infections or hereditary diseases can affect the quality of vision and the overall clarity of the cornea. When your cornea is injured or infected by a disease, it may become swollen or scarred. When this happens, the clarity of your cornea may be lost. Scars, swelling or irregular shape can cause the cornea to scatter or distort light which will result in blurred vision. To learn more read below!

The function of the endothelial cells is to pump fluid out of the cornea which keeps it crystal clear and thin. When many endothelial cells are injured or lost, the fluid that circulates inside the eyeball goes into the cornea, causing it to become cloudy and swollen. Once this occurs, medical treatments usually will not work, and a cornea transplant is recommended.

A cornea transplant replaces your damaged cornea with a healthy cornea that has been donated to an eye bank. Once it is decided that surgery is the only option, your ophthalmologist will present you with your options and recommend the best cornea transplant procedure.

The transplant procedure involves removing a small circle of tissue from the patient's cornea and replacing the tissue with the aforementioned donor cornea. The donor tissue is screened carefully to ensure compatibility and prevent transmission of disease(s) to the recipient. The new donor cornea is gently stitched in position using extremely thin nylon thread. These sutures are barely visible and do not cause pain, although the eye may feel slightly irritated for the first few days after surgery. For the first few weeks following surgery, vision for most patients will be blurry. After a few weeks, the vision begins to clear, and within three or four months new spectacles can be prescribed, which should improve vision further.

A corneal abrasion is a condition involving the loss of the surface epithelial layer of the eye's cornea.  This condition is typically caused by eye trauma, such as scratching the eye on a tree branch or a fingernail, and may be more likely to occur in individuals who have dry eye syndrome.

Common symptoms of corneal abrasion include pain, intolerance of light or light sensitivity, foreign body sensation, and an abnormal excess of tears. Signs include epithelial defects, edema, and often conjunctival injection, swollen eyelids, and enlarged pupils. The vision may be blurred from both swelling of the cornea and excessive tears, the latter of which may cause a crusty buildup.

Many people get minor abrasions on their corneas and are fine without treatment.  More serious corneal abrasions can be treated by patching the eye to prevent blinking and irritation, applying lubricated drops or ointment(s) to the eye, and using antibiotics to prevent infection. Treatment will sometimes involve wearing a bandage contact lens to help healing. Minor abrasions will usually heal within a day or two, while larger abrasions may take up to a week.

Corneal erosion is caused by a loosening of the corneal epithelial cells from the underlying basement membrane (Bowman's Later). Corneal erosion frequently occurs at the site of an earlier abrasion. Erosion can also occur in dry eyes.

The symptoms of erosion are similar to those of abrasions and often occur upon waking up. Treatment for corneal erosion is the same as for abrasions. If symptoms of erosion persist, further treatment may be required.