Corneal edema occurs when the cornea, the protective dome-shaped outer layer of tissue that covers the front of the eye, becomes dehydrated due to a fluid build-up. The cornea is about 0.5 millimeters thick and consists of five layers. Each membrane is vital light entering the eye’s pupil. The lens of the eye is needed to help focus light, but the cornea is twice as effective in this role.
The transparency of the cornea is necessary for clear sight and the health of the cornea determines this. If there are any factors affecting it, like dryness, poor vision can be a result. Below, we’ll discuss corneal edema’s symptoms, causes, and treatment.
What Is Corneal Edema?
Corneal edema occurs when water is retained in the endothelial level of the eye. Fluid builds up when the endothelial cells are injured or damaged, which can be from a variety of causes. The pressure increases in the eye and cells can be further damaged if the edema is left untreated. Endothelial cells rarely regenerate when injured, so proactive treatment is encouraged to protect the surviving cells.
With the increase of fluid, the clarity of the cornea is compromised and vision becomes blurry in the patients. If a few cells are destroyed, the remaining endothelial cells will not create more. Instead, they will grow to fill the gaps from the missing cells. If too many cells have died already, the corneal stroma of the eye is exposed to fluids, which further compromises vision. If the epithelial cells change size in an attempt to protect the eye, the protein fibers will also change. This affects the light-bending properties of the cornea as well.
Any damage or change to the eye’s environment, especially to the cornea, can result in serious and permanent damage to the patient’s eyesight.
Corneal edema usually appears in patients that are 50 years or older.
Causes of Corneal Edema
Corneal edema can be caused by a variety of reasons including dehydration, endothelial disorders, surgery to the eye, a viral infection, injury, increased pressure, or even invasive toxins. One of the most common causes of corneal edema is Fuch’s dystrophy. This is a genetic disorder that is the gradual loss of the endothelial cells around the eye. It is a serious disorder with new treatment options currently developing. Women generally have a higher risk of developing this condition than men.
A herpes viral infection can cause an inflammatory response in the cornea which can lead to temporary corneal edema. This condition is similarly noted to occur in patients after ocular surgery, especially patients that had cataract surgery performed.
Symptoms of corneal edema include distorted and blurred vision, which is noted to be the earliest sign of corneal edema, eye discomfort, halos around light, eye sensitivity, and increased sensitivity to light. As the edema worsens, blisters can appear on the surface of the eye and even cause corneal nerves to rupture, which results in severe pain to the patient.
Corneal Edema Treatment Methods
The early symptoms of corneal edema resemble cataracts. An eye exam by an optometrist is necessary to differentiate between the two conditions. An optometrist may use an ultrasound, specular microscopy, or an optical pachymetry test, which measures the thickness of the cornea, for aid in diagnosis.
The causes of corneal edema are usually underlying symptoms, as you can see in the earlier section. Consequently, it is necessary to determine the cause of the edema and correct that issue. An example of this could be a patient wearing ill-fitting contact lenses and switching to another brand.
Hypertonic saline drops can temporarily reduce the swelling of the cornea and provide relief to patients suffering from mild forms of the edema. There are no healing treatment options available to target any damaged endothelial cells.
The effects of corneal edema are worse in the morning as evaporation is not possible when the eyelids are closed. This is especially noted when saline drops are prescribed to encourage fluid evaporation. The patient can apply a stronger concentration of the saline solution to the eyes just before bedtime to help combat this side effect.
Severe corneal edema that cannot be relieved from saline solutions can be helped with a procedure known as Anterior Stroma Puncture. Shallow punctures through the outermost layer of the cornea help fluid dissipate.
If a patient is suffering from corneal edema as a result from eye surgery, they may have to wear a post-operation bandage lens. This bandage lens helps the epithelium fix to the cornea, but it may worsen corneal edema.
Corticosteroids can be prescribed along with antibiotics to help reduce corneal edema inflammation and lower the patient’s chance of infection.
If medical therapy is not an option, there is a surgery available called Descemet’s stripping automated endothelial keratoplasty. In extreme circumstances, the doctor may recommend a corneal transplant if other treatments fail. There is no preventative treatment available for corneal edema.
To Sum It All Up
Corneal edema can result from a variety of symptoms; from as simple as an ill-fitting contact lens to the diagnosis of a permanent, genetic disorder like Fuch’s dystrophy. Patients suffering from eye discomfort and blurred vision should seek out professional help. Proper treatment and care is key to ensuring the cornea and layers of the eye are in good health and functioning well.
Corneal edema generally appears in older patients and in patients recovering from eye cataract surgery. It is important to contact the eye surgeon if there are any abnormal or irregular symptoms following eye surgery. There are a variety of treatment options to help alleviate the pressure in the eye including prescription eye drops, medication therapies, or the possibility of surgery to correct the concern. It is important to be proactive and respond quickly to protect the remaining endothelial cells of the eye and maintain those that are still in good health. This is a serious condition, but with proper treatment, restoring the patient’s vision is possible.