Introduction
Corneal edema is also called corneal swelling, characterized by swelling of the cornea or the front surface of the eye. Swelling of the cornea can occur due to inflammation, infection, injury, or post-surgery. Some eye conditions can also result in corneal edema. When this condition is left untreated, it can result in vision disturbances like cloudiness, discomfort, or sensitivity to light. Any disturbance in the vision should be consulted with the doctor as soon as possible.
What Is Meant by Corneal Edema?
Cornea is a clear surface composed of smooth and domed-shaped tissue; it helps block debris and monitor how light enters the eye. The cornea's main function is to protect the eye and focus the vision. Corneal edema is the inflammation caused in the outer layer of the eye. The cornea contains cells in the inner layer called the endothelium, which helps remove the liquid from the cornea, maintaining corneal health and producing clear vision. When this endothelium is damaged, it can result in fluid buildup, making the cornea swell and impairing vision. This condition is prevalent among the older population aged 50 years and above. Usually, women get more affected than men.
What Are the Causes of Corneal Edema or Swelling?
The common cause of corneal edema is fluid buildup in the eyes. This can be caused due to many factors, such as:
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Trauma or injury.
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Infection of the eyes.
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Inflammation of the eyes.
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Irreversible corneal edema developed after cataract surgery is called pseudophakic corneal edema (PCE) or pseudophakic bullous keratopathy (PBK).
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Severe corneal conditions such as posterior polymorphous corneal dystrophy (PPCD).
Damage to endothelial cells causes fluid buildup, which can result in corneal edema. The specific condition causes damage to the endothelial cells; some are
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Fuchs Dystrophy: A gradual deterioration of the endothelial cells characterizes this condition which becomes evident when the affected ones are in their 50s. Due to damage in the endothelial cell, there will be fluid buildup in the cornea resulting in corneal edema.
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Chandler's Syndrome: This condition results in the quick multiplication of endothelial cells.
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Endotheliitis: This is the inflammation of the endothelium caused due to Herpes simplex virus (HSV), mumps, cytomegalovirus virus, and bacterial infection.
Certain medications can also result in corneal edema; some are:
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Amantadine is used to manage Parkinson's disease.
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Benzalkonium chloride is a preservative in topical eye drops and anesthesia.
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Chlorhexidine is an antiseptic to prepare the skin for surgery or injection.
What Are the Signs and Symptoms Associated With Corneal Edema?
Some common symptoms are,
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Blurred vision.
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Cloudy vision.
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Sensation of something present in the eye.
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Light sensitivity.
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Glares of light.
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In severe cases, there may be an occurrence of blisters in the eyes.
How Is Corneal Swelling or Edema Diagnosed?
Initially, the doctor reviews the medical and family history. Clinical diagnosis is made when the eye is examined using magnifying tools like a slit lamp or ophthalmoscope to rule out clouding and to get a better view of the eye structure.
Few diagnostic tests are,
1. Pachymetry - In this procedure, the thickness of the patient's eye is measured. For this procedure, a device named pachymetry is used to obtain the measurement required, which can be helpful before any eye surgery or can also be useful to rule out the presence of glaucoma.
2. Specular Microscopy - Specular microscopy is used to get an image of the corneal endothelium. The eye affected by corneal edema shows no significant reading in specular microscopy. In such a condition, the other eye can be checked.
3. Anterior Segment Optical Coherence Tomography (ASOCT) - This imaging procedure shows results of quantitative and qualitative information related to the cornea, anterior chamber angle, and iris. This is one of the primary diagnostic methods to rule out the presence of corneal edema.
How Is Corneal Edema Managed?
Generally, corneal edema is treated by treating the underlying cause of the condition, such as inflammation, eye infection, etc. In some severe cases, medical therapy and medical intervention are required.
Medical Therapy:
1. Hypertonic Solution - Five percent Sodium chloride ophthalmic solution or ointment can help to manage mild corneal edema by increasing surface dehydration as they form a hypertonic tear film, which helps to eliminate the fluid from the cornea. When applied at night, this solution or ointment helps prevent fluid buildup. This solution acts best if the corneal edema is confined only to the epithelium.
2. Bandaged Contact Lenses - These extended-wear hydrophilic contacts help temporarily manage corneal pain and discomfort related to epithelial bullae (blisters filled with fluid). They form a precorneal protective layer that eliminates the swollen epithelium by the lid movements and prevents bullae rupture. But using these lenses for the long term is not advisable as this can increase the risk of infection.
3. Antibiotics, corticosteroids, and beta-adrenergic blockers are used.
4. Surgery - Surgery is recommended for people with poor vision and severe pain caused due to corneal edema. A 25 gauge needle makes small superficial punctures in the affected corneal area. The puncture depth should be at or below the Bowmen layer, a smooth, acellular layer between the stroma and the superficial epithelium in the cornea. The epithelium scars in the treated region. This procedure helps in the resolution of bullae and reduces pain. A bandaged contact should be placed over the cornea for about one to two weeks, which allows healing time for the epithelium to attach to the underlying cornea.
Some surgical procedures are,
- Corneal Transplant - During this procedure, the center part of the cornea is eliminated and replaced with a healthy tissue called a graft. Following this procedure, the patient will be asked to use steroid drops until the body adjusts to the new graft, which also helps prevent infection, swelling, or discomfort.
- Descemet's Stripping Endothelial Keratoplasty (DSEK) - In this procedure, the damaged endothelium is replaced. The surgery and recovery time are less than the corneal transplant method. Steroid eye drops are recommended to be used by the patient following the procedure.
How Can the Eye Affected by Corneal Edema Be Taken Care Of?
It is essential to care for the eye whether or not a person experiences any eye condition. Though corneal edema is not life-threatening, it should be consulted with the doctor immediately. A person should have an eye examination every year to ensure the vision and the healthy functioning of the eye.
Conclusion
Corneal edema is the swelling of the cornea caused due to fluid buildup in the eye, which usually occurs in people over 50 years of age. This condition can be caused due to underlying infection, inflammation of the eye, etc., which can result in vision disturbances. There are many medical therapy and surgical treatments which can help to manage the condition.
