Corneal Edema: What is it?

The cornea is a protective, transparent dome-shaped layer of clear tissue that covers the front of the eye. In corneal edema, it becomes excessively hydrated due to the accumulation of fluid. 

An adult cornea is about 0.5 millimeters thick. It consists of five major layers: epithelium, Bowman's membrane, stroma, Descemet's membrane, and endothelium. 

As there are several nerve endings in the cornea, it is overly sensitive. Furthermore, it is devoid of blood vessels, hence it appears translucent. 

In this article, we will discuss Corneal Edema, its various symptoms and how it can be treated. 

What is Corneal Edema: 

The cornea works like a powerful refracting medium, contributing to the focusing power of the eyes. It is kept clear by pumping of water from the endothelium layer.

When there is water retention in the cornea area, it causes corneal swelling, which leads to corneal edema. 

Causes of Corneal Edema: 

This medical condition is caused by problems associated with dehydration, endothelial disorder, ocular surgery, viral infections, traumatic injury, increased ocular pressure, and toxins. 

Endothelial Fuch's dystrophy is the most common cause of this problem. It is a genetic disorder, which is characterized by the gradual loss of the endothelial cells. Women are usually at a higher risk of endothelial dystrophy than men. 

An infection by herpes virus also results in inflammatory responses in the cornea, leading to corneal edema. This condition may also occur right away or after few years of undergoing any kind of ocular surgery. 

This medical condition may also arise due to damage of the Descemet's membrane, injury of the endothelial layer by ultrasound radiation, and/or infusion of toxic medications in the cornea. Additionally, powerful topical and systemic medications may also cause corneal edema.

Symptoms of Corneal Edema: 

Distorted or blurred vision is the most notable early symptom of corneal edema. It may often become worse when the person wakes up after a night’s sleep and then improves throughout the day. 

Other notable symptoms of corneal edema are: eye discomfort, halos around light, sensitivity to foreign particles, and photophobia (increased sensitivity to light). 

As corneal edema progresses, it may become more painful and include blisters that form on the surface of the eye. The disorder may cause corneal nerves to rupture, resulting in severe pain. 

Corneal Edema Treatment: 

Since the early symptoms are similar to cataracts, it is necessary to go through an ocular evaluation for accurate diagnosis of this problem. 

The eye care expert may use ultrasound, specular microscopy, and optical pachymetry (measurement of corneal thickness) to confirm the condition. 

The treatment is based on the exact cause of the edema. If corneal inflammation is caused by ill-fitting or continuous wearing of contact lenses, the use of correct contact lenses is recommended. 

If the swelling is due to a post-surgery complication, it can be improved by using over the counter diuretics prescribed by the doctor. The eye care expert may also recommend antibiotics and anti-inflammatory medications to treat corneal edema.