What Is Corneal Edema?

Corneal Edema is one of two types of eye edema, which is characterized by swelling and / or corneal inflammation. Corneal edema can cause eye infections. Corneal edema not only severely affects vision, but also indicates that the eye lesions are in active phase and need to be treated in time. For long-term cure, poor vision, corneal endothelial dysfunction, penetrating corneal transplantation can be done.

Basic Information

English name

corneal edema

Visiting department

Ophthalmology

Common locations

cornea

Common causes

Caused by increased intraocular pressure, corneal endothelium damage, and anterior chamber inflammation

Common symptoms

Corneal swelling, corneal inflammation

Causes of corneal edema and common diseases

The amount of water in the cornea (78%) is constant. If the content increases, corneal edema will occur. The corneal endothelium has the function of pumping water and leaking water. Through the interstitial space of the endothelial cells, the aqueous humor enters the stroma; the cornea continuously pumps out the water in the stroma, and its leakage rate is equal to the pumping rate. Endothelial barrier and pump function are affected by many factors. Various diseases that cause corneal endothelium damage (glaucoma, keratitis, corneal dystrophy, and iridocyclitis) and surgical trauma can cause corneal edema.

The corneal fluid content exceeded normal, causing the corneal gloss to disappear and appear cloudy. Normal cornea contains 70% water, and if it is increased by 10%, edema occurs. Corneal edema occurs due to trauma, inflammation, degeneration, and significant increase in intraocular pressure. The corneal epithelium and endothelium lose pump and barrier functions, which is edema. The corneal sheet cannot be stretched until the stroma layer expands in the anterior chamber; the corneal thickness increases due to the hydration of the mucopolysaccharide matrix; the corneal edema occurs due to the disturbance of the collagen fibers arranged in a grid pattern.

1. Increased intraocular pressure ^[1]

Common causes of corneal edema are increased intraocular pressure, which causes sodium water retention in the cornea and edema.

Trauma

Corneal endothelial injury; contusion of the eyeball, cataract cryosurgery, intraocular lens implantation, vitrectomy without silicone oil or gas filling can all damage the corneal endothelium, all of which can cause corneal edema.

3. Inflammation

The inflammatory response in the anterior chamber can contact inflammatory cells with endothelial cells, and the toxic effect of inflammation itself can also cause the destruction of corneal endothelial cells and produce edema.

4. The corneal endothelium itself is not functioning properly

Reduced number of endothelial cells and corneal dystrophy in the elderly can also cause corneal edema.

5. Common diseases

Among them, Fuch iris heterochromia is the most common cause of corneal edema.

Differential diagnosis of corneal edema

Clinical manifestations include dull gloss, turbidity, increased thickness, conscious blurred vision, iridescence, and pain. Symptoms of corneal edema, most noticeable early deformation or blurred vision, halo around the particles, eye discomfort, photophobia (increased light sensitivity) and sensitivity. Corneal edema can be divided into epithelial edema, stroma edema, and endothelial edema ^[2] .

Keratitis

Refers to diffuse inflammation in the corneal parenchyma. Such as congenital syphilitic keratitis. But it can also be seen in tuberculosis, viruses and certain mold infections.

Corneal lesions

From the peripheral starter, the corneal edge first darkened and appeared slightly turbid, mostly starting from above the cornea and gradually expanding towards the center . This turbidity resides deep and is off-white. Epithelial edema may form blistering. If you use a slit lamp, you can see that corneal edema is thickened; the deep gray turbidity of the cornea is snow flakes, small dots or lines.

3. Iris ciliary body inflammation

It is a common complication, with mild iris congestion, corneal endothelial edema, deposits, and wrinkles in the posterior elastic layer. In severe patients, posterior iris adhesions can be seen, the pupil membrane can be closed, locked, or the shaped iris ciliary body Inflammation, eventually shrinking the eyeballs.

Corneal edema examination

Confirm the diagnosis with slit lamp and A-ultrasound.

Corneal Edema Treatment Principles

First, actively remove the various causes of edema; topically use hypertonic glycerol, hypertonic sugar, hypertonic eye ointment, drops, etc. to dehydrate the corneal endothelium and transfer water to tears; patients with high intraocular pressure should actively reduce intraocular pressure To reduce the penetration of aqueous humor into the corneal endothelium, use acetazolamide to reduce corneal edema; use a soft contact lens to protect the corneal epithelium while giving medical treatment; for those who have long-term cure, poor vision, and decompensated corneal endothelium, Make a penetrating corneal transplant.