Corneal Edema Symptoms, Causes, & Treatments

It can be concerning if you feel swelling in your eye. If you notice any swelling, contact an eye doctor because it might be corneal edema.

Corneal edema occurs when fluid accumulates in your cornea, resulting in swelling that leads to blurred or cloudy vision. While it usually occurs in people 50 or older, corneal edema can develop in anyone at any age. 

This condition can significantly affect your daily activities. Understanding corneal edema gives you a clear path towards effective treatment and relief.

What Causes Corneal Edema?

The most common cause of developing corneal edema is fluid buildup in your eye. The cornea's endothelium controls the build-up and release of fluid. 

You can damage the endothelium and develop corneal edema in several ways:

• Fuchs’ endothelial dystrophy and posterior polymorphous corneal dystrophy (diseases that affect the endothelial cells)
• Endotheliitis (an immune response to herpes)
• Other endothelial dystrophies
• Glaucoma
• Keratitis
• Certain medications (antimalarials and antipsychotics)
• Ocular trauma
• Infections or inflammation
• Corneal transplant problems 
• Eye surgery
• Over-wearing contact lenses

How Does Corneal Edema Happen?

The endothelium is a sheet of microscopic cells that remove excess fluid in your cornea to keep it transparent through a process known as corneal deturgescence. 

Throughout this process, fluid leaks into your cornea, while endothelial cells use carbonic anhydrase enzymes to pump it back out. Over time, aging or damage reduces endothelial cells, risking an imbalance.

If cell density falls below approximately 700 cells/mm², the cornea struggles to remain clear, and significant swelling (edema) develops. Corneal edema can be acute or chronic and often needs medical treatment.

Here’s a quick breakdown of how cell density naturally declines with age:

Age Group	Typical Cell Density (cells/mm²)	Edema Risk
Teens	3,000 to 3,500	Very low
40 to 60	2,500 to 3,000	Low, but increasing
70+	1,500 to 2,300	Moderate
Critical	Below 500 to 700	High (chronic edema)

What Are the Symptoms of Corneal Edema?

Corneal edema can be uncomfortable due to corneal swelling and endothelial damage. You may also experience some or all of these symptoms if you have corneal edema:

• Eye pain
• Glare
• Blurriness
• Distorted eyesight
• Seeing halos or rings around light
• Increased sensitivity to light
• Eye soreness
• A scratching sensation in the eye
• Blisters on the cornea (in severe cases)

How Does Corneal Edema Affect Your Quality of Life?

Corneal edema produces various symptoms, ranging from mild inconvenience to severe impairment. Initially, you may notice blurry vision upon waking up, which gradually clears throughout the morning.

As the edema worsens, the blurring persists longer, eventually becoming constant. You may also start seeing glares and halos, causing discomfort in bright conditions.

Meanwhile, in advanced stages, fluid-filled blisters (bullae) form on your cornea. When the bullae rupture, they expose the nerves, resulting in sudden, sharp pain.

Lastly, studies show that moderate-to-severe edema significantly limits daily activities like reading, driving, and outdoor mobility.

What are the Stages of Corneal Edema?

Here are the stages of corneal edema:

• Stage 1 (mild). Slight glare, minimal or no swelling; vision mostly unaffected.
• Stage 2 (moderate). Morning haze clears by afternoon; mild swelling, increasingly noticeable glare.
• Stage 3 (severe). Persistent blurred vision; painful episodes from ruptured bullae, significant lifestyle impact.
• Stage 4 (advanced). Chronic severe edema, corneal scarring, vision severely impaired; may require urgent surgical intervention.

How is Corneal Edema Diagnosed?

Your eye doctor will conduct specific tests to accurately diagnose corneal edema, understand its severity, and identify underlying causes:

• Slit-lamp examination. Uses a high-powered microscope to detect subtle signs like endothelial guttae, stromal folds, and fluid-filled bullae.
• Pachymetry measurements. This quick, painless test measures your corneal thickness. Normal corneas measure around 540 microns; thickness above 600 microns strongly suggests significant edema.
• Specular microscopy. This imaging method evaluates endothelial cell health, density, and shape.
• Anterior segment OCT. Optical coherence tomography provides cross-sectional images of your cornea, clearly visualizing subtle edema, thickened Descemet’s membrane, and structural irregularities.

What Are the Possible Findings of these Tests?

Your doctor uses these tests in combination to pinpoint the precise cause:

Diagnostic Test	Main Finding	Indicates
Slit-lamp	Guttae, bullae, stromal folds	Fuchs dystrophy, advanced edema
Pachymetry	Thickness > 600 microns	Significant edema
Specular microscopy	Low cell density, irregular shape	Endothelial dysfunction
OCT	Thickened Descemet’s membrane	Fuchs dystrophy

Unilateral findings typically suggest trauma or infection, while bilateral changes often point toward chronic dystrophies like Fuchs dystrophy.

How is Corneal Edema Treated?

Fortunately, surgical and non-surgical options are available to treat corneal edema. Depending on your diagnosis, some surgical treatment options may include:

• Corneal transplant
• Lens implant exchanges (a dislocated lens implant may cause corneal edema)
• Removal of vitreous materials or remaining lens materials after cataract surgery
• Descemet Stripping Endothelial Keratoplasty (DSEK) to replace the corneal endothelium through a small incision

However, if your case isn’t severe, general eye care can help reduce symptoms. You can also switch to glasses or a new type of contact lenses. 

You can take medications to treat infection, inflammation, or glaucoma. Lastly, your doctor may recommend diuretics, hypertonic saline drops, or prescription eye drops.

Is Corneal Edema Serious?

Although mild cases often go away on their own, corneal edema is serious. While it’s not life-threatening, leaving it untreated can lead to long-term vision problems.

Depending on the severity of your diagnosis, untreated corneal edema can significantly affect your visual acuity. Talk to your ophthalmologist about the best treatment option, given your diagnosis, budget, lifestyle, and other factors that could influence your decision.

When to Call an Eye Doctor?

Consult an eye doctor if you experience any of these symptoms:

• Blurred or cloudy vision that persists beyond the morning.
• Persistent glare or halos, especially at night.
• Frequent eye pain or sudden sharp pain.
• Rapid changes in vision or a noticeable increase in corneal swelling