Introduction to eye anatomy and function

The eye is a complex organ that functions in a precise and organised manner. Two important structures in the eye are the iris and the cornea. The iris (the coloured part of the eye) controls the amount of light that goes into the eye. The cornea, the clear front surface of the eye, protects it from germs and dust. On the inside of the cornea, there are endothelial cells. These cells control the amount of fluid that passes through. Normally, the cornea regulates the amount of fluid entering it, preventing excess fluid from gathering.¹ This helps the eye maintain its focus, sharpness, and clear vision. 

How eye conditions disrupt vision

Healthy eyes can be disturbed, causing blurred and cloudy vision, and in severe cases, even blindness. One such example is iridocorneal endothelial syndrome (ICE syndrome), which is a group of three related eye conditions:²

• Essential Iris Atrophy (EIA)
• Cogan-Reese syndrome (CRS)
• Chandler's Syndrome (CS)

ICE syndrome subtypes

Essential iris atrophy (EIA)

The abnormal growth of endothelial cells in EIA causes the iris to misshape and shrink, and in severe cases, even creates holes in the iris.² Due to the intense internal damage to the structure of the iris of the eye, if not treated and diagnosed immediately, vision loss could occur faster than in the other subtypes.

Cogan-reese syndrome (CRS)

CRS consists of the appearance of small bumps on the iris.² These bumps are made of the same small abnormal endothelial cells. This, in turn, interferes with the eye’s fluid regulation.  

Chandler's syndrome (CS)

CS affects the cornea of the eye. The abnormal growth of the endothelial cells causes swelling of the cornea, which obstructs its function, resulting in swelling of the eye.³

Chandler’s syndrome

Chandler’s Syndrome (CS) accounts for approximately 50% of ICE cases.³ It is known to affect only one eye and tends to progress over time. Normally, women between the ages of 20 and 50 are more at risk.⁴ The actual cause of CS remains unknown. However, some research suggests that the hepatitis B Virus (HBV) may be related to how CS is developed.^3,2

In CS, the cornea of the eye is involved. The cornea acts as a protective barrier of the eye, stopping dust and germs from entering the eye and helping to keep the surface of the eye clear. Endothelial cells are cells that line the back of the cornea. Their job is to help pump fluid out of the cornea to keep it clear.³

Sometimes, these endothelial cells begin to grow, multiply, and spread into areas where they don’t normally belong. This includes the angle of the eye. The angle of the eye is a structure that plays a vital role in maintaining normal eye pressure. It is the structure that pumps excess fluid out of the eye. This role is extremely important, as it helps maintain the balance of fluid in the eye, which is essential for clear and comfortable vision.³ 

Risk of corneal decompensation

When the endothelial cells begin to behave abnormally, they spread and form a thin membrane, which starts to block the drainage of fluid from the eye. This leads to excess fluid building up, disturbing the clarity of the cornea and causing blurry vision.⁵ As the fluid continues to accumulate, the pressure inside the eye increases, which can result in a condition called glaucoma.

As the disease progresses, more endothelial cells are affected, leading to a significant risk of corneal endothelial decompensation. This means the cornea can no longer remain clear, resulting in blurred and cloudy vision, along with increased light sensitivity.⁵ Eventually, the cornea becomes permanently swollen, causing irreversible damage and potentially leading to blindness.

Unfortunately, once endothelial cells are lost, they are not able to regrow by themselves.⁸ This is why CS must be detected as early as possible to prevent or delay endothelial decompensation.

In more advanced cases, reducing corneal decompensation is crucial in managing CS. Lowering eye pressure is the main intervention to help control the disease and maintain long-term visual potential.² A corneal transplant is vital to improve vision and overall quality of life in more advanced cases.

Monitoring and management

Corneal transplant is also a viable option to prolong vision; it is a good option to help maintain vision in CS; however, it needs to be performed before endothelial cell decompensation occurs, which is when endothelial cells become too damaged. Research has shown that a corneal transplant could fail due to endothelial decompensation.⁸ Therefore, it is crucial to have regular eye check-ups to prevent disease progression.

Surgical treatment: DMEK

Descemet Membrane Endothelial Keratoplasty (DMEK) is a safe and effective corneal transplant technique that is used to restore the cornea by replacing the damaged cells of the cornea.⁶ Healthy donor tissues are used to replace the diseased endothelial layer. However, Monitoring and keeping glaucoma under control are critical for the long-term survival and success of these transplants.⁶

Conclusion

Chandler’s Syndrome cannot be cured, but it is very important to catch it early to avoid reaching the stage where the damage becomes irreversible and where vision is lost. Monitoring and early treatment are essential. The condition can be managed in several ways.

One way is by using eye drops that reduce the swelling in the cornea, which can help improve vision. Glaucoma, which often occurs with CS, needs to be managed by regular check-ups and controlled carefully. Ongoing checks with an eye specialist are very important to detect and avoid the progression of the condition.

CS cannot be cured; the main goal is to protect the vision and make symptoms easier to live with. In some cases, if the endothelial cells are badly decompensated, a corneal transplant is possible to help improve sight.⁶

Without regular check-ups and controlling glaucoma in patients with CS, they would be at a real risk of irreversible problems and life-threatening vision problems.

More research is needed to understand the cause of the condition, and this will help scientists understand how it works and may help them find better ways to treat patients with CS in the future.

The risk of endothelial cell decompensation in Chandler’s Syndrome emphasises how important it is to make an early diagnosis to be able to manage the symptoms and to preserve vision.

FAQs

What is chandler’s syndrome?

Chandler’s syndrome is a rare, irreversible eye condition that accounts for about 50% of ICE syndrome cases.³ It involves the dysfunction of the clear front part of the eye called the cornea.

What are the symptoms of chandler’s syndrome?

Normally, patients refer to the symptoms as “halos around light”⁷ or blurred vision.  Some patients also present with vision impairment. Alternatively, some are diagnosed through a thorough eye examination where the abnormal shape of the cornea is visible.⁷

What is the endothelial cell, and why is it important?

Endothelial cells are cells that line the back of the cornea. These cells help maintain the cornea by balancing the fluid of the eye. This helps us see with clear vision. If the internal balance is disturbed, the eye vision will become blurry and cloudy. ⁽³⁾

What does corneal endothelial dysfunction mean?

It means that the endothelial cells are not working properly. They start to grow and move to places they do not belong. When this happens, the cornea of the eye can get swollen and cloudy, making it harder to see clearly.

What does decompensation mean, and how does it affect a person’s vision and eye health?

Endothelial decompensation is when the endothelial cells act strangely, which in turn causes the cornea to swell, and hence, the cells cannot keep up with their normal function.⁸ If the cornea swells, it can affect daily activities because the eye becomes cloudy, and vision becomes blurry.

What treatments are available if corneal decompensation occurs?

If diagnosed at an early stage, the problem could be managed by eye drops or simple, easy surgery like a corneal transplant to replace the damaged cells and perhaps restore clear vision.^8,6

Can corneal endothelial dysfunction in chandler’s syndrome be prevented or slowed down?

Early detection and treatment can slow down the damage; however, it cannot always be prevented. Regular check-ups and avoiding infections can help.