Introduction

One of the most important organs in the body is the eye. Just like every other part of the body, the eye can also become damaged through known and unknown factors. Some of these conditions include Refractory glaucoma, which is secondary to Chandler’s syndrome. 

Chandler's Syndrome is a rare condition that affects the eyes. In this condition, the endothelium (the single layer covering the inside of the cornea) proliferates, causing corneal oedema, a change in the shape of the iris and an increase in the pressure in the eye. 

Refractory Glaucoma, on the other hand, is a more serious condition; it is a type of glaucoma that occurs when the pressure inside the eye cannot be controlled with medications (medications can be used as an adjuvant but not as the main treatment).1 Because it cannot be controlled with medications only, this makes the optic nerve worse and less effective. When the eye is affected and cannot be treated, it deteriorates in function, and this can lead to loss of vision. One of the most effective methods used in managing refractory glaucoma is the "Aqueous Shunt”. Aqueous shunt is a medical device used to drain excess fluid out of the eye to reduce eye pressure. Aqueous shunt has been proven to be effective in the management of refractory glaucoma when medication fails.

What is the main pathology of chandler’s syndrome?

Chandler's Syndrome is one of the three most common Iridocorneal endothelial syndromes (ICEs). Others include: 

• Progressive iris atrophy 
• Cogan-Reese syndrome

There is a clear window in the front part of your eyes called the cornea. It has a thin layer covering in front of it (endothelium) that keeps your eyes clear and healthy. In Chandler's syndrome, the thin-layer cells begin to behave abnormally.² This can lead to:

• Swelling of the cornea (cornea edema): This can lead to blurred vision
• Changes in the structure of the iris: These changes can make your iris look distorted 
• Increased pressure in the eye (glaucoma): This can damage your optic nerve

How does glaucoma function in the eyes?

The aqueous humour in your eyes drains out of the eyes into your bloodstream to keep your eyes from being swollen. But in Chandler’s Syndrome, there is an abnormal growth of endothelial cells which blocks fluids from leaving your eyes. This makes the fluid in your eyes build up, which leads to increased intraocular pressure (IOP).⁴

What is refractory glaucoma?

Refractory glaucoma can be described as a type of glaucoma where the pressure inside your eyes remains high and continues to damage your vision. Even after using eye drops, medicine or going for an eye surgery, these treatments may fail. Because the success rate of trabeculectomy is around 80%, there is a need for an alternative treatment.

How do you treat chandler’s syndrome?

In mild or early stages, you can make use of eye drops to reduce and manage eye swelling. Mild corneal oedema can be treated with soft contact lenses and hypertonic saline solutions, which draw fluid out of the cornea.²

In severe cases where the swelling becomes extreme and a person’s vision is affected, corneal surgery is required. Either endothelial keratoplasty or penetrating keratoplasty (corneal transplant) may be needed. These surgical procedures may carry a high risk of failure, and repeated grafts may also be required.

In Glaucoma management, medical therapy begins with aqueous suppressant eye drops, which suppress and prevent you from having ocular hypertension or more severe eye damage. In some cases, surgeries may be required. They include surgery options like:

• Trabeculectomy: It is the most common type of glaucoma surgery and the most effective
• Aqueous Shunts: (Glaucoma drainage devices): Although larger studies are needed to confirm their effectiveness. It has shown promising results in a few number of patients
• Laser surgery: Has been shown to be rarely effective in this condition

Role of aqueous shunts in refractory glaucoma (including chandler’s syndrome)

Aqueous shunts are also known as a tube shunt, or a glaucoma drainage device (GDD). They lower intraocular pressure when other treatments fail.⁶ They are effective in treating refractory glaucoma (which is seen in Chandler’s syndrome), where other therapies aren’t effective. 

Sometimes, trabeculectomy fails because the abnormal membrane can regrow and scar the new drainage channel.⁵ This makes aqueous shunt a more preferable option for long-term pressure control. 

The benefits of aqueous shunts include:

• Effective in pressure control: It uses a small permanent tube that allows fluids to leave the eyes easily
• Drains the fluid in a way that causes less scarring
• Lowers the risk of scarring-related failure compared to ICE-related glaucoma
• Has a built-in plate that controls and directs where the fluids flow, helping the drainage area to stay safe and stable

The complications of aqueous shunts include:

• Eye infection
• Hypotony 
• Tube damage 
• Bleeding inside the eye (hyphema)
• Damage to the cornea causes blurred vision
• Loss of vision
• Treatment failure

FAQs

What is the success rate of aqueous shunts?

The success rate is 85% in 3 years and 70 % in 5 years. However, some patients may need to use eyedrops to maintain a normal eye pressure level.

How long after aqueous shunt surgery is vision blurry?

It may take a few weeks after the surgery before your eye recovers.

How long does a tube shunt last?

It is difficult to predict how long a shunt lasts in the eye, although doctors have discovered that half of them require replacement after 5 to 6 years.

Summary

Refractory Glaucoma, which is secondary to Chandler’s Syndrome, is a severe type of glaucoma (eye disease) that causes an increase in the eye pressure, which can cause progressive damage in the eye and can lead to eye loss. One of the newly tested methods for treating refractory glaucoma is the aqueous shunt. It is effective in controlling the pressure inside your eye (intraocular pressure), especially in cases where a previous surgery (tuberectomy) has failed. Compared to other treatment options, aqeous shunt is fairly more reliable and needs fewer follow-up visits. More research is needed to determine its efficacy.