What are the other Names for this Condition? (Also known as/Synonyms)

• Aqueous Misdirection Syndrome
• Ciliary Block Glaucoma
• Malignant Glaucoma

What is Aqueous Misdirection? (Definition/Background Information)

• Aqueous Misdirection (AM) is a complication that occurs following surgery for acute closed angle glaucoma. The condition can occur as a complication of other intraocular surgeries too, such as cataract surgery, surgical iridotomy, and laser iridotomy
• Glaucoma is a group of eye disorders in which the optic nerves connecting the eyes and brain are progressively damaged, leading to reduced peripheral vision and potential blindness. This condition is usually caused by increased pressure within the eyes, known as intraocular pressure (IOP)
• Aqueous Misdirection usually involves the eye that has undergone the surgical procedure. It is described as a form of secondary angle closure glaucoma. The development of AM post-operatively in one eye indicates an increased risk that it could occur in the other eye following a similar surgery
• The occurrence of the condition is noted with higher incidence in individuals who have hyperopic eyes (longsightedness) and a history of primary closed angle glaucoma. Aqueous Misdirection classically occurs during the early post-operative period after incisional eye surgery; however, in some cases it may occur after a long period too (after many months and years)

Who gets Aqueous Misdirection? (Age and Sex Distribution)

• Aqueous Misdirection is typically rare and is only observed in individuals who have undergone eye surgery typically for angle-closure glaucoma
• Both males and females may be affected; a female preference is reportedly noted
• Worldwide, individuals of all races and ethnicity are prone to developing the condition

What are the Risk Factors for Aqueous Misdirection? (Predisposing Factors)

The risk factors for Aqueous Misdirection may include the following surgical procedures:

• Trabeculectomy (guarded filtration procedure) for glaucoma - the most common cause for Aqueous Misdirection
• Cataract surgery
• Surgical and laser iridotomy
• Pars plana vitrectomy
• Diode laser cyclophotocoagulation
• Trabeculectomy bleb needling

The following underlying factors/conditions may contribute to the development of Aqueous Misdirection:

• Corneal hydrops
• Eye inflammation
• Fungal keratomycosis endophthalmitis
• Miotic therapy
• Nocardia asteroides endophthalmitis
• Retinopathy of prematurity
• Trauma to the eye

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Aqueous Misdirection? (Etiology)

The underlying mechanism for development of Aqueous Misdirection following an intraocular surgery is unknown.

• Researchers believe it may occur due to abnormalities in aqueous flow into the posterior segment region of the eye post-surgery
• This abnormal flow results in abnormal functioning of ciliary body processes, lens, and anterior chamber of the vitreous
• Aqueous Misdirection typically increases the intraocular pressure (IOP); although, on some occasions, the IOP can be normal or low too

There may be an increased risk for Aqueous Misdirection against a background of other factors such as eye conditions, trauma, or inflammation. Nevertheless, it may develop without any pre-existing risk factors too.

What are the Signs and Symptoms of Aqueous Misdirection?

The following signs and symptoms of Aqueous Misdirection may be noted:

• Redness of the eye
• Eye pain
• Progressively decreasing vision following eye surgery
• In some individuals, an improvement in their near vision is noted before it starts getting worse

How is Aqueous Misdirection Diagnosed?

The diagnosis of Aqueous Misdirection can be challenging and hence a strong index of suspicion is required by the healthcare provider for early diagnosis of the condition following the surgical procedure. Typically, Aqueous Misdirection is a diagnosis of exclusion. The following observations and tests may also be necessary:

• Physical examination and medical history evaluation (including history of eye surgery for glaucoma or other conditions)
• Assessment of the presenting signs and symptoms
• General eye exam to check for post-surgical complications
• Fundoscopic (ophthalmoscopic) examination by an eye specialist, who examines the back part of the eye (or the fundus)
• Visual acuity test using a special and standardized test chart (Snellen chart)
• Slit-lamp examination
• B-scan ocular ultrasonography and ultrasound biomicroscopy (UBM)
• Anterior segment optical coherence tomography (OCT)

A differential diagnosis to eliminate other conditions may be considered, before arriving at a definitive diagnosis. These may include:

• Choroidal effusion
• Choroidal hemorrhage
• Intumescent lens
• Pupillary block

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Aqueous Misdirection?

The complications of Aqueous Misdirection may include:

• Emotional stress
• Complete loss of vision in the affected eye
• Necessity to undergo multiple surgeries

How is Aqueous Misdirection Treated?

The treatment of Aqueous Misdirection is based on the severity of the condition.

• Medications using cycloplegics and ocular antihypertensives form the first line of treatment
• If medical therapy does not result in improvement of the condition, then additional surgeries may be needed to manage this post-surgical complication

If the known risk for the development of Aqueous Misdirection is high, then the following treatment strategies may be considered on a case-by-case basis to prevent its development:

• Disrupting the hyaloid membrane during cataract surgery may help in prevention of Aqueous Misdirection
• Transcorneal needling
• Anterior vitrectomy via pars plana approach (with/without lens removal)
• And/or, with/without laser treatment of ciliary processes
• Medication agents, such as miotics, should be avoided as they can worsen the condition

Close follow-up is recommended to evaluate treatment response and prevent any further post-surgical complications.

How can Aqueous Misdirection be Prevented?

Currently, there are no preventive measures for Aqueous Misdirection. An early recognition and treatment of this potential complication will help prevent vision loss.

• Individuals with certain pre-surgical eye conditions may need to be made aware of surgical risks and complications
• Healthcare providers are informed to adhere to best medical practices while performing intraocular (and other eye) surgeries

What is the Prognosis of Aqueous Misdirection? (Outcomes/Resolutions)

• The prognosis of the Aqueous Misdirection depends on the severity of the condition and timeliness of management
• Prompt recognition and treatment is important to avoid progressive vision loss and total blindness

Additional and Relevant Useful Information for Aqueous Misdirection:

Please visit our Eye & Vision Health Center for more physician-approved health information:

https://www.dovemed.com/health-topics/vision-center/