The leading cause of irreversible blindness, glaucoma occurs when a blockage in eye fluid drainage causes an increase in internal eye pressure, or intraocular pressure (IOP), leading to progressive deterioration of the optic nerve and gradual vision loss. Elevated IOP is the main risk factor in the disease and the focus of treatment.

Juvenile Open-Angle Glaucoma

Affecting over two million Americans, open-angle glaucoma is the most common form of the disease and most often arises in older adults as adult-onset primary open-angle glaucoma (POAG). In POAG, there is still a normal, wide, and open angle between the iris and the cornea, but there is a slow-forming drainage block that raises IOP.

Many are unaware, however, that primary open-angle glaucoma can also impact children and young adults. A form of childhood glaucoma and a less common form of POAG, juvenile open-angle glaucoma (JOAG) develops between ages 3 and 40, and involves higher IOP and more severe visual loss than adult-onset POAG. JOAG affects about 1 in 50,000 people.

How JOAG Happens

In the rear (posterior) chamber of the front part of the eye, in front of the lens, a clear fluid called aqueous humor is constantly produced that nourishes the eye and keeps it inflated. This fluid is pushed through the pupil into the frontal (anterior) eye chamber, where it drains from the eye primarily through a drainage system called the trabecular pathway, involving Schlemm’s canal (a circular structure that captures the fluid and carries it to blood vessels) and the trabecular meshwork (which supports the canal and holds it open). 

In JOAG, the trabecular meshwork is often malformed or underdeveloped, causing insufficient drainage of aqueous humor, increased IOP, and optic nerve damage. Known risk factors for JOAG include:

• Male sex
• Nearsightedness (myopia)
• Severe IOP (generally over 40 mm Hg)
• African ancestry
• Myocilin (MYOC) gene mutation

We don’t yet fully understand why these malformations occur. 

Determining JOAG

While many with JOAG show no symptoms, others can exhibit:

• Eye enlargement
• Blurred vision/Low visual acuity (sharpness)
• Eye pain
• Tearing
• Blinking
• Glare (when bright light hurts the eye and makes it difficult to see)

Complete family glaucoma and medical histories should be completed to rule out an identifiable cause of increased eye pressure (i.e., secondary glaucoma).

Evaluating JOAG involves measuring/assessing:

• IOP,
• Visual acuity,
• Optic disk, or head of the optic nerve,
• Corneal thickness (thinner corneas increase JOAG risk), and
• Anterior chamber angle.

JOAG can be mistaken for primary congenital glaucoma (a second kind of childhood glaucoma presenting at birth), and other forms of glaucoma. Obtaining an accurate diagnosis is crucial for effective treatment.

Treating JOAG

Treating JOAG centers on reducing IOP to prevent further optic nerve damage. To do so may require imaging of the optic nerve to determine disease progression.

There are several methods of treating JOAG:

Medication

Medical therapy is the first line of treatment for JOAG, though IOP is often resistant to medication and surgery is typically needed. Often, medication is used in the lead-up to surgery. Medical therapy for JOAG includes:

• Beta-blockers, 
• Topical carbonic anhydrase inhibitors, 
• Prostaglandin analogs, and 
• Alpha-adrenergic agonists. 

If there are no contraindications, such as asthma, beta-blockers are typically tried first, as they tend to be more effective and have fewer side effects than the other options.

Surgery

There are multiple surgery options for JOAG: trabeculectomy, drainage implants, angle procedures (goniotomy, trabeculotomy), and cycloablative procedures, for example. But trabeculectomy (a procedure used to create a new drainage pathway for fluid inside the eye) is first-line therapy, producing good results in research. In one study of 60 eyes, 50%-87% of 41 patients were able to control their IOP without medication for over 3 years post-surgery. Glaucoma drainage implants (GDIs), such as the Ahmed glaucoma valve, can be useful when trabeculectomy is not possible due to conjunctival scarring. In one study involving 71 pediatric patients, the Ahmed valve had a 100% success rate over 1 year.

Laser

Laser trabeculoplasty, such as selective laser trabeculoplasty (SLT), is another option for lowering IOP. To decrease eye pressure, laser therapy increases fluid outflow from the eye through the trabecular meshwork. SLT generally isn’t as effective at lowering IOP in JOAG as surgery. Because of the tendency for misdevelopment in the eye’s anterior chamber in JOAG, SLT is generally more effective for other forms of POAG.

Disease Outlook

The prognosis for JOAG is generally good, provided it is diagnosed and treated early. Even if a trabeculectomy is needed, IOP can be lowered and loss of vision stopped.

If left untreated, however, impaired vision and blindness can result. Because glaucoma can be asymptomatic until it has become advanced, it isn’t uncommon for the diagnosis to be delayed.

Healthcare providers must have good intercommunication to improve visual outcomes in JOAG, since patients’ first medical encounter may be with emergency department personnel or a primary care provider, for example. Patients should be referred to an ophthalmologist as soon as possible, since a good prognosis is dependent on early diagnosis and treatment.

Patient and Parent Engagement

While JOAG is uncommon, information about the disease should be provided to patients and their parents. The nature of JOAG and its symptoms should be understood to help ensure early diagnosis and treatment, which is needed to maximize the odds of preventing permanent vision loss.

*Alkader Jafer Chardoub, A. & Blair, K. (2022, January 2). Juvenile Glaucoma. Treasure Island (FL): StatPearls Publishing LLC. https://www.ncbi.nlm.nih.gov/books/NBK562263