Secondary Glaucoma

Key Takeaways

• Secondary glaucoma is caused by an underlying medical condition that increases eye pressure. If not treated, glaucoma can cause vision loss and blindness.
• The most common causes of secondary glaucoma are diabetes, inflammation, prolonged steroid use, and eye injury. 
• Symptoms of secondary glaucoma may not present in the early stages of the disease.
• Late-stage symptoms occur when the optic nerve is permanently damaged.
• Initial treatment for secondary glaucoma focuses on finding the root cause of the IOP increase and using medication to lower it.

Glaucoma is a group of eye diseases that can cause vision loss and blindness by damaging the optic nerve in the back of the eye. The most common types of glaucoma stem from problems with the drainage angle.

Secondary glaucoma is triggered by an identifiable medical event, and it can happen at any age. It’s often asymptomatic in its early stages and poses a significant threat to vision.

Understanding its various causes, types, and available treatments is crucial for early detection and effective management. If you’re worried about this condition, we strongly encourage you to consult a qualified healthcare professional for diagnosis and treatment.

What Causes Secondary Glaucoma?

Secondary glaucoma is caused by an underlying medical condition that increases the eye’s intraocular pressure (IOP), leading to permanent optic nerve damage. These conditions include:

• Eye injury
• Eye inflammation
• Diabetes
• Certain medications (steroids)
• Tumor
• Cataracts
• Sickle cell disease

People with diabetes are 50% more likely to develop glaucoma. If you have diabetes, we encourage getting annual eye exams to monitor your eye health and prevent secondary glaucoma.

Types of Secondary Glaucoma

Secondary glaucoma can be classified as either secondary open-angle glaucoma or secondary angle-closure glaucoma and may occur in one or both eyes. 

The different types of secondary glaucoma are:

1. Steroid-Induced Glaucoma

Steroid-induced glaucoma is open-angle glaucoma caused by prolonged steroid use (longer than 3 weeks). It interferes with the outflow of aqueous humor, gradually increasing eye pressure.

Because the increase in eye pressure is slow, steroid-induced glaucoma is typically asymptomatic. Some people may notice blurry vision as an early warning sign. Eyebrow pain has also been associated with IOP. However, these symptoms only occur if IOP is very high.

The treatment for steroid-induced glaucoma involves stopping or reducing steroid use. Glaucoma medications can also help lower eye pressure. However, while the increase in eye pressure is treatable, damage to the optic nerve is irreversible.

2. Trauma-Induced Glaucoma

Trauma-induced glaucoma is caused by an eye injury that usually involves blunt trauma or penetrating eye injury. Penetrating and blunt trauma injuries can block your eye’s drainage system, gradually increasing IOP over time.

However, the symptoms of traumatic glaucoma depend on the nature of the injury and how fast IOP increases. For example, glaucoma from a penetrating eye injury may develop after the wound heals. Oftentimes, glaucoma symptoms won’t develop for months or years later.

After an eye injury, your doctor may recommend glaucoma medication, steroids, and antibiotics. These can reduce IOP, prevent inflammation, and reduce the risk of infection.

3. Uveitic Glaucoma

Uveitis is an inflammation of the eye’s middle layer (uvea) caused by infection, trauma, or an autoimmune disorder. Twenty percent of uveitis cases will lead to uveitic glaucoma.

Debris from the inflammation can clog the eye’s drainage system, leading to increased IOP and eventually uveitic glaucoma. Scar tissue can also disrupt the outflow of eye fluid, which often increases IOP. 

Symptoms of uveitis include:

• Redness 
• Pain
• Light sensitivity
• Floaters
• Blurry vision 

Because high eye pressure usually develops over time, uveitic glaucoma may not produce symptoms until it permanently damages the optic nerve. This is typically treated by addressing the underlying cause of uveitis.

4. Neovascular Glaucoma

Neovascular glaucoma is caused by new blood vessels growing over the angle or drainage system. Growth occurs where the iris meets the cornea, causing angle blockage, disrupting fluid flow, and increasing eye pressure.

Diabetes is a common cause of neovascular glaucoma. Other causes include:

• Chronic retinal detachment
• Tumor
• Ocular ischemic syndrome (decreased blood flow to the eye)

New blood vessel growth can occur when blood flow to the eye decreases. The eye releases chemicals called vascular endothelial growth factor (VEGF) to compensate for low blood flow, which prompts new blood vessel growth to supply the eye with more oxygen.

The symptoms of neovascular glaucoma include vision loss, pain, and redness. During its early stages, you may not produce any symptoms. The best way to catch it early is to get annual eye exams.

5. Exfoliative Glaucoma

Exfoliative glaucoma, or pseudoexfoliation, is the most common type of secondary glaucoma. It’s caused by a buildup of flakey protein in the eye’s drainage system, increasing IOP.

Exfoliative glaucoma is associated with higher and faster rates of increased eye pressure. This makes it harder to treat and manage than other types of secondary glaucoma.

As with other forms of glaucoma, people with exfoliative glaucoma might not have any symptoms until there is damage to the optic nerve. Additionally, people from Russia, Scandinavian countries (Sweden, Finland, Norway), and Greece are at a higher risk of developing exfoliative glaucoma.

6. Pigmentary Glaucoma

Pigmentary glaucoma is caused by pigmentary dispersion syndrome. It involves pigment flaking off the iris and falling into the aqueous humor.

These flaking pigments can block your eye’s drainage system and eventually lead to glaucoma. About 30% of glaucoma cases are caused by pigmentary dispersion syndrome.

Vigorous exercise, such as jogging or playing basketball, has been linked to pigmentary glaucoma. This type of secondary glaucoma occurs more frequently in young Caucasian males who are nearsighted.

Early signs of pigmentary glaucoma include blurry vision and halos around lights. Eye doctors treat it with medication that lowers eye pressure. 

7. Congenital Glaucoma

Congenital glaucoma, or newborn glaucoma, occurs due to the improper development of the eye’s drainage canals before birth. Secondary congenital glaucoma may be caused by a tumor, infection, etc.

It’s a rare condition found in babies and 3-year-old children or younger. Symptoms of congenital glaucoma include:

• Overflow of tears
• Involuntary eye twitching 
• Light sensitivity
• Enlarged eyes
• Hazy cornea
• Closing of the eyelid
• Redness

Fortunately, congenital glaucoma can be corrected with surgery. Although the condition isn’t completely reversible, treatment can prevent complete vision loss.

Treatment for Secondary Glaucoma 

Treatment depends on the cause and type of secondary glaucoma. The initial goal of treating glaucoma is to get the intraocular pressure down to a normal level through daily eye drops and other medications.

An eye doctor might recommend laser or traditional surgery if your medication can’t lower eye pressure effectively. These surgeries may include:

• Trabeculoplasty. Improves the drainage angle for better fluid flow
• Iridotomy. Creates a small hole in the iris to improve fluid drainage
• Trabeculectomy. Creates a new drainage channel
• Glaucoma drainage device. Implants a tiny drainage tube

Regular eye exams are your best defense against secondary glaucoma. Don’t hesitate to schedule an appointment with your eye doctor and discuss your concerns.