Glaucoma – Diagnosis, Symptoms, and Treatment

What is Glaucoma?

Glaucoma is the elevation of the pressure within the eye. These elevated pressures can lead to damage to the delicate retina which results in gradual loss of vision. 

There are two types of glaucoma “open angle” and “closed angle.” Open angle glaucoma is a painless, slow, and often missed condition that leads to gradual visual loss.  Closed angle glaucoma is a painful, rapid, and severe condition that leads to acute blurring of the vision and may result in permanent vision loss only hours after it begins. 

Glaucoma is one of the leading causes of blindness in the United States and Worldwide but is easily treated if recognized. Due to the importance of recognizing and rapidly reversing this condition, it is critical that patients understand its causes, symptoms, and treatment.

What Causes Glaucoma?

Closed-angle glaucoma, also known as acute angle closure glaucoma, is caused by blockage of small passages just below the outer layer of the eye. These passages drain aqueous humor, which circulates through the eye . This blockage leads to dramatically increased pressure within the eye which damages the optic nerve.  The optic nerve is critical for normal vision – consequently, patients with this condition often rapidly lose vision.  Closed-angle glaucoma is an emergency as it can quickly lead to blindness.

Open-angle glaucoma is an optic nerve disease (neuropathy) characterized by progressive visual loss – the disease is often associated with elevated intraocular pressure.  The condition is thought to be related to increased production of  aqueous humor in the eye. Blockage of the pores that remove aqueous humor is also thought to be a factor, but this blockage is much less severe than what is seen in acute angle closure glaucoma. 

There are several risk factors that increase the chance of developing both acute and chronic glaucoma. The most common of these are:

• Advanced age
• African American race - In open angle glaucoma
• Chinese, Korean, or Japanese ancestry - In closed angle glaucoma
• Family history
• Increased intraocular pressure

How Common is Glaucoma?

Glaucoma is relatively common in the United States. According to the United States Center for Disease Control 2.7 million Americans are living with chronic open-angle glaucoma. Closed-angle glaucoma is far more rare and estimates about its prevalence vary widely. 

The most common complication of untreated glaucoma is blindness. It is estimated that 15% of individuals with glaucoma eventually become legally blind in one eye. This is most often due to slow recognition of the disease, poor compliance with treatment, or disease that is extremely resistant to treatment. 

Signs and Symptoms

Open-angle glaucoma often has no symptoms, it is usually recognized by an optometrist or ophthalmologist during a yearly eye examination. The pressure within the eye, known as the intraocular pressure, almost always becomes elevated in glaucoma. Measurement of this pressure is a routine part of the eye exam. If open angle glaucoma goes untreated loss of the peripheral vision is often the first symptom. This generally goes unnoticed by the patient as it occurs so slowly. People close to the patient may notice decreased attention, difficulty with driving, and and increased number of falls. 

Closed-angle glaucoma is far more severe and almost always presents with a combination of the following symptoms:

• Loss of vision,
• Headache
• Eye pain
• Nausea & vomiting

With closed-angle glaucoma your doctor may notice eye redness, cloudiness of the cornea, and a poorly reactive mid-dilated pupil.  This is an emergency and often requires surgical treatment by an ophthalmologist. 

Diagnosis

The diagnosis of glaucoma depends upon its status as open-angle or closed-angle. 

Angle-closure glaucoma is generally suspected based on the symptoms and signs listed above. The definitive diagnosis of angle-closure glaucoma requires gonioscopy.  Gonioscopy is an ophthalmologic examination of the anterior (front) chamber of the eye.  Both eyes are typically checked.

Open-angle glaucoma is diagnosed by performing a funduscopic examination and visual field testing. Physical abnormalities of the optic nerve and a reduction in the visual field are the classic findings that suggest open-angle glaucoma.  They may also have elevated intraocular pressure. Screening for open-angle glaucoma should be done in all patients over the age of 40. 

Glaucoma Medication and Treatment

Angle-Closure glaucoma and open-angle glaucoma have surprisingly similar medical treatments despite their differences in severity. The main difference is that angle-closure glaucoma often require a combination of surgical and medical treatment by an ophthalmologist in the emergency setting. Open-angle glaucoma is generally treated in the outpatient setting with medical therapy alone. 

The mainstay of treatment in angle-close glaucoma are eye-drops that are designed to lower the intraocular pressure. The most common of these are:

• Timoptic (timolol) - beta-blocker
• Iopidine (apraclonidine) - alpha agonist
• Isopto (pilocarpine) – produces pupil narrowing (miosis)

Patients also typically receive one or more of the following medications during an attack of angle closure glaucoma to reduce pressure within the eye:

• Diamox (acetazolamide)
• Osmitrol (intravenous mannitol)
• Oral glycerol
• Isosorbide

Definitive therapy for angle-closure usually involves laser peripheral iridotomy – this procedure allows aqueous humor to drain out of a small hole in the iris.  Individuals that undergo this procedure should typically avoid medications such as decongestants or anticholinergics as these may cause an attack of angle-closure.

Open-angle glaucoma can be treated with medications, laser therapy, or surgery.  The first-line medical treatment is a topical prostaglandin such as:

• Lumigan (bimatoprost)
• Xalatan (latanoprost)
• Zioptan (tafluprost)

Sometimes eye drops from the classes listed above are combined with prostaglandins – this may result in a larger decrease in eye pressure than use of one agent alone.  Combinations may include a beta-blocker plus prostaglandin or beta blocker plus carbonic anhydrase inhibitor.

These prescription eye drops can be ordered online at discount savings. We offer up to 80% savings compared to your local pharmacy and you can have the medication shipped right to your door.

References:

1. Prum BE Jr, Rosenberg LF, Gedde SJ, et al. Primary Open-Angle Glaucoma Preferred Practice Pattern(®) Guidelines. Ophthalmology 2016; 123:P41. - https://www.aaojournal.org/article/S0161-6420(15)01276-2/pdf
2. Weinreb RN, Khaw PT. Primary open-angle glaucoma. Lancet 2004; 363:1711. - http://www.journalor.com/index.php/OR/article/view/30106
3. Pokhrel PK, Loftus SA. Ocular emergencies. Am Fam Physician 2007; 76:829. - https://www.ncbi.nlm.nih.gov/pubmed/17910297