Many glaucoma patients are informed that treating high intraocular pressure (IOP) will prevent their vision from deteriorating. In some patients, however, this isn’t the case—your vision can continue to deteriorate even with your glaucoma under control.

Glaucoma is a complex disease that medical professionals and scientists are still learning more about every day. Controlled glaucoma may sometimes still lead to progressive vision loss, but there are several recommendations to prevent vision loss from occurring and/or worsening.*

How is “controlled glaucoma” defined?

Every glaucoma patient is diagnosed with a stage of glaucoma, which determines the severity and aggressiveness of the disease.

Your doctor determines this by looking at: 

• IOP
• Fluctuation in IOP (as many people have higher IOP in the morning)
• Damage to the optic nerve and visual field 

From there, your doctor can determine if your glaucoma is controlled during follow-up visits.

“Controlled glaucoma” means: 

• Your IOP is within a certain range during an entire day with consistent use of glaucoma medications and/or after an operation.
• You take your glaucoma medications as prescribed. 

Why can progressive vision loss occur in controlled glaucoma?

• High IOP fluctuations: Certain types of secondary glaucoma—mainly pseudoexfoliative and pigmentary glaucoma—are more difficult to control. Even when monitoring your IOP multiple times a day, your IOP peaks may be unpredictable in both time and duration.
• Increased IOP in a supine position: Research shows IOP increased in individuals when lying down. Since most people spend at least six to eight hours a day asleep, this could be a cause for worsening vision. 
• Increased IOP when sleeping on affected eye(s): When your affected eyes are pressed up against a mattress or pillow at night, your IOP can increase by 33%.
• Antihypertensive drugs at bedtime: If you have atherosclerosis and/or systematic hypertension, you may be prescribed to take antihypertensive drugs before you go to sleep. These drugs decrease blood flow to the optic disc, which increases the risk for anterior ischemic optic neuropathy (AION) before bedtime. Ultimately, this damages the optic nerve and leads to vision loss.
• Continuation of neuronal apoptosis: Glaucoma patients with high IOP lose optic nerve function, particularly due to the loss of axons. Axons are long cables along which the neurons of the eye send electrical impulses to other neurons. While high IOP may initiate apoptosis, neuronal apoptosis (programmed neuron death) may continue even when IOP is treated with medication and/or surgery. 

What can help prevent further vision loss with controlled glaucoma? 

For patients with uncontrollable IOP, your physician may suggest early surgery, such as trabeculectomy with mitomycin C or tube-shunt surgery.

Other recommendations to prevent vision loss include: 

• Try to sleep at a 20- to 30-degree angle with your head facing upwards. Research shows this may decrease IOP by nearly 10% in glaucoma patients.
• Avoid sleeping on your affected eye(s).
• Take your antihypertensive medications when you’re awake and active, not at bedtime.
• Work with your physician on treatments to slow down neuronal apoptosis. Certain antibodies have been proven to be helpful. 

*Rumelt, S., & Schreiber, S. (2018, Sept. 19). Why Do Patients with Controlled Glaucoma Continue to Lose Their Vision?. Intech Open. https://www.intechopen.com/books/causes-and-coping-with-visual-impairment-and-blindness/why-do-patients-with-controlled-glaucoma-continue-to-lose-their-vision-

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