When diagnosed with wet age-related macular degeneration, patients may already have more advanced signs of the disease and suffer from conditions like blurry vision, difficulty recognizing faces or issues reading without bright light . Vision is threatened due to the underlying pathology at play. When patients have wet macular degeneration, blood vessels are growing on the surface of their macula in an effort to save tissue that is no longer receiving nutrients or oxygen . Long-standing cigarette use or hypertension are two likely culprits of why this happened in the first place . In order to save the vision, macular degeneration treatment needs to be started immediately generally in the form of Anti-VEGF therapy . Even if this the best option available to save your vision, patients may notice increased eye pressure after intravitreal injections. Here, I will explain why this happens and what you can do to help manage the discomfort.
Why Does Your Intraocular Pressure Increase After Intravitreal Injections?
Patients may notice increased eye pressure after intravitreal injection that can last for short or long periods of time. Short-term spikes in intraocular pressure are quite common and they are self-limited but long-term increases in pressure can also occur and are less understood by modern medicine . When discussing the short-term increase in intraocular pressure, the mechanism behind it is pretty self-explanatory. When a patient has more fluid added to his eye after an injection, there will be a natural increase in eye pressure because of more fluid in the same small cavity. As patient ages, their sclera will naturally become more rigid. Most patients also have hyperopic eyes and are already using reading glasses to help them see. Both of these are the main reasons why this fluid is unable to pass very freely between chambers of the eye. 
In one study attempting to quantify the increase in pressure, patients noticed intraocular pressures of over 30 mmHg in 89 percent of patients receiving intravitreal injections . These studies also showed that intraocular pressure returned to near-normal or normal levels within 30 to 60 minutes after injections (under 15) .
Long-term increases in pressure are more problematic because there are usually underlying problems associated with the eye health. May patients have glaucoma that have extended periods of increased intraocular pressure and patients require medications in order to reduce the pressure of their eyes. Studies show that this is a problem in 2.1 percent of cases for longer than a 2 year period, compared to 0.4 percent of the control group .
What Can You Do About It?
As you can see, in most cases of increased intraocular pressure, patients will have a resolution of symptoms within the first hour after the injection but that does not mean that every patient will be so lucky. When more aggressive management is necessary, physicians will do their best to ensure that the intraocular pressure drops to prevent any long-term complications or discomfort. Doctors will typically use a combination of drugs like bimatoprost and timolol in order to dilate drainage canals that are found within the eye in order to allow some of the excess fluid to escape and relief the pressure .
In some experimental investigations, it was proposed that patients with long-standing increased intraocular pressure could be managed similarly to patients suffering from glaucoma. In one particular investigation, patients underwent surgical procedures to put in metal implants to ensure the canal that drains fluid from the eye stays open. This investigation was run for a period of 3 years and patients were found to have intraocular pressures near-normal at 15, 16.5 and 16 respectively during the 3 years compared to control values found over 23. This shows that this is a potential solution to help reduce the pressure in the eye over a long period of time. 
If the intraocular pressure is not managed appropriately, patients risk the potential development of glaucoma. This is a condition marked by permanently elevated levels of intraocular pressure that can damage the optic nerve innervating the eye and giving you vision. Not surprisingly, if you do not prevent the optic nerve from getting damaged, patients may never regain vision and will suffer from painful headaches in the process. 
All in all, macular degeneration is more threatening than glaucoma so patients need to seek macular degeneration treatment even with the slight chance of developing long-standing increased intraocular pressure. Thankfully, the increased eye pressure after intravitreal injections will be something that resolves quickly in most cases when patients have injections and patients will only have the benefit of anti-VEGF without the risks of long-term complications.