Ischemia, whether due to narrowing or blockage of a blood vessel, is often thought of in relation to the brain, but there are several types of ischemia that specifically affect the eye. Early recognition of symptoms and prompt treatment may reverse damage or preserve your remaining vision.
There is no way to entirely prevent ischemic eye conditions, but there are certain risk factors that increase the likelihood of occurrence. Much like stroke, the risk of ischemic conditions often increases as you age. Chronic diseases, such as hypertension, diabetes, and high cholesterol also increase the risk of ischemic eye condition. All of these chronic conditions have adverse effects on the vascular system, which can lead to increased eye pressure (hypertension), scarring of blood vessels (diabetes), and/or blood vessel blockages (high cholesterol).
Another risk factor is systemic inflammatory conditions, such as autoimmune diseases. One specific type of inflammatory condition, giant cell arteritis (GCA), may occur alone or is also more likely to co-occur in people with other rheumatic diseases. GCA may cause the arteries anywhere in your body to swell and constrict blood flow. This constriction may affect the blood vessels responsible for nourishing the eye, leading to decreased vision or sudden vision loss. Other ischemic conditions include stroke affecting the retinal arteries and its branches.
When you have certain risk factors, it is important to engage in a risk assessment and do what you can to control the underlying disease process. Additionally, regular eye exams are important. You should also speak with your doctor or optometrist about having routine vision exams with an ophthalmologist. Some people with elevated risk factors need thorough exams from an ophthalmologist each year.
In the case of GCA, there are unusually other symptoms that warrant thorough investigation into eye health. Since the condition has a systemic inflammatory component, blood work may show an elevated erythrocyte sedimentation rate (ESR or SED rate) or elevated c-reactive protein (CRP). Other symptoms may occur with GCA, such as scalp tenderness and musculoskeletal pain. When an eye doctor exams the eyes for indications that GCA has affected the eye, they are typically looking for pulse pressure in the eye's blood vessels. If the pulse pressure is below normal, this can indicate the vessel is becoming constricted and there is inadequate blood flow.
Unfortunately many ischemic conditions are not caught in the early stages and are only diagnosed when partial or complete vision loss occurs, especially blockage of the retinal arteries. Your eye doctor can test blood flow through the retinal arteries by injecting a special dye and watching it spread. If there is a blockage of the retinal arteries, there will be little or no dye traveling through the blood vessels.
Treatment for GCA often involves taking steroids to reduce inflammation. Some symptoms may resolve with steroid therapy, but depending on the extent of damage, some vision loss may be irreversible. Your doctor may use burst dosing to help you achieve benefits, while reducing the risk of steroid-related side effects. If necessary, you may need to be on a long-term, low-dose steroid therapy to keep your eyes stable and retain your current vision.
For blockages of the retinal arteries, treatment is time-sensitive. Much like a stroke affecting the brain, any efforts to dissolve the clot must be administered within a few hours of symptom onset to possibly reverse any vision loss. If you notice any changes or loss in vision, it is important to seek emergency treatment promptly. The quicker an eye condition is diagnosed, the more treatment options may be available.
Awareness and understanding your risk factors for ischemic eye conditions is the first step in catching problems before they occur. If you are at an elevated risk, it is important to have thorough eye examinations regularly to possibly treat problems before they lead to significant vision loss.