“At this time, there is no treatment for an ocular infarction that has been proven to restore vision. Because the consequences of the infarction are so severe, scientists are continuing their search for an effective treatment. For example, there is currently a lot of focus on treatment with thrombolysis, an IV infusion that uses medication to dissolve the blood clot,” explains ophthalmologist Irene Temmerman of the Rotterdam Eye Hospital.
Temmerman: “There are currently three studies underway in Europe investigating the treatment of retinal infarction with thrombolysis. However, it has proven challenging to find enough patients to participate in these studies. This is because it is important that patients receive the infusion within 4.5 hours of the first symptoms. If you wait longer than that, the treatment is no longer effective, because the retina has been too severely damaged by the lack of oxygen. This was demonstrated in earlier studies conducted in 2010 and 2011. These studies were halted early because initial results showed that vision did not improve, but patients could experience serious complications, such as a brain hemorrhage. These initial studies treated patients who sought medical attention within 24 hours of the onset of symptoms. However, later research showed that improved vision occurred only in patients who were treated within 4.5 hours. Armed with this knowledge, new studies have been launched that take this time frame into account.
Extensions of the brain
In neurology, people with a cerebral infarction are already treated with thrombolysis. Dr. Temmerman: “A cerebral infarction and an ocular infarction are not so different. You can think of the eyes as a kind of special extension of the brain. The artery that carries oxygen to the brain via the neck also has a branch that supplies the artery leading to the eye.”
An ocular infarction usually means that the patient’s other blood vessels are also in poor condition. Often, the artery in the neck has narrowed, causing small blood clots to travel from there to the eye. Of course, such a blood clot can also travel on to the brain. So when someone with an ocular infarction comes to us, we quickly refer the patient to the neurology department. About thirty percent of patients with an ocular infarction have also had a cerebral infarction without realizing it. The neurologist, possibly in collaboration with a cardiologist, assesses the condition of the blood vessels. Depending on the results, medications such as blood pressure-lowering drugs and cholesterol-lowering pills may be prescribed to protect the blood vessels from further damage. Blood thinners may also be prescribed to reduce the risk of another blood vessel blockage.”
Follow-up remains important
The ophthalmologist continues to monitor patients with a blind eye during follow-up appointments. Dr. Temmerman explains why: “The lack of oxygen caused by the infarction causes the cells in the retina to produce extra molecules. This can lead to the growth of new blood vessels. In 15 to 20 percent of patients, these new blood vessels form at the front of the eye. This causes high intraocular pressure and can eventually lead to a painful, blind eye. That is why it is important to continue monitoring patients after an eye infarction, even if there is little more we can do to preserve their vision.”
