What is Ophthalmic Pathology of Preeclampsia?

Preeclampsia, previously known as toxemia of pregnancy, is a condition that can impact pregnant women, often in the last trimester. It introduces high blood pressure and protein in the urine, which can affect various bodily organs and lead to significant malfunctioning. Between 3% to 8% of pregnancies worldwide experience preeclampsia.

Another related condition is eclampsia, which is when a woman with preeclampsia experiences seizures that are not due to any existing neurological condition. Although it affects fewer pregnancies (0.3%), eclampsia often causes visual symptoms.

HELLP syndrome (Hemolysis, Elevated Liver enzymes, and Low Platelets) is another condition associated with preeclampsia, typically found in the last trimester or shortly after birth. It represents a severe form of preeclampsia where high blood pressure and kidney abnormalities are present, but not the primary concern.

About 25% to 40% of preeclampsia patients experience visual symptoms impacting almost all parts of the visual system, including decreased vision, double vision, blind spots, or flashes of light. Although reports of such visual disruptions in preeclampsia have been documented since the 1930s, the exact reasons remained unknown until the 21st century. While most body changes brought about by pregnancy usually return to normal after giving birth, preeclampsia-related vision and cognitive changes can persist. Recognizing the exact causes of such visual issues in preeclampsia can facilitate targeted treatment and prognosis.

What Causes Ophthalmic Pathology of Preeclampsia?

There are many reasons for changes in vision associated with preeclampsia, as well as a range of ways these changes might appear. Preeclampsia is a condition that can develop after the 20th week of pregnancy. It’s characterized by high blood pressure (with a systolic value above 140 mm Hg or diastolic value above 90 mm Hg) and a high level of protein in the urine (more than 300 mg/day).

Eye issues caused by preeclampsia can occur on their own or arise from existing eye or brain conditions made worse by high blood pressure, a common feature of preeclampsia. Blood sugar problems, also linked with preeclampsia, can add to these complications.

In addition, certain drugs used to treat pregnancy complications (like magnesium sulfate, benzodiazepines, and phenytoin) may cause vision problems. So, if you’re being treated for preeclampsia, these medications might also contribute to any changes in vision you’re experiencing.

Risk Factors and Frequency for Ophthalmic Pathology of Preeclampsia

During pregnancy, changes in vision are normal. These changes can occur due to alterations in the eye’s structure such as the ocular surface, corneal stroma, and lens thickness, and are often brought on by the hormonal shifts associated with pregnancy. While these changes usually lead to a minor shift in nearsightedness, it can be difficult to distinguish them from vision problems associated with a condition known as preeclampsia without a comprehensive eye examination.

Abnormalities in the retina’s arteries and structure are found in 30 to 100% of patients with preeclampsia and eclampsia. 70% of these patients will exhibit retinal vascular changes such as arteriole narrowing, tortuosity, or segmental retinal artery spasms. Additionally, a type of retinal detachment known as serous retinal detachment (SRD) occurs in 1 to 2% of patients with severe preeclampsia and 10% of patients with eclampsia. SRD has also been described as the only symptom for some patients with a condition called HELLP syndrome.

The condition of either temporary or permanent blindness has been reported in 0.1% to 3% of cases. One study even reported that out of more than 84,000 deliveries at a specialized hospital, 0.17% of patients suffered from blindness, and the main cause was cortical blindness – a condition commonly associated with preeclampsia, and found in 1% to 15% of such complicated pregnancies. Notably, almost a third of people with preeclampsia and eclampsia develop a reversible brain disorder called Posterior Reversible Encephalopathy Syndrome (PRES), which often results in cortical visual impairments.

The highest risk factor for cortical blindness is a history of seizures and having had multiple pregnancies. So far, little research has been done to understand the occurrence of vision problems specifically for those with preeclampsia. No studies have been identified that outline specific risk factors for acute ischemic stroke leading to visual symptoms or the toxicity of commonly administered medication leading to vision problems in patients with preeclampsia.

Signs and Symptoms of Ophthalmic Pathology of Preeclampsia

When a patient with preeclampsia experiences changes in their vision, there are several important pieces of information that can help identify the cause. This includes understanding their previous pregnancy and eye health history, medical history, any treatments they’ve received, specific details about how their vision has changed, and how these visual symptoms have progressed over time. For example, a blurry vision complaint could actually involve seeing double (diplopia), having defects in the visual field, seeing distorted shapes (metamorphopsia), or other unusual visual distortions.

For patients whose vision issues are caused by issues within the brain, a physical exam could reveal related neurological problems, associated with where the issue in the brain is located. A specific part of the eye exam, called a dilated fundus examination, is common in patients with preeclampsia. This test often shows a narrowing of the arteries, suggesting high blood pressure. Other possible findings could include swelling around the optic nerve, bleeding in the retina, fluid buildup causing retina detatchment and other issues.

Prior pregnancy history
Ocular history
Medical history
Therapeutic interventions
Specific descriptions of the visual deficit
The time-course of visual symptoms
Physical examination
Dilated fundus examination

Testing for Ophthalmic Pathology of Preeclampsia

Checking blood pressure levels and a blood test called serum creatinine are standard procedures for monitoring patients with a condition known as preeclampsia. These tests can also help predict changes in the eye examination where the doctor checks the back of the eye (this is called a dilated fundus examination).

Eye evaluations during pregnancy need a careful balance. We need to take into account the unknown risks to the baby from different diagnostic methods, against the risk of the mother developing eye and systematic diseases. One commonly used method, called Retinal angiography, uses a fluorescent dye injected into the veins to diagnose eye vascular disease. While this dye can cross into the unborn baby and can be found in breast milk, there are no known studies indicating that it’s dangerous during pregnancy. However, its use is categorized as a “pregnancy category C drug” by the FDA. This means that the risk is unknown and can’t be ruled out.

On the other hand, there are other diagnostic tools used by eye doctors that don’t pose a risk to the unborn baby. These include fundus autofluorescence, B-scan ultrasonography, and optical coherence tomography. These non-invasive tools are essential to evaluate any issues with the retina, optic nerve, and choroid (part of the eye).

“Visual field testing” is another harmless diagnostic tool. This test can identify areas in your vision where it’s difficult to see (also known as scotomata) and it can help point to where the problem might be. Issues identified by this test can include enlarged blind spots or specific patterns of sight losses.

Additionally, magnetic resonance imaging (MRI) of the brain poses no known risk to both the mother and baby. This test can reveal brain-related issues, such as swelling in the backside of the brain (a condition known as PRES), and the presence of brain strokes, either caused by blockage (ischemia) or bleeding (hemorrhage).

Treatment Options for Ophthalmic Pathology of Preeclampsia

Figuring out the cause of vision problems is crucial in predicting the health of your eyesight. This can also help manage related health conditions and determine risks for both mother and unborn child. For patients with HELLP syndrome, a pregnancy complication that can lead to serious health issues, treatment could include blood transfusions, a possible liver transplant, and delivering the baby as quickly as possible. Identifying this condition can practically be done through a detailed eye check-up.

In the case of visual problems caused by preeclampsia, a condition that can cause high blood pressure during pregnancy, treatment involves controlling the factors responsible for the condition. This can include medication to stabilize abnormal vital signs and imbalances in body chemistry. On top of that, a medicine called magnesium sulfate may be given to prevent seizures, as well as initiating labor or arranging for delivery as soon as possible.

On related note, if preeclampsia leads to a type of vision loss called cortical vision loss due to a condition named PRES, treating the blood pressure abnormalities can help recover vision and eliminate the physical signs of the condition seen in medical imaging.

Vogt Koyanagi Harada Syndrome: Patients with this condition may show signs like watery detachments in their retinas, but they also experience other symptoms. These can include eye inflammation in both eyes, skin or hair discoloration, eye pain, and hearing issues.

Changes in posture and less body fluid can lead to vision changes: If patients are dehydrated, they can have short periods of vision loss because less blood is flowing through their arteries.

Posterior Ischemic Optic Neuropathy: In severe cases where a lot of fluid is lost from the body, like after childbirth complications, vision loss can occur. This is due to a drop in blood supply to the optic nerve at the back of the eye.

Amniotic Fluid Embolus: In some cases, delivery complications like the release of amniotic fluid into the bloodstream have resulted in changes in the back of the eye, leading to retinopathy, a disease that causes damage to the retina.

Increased Intracranial Pressure: When pressure in the skull is higher than normal, this often results in swelling of the optic nerve, headaches, and changes in vision. This can be caused by a variety of factors, such as a space-occupying lesion in the brain, clotting in the brain’s venous sinuses, seizures during or after childbirth, or meningitis. In pregnant patients, it can be hard to tell if the pregnancy and related changes are causing this condition, known as idiopathic intracranial hypertension, or are just making a pre-existing condition worse. It’s important to catch venous sinus thrombosis in these patients, as it happens more often in pregnant women and is thought to cause about 2% of strokes related to pregnancy.

What to expect with Ophthalmic Pathology of Preeclampsia

Visual problems and blindness due to preeclampsia, a condition that occurs during pregnancy, are generally reversible. Many patients who suffered from eyesight issues related to preeclampsia eventually regained their full vision after giving birth. However, longer studies of individuals with preeclampsia have revealed lasting changes in the tiny blood vessels of their retina (the back part of the eye) and cerebral white matter, which is an essential part of the brain.

The study also found that these patients have an increased likelihood of developing disease in the retina’s structure and vessels. Specifically, patients with preeclampsia have a 5.3 times greater risk of tractional retinal detachments (a condition where the retina pulls away from its normal position), an 8.5 times higher chance of having retinopathy (damage to the retina) whether or not they have diabetes, and also a 3.7 times heightened risk of retinal breaks (tears or rips in the retina) later in their life. Moreover, these retinal changes remained noticeable for at least six years after giving birth.

Additionally, patients with preeclampsia exhibited higher risks of lesions (damaged areas) in their cerebral white matter after giving birth. One small study found significant differences in where these lesions were located in patients with preeclampsia compared with those who did not have this condition. In patients with preeclampsia who had these lesions, all of them experienced frontal lesions (damage to the front part of the brain), and they had the highest rate of temporal white matter lesions (damage to an area toward the side of the brain). Patients who developed eclampsia, a severe form of preeclampsia, most commonly had parietal white matter lesions (damage to an area toward the back of the brain). These lesions resulted in significant vision issues for those with a history of eclampsia. However, visual field testing, which checks a person’s range of vision, was found to be normal in patients who had preeclampsia and eclampsia.

Possible Complications When Diagnosed with Ophthalmic Pathology of Preeclampsia

Changes to the blood vessels in the retina of the eye can indicate a higher risk of death for both the mother and baby. If conditions like preeclampsia and eclampsia (high blood pressure during pregnancy) are not properly treated, they can cause everlasting vision problems. In fact, up to 8.5% of patients with preeclampsia may end up with a condition known as geographic atrophy, which can severely affect the central vision. Some brain changes have been observed to last well after the woman has given birth and fully recovered. Certain studies suggest that women who have had preeclampsia have a higher occurrence of certain lesions in the brain, regardless of overall heart health, and this appears to increase as more time passes after delivery.

Notable Effects:

Increased maternal and fetal mortality risk
Potential permanent vision impairment due to preeclampsia and eclampsia
Possibility of developing geographic atrophy that affects central vision
Persistent brain changes post-delivery

Preeclampsia also increases the risk of a stroke later in life. The risk of a stroke is believed to be about 80% higher for these patients, and the odds ratio (which measures the relative risk) is between 1.87 and 2.02. Simply bearing a child can increase the risk of certain conditions like atherosclerosis and carotid disease, which can cause vision problems. Additionally, stroke and heart diseases during or after pregnancy can also lead to various causes of vision impairment. It’s also important to note that women with preeclampsia have a higher risk (between 2 and 7 times more) of developing heart and kidney diseases.

Notable Risks:

Increased risk of stroke in the future
Risk of developing atherosclerosis and carotid disease from carrying a child
Possible vision impairment from stroke and heart disease during or after pregnancy
2 to 7 times higher risk of cardiovascular and renal diseases

Preventing Ophthalmic Pathology of Preeclampsia

Changes in vision during pregnancy, especially for those experiencing preeclampsia, are often due to issues with the eyes or brain. Sometimes, these changes can be a side effect of medical treatment. It’s important for patients to be checked out by a pregnancy specialist (obstetrician) and an eye doctor (ophthalmologist) to figure out what’s causing these changes. If a patient develops preeclampsia during their pregnancy, it could lead to a higher risk of developing other diseases that affect the eyes or brain after childbirth.