What is Retinal Macroaneurysm?
Retinal macroaneurysm is a term that refers to a condition of the eye wherein an artery in the retina (the part at the back of the eye) swells, it was first named by Robertson. This swelling generally happens in the back part of the retina where the central retinal arteries divide into smaller branches two or three times, or where arteries cross with veins. The artery at the upper outer part of the retina is usually affected most often. This condition can be related to high blood pressure and cardiovascular diseases that cause hardening of the arteries.
Most often, people with a retinal macroaneurysm do not notice any symptoms. Changes in vision may happen if there is swelling in the macula (the portion of the retina that allows us to see fine details clearly), blockage of the tiny arteries due to a clot, or bleeding caused by the bursting of the swollen artery. Some of these swellings can go away on their own due to the formation of a natural clot, but others might need treatment.
To properly manage retinal macroaneurysms, it is essential to identify them early and control any underlying health issues like high blood pressure. Several tools are used for diagnosing and managing this condition. These include fundus fluorescein angiography, indocyanine green angiography, optical coherence tomography, and ultrasonogram B scan – all of which are types of eye imaging tests. If the condition is complex, treatments like laser seals on the affected area, injection of medication into the eye, procedures to clear out excess fluid from the eye, or surgery may be needed.
What Causes Retinal Macroaneurysm?
The main risk factors related to Retinal Artery Macroaneurysms (RAM), a condition where the blood vessels in the retina of the eye balloon and may burst, are long-term high blood pressure (found in 75% of patients), hardening of arteries (arteriosclerosis), abnormal cholesterol levels, and in-born issues with the structure of blood vessels. These conditions lead to a lack of blood flow to the walls of blood vessels, resulting in increased leakage from the vessels and changes to the tissue. This can cause the vessels to form balloons (or aneurysms) in either a sac-like or spindle-shaped manner.
Other possible risk factors include Coat disease, von Hippel-Lindau disease, diabetic retinopathy, and radiation retinopathy, all conditions that affect the retina of the eye.
Retinal arteriolar aneurysms, a specific type of RAM, may be seen along with ocular sarcoidosis, peripheral multifocal chorioretinitis, and IRVAN (a condition involving inflammation of the retinal blood vessels, aneurysms, and neuroretinitis).
Retinal capillary macroaneurysms or microaneurysms are results of a lack of blood flow due to blockage in the veins. These are commonly seen with diabetes or diseases that cause blockages in the veins.
Retinal venous macroaneurysm, another specific type of RAM, can occur in branch retinal venous occlusion. This type of aneurysm can often be seen in patients with long-term high blood pressure. However, there have also been cases where these type of aneurysms occurred without any blockage in the veins.
Risk Factors and Frequency for Retinal Macroaneurysm
Retinal arterial macroaneurysms (RAM) are generally found more frequently in elderly people, particularly between the ages of 66 and 74, and are more common in women, with women accounting for 70% of cases. In the adult Chinese population, the occurrence of these macroaneurysms is estimated to be 1 per 9000 eyes, based on research from the Beijing Eye Study. Although most cases involve just one macroaneurysm affecting one eye, some people may have multiple aneurysms. This is the case for 15 to 20% of people with retinal arterial macroaneurysms. Also, around 10% of people with this condition have it in both eyes. According to a study by Nangia and others, in Central India, there is 1 case of retinal artery macroaneurysm for every 1500 people over the age of 30.
- Retinal arterial macroaneurysms (RAM) are more frequently observed in elderly individuals aged 66 to 74.
- Women account for 70% of RAM cases.
- In the Chinese adult population, the occurrence of RAM is roughly 1 per 9000 eyes.
- Most RAM cases involve a single macroaneurysm in one eye, but 15 to 20% of cases can have multiple aneurysms.
- About 10% of people with RAM have the condition in both eyes.
- In Central India, the prevalence of RAM is about 1 in 1500 people over the age of 30.
Signs and Symptoms of Retinal Macroaneurysm
Retinal artery macroaneurysm is a condition related to the heart of the retina. It can be simple or complex. The complex ones usually have additional complications such as hemorrhage. They typically occur in the temporal part of the retina, often affecting the upper part of the temporal vessel and the lower-temporal arcade.
Many times, the patients do not notice any symptoms unless the area of the retina responsible for central vision is affected. Some symptoms may include changes in vision, decreased visual sharpness or floaters due to bleeding or swelling of the macula. In some cases, rapid and severe vision loss can occur. The symptoms and the severity depend on the type of macroaneurysm which are generally of three types:
- In a quiescent form, visual symptoms are uncommon. There’s little or no bleeding or swelling – and if there is, it doesn’t affect the macula and is less than one-disc diameter in size.
- In a hemorrhagic form, which accounts for half of all cases, rapid vision loss can occur due to significant bleeding of an area larger than one disc diameter. This type of macroaneurysm is often found closer to the disc and is associated with several types of bleeding, that can be simultaneously present. Certain anticoagulant and antiplatelet drugs can also lead to subretinal bleeding.
- In the exudative form, there’s a slow drop in visual acuity over time. Swelling or leaking occurs from damaged vessels around the macroaneurysm, causing long-lasting deposits and chronic macular swelling. Sometimes – though it doesn’t affect vision – you might see swelling just around the macroaneurysm, which usually has a good prognosis.
Sometimes, you might see spontaneous pulsations adjacent to the arterial wall in a simple macroaneurysm, which suggests an impending rupture. However, this is still a subject of debate, as there are no definitive indicators of an impending rupture.
The hemorrhagic form is often linked with high blood pressure or heart conditions, while the exudative form is associated with blockage in the retinal vein. There can also be mixed variants with either a predominant bleeding or a swelling component. Retinal capillary macroaneurysms typically cause swelling of the surrounding retinal tissue, and retinal venous macroaneurysms could cause a bleeding in front of the macula.
Testing for Retinal Macroaneurysm
If your doctor suspects an eye-related problem, they might conduct a series of tests and examinations to make an accurate diagnosis. This usually involves a thorough eye check, which includes an examination of the inner lining of your eye (fundus examination), blood pressure measurement, and lipid profile test. These routine evaluations help to identify any related health issues.
Fundus Fluorescein Angiography (FFA) is one such test that’s essential to diagnose and outline the lesion or abnormality. FFA is very useful, especially when the aneurysm—an abnormal bulge in the wall of a blood vessel—within your eyes is hard to see due to blood leakage or changes over time. This test allows doctors to observe any unusual pooling of dye that could indicate aneurysms.
Some areas with abnormal blood vessels may leak and contribute to swelling in the retina, which can cause blurred or distorted vision. If there’s a heavy blood leakage or a considerable amount of lipid present in your eye, it can block the ability to see clearly during the test.
FFA can also provide useful hints regarding other irregularities such as tiny outpouchings from the walls of capillaries, areas of poor blood flow, unusual blood vessel formations, and small irregular dilations in blood vessels.
Another diagnostic tool is Indocyanine Green Angiography (ICG-A). This is useful when blood leakage obscures the view of the aneurysm because this test uses near-infrared light which can penetrate more deeply into the eye. ICG-A helps pinpoint the location of the aneurysm, which is essential for treatment planning. This test can also rule out certain eye conditions that can also cause a similar type of bleeding.
Optical Coherence Tomography (OCT) is another helpful tool in diagnosing retinal artery macroaneurysm. This non-invasive imaging test uses light waves to take cross-section pictures of your retina, helping to identify any abnormal elevations or fluid accumulation in your eyes’ internal layers. OCT is also useful in quantifying the amount of swelling and differentiating various levels of blood accumulation.
OCT Angiography is a recent diagnostic technique useful to display the small outpouchings in blood vessels and changes in fluid and blood vessels over time. This tool is helpful in plan the treatment steps.
Ultrasound B-scan, USG B Scan, is useful when the internal lining of the eye is not visible or in cases of substantial blood leakage. It also helps distinguish the retinal tears or detachments from aneurysm or other related conditions causing breakthrough bleeding.
All of these diagnostic modalities can also be used to identify other eye conditions. The most important thing to remember about retinal artery macroaneurysm is that it’s directly connected to an arteriole (small artery branch), and there’s the presence of bleeding in multiple retinal layers.
Treatment Options for Retinal Macroaneurysm
Retinal artery macroaneurysms, or RAMs, are bulging blood vessels in the eye. Many of these macroaneurysms tend to get better on their own, so doctors usually just keep a close eye on them. It’s important for patients with RAMs to manage any other health conditions they have, such as high blood pressure, to decrease the risk of the macroaneurysm breaking open, or rupturing.
When a ruptured RAM leads to bleeding but doesn’t affect the part of the eye responsible for sharp, central vision (the macula), the doctor might decide to monitor the patient closely at first and then every one to three months to see if the macroaneurysm has healed itself. In some cases, patients with RAMs that threaten their vision due to severe bleeding may also be watched closely for three months because these macroaneurysms can sometimes get better on their own without causing a lot of harm.
Treatment is usually recommended when the macroaneurysms become complicated or fail to get better over time. There are a variety of treatment options available:
1) Laser Photocoagulation – This treatment uses a laser to seal the macroaneurysm and stop it from leaking. It’s typically used in cases of a hemorrhage (bleeding) or exudation (leakage of fluid) involving the macula.
Direct laser photocoagulation involves applying the laser directly to the macroaneurysm. Indirect laser photocoagulation works by reducing oxygen consumption and blood flow to the aneurysm.
There’s also a specialized type of laser photocoagulation called subthreshold laser which is useful when the area around the macula is affected. This treatment doesn’t create a visible burn but instead causes a selective damage to certain cells in the eye.
2) Intravitreal Injection of Anti-VEGF – This treatment involves injecting medication directly into the eye to reduce the swelling and leakage from the macroaneurysm.
3) YAG Laser Hyaloidotomy – This method is used for treating pre-retinal hemorrhages, or bleeds in front of the retina. It allows the blood to dissolve into the vitreous, the jelly-like substance inside the eye.
4) Pneumatic Displacement with or without tPA Injection – This treatment is used for submacular hemorrhages, or bleeds under the macula. It utilizes gas bubbles and the force of gravity to move the blood out of the macular area.
5) Pars Plana Vitrectomy (PPV) – This surgical procedure might be needed in patients with ongoing or severe vitreous hemorrhage. The surgeon will remove the vitreous gel from the eye and replace it with a saline solution to clear up the patient’s vision.
Even with these treatment options, it’s important for doctor and patient to carefully weigh the benefits and potential complications. If in doubt, seek a second opinion before proceeding with any treatment plan.
What else can Retinal Macroaneurysm be?
When assessing retinal macroaneurysm, physicians would look into ruling out several other conditions that might exhibit similar symptoms. These conditions include:
- Diabetic retinopathy
- Retinal telangiectasia
- Von Hippel-Lindau disease
- Radiation retinopathy
- Retinal capillary angioma
- Cavernous hemangioma
- Malignant melanoma
- Polypoidal choroidal vasculopathy
- Valsalva retinopathy
- Hemorrhagic pigment epithelial detachment of age-related macular degeneration
It’s also critical to differentiate vitreous hemorrhage in a retinal macroaneurysm from conditions like retinal vein occlusion, acute posterior vitreous detachment, or proliferative diabetic retinopathy.
Meanwhile, conditions like Coats disease, Leber miliary aneurysms, and angiomatosis retinae are important to consider when there’s significant fluid leakage in the retina. Further, a host of factors such as tumors, high myopia (nearsightedness), trauma, and Valsalva retinopathy can cause submacular bleeding, which is when blood collects beneath the central part of the retina.
Specific conditions, such as angioid streaks, coagulopathies, diabetic retinopathy, central retinal vein occlusion, choroidal neovascularization, and certain medications like aspirin, warfarin, and clopidogrel are all associated with subretinal hemorrhage, where blood accumulates beneath the retina.
Retinal capillary macroaneurysms are usually linked with diabetic retinopathy and reduced blood flow secondary to disorders that cause vein blockages. Other related conditions can include infectious, inflammatory, blood-related, and radiation-related disorders. It is also worth mentioning that retinal venous macroaneurysm can coexist with branch retinal venous occlusion, or exist independently without any history of eye or systemic disease.
Multiple retinal arterial aneurysms are commonly associated with conditions like idiopathic retinal vasculitis and neuroretinitis, which may also present as Retinal Venous Macroaneurysm (RVM). They can come in different shapes and forms including spheroid, Y-shaped, and fusiform.
In some cases, multiple retinal arterial macroaneurysms can occur in an inflamed eye in people with ocular sarcoidosis, a condition where inflammatory cells produce small lumps called granulomas. Aneurysms are more common in the chronic phase of ocular sarcoidosis, and more than one aneurysm can exist in a single eye. Moreover, Retinal Macroaneurysms can occur in ocular sarcoidosis along with optic disc granuloma, arteritis, and uveitis.
What to expect with Retinal Macroaneurysm
The future of your eyesight, or your visual prognosis, can depend on several factors:
* The type of RAM (retinal macroaneurysm) – There are different types of RAM, which is an enlarged blood vessel in the eye. The ‘sleeping’ form, or quiescent retinal macroaneurysm, gives you the best chance of maintaining good vision. If the enlarged blood vessel bleeds but doesn’t damage the central area of the retina (macula), the prognosis is also good as it can usually heal on its own without treatment.
* Presence of exudates/edema – When there’s a build-up of certain material (exudates) or swelling (edema), you can experience permanent vision loss. This build-up or swelling can be caused by leakage from the enlarged blood vessel or other damaged vessels around it.
* Severity – An enlarged blood vessel that results in more extensive blood or fluid build-up could lead to more serious vision loss.
Time and location also play important roles:
* Duration – Long-lasting swelling or build-up is less likely to see improvement.
* Position – Blood in front of or within the jelly-like substance in your eye (pre-retinal and vitreous hemorrhage) can clear up and result in good results for your vision. However, if the blood gets under your retina (subretinal or submacular hemorrhage), it can damage important layers of your eye and cause poor sight. This is because it prevents the transport of essential nutrients, exposes your eye to iron toxicity, and can damage your retina. Within as little as two days to up to two weeks, permanent and irreversible damage can occur.
Keep in mind that each of these factors could influence each other, making your overall prognosis more complex.
Possible Complications When Diagnosed with Retinal Macroaneurysm
Retinal artery macroaneurysm can lead to various issues in different layers of the eye, including multilayer blood leakage and long-standing macular swelling or “edema”. It can trigger secondary angle-closure glaucoma (a type of eye pressure problem), blockage in retinal vein, a buildup of clear or bloody fluid under the retina, growth of new blood vessels under the retina, development of a fibrous membrane on the eye’s surface, or even the creation of a hole in the macula, the part of the eye responsible for sharp central vision.
Side Effects:
- Multilayer blood leakage
- Chronic swelling of the macula
- Secondary angle-closure glaucoma
- Retinal vein blockage
- Serous or bloody fluid buildup under the retina
- New blood vessel growth under the retina
- Development of fibrous membrane on the eye’s surface
- Creation of a hole in the macula
If retinal capillary macroaneurysms persist, they can lead to a condition called Type 3 macular neovascularization.
Preventing Retinal Macroaneurysm
Patients with RAM, which is a condition affecting the blood vessels of the eye, need to be checked for conditions like high blood pressure, high cholesterol, and stiffening of arteries by their regular doctor in order to prevent this eye condition. They also need to understand what RAM is, the possible issues that it can cause, and the different ways we can treat it. It’s very important that patients understand that they can prevent this condition, but it requires them to follow the advice given by both their primary doctor and their eye specialist.
