What is Macular Edema? What Are Its Symptoms? How Is It Diagnosed and Treated?

This condition, which occurs as a result of fluid accumulation in the macula region located at the back of the eye, directly affects your daily activities such as reading, distinguishing details, and facial recognition. In fact, cystoid macular edema can develop with a 1-3% probability after cataract surgery. In this article, you will find what you need to know about macular edema symptoms, diagnosis, and treatment.

What is Macular Edema?

There is a small but extremely important area approximately 5 millimeters in diameter at the very center of the retina layer at the back of the eye. This region is called the macula. It covers only 5% of the retina, but it is responsible for almost 95% of your visual function.

The macula contains millions of photoreceptor cells. These cells convert the light entering your eye into electrical signals and transmit them to the brain. This region, which is particularly rich in cone cells, allows you to see in color and with sharpness.

In daily life, your activities such as reading, driving, recognizing faces, and noticing fine details depend on the healthy functioning of the macula. The very center of the macula is called the fovea, and this area has the highest density of photoreceptor cells, thus forming your point of sharpest vision.

Mechanism of Edema Formation

Macular edema occurs with the accumulation of fluid and protein deposits in this region. There are basically two mechanisms involved: increased permeability of retinal vessels and impaired vascular circulation.

When the wall of the retinal vessels weakens or their permeability increases, fluid begins to leak from the blood into the tissue. This leakage accumulates in the macular region over time, making the tissue thicker than normal. When circulation is impaired, the retina cannot be nourished sufficiently, which makes the vessels more prone to leakage.

In conditions such as diabetes, the constant elevation in blood sugar levels leads to damage in the small blood vessels of the retina. Fluid and protein leaking from the vessels accumulate in the macular region over time. Edema disrupts the normal structure of the macula, preventing light from focusing correctly.

Effects on Vision

When edema develops, your central vision is impaired. Since fluid accumulation in the macula affects light refraction, your vision becomes blurred. You may experience difficulty distinguishing letters while reading a newspaper, images appearing distorted while watching television, or objects becoming indistinct.

Straight lines appearing wavy or curved (metamorphopsia) is a common effect. Experiences such as lines blending together or letters shifting while reading may occur. Perceiving colors as faded or different is also among the changes that may be seen.

These visual changes can seriously affect your independence and quality of life. In some people, complaints increase gradually, while in others, they become noticeable in a short time.

Causes and Risk Factors of Macular Edema

Macular edema can be caused by more than one reason. Some conditions make one more prone to this problem. Understanding which causes are prominent is important for both diagnosis and treatment planning.

Diabetic Macular Edema

Diabetes is one of the primary causes of macular edema development. At least 30-40% of diabetic patients face this risk. Uncontrolled blood sugar weakens the walls of small vessels in the retina and increases their permeability.

Fluid, protein, and fat leaking from the vessels accumulate in the macula, creating edema. This clinical picture is called "diabetic macular edema" and is the leading cause of blindness in people with diabetes. High blood pressure, cardiovascular disease, and smoking further increase this risk.

The risk increases especially as the duration of diabetes lengthens. Regular eye examinations are essential because macular edema can develop even in newly diagnosed diabetic patients.

Retinal Vein Occlusion

Retinal vein or artery occlusions lead to fluid accumulation in the macula. Circulation is impaired in the area of occlusion, and sudden vision loss may occur. Complaints, which usually start in one eye, are noticed as "one of my eyes sees more blurredly."

Hypertension is a significant risk factor for retinal vein occlusions. Additionally, cardiovascular diseases, clotting tendencies, and high blood lipids are factors that should be investigated.

Intraocular Inflammation (Uveitis)

Intraocular inflammatory conditions can trigger macular edema by increasing vascular permeability. In addition to blurred vision, sensitivity to light, redness in the eye, or pain may be seen while the inflammation is active.

Rheumatic diseases or certain systemic conditions can be the cause of uveitis. Targeting only the edema without bringing the inflammation under control does not yield sufficient results.

Edema After Cataract Surgery

Cystoid macular edema may develop in some people after cataract surgery. This is one of the most common complications after uncomplicated cataract surgery. It usually appears 4-8 weeks after the surgery.

The surgery triggers a natural inflammatory response within the eye, and the permeability of the blood-retina barrier increases. Risk factors include the difficulty of the surgery, diabetic retinopathy, the presence of uveitis, and complications that occur during the surgery.

Other Risk Factors

Systemic risk factors that are effective in the development of macular edema are as follows:

Advanced age

Long duration of diabetes

High blood sugar and HbA1c values

High triglyceride and LDL cholesterol levels

Renal dysfunction (high BUN and creatinine)

Uncontrolled hypertension

Some hereditary retinal diseases, eye tumors, and rare retinal pathologies can also pave the way for macular edema.

What Are the Symptoms of Macular Edema?

Symptoms of macular edema usually start slowly and may worsen over time. Noticing the symptoms early increases the success of treatment. Since the other healthy eye can compensate for the lack of vision, it may be difficult to notice in the early stages. However, as the disease progresses, the symptoms become more pronounced and bothersome.

Central Vision and Blurring

The most common complaint is blurring and distortion in central vision. A feeling of darkening, a gap, or loss in the very center of the objects being looked at may be experienced. A hazy image or a dark spot forms in the center of the area you are looking at directly.

The clarity of the image decreases, and it becomes difficult to focus in front of a screen. Difficulty is experienced especially while reading or doing detailed work. In some people, complaints increase gradually, while in others, they become noticeable in a short time. More pronounced vision loss may be seen in one eye.

Reading Difficulty and Loss of Detail

Blurring in the center and loss of detail are among the prominent complaints. Text may become faint, and letters may blend into each other. Overlapping of words or disappearance of letters occurs.

Skipping lines while reading and letters appearing distorted are common situations. Difficulty is experienced in recognizing faces clearly or noticing fine details. Delicate tasks such as threading a needle become difficult. There may be difficulty reading or working under normal lighting conditions.

Visual fluctuations may also occur. Vision may change throughout the day, becoming clearer or more blurred. A feeling of discomfort in bright light emerges.

Distortion and Waving in Lines

The appearance of straight lines as curved or wavy is a distinguishing feature among macular edema symptoms. Patients notice that straight lines appear wavy or crooked. Lines that should normally be straight, such as door edges, window frames, and tile gaps, are perceived as wavy, slanted, or bent.

Experiences such as lines blending together or letters shifting while reading occur. While reading a book, letters appearing crooked, straight lines appearing curved, or breaks in the image are noticed. These changes may not be sudden; they can develop silently over time.

Changes in Color Perception

Colors appearing faded or less vivid is among the symptoms of macular edema. Difficulty in color perception may be experienced. Colors may appear less vivid or faded.

The loss of vibrancy of the colors seen, and perceiving them as more faded and matte than before, is a possibility. Perceiving colors differently is also among the changes that may be seen. In some cases, difficulty is experienced in distinguishing certain colors. It can cause difficulties in activities where colors are important, such as choosing clothes or preparing food.

How Is Macular Edema Diagnosed?

The diagnostic process focuses on showing whether there is fluid accumulation in the macular region and clarifying the underlying cause. The evaluation, which starts with a detailed eye examination, is supported by special imaging tests. Which tests are necessary is determined according to examination findings and the possible cause of the edema.

Fundus Examination

Fundus examination is the first step for the diagnosis of macular edema. The pupil is dilated with drops, and the retina and macular region are examined in detail. An ophthalmoscope or biomicroscope instrument is used in this examination. The light transferred into the eye through the pupil allows the imaging of the structures at the back of the eye.

During the examination, enlargement in retinal vessels, hemorrhage foci, signs of leakage, or changes that may indicate vascular occlusion can be seen. Suspicion of thickening in the macula, changes in vascular structure, and inflammatory findings are detected. This examination answers the question of "where is the problem" and determines which tests will be necessary.

OCT (Optical Coherence Tomography) Examination

OCT is considered the gold standard in the diagnosis of macular edema. This method, which provides a cross-sectional image of the retinal layers, precisely shows fluid accumulation and thickening in the macula. It is a non-contact procedure; no device touches the inside of the eye.

The scan usually takes a few seconds, and there is no feeling such as pain or burning. The patient looks at a fixed point inside the device, and the device creates cross-sectional images by scanning the macular region. OCT has been found to be 100% sensitive and 97% specific in detecting macular edema.

It measures the location and amount of fluid accumulation and the thickness of the retina in micrometers. After the diagnosis is made, comparative follow-up can be performed with the same method to monitor the response to treatment. Its most important contribution is showing fluid accumulation in detail, which is not always clearly understood during examination.

Fluorescein Angiography

Photographs of the retinal vessels are taken by injecting a special dye from a vein in the arm. FFA allows the imaging of retinal vessels using a substance called fluorescein. This test shows leaking vessels and blood flow problems.

It helps in showing which area the vessels are leaking from, where circulation is impaired, and areas of occlusion. It can be a guide, especially in diabetes-related vascular changes, retinal vein occlusions, or situations where the treatment plan is not clear. Angiography is not routinely applied to every patient.

Other Methods Used in Diagnosis

The Amsler grid test is a simple test that the patient can perform by themselves even at home. Straight lines appearing curved, wavy, or missing may indicate a macular problem.

OCT angiography is an important test that has come into use in recent years. It can examine the retina and its important vascular structures without injecting any substance into the vein. It is a method that has no harm and can be easily performed even on pregnant women.

How Is Macular Edema Treated?

The treatment plan is prepared specifically for the individual according to the cause, severity of the edema, and general health status. The goal is to reduce fluid accumulation, improve or stabilize vision, and prevent permanent damage.

Intravitreal Injection Treatments

Intravitreal drug injections are one of the most effective methods in the treatment of macular edema. Anti-VEGF drugs block the effect of the VEGF protein, which causes vascular leakage. Today, three main anti-VEGF drugs are used: Avastin, Lucentis, and Eylea.

The procedure is performed in a sterile environment, and the risk of serious infection in the eye is at the 0.01% level. The drug is administered with a thin needle into the eye, which is numbed with anesthetic drops. The patient can return to their daily activities 10-15 minutes after the injection. It is particularly effective in diabetic macular edema and edema due to retinal vein occlusion.

Treatment usually continues in the form of regular injections lasting several months. Sometimes an increase in intraocular pressure may be seen, but this situation is usually temporary. Steroid injections or implants also control edema by reducing inflammation in the eye.

Laser Treatment

Laser photocoagulation is used to close leaking vessels or reduce vascular permeability. Focal laser treatment is applied to leakage points at a distance of 500-3000 microns from the center of the macula.

The procedure is performed on an outpatient basis in polyclinic conditions. Anesthetic drops are instilled into the eye, and the treatment usually lasts 10-30 minutes. Today, it is preferred more as an adjunctive treatment together with anti-VEGF treatments.

Inflammation Control and Drug Treatments

Corticosteroids reduce prostaglandin synthesis and regulate vascular permeability. They can be injected into the eye or used in the form of implants that provide long-term effect. They are preferred in macular edema due to uveitis and some diabetic edemas.

Long-acting implants such as dexamethasone implant and fluocinolone acetonide reduce the number of injections. However, increased intraocular pressure and cataract development are the most common side effects.

Surgical Intervention Options

Vitrectomy surgery may be necessary if traction between the gel inside the eye and the macula is causing macular edema. In this operation, the gel inside the eye is removed, and the pressure on the macula is lifted. It can also be applied in treatment-resistant cases.

Control of the Underlying Disease

If systemic diseases such as diabetes, high blood pressure, or high cholesterol are contributing to macular edema, their strict control is of critical importance for treatment success. It is essential for diabetic patients to follow their blood sugar levels regularly and keep them under control.

Frequently Asked Questions About Macular Edema

Does macular edema go away on its own?

In some cases, macular edema may show spontaneous regression. Especially in edema that develops after cataract surgery, the rate of spontaneous recovery is around 80%. However, this is not always guaranteed.

In cases where vision is not significantly affected and signs of inflammation are mild, your doctor may prefer to monitor before starting treatment. Regular check-ups are performed during this process. If the edema progresses or vision begins to decrease, treatment is planned.

What happens if it is not treated?

Untreated macular edema can lead to permanent vision loss. Permanent damage develops in the macula, and central vision can decrease significantly. Daily activities such as reading, driving, and recognizing faces become difficult.

It is easier to protect vision when evaluated in the early period and an appropriate follow-up and treatment plan is made. In case of delay, the risk of permanent effects on visual clarity may increase. Therefore, it is important to consult an ophthalmologist without delay when you notice the symptoms.

How long does the treatment take?

The duration of treatment varies from person to person. Full recovery can take between two months and one year. While vision improvement is seen in some patients within a few weeks, in some cases, more than one injection and a follow-up process of several months may be required.

The recovery time is 65 weeks on average in cases with vitreous at the wound site, and 25 weeks in cases without. If there is an underlying health condition, recovery may take longer. The more successfully you respond to treatment, the shorter your treatment duration will be.

Which foods should I avoid?

There are no specific foods forbidden specifically for macular edema. However, if you have diabetes, blood sugar control is of critical importance. As blood sugar regulation deteriorates, the risk of edema increases.

In diabetic patients, the control of blood sugar is extremely important to prevent the recurrence of edema. Avoiding high-sugar foods, processed carbohydrates, and excessively salty foods is beneficial for your general health. You should create your nutrition plan together with your diabetes team.

Can it happen in both eyes at the same time?

Yes, macular edema can affect both eyes. If you have the disease in one eye, the probability of having similar involvement in the other eye is at the 50% level. Therefore, even if you have a problem in one eye, regular check-ups of both your eyes are required.

Especially in edema due to systemic causes such as diabetes or retinal vascular diseases, both eyes are at risk. Thanks to regular follow-ups, your success of early intervention increases.

Does macular edema recur?

Macular edema can recur, especially if diabetes control is not good. After the treatment is successful and vision improvement is achieved, a relapse may develop again. The rate and timing of the development of relapses change according to the severity and stage of the disease and the individual eye response.

For this reason, regular retina examinations should be performed after treatment, and blood sugar levels should be followed carefully. Early intervention plays a critical role in preventing vision loss. Not skipping your check-ups is essential to catch recurrences early.

In Summary, Macular Edema

Macular edema directly affects your central vision, but it is a treatable condition with early diagnosis. It is essential to consult your ophthalmologist when you experience blurred vision, waving in lines, or difficulty reading.

Especially if you have chronic diseases such as diabetes or high blood pressure, you should have regular eye check-ups. Treatment options are quite advanced today, and most patients respond positively to treatment.

The important thing is to take action without wasting time when you notice the symptoms. Regular check-ups and good management of your systemic diseases are of critical importance to protect your visual health.

Macular edema occurs with fluid accumulation in the eye and affects central vision. Read our article for detailed information about its symptoms, diagnosis, and treatment methods.