Retinal thickening is a sign of an underlying issue within the eye. It signifies that fluid has accumulated in the retina, the light-sensitive tissue lining the back of the eye, causing it to swell and increase in thickness. This swelling occurs when nearby blood vessels are damaged or abnormal and predominantly affects the macula, the central part of the retina responsible for sharp, detailed, and color vision.
The retina’s job is to convert light that enters the eye into electrical signals, which are then sent to the brain to create the images we see. When the retina thickens with fluid, this process is disrupted, particularly impacting central vision. This can interfere with everyday activities that require clear sight, such as reading, driving, or recognizing faces.
Associated Medical Conditions
A primary cause of retinal thickening is diabetic retinopathy, a complication of diabetes. Persistently high blood sugar levels can weaken and damage the walls of the tiny blood vessels throughout the retina. These compromised vessels can begin to leak fluid, blood, and fats into the retinal tissue. As this fluid accumulates, the retina swells, a condition known as diabetic macular edema.
Another condition is wet age-related macular degeneration (AMD). In this disease, abnormal and fragile blood vessels begin to grow underneath the retina in a process called neovascularization. These new vessels are unstable and prone to leaking blood and fluid directly into the macula. This leakage leads to rapid swelling and subsequent vision distortion.
Retinal vein occlusion (RVO) is a further cause, acting like a blockage in the eye’s drainage system. When one of the small veins that carries blood away from the retina becomes blocked, pressure builds up in the capillaries. This pressure forces fluid out of the blood vessels and into the retinal layers, causing macular edema.
Other issues can also lead to a thickened retina. Inflammation within the eye, a condition called uveitis, can cause blood vessels to become leaky and result in swelling. Additionally, some patients may experience temporary retinal thickening after undergoing eye surgery, such as for cataracts. The inflammatory response to the surgical procedure can lead to fluid buildup in the macula.
Recognizing the Symptoms
Symptoms of retinal thickening are centered on central vision. One of the most common signs is metamorphopsia, where straight lines appear wavy or distorted, making objects like door frames or text look crooked. This distortion is a direct result of the fluid buildup physically altering the shape of the macula.
A general blurring of central vision is also a frequent complaint, making it difficult to perform tasks that require sharp sight like reading or recognizing faces. This blurriness occurs because the swelling interferes with the retina’s ability to focus light accurately.
Colors may seem faded or washed out, a symptom known as dyschromatopsia. The fluid in the retina can affect the function of the cone cells, which are responsible for color perception. Some individuals might also notice a dark, gray, or blank spot in their central vision, which can vary in size.
Diagnostic Procedures
To confirm retinal thickening, an eye doctor will perform a series of diagnostic tests. The process begins with a dilated eye exam, where drops are used to widen the pupils, allowing the doctor a clear view of the retina. During this examination, the doctor can often see visible signs of swelling or fluid.
The most definitive tool for diagnosing and quantifying retinal thickening is Optical Coherence Tomography (OCT). This non-invasive imaging test uses light waves to create a high-resolution, cross-sectional map of the retina’s layers. An OCT scan allows the doctor to precisely see and measure the thickness of the retina and identify the exact location of fluid accumulation.
To assess the condition of the retinal blood vessels, a fluorescein angiogram may be performed. This procedure involves injecting a dye into a vein in the arm. As the dye circulates to the eye, a special camera takes a series of photographs of the retina. These images highlight the blood vessels and can reveal any areas where vessels are leaking fluid, helping to pinpoint the cause.
Available Treatment Options
Treatment for retinal thickening focuses on addressing the fluid leakage to reduce swelling and preserve vision. The most common approach involves medications known as anti-vascular endothelial growth factor (anti-VEGF) agents. These drugs are administered by injection into the eye and work by blocking the action of VEGF, a protein that stimulates abnormal blood vessel growth and leakage.
For cases involving inflammation, steroid treatments may be recommended. Steroids can be administered as injections or as a surgically placed implant that slowly releases the medication over time. These treatments are effective at reducing inflammation-related swelling within the retina.
Laser therapy is another option, though it is used more selectively today. Focal laser photocoagulation uses a low-energy laser to seal specific, leaking blood vessels in the retina. This procedure helps to stop the leakage at its source, allowing the swelling to resolve over time.
Managing the root cause of the retinal thickening is a component of long-term success. For individuals with diabetic retinopathy, this means maintaining strict control over blood sugar, blood pressure, and cholesterol levels. By managing the systemic disease, patients can help prevent the recurrence of retinal swelling and protect their vision.