AMD Look-Alike Conditions
Making a diagnosis of AMD and ruling out other similarly presenting conditions can be quite difficult, and will depend on physical exam findings, symptoms experienced, and the results of imaging tests. Several of these imaging tests include optical coherence tomography (OCT), fundus autofluorescence (FAF), and more. Even with all of this information, it can still be challenging to definitively make an AMD diagnosis, since there are several conditions that can look and present in similar ways. Several of these AMD look-alike conditions include, but are not limited to the following.
Best’s disease, or vitelliform macular dystrophy, is an autosomal dominant genetic condition, meaning it commonly runs in families. Individuals with Best’s disease have central field of vision loss that often starts between ages 50 and 60, although it can present anytime. Some individuals start noticing initial symptoms and vision changes before they are 40 years old, with some noticing symptoms as children. Another common symptom associated with Best’s disease is farsightedness (hyperopia). An individual with Best’s disease will test positive for a genetic mutation on a gene called the BEST1 gene.
The term pattern dystrophies refer to a group of damaging eye conditions that are inherited (passed down) within families. The name for each pattern dystrophy reflects the pattern the damage takes in the tissues of the eye.
- Butterfly-shaped pigment dystrophy
- Adult-onset vitelliform macular dystrophy
- Multifocal pattern dystrophy
Individuals with pattern dystrophies often have mild issues with central vision later in life. These issues may arise in one or both eyes, and may change over time, however, most individuals with pattern dystrophies have enough vision preserved that they can keep driving until age 70 and beyond.
Central serous chorioretinopathy (CSC)
Individuals with CSC have a buildup of fluid behind their retina (subretinal fluid). Individuals who are taking steroid-containing medications, have high levels of stress, have chronic illnesses, or who are pregnant are at a higher risk of getting CSC. CSC often affects younger individuals and resolves on its own over time. However, after an episode of CSC has resolved it can come back later on (or come back multiple times) and become chronic (long-term), which is typically diagnosed around 60 years old. Individuals with short-term, or acute CSC may not have significant symptoms or may have mild symptoms in one or both eyes, however, individuals with chronic CSC may have significant vision issues.
Telangiectasia is a dilation of tiny blood vessels called capillaries. When telangiectasias develop in the retina (macular telangiectasias) it can be due to a blood vessel-specific condition (called a vasculitis), a blockage in a retinal vein, or as the result of another underlying health issue, like diabetes, infection, inflammation, or high blood pressure. Macular telangiectasia can also occur for no reason at all, often called idiopathic macular telangiectasia. Symptoms of macular telangiectasia usually start after age 40 and lead to a progressive decline in vision. This decline is often slow and may include issues seeing straight lines (metamorphopsia), reading difficulties, or small spots of vision loss (scotomas).
Angioid streaks are caused by breaks in a structure within the eye called the Bruch’s membrane. These streaks, or lines, travel from the optic disc to the peripheral retina and typically don’t have any associated symptoms. However, eventually, individuals with angioid streaks may experience changes in their retina that can lead to choroidal neovascularization (CNV, a complication also associated with AMD), or other complications that can cause vision issues. Angioid streaks are often associated with whole body-involving health conditions, including sickle cell anemia, thalassemia, spherocytosis (all blood-related conditions), Marfan syndrome, and pseudoxanthoma elasticum (PXE, a condition that involves calcium and minerals depositing into the connective tissue within the body). The majority of those experiencing angioid streaks also have PXE.1-4
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