Choroidal Dystrophy
Choroideremia, Gyrate atrophy, Central areolar choroidal dystrophy
Choroidal dystrophies are a group of inherited eye disorders that affect a critical layer of blood vessels in the eye, potentially leading to progressive vision loss. While these conditions primarily affect males starting in childhood, understanding their nature and available support can help those affected maintain their quality of life.
Table of contents
What Is Choroidal Dystrophy?
Choroidal dystrophies are eye disorders that involve a layer of blood vessels called the choroid, which is the layer of blood vessels and tissue that lies between the sclera (the white outer part of the eye) and the retina (the light-sensitive tissue at the back of the eye)[1]. The choroid plays an essential role in providing oxygen and nutrients to the retina.
- Choroid (layer of blood vessels)
- Retina
- Sclera
These conditions belong to a heterogeneous group of genetically determined diseases that cause progressive degeneration of the choroid, pigment epithelium (a specialized layer that supports the retina), and retinal tissues[12]. The term encompasses several specific conditions, including choroideremia, gyrate atrophy, and central areolar choroidal dystrophy.
Causes and Inheritance
In most cases, choroidal dystrophy occurs due to an abnormal gene that is passed down through families[1]. These conditions are caused by genetic mutations, also known as pathogenic variants, which can be hereditary when parents pass them down to their children[3].
The condition most often affects males and typically starts in childhood[1]. Different types of choroidal dystrophies have different inheritance patterns. For example, choroideremia follows an X-linked recessive pattern, while gyrate atrophy is inherited in an autosomal recessive manner[12].
Because these conditions are genetic, family history plays an important role. If you suspect you may have this disease, collecting information about other family members who have had similar symptoms can be helpful for your medical team[3].
Early Symptoms
The first symptoms of choroidal dystrophy typically include loss of peripheral vision (side vision) and vision loss at night, a condition known as night blindness[1]. Some forms of the condition primarily affect central vision instead.
The symptom pattern varies depending on the specific type of choroidal dystrophy. For instance, in central areolar choroidal dystrophy, people usually begin noticing vision problems between the ages of 30 and 60[3]. This particular form causes a large area of atrophy (tissue breakdown) in the center of the macula (the part of the retina responsible for sharp, central vision), resulting in progressive decrease in visual sharpness[3].
Diagnosis
An eye doctor who specializes in the retina can diagnose choroidal dystrophy[1]. The diagnosis typically involves a comprehensive eye examination that may include several specialized tests.
The following tests may be needed to diagnose the condition[1]:
- Electroretinography: A test that measures the electrical activity of the retina in response to light stimulation
- Fluorescein angiography: An imaging test that uses a special dye and camera to examine blood flow in the retina and choroid
- Genetic testing: Analysis of a blood or saliva sample to detect specific gene mutations associated with choroidal dystrophies
These examinations help assess the extent of damage to the retinal and choroidal tissues and can monitor the progression of the disease over time.
Treatment Options
Clinical trials have been underway to try to slow the disease progression by injecting a form of the missing genetic material under the retina[1]. This represents an emerging approach called gene therapy, which aims to address the underlying genetic defects that cause these conditions.
Currently, there is no cure for most forms of choroidal dystrophy. However, it is important to remember that even without treatment for the underlying condition, you will not lose all your sight, as peripheral vision is typically preserved in many forms of these disorders[12].
Management of choroidal dystrophy focuses on several key areas. Regular comprehensive eye examinations are essential, as well as consultations with general practitioners and clinical geneticists when appropriate[12]. Evaluation of family members is also important to identify carriers and individuals who may have inherited the condition. Both genetic counseling and career counseling may be beneficial, as knowledge about potential visual changes can influence career choices[1].