Introduction
Eyes are prone to a lot of infections and injuries from environmental factors, during the course of life. But there are conditions that will be inherited from the parents. One such condition, which is inherited from a parent is the stargardt disease, also known as fundus flavimaculatus.
What Is Stargardt Disease?
Stargardt disease is an inherited disorder and macular degeneration disorder of the eye's retina, affecting children and young adults. The retinal layer of the eye carries out the main function of transferring signals received from the environment to the brain from where an image for vision is produced. This retinal layer has a central part, namely the macula, which is responsible for central vision. Once affected by stargardt disease, the macular site forms a yellow or white ring and it also gets accumulated with a fluorescent pigment called lipofuscin, resulting in the loss of vision. It is a very common condition affecting both males and females.
It is a genetic disorder caused by inheriting a faulty gene from the parents. A medical condition can be inherited in two forms - dominant and recessive.
-
In the case of dominant form, only one faulty gene from the parent is inherited. The parent will have the condition already and the chances of passing it onto the child are 50 %.
-
In the case of recessive form, faulty genes will be inherited from both parents. The parent will carry the gene but the condition will not be present. The chances of passing it onto the child are 25 % in this case.
Stargardt disease is majorly a recessive form and is caused by alterations in the ABCA4 gene part of chromosome 1. Rarely, ELOVL4 altered genes cause a dominant form of the disease.
What Are the Symptoms of Stargardt Disease?
The signs and symptoms of stargardt disease start showing between 6 and 12 years of age or within 20 years of age. Rarely, signs start showing after 50 years of age. The symptoms of the condition include,
-
Decreased vision.
-
Dim light vision becomes difficult. This is because the eyes will lose their ability to adapt from a light-to a dark environment.
-
Eyes will become sensitive to light.
-
The objects appear wavy (distorted vision).
-
Blurred vision.
-
Color vision will be affected.
-
Patients tend to find some blind spots (the path of vision will be obstructed).
The grade of vision loss differs from person to person. For some, the vision gradually reduces, and for some it will rapidly reduce in the beginning, and it only worsens over time.
How to Diagnose Stargardt Disease?
An ophthalmologist will suggest the patient undergo a few tests to diagnose the condition.
-
Vision Field Test - Vision field test is done to check if there are any scotoma (blind spots) present. The patients will be made to sit with their chin on a platform, and the eyes are focused through a special instrument, through which flashing lights will be initiated. The patient will be instructed to press the button, whenever they see the flashing light. Through this, the part of the retinal layer affected and the presence of blindspots can be diagnosed.
-
Electroretinography - The retinal layer of the eye is made of various cells and photoreceptors such as rods and cones. This test is done to measure the electrical response of the retinal cells. The patient will view through a special instrument, which will flash lights at regular intervals. The electrical responses of the retinal layer are recorded on a monitor. Abnormal patterns of the responses will suggest the presence of a retinal degeneration disorder like stargardt disease.
-
Optical Coherence Tomography - It is an imaging technique used to gather cross-sectional images of the retina to assess if any abnormalities are present. The patient’s eye will be focused using a special instrument through which it transmits low coherent light waves, to produce cross-sectional images of the retina. Sometimes, this test will be combined with infrared scanning laser ophthalmoscopy to provide surface images of the retina. This test enables the doctors to diagnose stargardt diseases precisely.
-
Ishihara Test - This test is used to diagnose color blindness. The patient will be made to see a plate containing colored dots and different colored numbers or alphabets embedded among the dots. A person with color blindness will not be able to see the number or an alphabet like the normal ones.
-
Genetic Testing - It is not compulsory to undergo genetic testing . But a few people will be eager to know more about the faulty gene and the condition.
How to Manage Stargardt Disease?
There are no treatment modalities available to treat Stargardt disease. The condition is still under a lot of research to arrive at a cure. However, stargardt disease can be kept in check, and the quick tips are,
-
Wear sunglasses when going out in the sun. Sunglasses will help with light sensitivity and prevent further damage to the retinal layer.
-
Smoking is strictly prohibited in people affected by stargardt disease as smoking is believed to aggravate the rate of vision loss.
-
Vitamin A is known to be good for the eyes. Taking natural vitamin A from sources like carrots, pumpkin and sweet potatoes, are good to be eaten. But care should be taken in having vitamin A supplements, as taking larger amounts of it, can progress the stargardt disease.
-
Also, an unhealthy diet, and obesity have been found to progress the degeneration process. Opt for a healthy diet. Include lots of greens and fruits. Avoid alcohol consumption and smoking. Keeping the blood pressure level under control is mandatory.
Conclusion
Stargardt disease will affect the quality of life. A cure not available for this condition is truly distressing, but a lot of research is going on to arrive at a treatment. Many scientists are working hard to provide a cure for this condition. The loss of vision can be highly disturbing. Seeking a specialist doctor can help, as the doctor can provide alternative options available like handheld lenses, video magnifying devices, etc. to combat vision loss.
