What is Central Areolar Choroidal Dystrophy: Causes, Symptoms, Treatment, Prevention, Diagnosis

An important part of human eye, choroid is a globe shaped, pigmented layer that lies between the outside of sclera and towards the interior of retina. It can get affected and lead to several medical problems and central areolar choroidal dystrophy is one of them. Being a rare condition, there is less awareness about it. Know the cause, symptoms, diagnosis and treatment of central areolar choroidal dystrophy.

Being a vital part of uveal tract, the choroid resembles the shape of a round wine glass. The optic nerve originated from the base of choroid and the other two parts of the uveal tract are present anteriorly. This includes the iris and the ciliary body.

Choroid is composed of three layers which are named as follows:

• Capillary layer
• External Vessel Layer
• Bruch’s membrane

It is necessary to know about central areolar choroidal dystrophy to be able to deal with it in a better way. Medically, the genetic disorder is also known by different names such as choroidal sclerosis and the areolar atrophy of the macula.

Present as a main source of nutrient, choroid helps to nourish the retina while controlling the intraocular pressure. Further, it also helps to control excess heat around retina by absorbing excess light thereby preventing reflection.

The choroid is vulnerable to many kinds of disorders which can either arise genetically or due to external factors. These can include tumor development, chorio-retinal inflammation or choroidal dystrophy. While the former two are subjective to retina, dystrophy can be widespread and cause damage to other parts of the eye as well. Being a hereditary macular disorder, central areolar choroidal dystrophy is acquired genetically by a person and largely affects the retina and choroid while intervening the functioning of other parts of the eye. The signs and symptoms of central areolar choroidal dystrophy may become evident towards middle age. Despite being there in the genes, the symptoms worsen gradually and can even lead to complete blindness if not treated at the right time.

Mutation within a PRPH2 gene causes central areolar choroidal dystrophy. Moreover, being a hereditary disease, a family history is the most crucial factor that poses the biggest risk of occurrence.

As we already know it’s a congenital disorder manifested genetically, it usually affects people in the middle age i.e. during late 30’s and 40’s. The disease can affect men as well as women coming from different backgrounds. Though, it is actually a very rare disease with a prevalence factor of one in ten thousand. Any genetic history of the disease in the family is likely to increase the chances of suffering by 70 percent. However, risk factors do not mean that you are necessarily going to suffer from the condition. These factors tend to just increase the probability of occurrence for an individual when compared to any other individual not having those risk factors.

The symptoms of central areolar choroidal dystrophy develop in progression and are usually seen in the middle age. These symptoms can begin with facing difficulties in vision followed by loss of central vision. While in some individuals, the symptoms tend to develop at a slower pace, in others they might progress at a steady rate. In the beginning, the symptoms can be mild which can become severe over time.

The symptoms of central areolar choroidal dystrophy include loss of vision during night time, difficulties in low lighting etc. As already mentioned these symptoms are progressive and escalate in intensity over time causing complete vision impairment if left untreated.

If symptoms of central areolar choroidal dystrophy are not managed well, it can lead to several complications. It can cause detachment of retina wherein retina is completely parted from the eye structure which holds it. Finally, it can lead to complete vision loss.

Physicians may ask for several physical examinations and tests in order to confirm the diagnosis of central areolar choroidal dystrophy. This could include comprehensive eye examination, blood tests, imaging tests etc. However, we do not have any treatment available till present date that could be used to treat the genetic disorder and even the diagnosis of CACD is difficult and uncertain.

Moreover, considering the risk factors in some people, routine eye check-ups are vital, be it for children as well adult irrespective of age. While, children should definitely go for it, adults should also follow it to keep their health prescriptions maintained and to check if there are chances of occurrence of any eye disease.

There is no definitive way for treatment of central areolar choroidal dystrophy. However, medications are prescribed by the doctor to control the symptoms or lower down their progression. In case of complete vision loss, rehabilitation therapy is provided. Depending upon the intensity of symptoms and conditions, the doctor can prescribe the mode of treatment which can vary on individual needs and circumstances.

The projection for this genetic condition, central areolar choroidal dystrophy, is very uncertain and poor. The disorder can cause complete vision impairment around the age of 60-70 years. Though, the course of projection for disorder is poor yet it depends likely on the rate at which symptoms advance.

Since the disorder is genetically acquired, there are no methods or ways for prevention, but screening can help detect it early.

• Generally a comprehensive genetic testing is done to understand the family history. In case of pregnant mothers, molecular testing of the fetus can help in understanding those risks better.
• Genetic counselling may be alternatively suggested by the doctor when the family history for choroidal dystrophy is positive. This will help to analyze the condition and probability better.
• Studies around the world are being conducted to explore out possibilities and ways of treatment for central areolar choroidal dystrophy. Also, the efforts for mitigating the symptoms when diagnosed and its prevention are in full swing.