Achromatopsia: Causes, Symptoms, Diagnoses, Risk Factors and Treatment

Definition:

It is a condition that leads to the inability to see color. Approximately one in 30,000 people in the United States are affected by this disease.

This condition is much rarer than other forms of color blindness, such as blindness to red-green color and color blindness linked to the X chromosome.

Achromatopsia can be acquired due to damage to the brain’s cerebral cortex (acquired achromatopsia), or it can be inherited due to mutations in specific genes (congenital achromatopsia).

Usually, color is detected by cone-like cells in the eye’s retina. In congestive achromatopsia (a form of achromatopsia present at the time of birth), the conic cells no longer function correctly, resulting in color blindness.

In cases of acquired achromatopsia, conical cells are usually functional, and color blindness is the result of other brain damage.

The severity of achromatopsia can vary among patients. In addition to not distinguishing colors, patients may have blurred vision, nystagmus (involuntary movements of the eyes, such as tremors or wobbles), or greater sensitivity to light that may cause discomfort or pain.

 

Causes

Congenital achromatopsia: achromatopsia can result from a mutation or error in specific genes. This type of achromatopsia is inherited and is sometimes called congenital achromatopsia.

Several genes have been linked to achromatopsia, and it has been shown that mutations in these genes can lead to the development of the disease.

These genes include ACHM2 (CNGA3) and ACHM3 (CNGB3), which are ion channels that are found in cone-like cells (ion channels allow small electrically charged molecules, called ions, to enter or leave a cell), and ACHM4 ( GNAT2)), which is expressed in photoreceptors.

All three of these genes are involved in transmitting the light signal to the brain. Congenital achromatopsia is a recessive condition, which means that both copies of a gene must be defective for the disease to develop.

In congested achromatopsia, cone cells in the retina, which generally detect color, no longer function correctly. In general, this defect results in the inability of the cone cells to respond or see the light adequately.

Achromatic Acid: acquired achromatopsia is not inherited but is due to damage to the brain, often in the ventral occipital lobe.

People with acquired achromatopsia usually have cone-like cells that function correctly, but the brain can not perceive color.

Diagnosis

Congenital color blindness is usually present from birth. Excessive tremors or narrowed eyes may indicate that a child has this disease.

Electroretinogram: A test called electroretinogram can be used to measure the function of cells in the eye.

In this test, electrodes are placed on the cornea and near the skin of the eye, and the electrical activity in the eye cells is measured as the patient shows different visual stimuli.

This test can determine if cone cells are functioning correctly. It can confirm a diagnosis, especially in cases where the patient is too small to perform other vision tests.

Vision tests: achromatopsia can be diagnosed in older patients through color vision tests.

Genetic tests: genetic tests can detect mutations in genes that cause achromatopsia. These tests can confirm a diagnosis if there is a family history of achromatopsia or if there are symptoms if symptoms of this occur.

Signs and symptoms

It is the inability to see color. In the most severe form of the disease, called complete achromatopsia, the patient can not see any color.

Incomplete achromatopsia is a milder form of the disease in which the patient has a limited ability to see color rather than a complete loss of color vision.

Other vision problems may also occur, varying in severity among patients, depending on whether the patient has complete achromatopsia or incomplete achromatopsia.

These symptoms may include blurred vision, nystagmus (involuntary eye movements, such as tremors), or photophobia, a greater sensitivity to light that can cause discomfort or pain.

Achromatopsia is considered a non-progressive disorder, which means that the symptoms do not become more severe over time.

Complications

The vision problems experienced by patients with achromatopsia can be very detrimental to daily activities, such as reading or driving. Also, simply being outside during the day can be difficult for patients due to the bright light.

Patients with achromatopsia can make certain lifestyle decisions to increase their comfort. For example, some patients may avoid working, driving, or playing during the day.

Risk factor’s

The congenital form of achromatopsia is a hereditary recessive genetic condition. Individuals have two copies of most genes (one inherited from the father and the other from the mother).

In a recessive genetic disorder, both copies of a particular gene must be defective for the disease to manifest.

Several genes have been linked to achromatopsia, and it has been shown that mutations in these genes can lead to the development of the disease.

People who only have a mutated gene are called “carriers.” If only one parent is a carrier, none of the children will have achromatopsia, but 50% will also be carriers.

If both parents are carriers, then there is a 50% chance that a child will be a carrier and a 25% chance of having achromatopsia.

Treatment of Achromatopsia

There is no known cure for achromatopsia. There are several treatments to help reduce the severity of some of the symptoms.

Lenses: the greater sensitivity to light that some people with experience in achromatopsia can alleviate through visors or sunglasses with special filters or tinted lenses.

Red contact lenses have been developed that allow patients with incomplete achromatopsia to detect red lights, such as brake lights.

Microscopic glasses have been developed that could help patients with decreased vision clarity to read the fine print, as in newspapers.

Head positions: If a patient shows nystagmus, involuntary eye movements could be reduced by adjusting specific parts of the head or eyes.

Integral Therapies

Currently, there is a lack of scientific data on the use of integral therapies to treat or prevent achromatopsia.

Prevention

Currently, there are no known ways to prevent congestive achromatopsia. However, acquired achromatopsia can be prevented by following standard safety measures to protect against brain damage, such as wearing a bicycle helmet or a safety belt.