Progressive bifocal chorioretinal atrophy

Progressive Bifocal Chorioretinal Atrophy (PBCRA) is a rare, inherited eye disorder characterized by progressive loss of vision due to atrophy of the choroid and retina. This condition typically manifests in two distinct areas of the eye, leading to its classification as "bifocal." The disease progression leads to a gradual deterioration of the photoreceptors, which are critical for vision, particularly affecting the central and peripheral visual fields.

Symptoms

The primary symptoms of Progressive Bifocal Chorioretinal Atrophy include a progressive loss of visual acuity, difficulties with night vision, and a narrowing of the visual field. Patients may also experience photophobia, or light sensitivity, and, in some cases, complete blindness. The onset of symptoms usually occurs in childhood or early adolescence.

Causes

PBCRA is a genetic disorder, inherited in an autosomal recessive manner. This means that the condition occurs when an individual inherits two copies of the mutated gene, one from each parent. The specific genes involved in PBCRA have not been fully identified, making genetic counseling and prediction of the disease challenging.

Diagnosis

Diagnosis of Progressive Bifocal Chorioretinal Atrophy is primarily based on clinical examination, including a detailed patient history and a comprehensive eye examination. Imaging techniques such as Fundus photography, Fluorescein angiography, and Optical Coherence Tomography (OCT) are crucial for visualizing the extent of chorioretinal atrophy and confirming the diagnosis. Genetic testing may also be recommended to identify the presence of specific genetic mutations associated with the condition, although the availability of such testing is limited due to the rarity of the disease.

Treatment

There is currently no cure for Progressive Bifocal Chorioretinal Atrophy. Treatment focuses on managing symptoms and maximizing the patient's remaining vision. This may include the use of low vision aids, such as magnifying glasses or specialized electronic devices, and adaptive training to help individuals adjust to their visual limitations. Regular monitoring by an ophthalmologist is essential to address any complications that may arise, such as the development of neovascularization or secondary glaucoma.

Prognosis

The prognosis for individuals with Progressive Bifocal Chorioretinal Atrophy varies depending on the severity of the condition and the age at onset. While the disease is progressive, leading to a gradual decline in vision, many patients retain a degree of functional vision well into adulthood. Early diagnosis and intervention can help to optimize visual function and improve quality of life.

NIH genetic and rare disease info

• NIH info on Progressive bifocal chorioretinal atrophy

Progressive bifocal chorioretinal atrophy is a rare disease.