Bietti's Crystalline Dystrophy

What is Bietti’s crystalline dystrophy?

Bietti’s crystalline dystrophy (BCD) is an uncommon hereditary condition. In individuals with BCD, fatty acid crystals accumulate in the cornea (the transparent outer layer at the front of the eye) and the retina (the light-sensitive tissue layer located at the back of the eye).

Individuals affected by BCD may begin to experience symptoms during their teenage years or in their twenties, such as difficulty seeing in dim lighting or peripheral vision issues. As time progresses, this can result in significant vision impairment.

At present, there is no established treatment for BCD; however, vision rehabilitation can assist you in maximizing your remaining vision.

What are the symptoms of BCD?

The initial indication of BCD typically involves a change in visual clarity. You might observe that your vision is not as sharp as it once was. This can manifest as:

  • Blurred or hazy eyesight

  • Difficulty seeing in low-light conditions

  • Inability to perceive objects in your peripheral vision

  • Challenges in distinguishing certain colors

This condition impacts both eyes, although one eye may deteriorate more rapidly than the other.

These early signs tend to worsen over time. Ultimately, the majority of individuals with BCD experience significant vision loss, with many retaining some central vision, albeit often in a blurry state.

Am I at risk for BCD?

Your likelihood of developing BCD may be increased if:

  • Family members have been diagnosed with BCD

  • You belong to the East Asian ethnic group

What causes BCD?

BCD is a hereditary condition, meaning it is transmitted from parents to their offspring. Symptoms will only manifest if both parents carry the BCD gene and pass it on to you. If only one parent possesses the gene, you will inherit the BCD gene but will not exhibit any symptoms of the condition.

How will my doctor check for BCD?

Your eye care professional can diagnose BCD during a thorough dilated eye examination. This procedure is straightforward and painless — your doctor will administer eye drops to dilate (enlarge) your pupils and then examine your eyes for any signs of disease.

Additionally, your eye doctor may utilize genetic testing to verify the presence of BCD. These tests look for alterations in the gene responsible for BCD (CYP4V gene).

What's the treatment for BCD?

Currently, there is no verified treatment for BCD. Coping with vision loss or low vision due to BCD can be quite difficult. Low vision implies that even with corrective lenses, medications, or surgical interventions, your vision impairment hampers your ability to perform daily activities.

The positive aspect is that there are resources available to assist, such as low vision aids and rehabilitation (training) programs designed to help individuals adapt.