About BCD

BCD is an often-misdiagnosed retinal disease.
BCD is an often-misdiagnosed retinal disease

About BCD

Bietti’s Crystalline Dystrophy (BCD)  is a rare retinal degenerative disease. BCD was first characterized and reported by Italian ophthalmologist 
Dr. G.B. Bietti in 1937. 

Patients have small yellow or white crystals in the retina and also in the cornea for some patients. Retinal crystals may not be obvious in early- or late-stage patients.

To date, more than 100 papers have been published on BCD and reported BCD cases throughout the world.

Night vision starts to go

Impaired Visual Field & Visual Acuity

Infrared imaging to enhance visibility of retinal crystals

Caused by CYP4V2 mutations

  • BCD Early Stage

    Retinal pigment epithelium (RPE) atrophy in the posterior pole. Some visible yellow-white crystal deposits within the macular region.

  • BCD Mid Stage

    RPE atrophy extends beyond the posterior pole. Large amount of yellow-white crystal deposits all over the back of the eye.

  • BCD Late Stage

    Prominent diffuse atrophy of the RPE-choriocapillaris complex. Disappearing refractile crystal deposits.


Night blindness, distorted vision, restricted visual fields, reduced visual acuity, impaired color vision. Eventually legal blindness.

An image of the eyes signifying BCD onset.


During teenage or in the 20s or 30s. There are also reports of BCD pediatric patients.

An image of a man receiving eye examination

Misdiagnosis and Underdiagnosis

Researchers suggest that BCD may be underdiagnosed because its symptoms are similar to those of other eye disorders that progressively damage the retina. More on BCD Misdiagnosis.

An image of DNA signifying the genetic cause.

Genetic Cause

Mutations in the CYP4V2 gene.



BCD incidence rate is estimated to be 1:67,000 and therefore affect more than 100,000 people worldwide. On average, there are 3-4 people going blind due to BCD every day. More on BCD Prevalence.

An image of gene therapy


Currently, there is no approved treatment for BCD. ReflectionBio® is developing gene therapy for BCD. BCD gene therapy has shown promising results in preclinical study. We are advancing BCD gene therapy R&D into human clinical trial.

BCD Patient Organization

Invincible Vision is a patient-led nonprofit organization focused on serving the Bietti’s Crystalline Dystrophy (BCD) community. Founded in 2019 in the U.S., Invincible Vision is committed to raising awareness of BCD to accelerate research for a treatment while also supporting its global community of patients, family and friends. For more information on Invincible Vision, please visit www.InvincibleVision.org.

Various names of BCD (BCD Synonyms)

  • Bietti’s Crystalline Dystrophy (BCD)
  • Bietti Crystalline Dystrophy
  • Bietti’s crystalline retinopathy
  • Bietti crystalline corneoretinal dystrophy 
  • Bietti’s retinal dystrophy
  • Bietti’s tapetoretinal degeneration

BCD in other languages:

  • Spanish: Distrofia cristalina de Bietti
  • German: Bietti`s kristalline Retinopathie
  • French: dystrophie cornéo-rétinienne cristalline de Bietti or dystrophie crystalline de Bietti
  • Italian: distrofia cristallina di Bietti
  • Turkish: Bietti nin kristalin distrofisi
  • Chinese (simplified): 结晶样视网膜色素变性, 结晶样视网膜变性, Bietti结晶营养不良
  • Chinese (traditional): 結晶樣視網膜色素變性, 結晶樣視網膜變性, Bietti結晶營養不良
  • Japanese: クリスタリン網膜症
  • Korean: 비에티 결정 이영양증 or 비에띠결정색소망막이영양증
  • Hebrew: דיסטרופית קריסטלין ע״ש בייטי
  • Arabic: الحثل البلوري لبيتي
An image of the Earth signifying that BCD has been reported throughout the world.