Clinically, affected individuals experience reduced visual acuity, progressive night blindness, and visual field constriction, typically occurring around the third to fourth decades of life. Legal blindness is common in the fifth to sixth decade. Although patients with BCD have been described from Europe, North and South America, the Middle East, and Africa, the condition has been reported to be more common in East Asia, especially in Chinese and Japanese populations. Previous studies have documented full-field ERGs in affected adults ranging from normal to undetectable. There may be generalized dysfunction of both rod and cone systems with macular involvement evident on multifocal ERG or pattern ERG testing. Predominant or early rod-system dysfunction has also been reported, and significant ERG worsening of the condition can occur over time. Our 2 cases are unusual in that the condition was diagnosed during childhood for both patients, and it is evident that, at this early stage, the ERGs are normal despite there being extensive crystalline deposits.