The authors identified a case of Bietti crystalline dystrophy with central and paracentral keratopathy and the molecular analysis of the causative gene in a Spanish family. Data suggest a dose-dependent phenotype ranging from subclinical corneal changes in subjects carrying 1 mutant Ile111Thr CYP4V2 allele to the complete manifestation of the disease in homozygous subjects. In vivo corneal confocal microscopy is a useful technique in the diagnosis of this disorder.