Introduction: Progressive night blindness and constriction of the visual fields are features of Bietti crystalline corneoretinal dystrophy, but here we report a case with the most probable diagnosis of Bietti crystalline dystrophy and good central visual acuity and severely decreased electroretinogram.
Case presentation: The patient was a 28-year-old woman with complaint of decreased vision without night blindness. Her both eyes visual acuity were 20/25 with plano refraction. Fundus examination showed intraretinal crystals distributed in the posterior pole and also midperiphery. Fullfield electroretinogram showed decreased scotopic a and b-wave amplitudes.
Conclusion: In our patient central foveal region was relatively intact; and this can explain subnormal visual acuity. Although visual acuity was nearly spared, electroretinogram was extremely affected.