title: Nondetectable S-cone electroretinogram in a patient with crystalline retinopathy.
abstract: We examined cone and rod electroretinograms to ganzfeld stimuli in a patient with crystalline retinopathy. The 54-year-old man complained of night blindness, blurred vision, and metamorphopsia in both eyes. His visual acuity was 10/200 in the right eye and 10/20 in the left eye; his subjective dark-adaptation threshold was elevated 1 log unit, and he made one tritan error on the Farnsworth Panel D-15. Specular microscopic examinations revealed tiny crystalline deposits in the limbal cornea bilaterally. Ophthalmoscopically, crystalline deposits were found in the posterior fundi. His light-adapted cone electroretinograms to white stimuli were diminished (about 30% of those of normal controls), with normal implicit times. His dark-adapted rod electroretinogram amplitudes were 10% of those of normal controls. The S-cone electroretinogram was not detectable to different spectral stimuli with strong white background, while the L-M-cone responses appeared normal in waveforms with reduced amplitude. These ERG results indicated that the patient's S-cone system is more highly impaired than the L-M-cone system, supporting the psychophysical evidence that the S-cone system is more vulnerable than other cone systems in retinal diseases.
authors.affiliation: Department of Ophthalmology, Toyama Medical and Pharmaceutical University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Kataoka
authors.forename: M
authors.initials: M
authors.lastname: Kamiyama
authors.forename: S
authors.initials: S
authors.lastname: Hayasaka
mesh_terms: D003623:Dark Adaptation; D004596:Electroretinography; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D009755:Night Blindness / Q000150:complications; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D012164:Retinal Diseases / Q000150:complications / Q000503:physiopathology*; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology; D014786:Vision Disorders / Q000150:complications; D014792:Visual Acuity