[Congenital achromatopsia: electroretinogram in early diagnosis]. / Achromatopsie congénitale: interêt de l'électrorétinogramme pour le diagnostic précoce.

PURPOSE: Achromatopsia is a hereditary disease responsible for congenital low vision. Patients present with nystagmus, abnormal visual behavior or photophobia. Only the electroretinogram (ERG) can confirm the diagnosis in infants. PATIENTS AND METHODS: Thirty children referred for nystagmus or low vision were included in this retrospective study. A complete ophthalmological examination, an ERG and when possible a color vision test (Ishihara, Farnsworth 15 Hue test) was done. A Ganzfeld ERG was performed in accordance with ISCEV standards in patients more than 6 years of age. In younger patients, a simplified method using electroluminescent diode stimulation was used and a comparative ERG in accordance with ISCEV standards was performed when the patients were old enough. RESULTS: The ERG response was identical in children and adults. It confirmed the diagnosis of achromatopsia: the scotopic components obtained in dark adapted conditions were normal, (scotopic a-wave, b2 wave). The photopic components, recorded in light-adapted conditions, in order to inhibit the scotopic response (photopic wave, b1 wave), were not recordable. The color vision tests confirmed color blindness; however, in some patients color denomination was correct. CONCLUSION: The simplified ERG procedures performed in our series were reliable in detecting achromatopsia. However, it may not be sufficient to discriminate complete from incomplete achromatopsia.

[Jadassohn's sebaceous nevus]. / Naevus sébacé de Jadassohn.

We report the case of a child's Jadassohn sebaceous noevus, localised on the vertex cranii, the trunk and the limb, associated with the presence of ophthalmological and neurological abnormalities. The diagnosis of this syndrome has been difficult because all the signs were not present at birth. The surgical treatment of the vertex cranii lesions will be realised after expansion with sub cutaneous prothesis, allowing a large exeresis and an adequate reconstruction. Only the anatomo-pathological examination allows any malignant degeneration of the lesion.