Search

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.

Vitreoretinochoroidopathy with microcornea, glaucoma and cataract must be considered to be a distinctively autosomal dominant affection. The authors present evidence in the form of 18 carriers of the same anomaly detected with a pedigree extending up to six generations. Microcornea and vitreoretinochoroidal dystrophy are the prime characteristics; hypertonia and cataract are induced complications. The syndrome may be attributed to a hereditary dysgenesis affecting the anterior part of the globe with trabecular and preequatorial corneal alterations. The dystrophy has a slow development as shown by the clinical and electroretinographic course. Present treatment only consists of controlling ocular hypertonia and cataract.

The authors present part of a study concerning inherited retinal dystrophies as recorded among the inhabitants of the Nord-Pas-de-Calais region of France. This retrospective study, covering eighteen years (from 1972 to 1989) and covering a population of nearly 4 millions inhabitants, has enabled us to assess the prevalence of each disease. 1,660 cases have been detected and 650 pedigrees have been established. The spatial distribution of the patients in reference to their places of origin in relation to the spatial division of area into "communes" or districts roughly corresponded to the population density and revealed a few centres of dominant retinal dystrophies in rural areas. The analysis of the distribution and inheritance of the various forms of retinitis pigmentosa confirmed the results obtained in other recent and similar studies carried out in other countries. The age pyramid of the detected cases followed that of the population under surveillance. Detection of all dystrophies increased up to the age of 35, then followed the normal decreasing pattern for older generations. As for retinoschisis, detection usually took place in the first fifteen years after birth; for Stargardt's disease, it has occurred up to the age of 20 and for Best's dystrophy, the process was the most extensive and the slowest to appear. The global number of dystrophies studied, corresponded to a prevalence of 1:1,490, which allowed us to estimate that the number of cases in France was 33,800. If we apply the phenomenon to all the populations of the European Community, we must consider that more than 300,000 patients are now affected by disabling hereditary retinal dystrophies.

The authors evaluated a family with X-linked progressive cone dystrophy and special attention was paid to female carriers. Twenty-four members of the family were examined. One generation II--male and five generation III--males were affected. Two generation II--females who, in each case had affected children, but who were asymptomatic, underwent electrophysiological evaluations. The electroretinograms were found to be subnormal in both patients with alterations of cone-mediated responses and color vision. The discovery of abnormalities in female carriers emphasized the necessity of systematically performing electroretinography, together with color vision testing and pedigree examination, when assessing so called sporadic cone dystrophy or in cases where the modes of inheritance are not clear.