Untitled

Abstract

Hypovitaminosis A is associated with exocrine pancreatic insufficiency in cystic fibrosis. Peripheral retinal dysfunction is an early finding of vitamin A deficiency. We evaluated serum retinol and zinc as well as visual adaptation in 41 patients with cystic fibrosis, receiving generous pancreatic enzyme and micronutrient supplementation. Forty-one normal individuals matched for age and sex served as controls. Peripheral retinal function was measured by clinical electroretinography using an Electrophysiologic Personal Interfaced Computer and applying a standard protocol. Serum retinol in cystic fibrosis was significantly lower than that of the control group (0.30+/-0.01 versus 0.39+/-0.02 mg/l, p<0.001). Serum zinc concentrations were normal in the cystic fibrosis group (1.21+/-0.03 mg/l) and significantly higher than that of the control group (1.02+/-0.01 mg/l, p<0.001). The overall visual adaptation, however, was found to be normal and comparable in the two groups. It is concluded that, in cystic fibrosis, despite appropriate vitamin A supplementation, retinol serum concentration may be low. As serum retinol does not reflect vitamin A status, evaluation of visual adaptation may be a more appropriate way to monitor for vitamin A deficiency in cystic fibrosis.

ERGs in children with pancreatic enzyme insufficient and pancreatic enzyme sufficient cystic fibrosis

“…Overall, our PI and PS groups were broadly similar to Fulton et al's data from healthy children, indicating no clear effects of cystic fibrosis in rod scotopic, maximal and cone photopic electrical responses. This also agrees with the findings of Tsinopoulos et al, who reported no difference between a supplemented PI population and a healthy comparison control group [10].…”

“…A lack of statistically significant difference between the ERG measures of PI and PS groups tested here indicates that nutrient supplementation levels in the PI group are adequate to allow approximately comparable retinal function in the groups with and without malabsorption. Previous work indicates that flash ERGs are normal in PI cystic fibrosis patients [10]. Our findings are in general agreement with this, and show that, within a CF population, flash ERGs are not obviously different between PI and PS groups.…”

“…It should be noted, however, that serum vitamin A levels do not necessarily indicate reduced scotopic vision, since tissue levels of vitamin A may be sufficient to allow normal function. In one previous study, PI cystic fibrosis patients with serum vitamin A levels significantly lower than controls showed normal flash ERGs, probably reflecting adequate tissue levels of vitamin A despite low serum levels [10].…”

“…Normal retinal function (as indicated by the ERG) appears to be maintained in CF patients with serum vitamin A levels significantly below normal [10], suggesting that retinal levels can be sufficient even when serum levels are reduced. In our study, serum vitamin A levels were within normal limits and were similar in the two groups.…”