a) Visual impairment in abetalipoproteinemia ( Bassen-Kornzweig syndrome ). This autosomal recessive disease develops due to the deficiency of the microsomal triglyceride carrier protein, which is necessary for the production of lipoproteins, which leads to malabsorption of fats and fat-soluble vitamins.  

The disease manifests itself in infancy by the lack of weight gain, developmental delay and steatorrhea. If untreated, spinocerebellar degeneration develops. The disease is accompanied by progressive retinal dystrophy, which can be stabilized by a low-fat diet and supplementation with vitamins A and E.

b) Visual impairment in case of lecithin-cholesterol-acyltransferase deficiency ( fish-eye disease , partial lecithin-cholesterol-acyltransferase deficiency ). Lecithin-cholesterol-acyltransferase catalyzes the formation of high density lipoprotein cholesterol esters.   

Complete failure of lecithin-cholesterol-acyltransferase causes renal failure, anemia, and corneal opacity developing in adulthood. Partial deficiency of lecithin-cholesterol-acyltransferase (fish-eye disease) does not cause any other disorders, except for progressive clouding of the cornea due to extracellular deposition of lipids in the corneal stroma. Turbidity can be detected in childhood, although they are asymptomatic. Some adults require corneal transplantation.

c) Vision with Apo A-1 deficiency . In several children with Apo A-1 deficiency, corneal opacities have been described. Other changes in this condition are early atherosclerosis and xanthomas.