Gravel areas where there is little traffic. Globally, far more roads are surfaced with gravel than with concrete or tarmac; Russia alone has over of gravel roads. Both sand and small gravel are also important for the manufacture of concrete. Large gravel deposits are a common geological feature, being formed as a result of the weathering and erosion of rocks. The action of rivers and waves tends to pile up gravel in large accumulations. This can sometimes result in gravel becoming compacted and lithified into the sedimentary rock called conglomerate. Where natural gravel deposits are insufficient for human purposes, gravel is
Granular corneal dystrophy Granular corneal dystrophy Granular corneal dystrophy is a slowly progressive corneal dystrophy that most often begins in early childhood. Granular corneal dystrophy has two types: Granular corneal dystrophy is diagnosed during an eye examination by an ophthalmologist or optometrist. The lesions consist of central, fine, whitish granular lesions in the cornea. Visual acuity is slightly reduced. Granular corneal dystrophy is caused by a mutation in the TGFBI gene, located on chromosome 5q31. The disorder is inherited in an autosomal dominant manner. This indicates that the defective gene responsible for the disorder is located on an autosome (chromosome 5 is an