Paragraph

where an optical appliance has lenses described in different paragraphs in column 1, the face value of a voucher for the appliance must be determined according to whichever lens would provide the greater face value;

subject to paragraph (c), where an optical appliance has a bifocal lens, the power of the lens must be determined according to the power of that segment of the lens designed to correct a defect in distant sight;

where an optical appliance has a bifocal lens, the reading segment of which is more than 4 dioptres more powerful than the distance segment, the power of the lens must be determined according to the power of the reading segment; and

a monocle must be treated as though it were glasses.