(1) The amounts in column 3 in Part I of, and in paragraph 2(a) and (b) of this Part of, this Schedule shall be increased as follows:—
(a) by £3.50 in respect of each single vision lens containing a necessary prism;
(b) by £4.50 in respect of each other lens containing a necessary prism;
(c) by £1.75 in respect of each necessary single vision tinted lens;
(d) by £2.25 in respect of each necessary other tinted lens;
(e) by £30.00 in respect of glasses for a person the distance between the centres of whose pupils is 60 millimetres or less;
(f) where the voucher is issued by a health authority, by £1.75 in respect of each necessary single vision photochromic lens and by £2.25 in respect of each necessary other photochromic lens;
(g) where the voucher is issued by a health authority, by £30 in respect of glasses the frame of which is certified by the health authority as being required to be specially manufactured on account of the patient’s facial characteristics.
(2) The increases provided for by sub-paragraph (1)(e), (f) and (g) of this paragraph do not apply in the case of a voucher relating to glasses if it is accepted in connection with the supply of contact lenses.
(3) In sub-paragraph (1) of this paragraph “necessary” in relation to a prism or a tinted or photochromic lens means that the prism, tint or photochromic quality has been prescribed on the basis of clinical need.