€1.47 cheaper than €39.99 in Portugal, for the same pack of 30 before delivery. Converted at the European Central Bank rate of 2026-11-09.
Check that the shop delivers to you, what delivery costs, and whether customs or VAT is added. Inside the EU there is normally no extra duty; from outside, there often is.
Buy the exact brand and model your optician prescribed. Lenses with the same power can differ in material, base curve and diameter.