Certain brands are cheaper there. Those frames made in the EU ones, usually brand names e.g. Mikli, Mykita, etc can be had for 20-50% less than in Singapore. Few years back, I got a pair of lindberg on sale for about half the price what they are selling for in Singapore. There is a chance that they may carry models that are not available outside EU.
In general lenses tend to be more costly there as there are lots of add ons. In Singapore, which has one of the highest rate of myopia in the world, the labs here IMO are quite efficient in sales and distribution of lenses and those sold to consumers are usually offered as a full multi-coat package rather than as optional add-ons. Most of the unprocessed lenses also yield from the far east except perhaps the newest higher end ranges that cost an arm and leg.