I've found a lighted loupe to be essential. Otherwise my hand, head, or body blocks ambient light and I can't see the edge of the blade well. I've got a cheap-ish loupe from Amazon that works just fine for edge inspection. It's a 10X and a "triplet". I think that means it has 3 lens elements and is optically more true. For the less than $15 I paid for it, it's an enormous bargain. The loupe REALLY showed me some things I was doing wrong and allowed me to see my progress in a way I hadn't before. Fantastic tool for evaluating and improving your sharpening.
Brian.