Temp "+23C" could be +23·4C; Dew Point "+23C" could be +22·5C.
But even if the two are truly identical, I'm not sure that the water droplets forming (by the condensation) necessarily have to be big enough to impede visibility. Isn't that why the visibility in some cloud/fog is better than in others? But I'm not a Met man.
Deano777, I don't think that you can have a measurable dew point – by definition – unless some water vapour is present in the atmosphere. [It would presumably be -273C if the air contained no water vapour.]