As already stated, no optics and no lasers. Shooter can wear corrective lenses.
If on an open gun you can have front and/or rear adjustable sights, full rib Aristocrat tri-sets. If for a Distinguished gun (pistol or revolver) no adjustable front sights, on the pistol (auto) you can have the tri-set if it is a catalogued item on that gun but it cannot be a full rib sight.
I suppose you could use the fiber-optic front sight (rule says they're legal) but I question why. Smoking the sights will cook out the fiber optic portion and the truth is you really only want a nice crisp black front sight to be hovering over the target.