The best replacement for optics is copper.

The best alternatives to optics are rated as following:
★★★★★  copper
★★★★  nightforce
★★★★  iron sights
★★  cable internet
★★  satellite
★★  copper wire
★★  vents
★★  oakley
★  binocular telescope
★  vortex optics
★  binoculars
★  schmidt and bender
★  leupold
★  coaxial cable
★  schmidt bender
★  copper wires
★  copper cable
  photonics
  geometric optics
  binoculars wot
  costa del mar
  digital cable
  nightforce scopes
  satellite tv
  dbscan
  o2 optics
  microwave
  swarovski

Your alternative for optics is not listed? Suggest!
Speaking about optics, one probably shouldn't forget about a2 front sight.

Other search terms related to optics and their ratings are:
★★★★★ a2 front sight
★★★ fixed front sight
★★★ iron sights
★ carry handle
★ front sight
You have in mind a companion for optics and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of optics in all years. Click on graph for more.
optics
copper
nightforce