If you are noticing eye issues with MVB's or any UV source, the first step should be to asses the minimum distances in your setup. For 100w MVB's, this should really be 13-14" from the TOP of the animal. The 12" figure quoted on the box is often a bit to optimistic, as even at 12" the UVB output is significantly higher then any flourescent tube
UVB light. If you are using a higher power MVB, then the minumum distance is going to be significant...20" at least.
If you are using a florescent UVB source, such as a Reptisun 10.0 or Reptiglow 8.0, then make sure they can get between 6-8" of the bulb. These are generally safer at closer distances however (reptisun is anyways)...and rarely do these two bulbs have reported cases of eye issues. There are other brands on the market...none of which are highly regarded (sans our UK brothers/sisters and their Arcadia bulbs). So if you are using a UVB coil or unknown UVB tube, its probably best to get a Reptisun 10.0 and call it a day. The only two bulbs that are pretty much universally recommended for bearded dragons are the Reptisun 10.0 and the Arcadia D3+ 12%.
My biggest beef with MVB's is their "1 bulb" advertising...using 1 bulb for light and heat can often make it next to impossible to get a correct setup with either. At the safe UVB distances, there isn't enough heat. Move the bulb closer to get more heat and you are suddenly blinding your dragon. Its best to plan on using a separate heat source no matter your UVB source. At least this way you'll be prepared for anything.