He's likely referring to how the yellow and white versions appear. The silver is darker than either of those two colors giving it the appearance of being upside down in reference to the start white/black of the original symbol.

78WARLOCK, on , said:

 

"Maybe Rand using the Eye started the process of the seals weakening. It held hidden a seal and Lews Ts' banner. Because later Rand with help from ??? at his school realizes he needs to break the seals. So in that respect, possibly they will need to refill the pool to reseal his prison as it is a part of the whole thing."

 

The pool was created with both men and women Aes Sedai. I don't believe the refilling of the pool to be a part of the resealing process for a few reasons that I can think of at present. 1.) Lews Therin has stated that the women refused to go with his plan so the pool couldnt have been part of the first sealing. 2.) An actual seal was inside the pool which I interpret as the pool being created after the sealing and then the seal placed in the pool afterward.

A couple more things:

In Rand's flashbacks of the Aiel's history in Rhuidean (specifically the 7th vision I believe), he see's from Jonai's perspective and enters on Aes Sedai discussing another person's visions and have Callandor and Lews Therin's banner at hand along with Someshta the Nyhm (aka The Green Man). They make mention of the taint on Saidin and a handful of young male Aes Sedai that they could get help from as it wouldn't be strong in them yet. So we know this is post sealing and the banner has yet to be hidden (thus lending to the fact that the pool was not already in place to hide the seal and/or the banner at that time).

We can also infer that the seals were hidden during and/or post breaking as in one of the earlier books it makes the comment about the Amyrlin Seat being titled "Watcher of the Seals", but that they no longer know where the Seals are located as the knowledge was lost around the time of the Trolloc Wars.

It's also unlikely that Rand using the power in the Eye caused the weakening of the seals as at this point it's clear they are ALREADY weakening considering at least Ishamael, Aginor and Balthamel had freed themselves from Shayol Ghul before the power there is used.

As far as the purpose of the Eye goes, it likely was involved in the Prophecies of the Dragon in some fashion and the Eye needed to be emptied to gain access to the Dragon banner which in turn was needed to direct the forces that were called by the Horn of Valere. Both Callandor and the banner were present when those ancient Aes Sedai were (presumably) discussing the visions of the Dragon being reborn (with the Green Man present no less) so they clearly must have been planning the securing/hiding of said items.

It perhaps even was placed in case of the need to 'kick start' the reborn Dragon into being made aware of his ability to use Saidin, or even to help bring Lews Therin and/or his memories near the surface. It's clear that some stuff was placed specifically for him (such as Callandor) and this could very easily be yet another such thing.