have been missing for ages

Yes they were found. The indication is this: "Hmmm... Oh, here they are!"

Then, should "There had been missing for ages be used instead of " .. they have ... "?

Many thanks.

No, it is "has been".

They (the glasses) have been missing (until now) - present perfect progressive is used for an indefinite time from the past up until now.

but: They had been missing for 2 hours until I found them - past perfect
progressive is used up to a specific time.

Many thanks, CalamityJane, for your lucid reply.

With all due respect to CalamityJane, I see things differently.

I believe the correct wording should be "They had been missing for ages."

Why?

Because the glasses are now found, but "They have been missing for ages" implies that they are still missing.

In contrast, "They had been missing for ages" shows that not being able to find the glasses is a state of the past, not the present.

Incidentally, the word "spectacles" (though technically correct) is most often used for reference to antiquated times (such as "Ben Franklin spectacles") or with jocular intent. In everyday English, "spectacles" can sound a bit odd. Sometimes "eyeglasses" is the word used in ordinary conversation.

If I'm not wrong, CalamityJane is correct.

A man of independent mind.

In Britain, we commonly talk of "glasses" or "specs" to refer to spectacles.

It makes perfect sense to me to say "Oh, there they are! They've been missing for ages" when you've just spotted them.

Are you referring to me? If so, thanks for the compliment.

In dialogue, I would expect someone to say "they have been missing."

I stand by my previously stated opinion.

It would be nice to hear from other members.