CINCINNATI — Tomas Nido’s vision, especially in night games, had diminished to the point the Mets were uncomfortable using him.

The catcher was placed on the injured list Wednesday with dry eye syndrome, a condition causing irritation in his eyes and vision problems.

The IL stint was retroactive to Saturday, and manager Buck Showalter expects Nido will return when he is first eligible.

Michael Perez was selected from Triple-A Syracuse to replace Nido.

To create room on the 40-man roster for Perez, the Mets moved pitcher Elieser Hernandez to the 60-day IL.

Perez appeared in six games last season for the Mets.

Nido has struggled this season, owning a .118/.148/.118 slash line with a drop-off in his previously strong numbers framing pitches.

“He just needs to get [the vision] corrected,” Showalter said before the Mets faced the Reds. “We have got some people that feel they can help him, and if it was an infielder where you thought you could get through the next three or four days … obviously with catcher, I know we were thinking about pinch-running [Tuesday] night, and I didn’t feel comfortable with him in the game.”

Showalter said he expects Nido’s issue will be resolved within the next three or four days.

“It’s not something that has been going on all season, but it hasn’t gotten better and we just want to get it corrected,” Showalter said. “They think they can.”

Max Scherzer was showing improvement, according to Showalter, a day after he was scratched from his start with neck spasms.

But any thought of trying to reinsert the right-hander into the rotation for Thursday’s series finale has been scuttled.

Kodai Senga will take his scheduled turn against the Reds, and Scherzer is a consideration for Friday’s series opener at Washington.

Carlos Carrasco will need a second minor league rehab start in his return from elbow swelling caused by a bone chip.

The right-hander threw 33 pitches (and another 12 in the bullpen afterward) in a start for Double-A Binghamton on Tuesday and needs to stretch out further before he can rejoin the Mets.

Showalter said the team was still working out the details of when and where Carrasco will pitch next in the minors.

Brooks Raley was scheduled to pitch in a minor league rehab game for Double-A Binghamton.

The left-hander, who is returning from elbow inflammation, is expected to be activated from the injured list this weekend.