Chief refereeing officer Howard Webb says the PGMO will continue to "be vigilant" over "impactful" grappling at set pieces following the "clear and obvious" foul on Arsenal goalkeeper David Raya.
West Ham were denied a 95th-minute equaliser on Sunday when referee Chris Kavanagh ruled out Callum Wilson's strike after VAR official Darren England recommended an on-field review.
The call was labelled the in the Premier League by Your Site' Gary Neville, while West Ham were set to contact the PGMO to raise concerns that the decision was not "clear and obvious" given it took four minutes and 17 seconds between the ball crossing the line and a foul being awarded.
Referees were told to and Webb has promised it will remain under the microscope.
Speaking on Match Officials Mic'd Up, Webb said: "We'll certainly continue consulting with stakeholders about the type of game they want to see because we have seen more involvement from set-piece coaches bringing players together in these areas, looking for those marginal gains.
"We'll continue consulting, but certainly we need to be vigilant. We need to identify those clear actions that are impactful.
"We've done better this year. We've penalised twice as many holding penalties as we did last year, but we've missed some as well.
"We've missed some holding situations. Not like this, though, where the goalkeeper's arms are being interfered with. This is different and this is why this one is a clear offence."
There were two minutes and 35 seconds between Wilson's strike going in and Kavanagh being sent to the monitor, where he then watched 17 replays before disallowing the goal. When the ball crossed the line, assistant referee Ian Hussin said: "I don't see any foul on the goalkeeper."
VAR also had to consider potential fouls by Arsenal players Leandro Trossard on Pablo and Declan Rice on Konstantinos Mavropanos at the corner.
"I don't like Trossard not facing the ball," said the assistant VAR Akil Howson as he analysed the incident in real time. "I agree, it's impactful [Pablo on Raya], it's just everything else that's going on as well. Let's say we're saying that's a foul, then what are we saying about Trossard's actions on the same player? What are we saying about Declan Rice behind?"
England replied: "I think, for me, we send him (Kavanagh) for an on-field review to look at the possible foul on the goalkeeper. And then we get him to look at the other incidents as well. I think that's the best decision in terms of this."
When Kavanagh was at the pitchside monitor, the referee said: "I can see the clear holding on him (Raya) across."
Then, on the potential Trossard foul, he said: "I don't think there's much in that at all, I'm happy with that. That's nothing."
Rice's grappling on Mavropanos was also highlighted by England. "But the foul happens on the goalkeeper before," he said and Kavanagh agreed.
Webb said: "The most significant contact, undoubtedly, is that on the goalkeeper.
"It stops him from doing something pretty routine of catching the ball, the arms across the neck, it's on his arm. He can't put his arms up and we've said that we'll penalise that.
"And we've been consistent in that particular aspect. We're not just talking about the contacts of players coming together. Therefore, that one stands out quite clearly and it happens early in the sequence as well.
"There's not something else that happens much before that that stands out either. When you look at that, that's clearly the clear and obvious offence that needs penalising."
Webb believes VAR had to get involved and took their time due to the other potential offences involved.
"Is it a foul on the goalkeeper? Categorically, yes," said Webb. "We've said all season, including in pre-season briefings with the players, that if a goalkeeper is impeded by an opponent grabbing or holding their arms and therefore they can't do their job, they'll be penalised.
"We're not just talking about contact with goalkeepers, we're talking about a specific type of contact when the goalkeeper's arms or hands are being interfered with, stopping them from doing their job.
"So, when you see the best angle on this, you'll see that that's what happens from Pablo. And on the video, it's clear and it's obvious, and it happens early. And even though it's not clear and obvious to the referee because he's got a huge sort of group of players in a penalty area and it's difficult to see, when the VAR sees this, of course they have to get involved.
"But what we also hear the VAR doing is going through everything else because he wants to make sure that this is the only clear and obvious offence that needs intervening upon.
"[It's] really impactful. Raya can't do what he would normally do in that situation, simply catch the ball or punch the ball and they intervene and they come to the right decision."
Webb added: "A good use of VAR. It took some time. We have to take our time to get it right. In this really important situation, we did."
