The Dome Patrol defenses seem more like myth than memory now.

And it only has a little to do with the New Orleans Saints’ struggles on defense in the past two seasons.

The numbers that defense put up in 1991 and 1992 just don’t make sense in today’s NFL. During those two seasons, the Dome Patrol — led by the brilliant linebacking quartet of Rickey Jackson, Sam Mills, Vaughan Johnson and Pat Swilling — held teams to 12.9 points per game over a two-year span as they stood atop the NFL in scoring defense. New Orleans gave up just 250.3 yards per game in those two seasons, finishing second in the league both times.

The last time a team gave up fewer than 13 points per game was in 2006, when the Ray Lewis-led Baltimore Ravens allowed 12.6, matching the Saints’ total from 1991. The Denver Broncos, who lead the NFL so far in 2015, are allowing 17.4 points per game.

Only one defense — Seattle’s — has allowed teams to average fewer than 300 yards per game in each of the past two seasons.

The Dome Patrol operated in an era ruled by defense. In 1992 and 1993, scoring league-wide dropped to 18.7 points per game, the lowest mark since 1978 — the same year that the “Mel Blount rule” was put in place, restricting defensive backs from touching receivers beyond 5 yards.

Scoring has been on the rise ever since. Teams are averaging 23.5 points per game in 2015, making a run at the NFL record of 23.6 points set in 1948.

All of these numbers prompt a question: In light of the NFL’s offensive explosion, do defenses have to be judged differently?

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A proliferation of passing, more rules changes for defensive backs that make the Blount rule seem tame in retrospect and a series of safety initiatives that keep defenses from dishing out punishment have sent offensive numbers skyrocketing.

But on a play-to-play and game-to-game basis, a defender’s task remains the same.

“The goal is to stop what they do,” Saints defensive tackle Kevin Williams said.

The rules changes simply make the task much harder — particularly for defensive backs.

Saints cornerback Brandon Browner’s league-leading 17 penalties come with the territory — he always has been among the league leaders in flags — but the early issues for fellow cornerbacks Delvin Breaux (four penalties in the first game) and Damian Swann (in the preseason) are an indicator of how much the NFL restricts defensive back play compared to the other levels of the sport.

“The things you’re allowed to do are different,” safety Jairus Byrd said. “Some of the vicious hits that guys would get coming over the middle now draw a flag. Some of the hits you get on a quarterback, you can’t do that now. That stuff affects the game. And you talk about what corners can do to receivers, they can’t do most of that anymore.”

All those rules have led to an increase in passing league-wide. Eight of the top 10 single-season marks for passing attempts have happened since 2010, including four such seasons by the Saints’ Drew Brees.

“I feel like defenses are tested in more ways now through the air,” Byrd said. “It’s turned more into a finesse ... I wouldn’t say finesse, I’d say a skill-position type game, rather than a game that’s played between the trenches. I mean, it’s still won up front, obviously, but it’s not just ground-and-pound like they used to just keep giving the ball to the running back and throw the ball every now and then.”

The rules changes have changed the way defenses evaluate themselves.

A dominant defense like the Seahawks’ can still lead the league in both total yards and scoring defense, but a team also can be successful even if its defense is hemorrhaging yards — provided it keeps teams out of the end zone.

In 2011, the New England Patriots and Green Bay Packers finished 31st and 32nd in yardage allowed, both giving up more than 411 yards per game. But the teams finished the season ranked 15th and 19th in the league in scoring, allowing them to ride their spectacular offenses to the playoffs — and, in the Patriots’ case, the Super Bowl.

“The big focus now is it’s not as much about yards as it used to be,” Williams said. “You can give up yards all day, but if they’re kicking field goals, you’re still in the game. You have a chance to win.”

A defense can make up for a yardage problem by creating turnovers and making situational stops. In 2011, Green Bay and New England finished first and second in the NFL in interceptions.

The 2009 Saints team that won the Super Bowl finished 25th in the league in terms of total yards, but New Orleans finished third in the NFL in interceptions and gave up a respectable 21.3 points per game.

“It’s about turnovers, the point differential and third down and I’d say the running game,” Williams said. “You stop the run game, make a team one-dimensional, and then you know what fight you’re fighting. But I think, at the end of the day, you look at your points. You don’t want to give up a lot of points.”

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New Orleans spent the offseason overhauling its defense in an effort to build the kind of group that could give its offense chances.

Under head coach Sean Payton’s direction, the Saints shifted to a man-to-man, single-high safety scheme far more simplified than the exotic, blitzing defense New Orleans ran in Rob Ryan’s first two seasons.

The Saints also overhauled the talent. Breaux has been a revelation at cornerback, second-year players like Kasim Edebali have emerged and a promising rookie class led by linebackers Stephone Anthony and Hau’oli Kikaha has been solid. Bringing in that young talent allowed the Saints to mix a youth movement with an emerging star in defensive end Cameron Jordan and plenty of experience in the secondary.

There have been glimmers of hope. New Orleans ranks fourth in the league in third-down stops, first in forced fumbles and 14th in sacks, a surprising number given that the Saints released Junior Galette right before the season.

“I feel that our defense is still learning,” Jordan said. “I wouldn’t say that’s a great thing at this point.”

New Orleans ranks 31st in the league in yards allowed per game (414.8), a bad number that is by no means crippling, as other defenses with prolific offenses have proved in the past.

The problem is the Saints haven’t done enough to offset the rest. New Orleans ranks 25th in the NFL against the run, giving teams plenty of options on third down.

New Orleans has just four interceptions, allowing opposing passers to post a rating of 112.0, a number that would be the worst in NFL history. Despite some early success in the red zone, New Orleans has struggled of late, giving up touchdowns on 72.7 percent of its chances in the past three weeks.

And it’s translating to the scoreboard: Despite the bright spots, the Saints are 31st in the NFL, giving up 29.8 points per game.

For the second straight season, Ryan finds himself under fire from fans as the Saints struggle to keep teams off the scoreboard. But the Saints’ embattled defensive coordinator still sees a light on the horizon.

“We’re playing a lot of post-safety defense, and it takes time to master it all,” Ryan said. “We know what we’re playing, we’re focusing and we need to play it better. We’ve got the right players, and it is all going to come together here pretty soon.”

A turnaround needs to happen quickly.

With the playoff picture taking shape, time is running out.