MELVILLE, N.Y. - Most women think it can’t happen to them. They live in sweet denial. But we’ve all seen it happen, and it’s time someone blew the lid off this dirty little secret.

We’re talking, of course, about BBD - Bridal Blindness Disorder - the sudden, inexplicable way brides lose their sight (if not their sanity) when choosing bridesmaid dresses. How else to explain the shocking number of god-awful dresses that faithful friends and relatives are forced to wear, marching lockstep a few feet ahead of the chick all in white? C’mon, bridesmaids, fess up - you’ve worn some dogs, in all their poofy, sherbet-toned glory.

Lisa Witzer has a basement closet full of them. Five so far. By May, she’ll have two more.

‘‘It’s like the bridesmaid closet,’’ says Witzer, 31, a personal trainer at Equinox in Woodbury, N.Y. ‘‘You always think in your head, ‘Maybe I’ll wear this again,’ but then you realize ... it’ll never happen.’’

Could be worse - she could be stuck with 20 more, like Katherine Heigl’s character in the new film ‘‘27 Dresses,’’ a sweet, romantic comedy that opens Friday. Heigl plays Jane, a woman who’s worn so many bridesmaid dresses she can’t close her closet door. The film comes from the same screenwriter as ‘‘The Devil Wears Prada,’’ so count on one heckuva dress montage.

‘‘There were plenty of women on the crew, and they’d say, ‘I’ll bring in my old dresses,’’’ says costume designer Catherine Marie Thomas. ‘‘It was kind of hilarious.’’

Heigl, just married in real life, not surprisingly looks beautiful in every zany outfit dreamed up by Thomas and her team, from the spike choker (Goth wedding) and pink flippers (underwater) to the Playboy, Greta Garbo and Bahama Mama getups. (Nothing, however, beats the saffron/fuchsia bridesmaid sari - complete with forehead bindi - for a Hindu-Jewish interfaith ceremony.)

Witzer’s collection isn’t quite so multi-culti. But she’s got some doozies. Looking at her stash, one can’t help but wonder: Can any of these dresses be saved?

We asked expert Port Washington dressmaker Nancy Sinoway to do a bit of satin-and-taffeta triage.

Sinoway approached the flock of five bad dresses with a discerning gaze, part Darwin, part Diana Vreeland.

‘‘This one is too far gone,’’ she declared, casting aside an acrid lilac two-piece with polyester chiffon shawl.

A ruby gown verging on drapery wasn’t too bad, nor was a Vera Wang-ish ivory strapless. A black gown with a useless white panel in back felt oddly reminiscent of ... Pilgrims. But the mother lode came in the form of a sequined, emerald number with ‘‘Dynasty’’-worthy shoulder pads and big, puffy sleeves.

‘‘If you can make this pretty again, I’d wear it,’’ says Witzer, who wore Big Green to a cousin’s wedding about 10 years ago.

Sinoway took up the challenge, making over both the green and black dresses - a process she says can cost anywhere from $125 to $300 (more for intricate work like beading).

The results: more surprising than any political primary.

‘‘I can’t believe they’re the same dresses,’’ says Witzer, feeling the fabric of one as if to double-check it’s hers.

Of course, being a bridesmaid is about more than just the dress.

‘‘Don’t go into it thinking you’re gonna wear it again,’’ says Millie Martini Bratten, editor in chief of Bride’s magazine. ‘‘Go into it knowing you’re there to support a friend, stand tall and smile on her wedding day. Because that’s what friends do.’’

Witzer couldn’t agree more. Still, she says, ‘‘If you have these dresses in your closet, it’s nice to know you can get some use out of them.’’

The tragic bridesmaid dress has ‘‘become a cliche’’ - they’re actually getting better, Millie Martini Bratten of Brides magazine insists.

Finer fabrics are available at lower prices, and designers now offer classic shades: black, brown, navy, bisque. The price point isn’t bad, either.

‘‘J. Crew and Ann Taylor carry bridal lines,’’ Bratten says. And last year, Isaac Mizrahi unleashed bridal looks priced at $35 and up at - where else? - Target.

Bridal wear has been improving since the 1990s, she says, when brides started scanning the red carpet for inspiration, and modern looks from Vera Wang (who began designing in 1992) and Amsale gained in popularity.

Weddings are much more fashionable now, Bratten says.

OK. And when they’re, uh ... not?

‘‘Kibitzing about the dress is all part of the fun,’’ she says.

‘‘Most brides, when looking at bridesmaid dresses, imagine how the dress would fit them, not their bridesmaids,’’ says dressmaker Nancy Sinoway.

That’s their first mistake. There are plenty more; here are some ways to avoid them.

FOR THE BRIDE

Get real. No single dress will work on a size 2 and a size 20, says costumer Cat Thomas. ‘‘Women’s bodies don’t work that way.’’ Even size 2’s - with ‘‘huge boobs or none’’ - can vary, she adds.

Money matters. Know what your bridesmaids can afford, notes Millie Martini Bratten, of Brides magazine. ‘‘They’re making a sacrifice for you, so try to do the best by them,’’ she says.

Let a bridesmaid pick her dress. ‘‘She knows what works for her undergarments, her body shape,’’ says Sinoway. Specify a certain designer, maybe a shade or two. ‘‘Even if one is strapless, another has a high neck and low back,’’ she says, ‘‘it’s still the same line and a cohesive look.’’

FOR THE BRIDESMAID

Suck it up. Agreeing to be a bridesmaid means being a part of the bride’s fantasy, says Bratten. ‘‘It’s her day, her vision, and you’ve agreed to support her.’’

Speak up, if you must. ‘‘I hate this dress’’ won’t work. Bratten suggests saying something polite like: ‘‘I love you and want to be a part of your wedding, but I’m so uncomfortable in this. What can we do about it?’’ (Adding a shawl, shrug or bolero to a strapless or otherwise bare dress works wonders, she notes.)