C177 PLT; DURING VFR FLT; ENTERS IMC.

Narrative

VFR FLT FROM N14 (LUMBERTON; NJ) TO ZZZ. RECEIVED WX BRIEF FROM AFSS AND DOUBLECHKED WITH COMPUTER AT N14. WX RPTED 10 MI IN HAZE ALONG RTE; SKC. TRIED TO TRANSITION NYC CLASS B AIRSPACE. THEY COULDN'T HANDLE ME. CLBED TO 7500 FT TO OVERFLY; AND 7500 FT WAS ABOVE HAZE. PAST LGA; 050 DEGS; APPROX 18 NM; THE HAZE THICKENED AND I SUDDENLY WAS IN IMC. POSTFLT; PAX RPTED SHE COULD SEE US APCHING CLOUD. EVIDENTLY MY SUNGLASSES REDUCED CONTRAST SO I COULDN'T TELL THE DIFFERENCE BTWN HAZE AND CLOUDS -- SHE WASN'T WEARING ANY. THIS BECAME OBVIOUS POST-INCIDENT WHEN I SWITCHED TO REGULAR GLASSES. ACCORDING TO GPS AND LORAN; I WAS AT THE LATERAL LIMIT OF CLASS B AIRSPACE. I KNEW THERE WAS VFR BELOW BECAUSE I WAS LISTENING TO APCH. RATHER THAN DO A 180 DEG TURN; I REDUCED PWR; KEPT THE WINGS LEVEL AND DSNDED. GND CONTACT WAS REGAINED APPROX 6500 FT. I CONTINUED DOWN TO 5500 FT AND COMPLETED THE FLT WITHOUT FURTHER DIFFICULTY. LOOKING BACK; I SHOULD HAVE PERHAPS DECLARED AN EMER BUT GETTING THAT SORTED OUT WITH APCH WOULD HAVE TAKEN MORE TIME THAN THE APPROX 1 MIN IT TOOK TO GET DOWN FROM THE CLOUD. A 180 DEG TURN WOULD HAVE HAD ME GOING IN THE WRONG DIRECTION FOR THAT ALT. I'M CERTAINLY GOING TO FREQUENTLY CHK DIFFERENCES IN VISIBILITY BTWN DIFFERENT GLASSES. I HAD BEEN CHKING ATIS/AWOS WX ALONG THE RTE AND HAD CHKED WITH FLT WATCH. I HAD GOTTEN NO RPTS OF CLOUDS AT THAT ALT.