"Park effect" can really distort the perception of a hitter, for the better or for the worse. Bob Watson is a great example of this. Watson spent his first 13 seasons with the Houston Astros, from 1966 to 1978. During that period, the Astros played their home games at the Astrodome, a very tough park for hitters. His production really suffered because of this. As Bill James notes in the New Bill James Historical Baseball Abstract, Watson has the same number of career home runs on the road as Ted Kluszewski (117). At home, though, Kluszewski holds a 162 to 67 advantage.
I don't think Watson wore glasses on the field at the start of his career. But I know he did wear them on May 12th 1974 in Cincinnati. Playing left field, Watson crashed head-first into the outfield wall and shattered his glasses. As he lay on the ground, Reds fans bombarded him with cups, beer and insults.
In 1979, the Astros traded Watson to the Red Sox. Watson immediately took advantage of his new surrounding, blasting 13 homers in 84 games for the Sox. In 1980, Watson played his last productive season with the Yankees and hit 16 homers. He became a part-time player after that and retired as an Atlanta Brave in 1984. During his career, he played 1088 games at first base, 570 in the outfield and 54 as a DH. He’s a career.295 hitter with a .364 OBP. He scored the 1,000,000th run in major league history in 1975.