If you'll permit me to smash two idioms together shamelessly, what a cockeyed optimist really needs is a pair of rose-colored glasses. Both idioms suggest the same basic premise, that a perpetual optimist may not be viewing the world very realistically. By wearing rose-colored glasses, a person's grasp of a situation or circumstance would be unnaturally filtered or soft-pedaled. While a more optimistic worldview is not a bad idea in itself, deliberately failing to acknowledge unpleasant or negative aspects of the human experience can be a form of delusion or denial.
The origin of the idiom "rose-colored glasses" is still a mystery to this day, although there are a few interesting and plausible theories. The idea of a idyllic rose-colored worldview can be traced back to at least the 17th century. Quite possibly the popularity of romantic imagery in artwork inspired viewers to associate optimism with the rose gardens and deep reds they saw. Victorians certainly were familiar with the idea of a "rosy glow" or "painting a rosy picture." Viewing the world through rose-colored glasses could be an extension of painting extraneous roses to liven up a painting or decoration.
Another theory concerns early mapmakers and their special corrective lenses. Because map making required a great deal of attention to detail, mapmakers needed to keep the lenses of their eyeglasses especially clean and scratch-free. It is believed by some that these mapmakers would use rose petals to clean any dust or other contaminants from their lenses. The rose petal's natural oils would protect the lenses, but often left a rose-colored stain. Therefore, viewing the world through rose-colored glasses would be the equivalent of focusing all of one's attention on the smallest details and ignoring the realities of the larger world around him or her.
The idea of looking through filtered lenses was also a familiar one by the 19th Century. Some people may have been accused of looking through blue or green-tinted glasses, which would have altered their perception of reality. Perhaps the same concept of a filtered worldview was applied philosophically to eternal optimists who preferred a sanitized or filtered version of reality to the one they were forced to live in by circumstances beyond their control.
One of the most entertaining theories suggests that the "rose-colored glasses" were not eye wear at all, but rather bar glasses. Viewing the world through the bottom of a glass containing red wine or rose-colored spirits might be considered the same as cockeyed optimism. Whether the soft-focused worldview was inspired by alcohol or an optimistic philosophy, it could be argued that a person looking at a situation through rose-colored glasses is making a conscious choice to accept or not accept certain realities.