A study that Bausch + Lomb conducted in the U.K. found that 90 percent of contact lens wearers keep their lenses in longer than they're supposed to. Half of those surveyed admitted that they would keep their lenses in for seven hours longer than advised; about 20 percent said that they sometimes wear them for a full 24 hours longer than instructed. Two thousand adults were questioned about their lens habits. The age group with a slightly higher rate of leaving their lenses in too long was 55 years and up, with almost 95 percent reporting that they flouted directions. The most common symptom of wearing contact lenses for too long was gritty, uncomfortable eyes, reported by 57 percent of those surveyed. Forty-three percent had itchy eyes, 31 percent had burred vision and 19 percent had bloodshot eyes. More seriously, 23 percent of respondents reported getting eye infections; 35 percent had their contacts stick to their eyes; and 13 percent experienced eye injuries.