Gradually blurring vision and trouble focusing the eyes indicate a possible need for eyeglasses, according to Urban Optiques. Headaches or squinting are some other signs that a person needs corrective lenses.
Signs of vision problems in children may include rubbing the eyes, trouble seeing the blackboard in school, head tilting and disruptive behavior, notes the New York Daily News. Many adults first notice problems when they're driving; 90 percent of one's ability to react in traffic depends on sight, according to ThinkAboutYourEyes.com. Some other signs of impaired vision are inability to focus clearly on print or computer screens, bad night vision, or eyestrain, says John W. Lahr, O.D. of EyeMed Vision Care. While these signs may not indicate a need for glasses, they should be checked out by an eye doctor.