A cylindrical power of -0.50 indicates a very mild degree of astigmatism, which is a common and harmless variation in the curvature of your eye. At this low level, wearing corrective glasses is generally optional. If you do not experience symptoms like eye strain, headaches, or blurred vision, especially during activities like reading, working on computers, or driving at night, you likely do not need glasses. However, if you do experience these mild discomforts, wearing glasses can help sharpen your vision and reduce strain. It is best to discuss your daily visual habits with your eye doctor to make a final decision.