The speaker looks into a mirror and no longer recognizes the face staring back. Once bright and untroubled, it now seems dimmed, worried, and aged. The eyes that used to be careless have become heavy with care. The speaker wonders what caused this change. Time alone cannot account for it, because something deeper and more painful is at work. That something is regret. More than ordinary sadness, regret has poisoned youth and twisted it toward madness. The mirror, though, can only show the surface. It reflects the tired face but cannot reveal how much bitterness the heart actually holds. The mood is quiet and sorrowful, with a sense of being haunted by past mistakes that leave marks no glass can fully show.
The Glass — Summary
Your face has lost The clearness it once wore, And your brow smooth and white Its look of light; Your eyes that were So careless, are how deep with care!
O, what has done This cruelty to you? Is it only Time makes strange Your look with change, Or something more Than the worst pang Time ever bore?--
Regret, regret! So bitter that it changes Bright youth to madness, Poisoning mere sadness ... O, vain glass that shows Less than the bitterness the heart knows.