In William Golding's Lord of the Flies, Piggy's spectacles are one of the novel's most powerful symbols. Golding invests this small object with large meaning, so that its fate charts the rise and collapse of order on the island.
They symbolise reason, science and intellect. Piggy is the most rational and clear-thinking of the boys, and his glasses represent the power of the human mind to see clearly and think logically. As long as the glasses are intact and Piggy is respected, reason has a voice in the group.
They are the source of fire. The boys use the lenses of Piggy's glasses to focus the sun's rays and light their signal fire. The fire represents both the hope of rescue and the practical benefits of civilisation. Thus the glasses are literally the means by which the link to the adult, ordered world is kept alive, and later the means by which Jack's tribe cooks its meat.
Their damage tracks the decline of order. The condition of the glasses mirrors the condition of the group. When one lens is broken during an early quarrel, it marks the first crack in the boys' unity and in the rule of reason. As savagery grows, the intellect is progressively blinded.
Their theft marks the triumph of savagery. Jack's hunters raid Ralph's camp at night and steal the glasses, seizing the power of fire for themselves by force rather than by cooperation. This theft, not the conch, shows that brute power has overthrown reason. Soon afterwards Piggy is killed and the conch shattered, and with the loss of the glasses' owner the last light of rational civilisation is put out.
The significance of Piggy's glasses, therefore, is that they embody clear-sighted reason and the fire of civilisation, and their breaking and theft dramatise humanity's descent from order into barbarism.