When someone dies, particularly in their sleep, curiosity often arises about the state of their eyes. The human body undergoes a series of complex biological changes at the moment of death and in the hours that follow, which directly influence the appearance and condition of the eyes. Understanding these processes can help clarify what happens to the eyes during this final transition.
The Immediate Answer
When a person dies in their sleep, their eyes typically remain closed. This is because the natural resting state of the eyelids during sleep is closed, and the muscular control that holds them open or actively closes them ceases at the point of death. However, it is not uncommon for eyes to be partially or even fully open at the moment of death. This variability depends on several factors, including the individual’s underlying health conditions and the exact physiological processes occurring as life ends.
Physiological Responses at the Moment of Death
Eyelid position is actively maintained by a delicate balance of muscle control. Specific muscles are responsible for closing and opening the eyelids, and both are regulated by the central nervous system. At the moment of death, brain activity ceases, leading to a rapid and complete loss of muscle tone throughout the entire body, a state known as primary flaccidity.
As central nervous system function stops, control over these eyelid muscles is lost. If the eyes were closed at the time of death, such as during sleep, they may remain in that position due to the relaxation of the muscles that would otherwise hold them open. However, in some instances, the overall relaxation can cause the eyelids to drift open partially or fully. Certain medical conditions that affect the central nervous system can also increase the likelihood of eyes remaining open at death. Additionally, the pupils of the eyes will dilate and become fixed, no longer reacting to light, as oxygen supply to the eye ceases and muscle tone is lost.
Post-Mortem Eye Changes
Following the immediate moment of death, the eyes continue to undergo further changes. One significant process is rigor mortis, the stiffening of muscles that occurs due to chemical changes. This stiffening typically begins in the facial muscles, including those around the eyes, within one to four hours after death. If the eyes were closed or partially open, rigor mortis can cause the eyelids to become set in that position, or in some cases, the slight contraction of muscles may even lead to a partial opening of previously closed eyelids.
If the eyes remain open after death, they are exposed to the environment, leading to a phenomenon known as corneal opacity. The cornea, the clear outer layer of the eye, begins to dry out and becomes hazy or cloudy. This clouding can start within approximately two hours post-mortem and progressively intensifies over the subsequent 24 to 48 hours. This drying process can give the eyes a dull, glassy, or grayish-blue appearance, even though the actual color of the iris does not change.
Furthermore, a dark, reddish-brown or black band, called tache noire, can form horizontally across the exposed sclera (the white part of the eye) due to drying and debris accumulation. As dehydration continues, the eyeballs may also recede slightly into their sockets.