The eyes offer distinct physiological indicators of the body’s shutdown as life nears its end. Changes in appearance are a direct reflection of systemic decline, particularly the gradual failure of circulation, oxygen delivery, and muscle control. These alterations progress through stages, moving from observable signs of decline to clinical markers of functional cessation and, finally, to post-mortem structural changes.
Observable Changes During the Dying Process
As a person enters the active phase of dying, the appearance of the eyes changes visibly due to decreased systemic function and muscle weakness. A common observation is a “glassy” or teary look, resulting from the diminishing ability to maintain proper lubrication and hydration. The body’s overall fluid levels drop, affecting the normal production of tears necessary to keep the corneal surface clear and moist.
The frequency of blinking significantly decreases as the orbicularis oculi muscles, responsible for closing the eyelid, become hypotonic and weakened. This reduced blink reflex contributes to a dull or unfocused appearance because the cornea is not being regularly lubricated. The eyes may settle into a fixed or unfocused stare as the muscles controlling eye movement lose their tone, preventing tracking or focusing normally.
The weakening of muscles and the loss of underlying fat tissue within the orbital socket can lead to a slight sinking of the eyes, known as enophthalmos. This makes the eyes and the surrounding temples appear more sunken or drawn. These alterations are a consequence of general muscle relaxation and fluid shifts happening in the final hours or days of life.
Clinical Signs of Functional Cessation
For medical professionals, specific ocular signs provide definitive evidence of brainstem function loss, marking the cessation of life. A primary clinical indicator is the state of the pupils, which become fixed and unresponsive to light. The pupillary light reflex causes the pupil to constrict when bright light is shone on it; the absence of this reflex signifies a failure of the neurological pathway that controls it.
In a dying individual, the pupils often become dilated and lose their ability to constrict, remaining fixed in size. This non-reactivity indicates absent brainstem function, as the centers that regulate this reflex are no longer functioning. The definitive marker is the complete lack of reaction to a light source.
Another definitive clinical sign is the loss of the corneal reflex, the involuntary blinking response when the cornea is lightly touched. This reflex involves a loop between the trigeminal nerve (sensation) and the facial nerve (muscle response). The absence of this involuntary blink confirms a lack of function in the brainstem, which houses the nuclei for this pathway.
Physical Alterations Following Death
Once clinical death is confirmed, the eyes undergo further physical changes as the body’s metabolic processes cease. A noticeable post-mortem change is the development of corneal clouding or opacity. This process begins quickly, often within two to three hours after death if the eyelids are open, but may be delayed if the eyelids remain closed.
Corneal clouding occurs because the transparent cornea loses its necessary metabolic activity and begins to dehydrate and swell, causing it to become hazy. Environmental factors, such as dry air, can accelerate this film formation on the surface of the eye.
If the eyelids are not fully closed, another distinct post-mortem sign may appear on the sclera, the white part of the eye, known as Tache Noire Sclerae. This appears as a yellowish, then brownish, and eventually black band or triangle of discoloration. The discoloration is caused by the drying and desiccation of the exposed sclera when it is open to the air. Tache Noire is a direct result of environmental exposure to the eye’s surface.