The visual changes in a person’s eyes near the end of life and immediately following death are direct physiological consequences of the body’s systems shutting down. These alterations progress through distinct phases, reflecting the decline of neurological function, the cessation of circulation, and finally, the effects of post-mortem physics and environmental exposure.
Visual Changes During the Final Hours
As a person enters the final hours of life, the appearance of their eyes begins to reflect the systemic decrease in bodily function, particularly in hydration and neurological activity. A common observation is a loss of clear, sustained focus, often described as a “faraway” or “glassy” look. This reduced visual engagement is linked to a decline in consciousness and a general slowing of the central nervous system.
The eyes may appear sunken into the orbits, a manifestation of severe dehydration and loss of fluid volume. The blink reflex, which normally keeps the corneal surface moist, slows significantly or ceases altogether, often leaving the eyes partially open. This lack of regular lubrication further contributes to the glassy appearance and can cause the eye surface to dry.
While the person is still alive, the pupils may respond to light, but this reaction is often sluggish compared to a healthy state. The muscles controlling the eyelids also experience reduced tone, which is why the eyes may not fully close, even during periods of deep rest or unresponsiveness.
Immediate Indicators of Death in the Eyes
Clinical death is marked by several distinct and medically verifiable changes in the eyes. The most notable change is the loss of the pupillary light reflex, where the pupil becomes fixed and unresponsive to a bright light source. This reflex, which is governed by the brainstem, ceases when the brain’s activity stops.
Immediately following death, the pupils often dilate widely, a change caused by the relaxation of the iris muscles that were previously under nervous system control. This fixed and dilated state is a definitive sign used in the determination of death, though the pupil size itself can vary. In addition to the light reflex, the corneal reflex vanishes; if the corneal surface is lightly touched, the eye will no longer blink or move.
Within seconds to minutes after circulation stops, a process called “cattle trucking” or Kevorkian sign can be observed in the retinal vessels through an ophthalmoscope. This phenomenon is the visible segmentation of the blood column within the arteries and veins of the retina, as the blood flow fragments due to the lack of pressure and circulation. This fleeting sign confirms the immediate collapse of the ocular vascular system.
Physical Alterations Hours After Death
As hours pass following death, the eyes undergo structural changes caused by the loss of internal pressure and exposure to the environment. The intraocular pressure (IOP), which normally maintains the eye’s spherical shape, begins to fall rapidly after death, dropping to zero within an estimated four to eight hours. This pressure loss causes the eyeball to soften and appear visibly flatter or more sunken within the socket.
Corneal clouding, also known as corneal opacity, is a post-mortem change that begins to appear as early as two hours after death if the eyelids were open. The cornea, which is normally transparent, develops a hazy or milky appearance because it is no longer receiving necessary nutrients and oxygen. The degree of clouding is often used forensically to help estimate the time elapsed since death.
A specific physical alteration known as Tache Noire (“black spot”) can develop on the sclera, the white part of the eye, if the eyelids remain open for several hours. Tache Noire presents as a reddish-brown, and eventually black, rectangular or triangular discoloration on the exposed sclera. This is caused by the drying of the exposed tissue and the subsequent deposition of cellular debris and dust.