The body of an elderly man is found in a river. The environmental conditions make the time of death difficult to determine. However, the postmortem exam (i.e. autopsy) finds that the potassium level of the vitreous humor in his eyes correlates with other physical findings, indicating he died less than 48 hours before.
A middle-aged woman is found dead in her bed. Her medical history reveals she was diabetic. Toxicology tests of her vitreous humor reveal elevated levels of glucose and ketones, indicating she died of diabetic ketoacidosis.
The eyes can tell a lot about a person, even after death. Similarly, optometrists can occasionally provide a unique contribution to assist law enforcement.
Here, youll see with your own eyes what the eye can show forensic investigators, and youll also learn how you can get involved with crime detection and prevention in your own area.
The word autopsy is Latin for seeing with ones own eyes. In an autopsy, the eye can provide unique forensic information, as well as contribute and confirm other physical evidence.
What follows are specific ways that the eye is used in the postmortem exam, according to Randy Hanzlick, M.D., chief medical examiner for Fulton County, Georgia, and professor of forensic pathology at Emory School of Medicine in Atlanta.1
Time of death. Determining the postmortem interval (i.e., time elapsed since death) is nowhere near as exact in real life as it is on television shows, Dr. Hanzlick says. But there are two ways that the eye can provide a ballpark estimate of the postmortem interval.
The first is corneal clouding. About two hours after death, the cornea becomes hazy or cloudy, turning progressively more opaque over the next day or two. This obstructs the view of the lens and back of the eye. (See A New Look at a Dead Retina, on page 80.) But this clouding may provide a rough estimate in helping to determine time of death.
The second way the eye can help determine the postmortem interval is through the measurement of potassium levels in the vitreous humor. After death, blood cells in the body break down and release potassium. In the eye, this process happens more slowly and at a more predictable rate than in the blood. Its also a process thats unaffected by temperature. Thus, a pathologist can sample the potassium level in the vitreous humor and use that value to calculate an approximate time of death, Dr. Hanzlick says.
These methods are used along with other physical findings such as rigor mortis (stiffening of the body), livor mortis (gravitational settling of the blood), algor mortis (cooling of body temperature) and decomposition of the body. Even so, the best estimate of time of death has a margin of error not of minutes but of hours or even days.
The ideal method to determine time of death is not an autopsy finding, Dr. Hanzlick says. Its having an eyewitness.
Other helpful indicators are remarkably simple things, like noticing on which day the newspapers or mail started piling up.
Cause of death. Medical examiners routinely check the conjunctivae and eyelids for pinpoint-sized petechial hemorrhages. Theyre caused by an increase in the hydrostatic pressure in the capillaries, Dr. Hanzlick says. You can see them in many forms of asphyxia, like strangulation or chest compression, but you can also see them if theres a [build-up of] pressure from heart failure or a sudden cardiac death.
When medical examiners see petechial hemorrhages, he says, they must suspect strangulation and homicide. This prompts them to look for other signs to rule out these causes of death.
|Can You Identify This Jane Doe?|
|This woman was found dead from a gunshot wound on October 6, 1995, near a campground in rural Tolland, Mass. Massachusetts State Police detectives believe she is not from their area. Can you help identify her?|
Some of usoptometrists and opticianscan remember a patient merely from a frame or a prescription, says Dr. Bertolli, who has been communicating with the state police detectives on this case. If the following description sounds like one of your patients, or if you have any information you can share, please contact Det. Sgt. Stephen Griffin or Lt. Barry OBrien at (413) 747-4810.
The woman was 30-50 years old with a light-skinned complexion, about 52-55 tall, medium build, about 120-130lbs., gray-brown hair, upper and lower bridge work with only a few of her own natural teeth left.
Her eyeglass prescription was 4.25 0.50 x 180 O.D., 3.50 0.25 x 170, in size 52/16-135 maroon/gold frames from the Metaline Collection (#7) line from Value Eyewear Inc., of Clifton, N.J., manufactured in China.
She was last seen wearing size 8P Bill Blass jeans, size 40B bra, and a unique drawstring hooded sweatshirt with the word Trends in a diamond on the left chest. Detectives tracked down the sweatshirt and found it was sold in stores in and around upstate New York, although the woman could have come from anywhere in the country.
Toxicology tests of the vitreous humorsuch as blood urea nitrogen (BUN) and creatinine testsmay also provide information about cause of death or presence of systemic disease. For instance, a BUN/creatinine test estimates how well the kidneys function, and can indicate if the person had significant renal disease or was dehydrated, Dr. Hanzlick says.
Tests of the vitreous can also show high levels of glucose and/or ketones, indicating a diabetic problem like diabetic ketoacidosis. Additionally, the eye seems to process alcohol more slowly than the blood. Toxicologists may test the blood, urine and vitreous fluid for a more accurate measure of a bodys level of intoxication at time of death, as in the case of a suspected drunk driving accident.
Erratum. Lastly, during the autopsy, the medical examiner must catalog the bodys appearance, including eye color, for absolute identification. These days, medical examiners have to look closely for colored contact lenses, Dr. Hanzlick says. A missing person known to have brown eyes, but wearing green colored contacts on autopsy, could remain missing if the examiner doesnt notice the colored lenses.
O.D. as C.S.I.
Although you may never be called to provide expertise at a crime scene, there could be unique occasions where investigators may bring evidence to you, says optometrist E. Robert Bertolli, who is a co-director of the forensic optometry division of the American College of Forensic Examiners International (ACFEI).
If you have good ties with your local law enforcement and you let them know youre willing to help, they may contact you to identify spectacle lens shards or contact lenses found at a crime scene, Dr. Bertolli says. If you can determine the Rx or maybe even the type of lens from the lens fragment, this could help identify a Jane or John Doe. A spectacle lens shard as small as 4mm could reveal the prescription, he says.
Of course, the investigators will have taken fingerprints and trace evidence from the lens material first. And to show some credibility, you should probably first take a course in crime scene investigation before approaching law enforcement to offer your services, Dr. Bertolli says. (Organizations that offer such courses include ACFEI and the International Association for Identification.)
Dr. Bertolli, along with optometrists D. Robert Pannone and Constantine J. Forkiotisan optometric state police surgeoninstructs a course in forensic optometry. The course teaches how to recover the Rx from a spectacle lens shard, and also how to match retinal and iris photos with those of Jane or John Does.
But probably the most common way, and most involved way, that optometrists can participate in law enforcement is by helping to instruct officers in how to assess the living not the dead.
|A New Look at a Dead Retina|
|In the living, the retina is a window to the systemic health or disease of the patient. Perhaps the retina could do the same after death. The only problem is that within hours after death, the cornea begins to cloud. |
Thats the main reason we dont know much about the retina in forensic medicine, because unless you get to the person a couple hours after they die, you cant really do a standard ophthalmoscopy, says forensic pathologist Neil L. Davis, M.D.
The only other way to see the retina is by enucleating the eye totally, he says. But enucleation is very time consuming, and also disfiguring to the body.
To that end, Dr. Davisworking through the medical examiners office of Suffolk County, N.Y.has undertaken the first large-scale study using an ophthalmic endoscope to help characterize cause of death. The endoscope has a barrel approximately the diameter of a coffee stirrer, the kind most commonly used in small joint endoscopy. With this, he punctures the sclera, and once you get into the globe, you get a beautiful panorama of the entire retina.
Some preliminary observations:
Carbon monoxide poisoning turns the retina bright pink. The cherry-red coloration of blood and organs is a well-known trait in forensic science. But it was very interesting to find that it carries over to the retina, Dr. Davis says.
Diagnosis of shaken baby syndrome (SBS) has a classic triad of three characteristics, one of which is retinal hemorrhages. Without taking a a scalpel to the body, the endoscope could spot the retinal hemorrhages (or lack thereof) to help in the decision of whether to continue to investigate for SBS.
Retinal folding after death has long been documented. But can the amount and appearance of retinal folds indicate the postmortem interval? We have some preliminary numbers that suggest that it can, Dr. Davis says.
Specifically, optometrists can offer expertise in the use of horizontal gaze nystagmus (HGN) testing as part of the visual science portion of drug impairment recognition training, Dr. Bertolli says. This tests for smooth pursuit, equal tracking, and onset of nystagmus. Alcohol, depressants and PCP are drugs that hamper the action of these visual tasks. (Unlike some of the other field sobriety tests, people cannot practice HGN.) Lack of smooth pursuit, nystagmus at maximum deviation, and onset of nystagmus before 45 degrees are all clues of intoxication; the closer to the nose the nystagmus occurs, the higher the blood alcohol content.
Evaluating the pupil also holds clues. Small pupils are consistent with narcotics. Dilated pupils that react slowly to changes in light intensity may be due to cannabis, stimulants and psychedelic drugs. Rebound pupil is known for cannabis use.
To get involved in instructing local law enforcement on these tests, contact the police instructor doing the course and ask to sit in on it first, Dr. Bertolli recommends. When you feel confident, then approach the instructor and offer your help. There are a lot of law enforcement [instructors] who will embrace having someone knowledgeable to do that visual science portion of the course, he says.
Do you think you never see victims of crime in your own practice? Think again.
If youre seeing patients, then youre seeing victims of domestic violence, says optometrist Denise Pensyl, who lectures about how O.D.s can spot domestic violence.
Specifically, nearly one in four women report being raped and/or physically assaulted by an intimate partner in their lifetime.2 In total numbers, nearly 1.5 million women are raped and/or physically assaulted per year.
|A pattern injury (handprint).|
|Commotio retinae. Photos: Denise Pensyl, O.D.|
In terms of eye injuries, as many as one-third of all orbital fractures in women may occur due to sexual assault or domestic violence.3 Other ocular findings include any kind of blunt trauma, corneal abrasions, black eyes, commotio retinae, retinal tears, choroidal rupture, torn irises and traumatic cataracts, Dr. Pensyl says.
More telling can be the characteristics of the injury, she says:
Symmetry. Often the injury has a symmetry to itsuch as bilateral torn irises or double black eyesthat everyday accidents dont have.
Sequence. Be suspicious of injuries in various stages of healing, like a fresh bruise here and an older scrape there.
Pattern. A pattern injury may identify the weapon used, such as hand mark, finger mark or boot mark bruises, ring indentation, or cigarette or rope burn.
Appearance. The injury doesnt match the patients description. Be suspicious if the patient with double black eyes, who appears to be injured nowhere else, says she fell down the stairs.
Also, any time I see an injury in a pregnant woman Im immediately suspicious, Dr. Pensyl says. Pregnancy is a huge risk factor for domestic violence.
Due to the high incidence of domestic violence, screen every female patient for it, she says. Start with a general statement then follow it with a direct question:
Violence in our society is very common and Ive started asking all the women I see this question: Are you now or have you ever been in a relationship where youve been afraid or not treated well?
(Dr. Pensyl doesnt use the term abuse because victims rarely see themselves as abused.)
Ask the patient if you can take photos of the injuries. Then let her know youll keep these in the record should she ever want to use them as evidence. Even if she denies abuse, note the injury and how the patients explanation is inconsistent with your observation.
Dont call the authorities or try to convince the patient to leave the relationship. Instead, offer information on services or shelters and let her decide.
For children, however, optometrists (like all medical providers) are required to alert the local child protective services department if they suspect abuse.
Even if youre wrong about the suspicion, youre protected from a lawsuit, so its better to be safe than sorry, says Michael Giese, Ph.D., O.D., associate professor of clinical optometry at The Ohio State University College of Optometry, who lectures on how optometrists can identify child abuse.
Ocular injuries in abused children include bilateral black eyes, subconjunctival hemorrhages and retinal hemorrhages, among others, Dr. Giese says.4 Be suspicious if theres a laceration to the face associated with the ocular injury.
Also, be on the lookout for unusual behavior. A lot of doctors will tell me its how the parent and child interact when they walk into the exam room, Dr. Giese says. They just get a suspicion immediately that somethings not right. In such instances, he says, the parent answers all the questions, or the child looks to the parent for approval before answering questions.
What dentists and other doctors have done is to separate the parent and caregiver, Dr. Giese says. Theyll keep the parent at the front desk filling out forms to give the doctor time to question the child.
As in domestic abuse cases, take photographs for evidence, if possible. Keep in mind that you must retain a childs medical record at least until he turns 21 for legal purposes, Dr. Giese says.
Although you likely will never attend an autopsy or inspect a crime scene, you can see with your own eyes how you can help law enforcement and prevent crimes.
- An interesting but unrelated fact: Dr. Hanzlick wrote and recorded the country music novelty song Id Rather Have a Bottle in Front of Me Than a Frontal Lobotomy.
- Tjaden P, Thoennes N. Extent, Nature, and Consequences of Intimate Partner Violence: Findings From the National Violence Against Women Survey. National Institute of Justice and the Centers for Disease Control and Prevention. Washington DC: July 2000. 5.
- Hartzell KN, Botek AA, Goldberg SH. Orbital fractures in women due to sexual assault and domestic violence. Ophthalmology 1996 Jun;103(6):953-7.
- Giese MJ. Ocular findings in abused children and infants born to drug abusing mothers. Optom Vis Sci 1994 Mar;71(3):184-91.