微视野仪在视功能评估中的应用

微视野仪是一种在直视眼底的条件下,能定量、定位地测量黄斑区域的视网膜光敏感度,同时可以全程记录被检查眼的固视轨迹,自动分析固视位置、固视稳定性,并能将微视野图与眼底像点对点重合,实现功能和结构上的组合。微视野仪的各项研究指标与主观视力有良好相关性,为定量评估视力提供了新手段,在法医学视功能的评定中将具有一定的应用潜力。本文综述了微视野仪的原理、方法及研究指标,并着重探讨微视野仪在视功能评估中的作用,以期为法医学视功能评估提供参考。     

A Simple Model for Teaching Postmortem Monocular Indirect Ophthalmoscopy

Abstract:  Although the ophthalmoscope was invented by Hermann von Helmholtz in 1851, pathologists until recently have relied almost exclusively on ocular enucleation to identify and describe postmortem fundal abnormalities. An inexpensive but valuable tool for forensic pathologists, the postmortem monocular indirect ophthalmoscope consists of a light source attached to a headband along with a hand-held lens. This permits a wide view of the fundus after death but the technique can be challenging to master for pathology residents and forensic pathology fellows. To facilitate skill acquisition in monocular indirect ophthalmoscopy, a simple and inexpensive teaching model can be constructed from hinged, cylindrical plastic containers. An artificial pupil created in the lid and a removable color fundal image placed in the bottom of the opaque container allows the pathologist-in-training to practice the technique of monocular indirect ophthalmoscopy and correctly identify, localize, and describe fundal abnormalities such as retinal hemorrhages.     

高度近视者眼球结构及其功能变化的法医学意义

高度近视者眼球可发生一系列不可逆的组织形态学改变。其中,眼轴、角膜曲率、前房深度、眼底形态、黄斑神经上皮厚度等改变与眼球的屈光状态及视觉功能有着密切的关系,玻璃体混浊、玻璃体脱离、白内障、青光眼、后巩膜葡萄肿、视网膜脱离等并发症的发生率也随着近视屈光度数的加深而增高。越来越多的研究表明高度近视者视觉功能改变是上述多种结构变化共同作用的结果。因此有望通过应用多项检查方法观察高度近视者眼球的结构变化,并根据这些变化分析评估高度近视者视觉功能的损害程度,为法医学评价眼部外伤与疾病的关系以及眼外伤的司法鉴定提供支持和依据。     

近视眼底改变与功能相关性的研究及其法医学意义

目的研究近视眼底改变与视觉功能的关系;研究近视者轻度眼部钝挫伤后眼底改变与视觉功能的关系。对象与方法选取不同程度的近视志愿者104人/170眼及眼部轻度钝挫伤的近视者56人/112眼分别作为实验组和眼外伤组,按眼底变化分为0至4级,并测定弧盘比值,分别检测其屈光度、矫正视力及静态视野。结果在实验组和眼外伤组中,眼底改变、包括弧盘比值均与近视屈光程度、矫正视力、静态视野平均缺失敏感度相关。结论运用眼底分级可以估计受检眼的视觉功能,弧盘比值可以作为有效的补充手段;轻度眼部钝挫伤的近视者若仅见视觉功能降低,而未检见明显的眼球结构损伤性改变,则不能简单地按照伤后检见的视觉功能水平作为法医学鉴定的依据。     

眼部损伤程度法医学鉴定60例分析

目的探讨眼外伤的特点及其损伤程度法医学鉴定要点。方法对60例眼外伤的法医学鉴定案例进行回顾性分析,对所有案例按照性别、年龄、职业、致伤物及损伤类型进行分类研究。结果眼外伤中农民、工人占61.7%,钝性损伤达85.0%,且大多属单纯挫伤,占63.3%。结论眼外伤大多属钝性外力所致,眼底病变是影响视力的重要原因,对外力与视力受损关系的评价要充分考虑致伤物种类、打击部位及伤前眼病史等诸多因素的影响。     

Electroretinogram and Histopathologic Changes of the Retina after Methanol Intoxication

In order to study the functional and structural alterations of the retina in SD rat model after methanol intoxication,35 rats were divided randomly into five groups administrated with saline,3-day high dose,7-day high dose,3-day low dose and 7-day low dose methanol separately.The retinal function of each group was assessed by flash electroretinogram(F-ERG) 3 and 7 days after methanol poisoning.The microstructure and ultrastructure of the retina were observed at the same time.The high-dose methanol intoxication induced irreversible retinal functional and structural damages 3 days after poisoning,which included prolonged latency and reduced amplitude of the Max-reaction of F-ERG.These injuries were aggravated 7 days after poisoning.Meanwhile,the latency and amplitude of the Cone-reaction of F-ERG were also affected 3 days after poisoning,but there were no further worsening tendency 7 days after poisoning.The retinal histological analysis showed cellular edema,heteromorphy and disarrangement,tissular loosen of the inner nuclear layer and photoreceptors layer.The mitochondrial damage began at the photoreceptors layer and developed further into the inner nuclear layer.The low-dose methanol intoxication only caused transient damage of the retina.Our results showed that the function and structure of the photoreceptor and inner nuclear layer were the primary target of methanol intoxication and that the rod cells were more sensitive to methanol intoxication than the cone cells.The mitochondrial damage developed from outer layer to inner layer of the retina.     

A first time for everything: homicide involving the Brenneke SuperSabot shotgun slug

Sabot shotgun slugs are not a new projectile, but the Brenneke SuperSabot shotgun slug has never been reported in a homicide. We present the case of a 28-year-old man killed with multiple gunshot wounds during an alleged "drive-by" shooting. At autopsy, a 496.2 grain slightly deformed projectile with a base diameter of 5/8' (1.7 cm) was found within the decedent's clothing. Six distinct bullet tracks were identified. An entrance of the anterior right thigh was 3/4 x 5/8' and ovoid, having only passed through the decedent's jeans. This bullet track passed through the soft tissue of the right thigh, exiting out the medial aspect and partially transecting the right greater saphenous vein, re-entering the medial left thigh and re-exiting out the posterior left upper thigh. With the exception of an irregular entrance on the sole of the left foot, which passed through the decedent's shoe, all other entrances were less than 1/2' in greatest dimension. Investigating officers recovered an additional projectile of the same type, which had undergone more extensive deformation after striking and penetrating the tailgate of a truck. Further investigation identified the projectiles as the Brenneke SuperSabot shotgun slugs.     

The retina in forensic medicine: applications of ophthalmic endoscopy: the first 100 cases

The retina reflects a variety of diseases in the living patient. However, the retina is not routinely examined in deceased persons, and therefore it is unknown if routine retinal examination would be a useful adjunct to the forensic autopsy. To examine this issue, the retinae of routine medical examiner cases were examined utilizing an ophthalmic endoscope. The results of the first 100 examinations are reported. Specific attention was given to changes that reflected the postmortem interval, the development of petechiae as related to cardiopulmonary resuscitation, and the association of retinal hemorrhages to subconjunctival hemorrhages. The procedure was helpful in cases of suspected shaken baby syndrome, exsanguination, and carbon monoxide poisoning and in cases with sudden increased intracranial pressure (Terson syndrome). It appears that lividity patterns exist in the retina, and this may be potentially useful in determining body position after death. Some natural disease processes, such as hypertension, were also identified. Finally, the utility of the ophthalmic endoscope as a means of circumventing the problem of corneal clouding is discussed, and ideas for further research using this technology are presented.     

Autoerotic asphyxia: part I

Fatal autoerotic asphyxia refers to death during solitary sexual activity with self-induced asphyxiation meant to be brief and reversible. However, an unexpected fatality results from a failure of a release mechanism apparatus. The large majority of victims of autoerotic death are Caucasian males between the second and fourth decade. While autoerotic death may encompass a myriad of other means of achieving sexual gratification, which includes asphyxia by plastic bag or inhalation of noxious chemicals, the most common method is by ligature about the neck. This study presents a 9-year retrospective review of deaths due to autoerotic asphyxia, specifically ligature asphyxia, in Kentucky between 1993 and 2001. Of the sixteen victims, all were Caucasian males between the ages of 14 and 59 years, with a mean age of 38.3 years. Cross-dressing was a feature in 4 cases. A thorough review of the decedent's background, meticulous scene investigation, and complete postmortem examination may shed light on the mechanism and psychosocial predisposition associated with autoerotic asphyxia.     

Molecular autopsy of sudden unexplained death in the young

Sudden unexplained death (SUD) claims over 4,000 persons between the age of 1 and 22 each year in the United States. Nearly half of all pediatric SUD cases have a normal structural autopsy evaluation and are dismissed without a diagnosis. With the discovery of the genetic basis for potentially fatal arrhythmias associated with the inherited long QT syndrome (LQTS), postmortem molecular diagnosis of this disorder is possible. The authors describe the results of a molecular autopsy performed on a 17-year-old boy found dead in bed. A novel clinical test involving an epinephrine challenge in the decedent's mother implicated a potential defect in the phase 3 potassium current encoded by the gene KVLQT1. Exon-specific amplification by polymerase chain reaction and direct DNA sequencing of KVLQT1 revealed a 5-base pair deletion in the genetic material recovered from the decedent's paraffin-embedded heart tissue. The ability to perform molecular autopsies on archived necropsy material undoubtedly will transform the forensic evaluation of SUD. The combination of catecholamine provocation testing in survivors and a postmortem LQTS gene analysis may unmask families with "concealed" LQTS and establish the cause and manner of death in SUDS.     

Morphometrical analysis of retinal hemorrhages in the shaken baby syndrome

A morphometrical analysis of retinal hemorrhages was performed in cases of physical child abuse including the shaken baby syndrome and in controls (severe head injury, intravital brain death, non-traumatic intracranial hemorrhage, SIDS including cardiopulmonary resuscitation). The extent of the retinal hemorrhages was significantly different between both groups. In all cases of physical child abuse, massive retinal hemorrhages in at least one eye could be found ranging between a maximum value of 19.2 and 73.2% of the entire retinal area. In contrast, only two cases of the control group (severe head injury with skull fractures and intracranial bleeding following traffic accident or fall) showed slight hemorrhages of 3.33 or 1.18% of the retinal area but only in one eye. Therefore, the results provide evidence that massive intraretinal hemorrhages indicate violent shaking — in particular in association with other signs of physical child abuse.     

Persistent Retinal Iron in Abusive Head Trauma

Retinal hemosiderin deposition is a histologic indicator of sustained hemorrhage but cannot be used to precisely estimate the elapsed time since an episode of trauma. A 5‐month‐old male infant was admitted to hospital after acute deterioration. Examination revealed encephalopathy, subdural hematomas, and retinal hemorrhages consistent with abusive head trauma (AHT). At the age of 3, he was readmitted to hospital with spontaneous osteopenic fracture of the right femur. The patient deteriorated and died after unsuccessful resuscitation. Ophthalmopathological investigation showed atrophy of the retina and optic nerve and hemosiderin deposition in both eyes. Retinal hemosiderin deposition is currently generally assumed to disappear within 6–8 weeks after the occurrence of hemorrhage in AHT. This case report describes an infant with bilateral retinal hemosiderin depositions due to hemorrhages sustained from AHT occurring 32 months prior to death. Implications of this finding for the interpretation of retinal hemosiderin depositions in AHT are discussed.     

Ophthalmologic Concerns in Abusive Head Trauma

When Abusive Head Trauma (AHT) is suspected in a child, a dilated eye examination by an ophthalmologist is an essential part of the medical workup, as the presence and pattern of retinal hemorrhages can have a high positive predictive rate for abusive head injury. This article proposes to review the clinical presentation, pathophysiology, natural history, sequelae, and differential diagnosis of retinal hemorrhages and other ocular lesions associated with AHT.     

Narcolepsy mimicking suicidal carbon monoxide poisoning

We present a case of narcolepsy mimicking suicidal carbon monoxide poisoning. The signs and symptoms of narcolepsy in this previously undiagnosed man were initially missed, which emphasizes the importance of extracting a detailed history of a decedent's behavior prior to his or her death. Narcoleptics are often involved in motor vehicle accidents. This report again demonstrates that narcolepsy and driving don't mix, even when the vehicle is stationary. We also briefly review the various sleep disorders.     

"Body property": challenging the ethical barriers in organ transplantation to protect individual autonomy

One of two articles related to the current organ shortage, this article advocates the need for legislation to recognize organs and tissues separated from the body as a distinct category of personal property. After addressing the legislative history of organ procurement and psychological barriers to donor consent, the article examines the importance of separating the lifetime rights of ownership in our own bodies from postmortem rights. Ultimately, the author proposes a futures market approach to this problem in which individuals before death, or surviving family members after death, are permitted sell the decedent's organs in a private contract.     

Etiology of pulmonary thromboembolism in the absence of commonly recognized risk factors

Pulmonary thromboembolism is an often fatal complication of venous thrombosis. Any component or combination of the components composing Virchow's triad (venostasis, hypercoagulability, and endothelial damage) increases the propensity for a thrombophilic state. Hypercoagulable states may be inherited or acquired. While the etiology in many cases may be evident either on physical examination or on evaluation of the decedent's medical history, this is often not the case. We conducted a retrospective study of cases presenting to the Jefferson County Coroner/Medical Examiner's Office in Birmingham, Alabama, who were given a diagnosis of pulmonary embolism. A search of cases within the past 23 years yielded 81 cases. An underlying cause was determined in 70 cases (86%). The remaining 11 (14%) cases had no identifiable cause. We believe that a number of these cases may represent an underlying thrombophilic disorder. Since these disorders may be of an inherited or acquired nature, the determination of an etiology may be relevant to the decedent's family. Postmortem blood analyses may in selected cases be useful and appropriate for the detection of some of these disorders. However, such analyses are not practical in all cases, with each case having to be evaluated on its own merits.     

Bones, blood, pellets, glass, and no body.

A man was found guilty of killing his wife, although her body was never found. The case centered on her car, which contained fragments of bone, glass, shotgun pellets, and dried blood. Deoxyribonucleic acid (DNA) fingerprinting techniques were used to establish the decedent's identity. Examination of the bone fragments revealed that they were from the skull. These two pieces of information, added to other evidence, proved that the defendant's wife had received a fatal injury in her car, and a guilty verdict was rendered.     

Autopsy findings in the eyes of fourteen fatally abused children

The eyes of fourteen fatally abused children and sixteen control cases were examined histopathologically. Ten of the abused children showed intraocular change. The most common ocular changes were subdural hemorrhage of the optic nerve and retinal hemorrhage which involved all the layers of the retina, but most commonly the nerve fiber layer, ganglion cell layer and inner nuclear layer. The presence of blood cavities within the retina partially supported the hypothesis of traumatic retinoschisis. The control cases of non-abused children rarely showed intraocular hemorrhage.     

Psychological factors in the determination of suicide in self-inflicted gunshot head wounds

Self-inflicted contact gunshot wounds to the head have usually been considered presumptive of suicide. This study evaluates whether sufficient psychological data are gathered in such cases to support a manner of death determination of suicide. We suggest that law enforcement agencies and coroner's departments do not fully explore the decedent's state of mind at the time of death. We studied the first 50 consecutive deaths in 1993 in a major metropolitan county due to self-inflicted gunshot wounds to the head. The sample consists primarily of unmarried, white males, with a median age of 35 years, who displayed psychiatric disturbance, primarily depression, before their death. Younger individuals were often under the influence of alcohol and/or drugs at the time of death. Stressors, such as the loss of a loved one, are common among young and middle-aged persons, while serious health problems are found among the majority of middle-aged and elderly individuals. Many of the findings of this study are consistent with the literature regarding individuals who commit suicide. Although data on many important psychological risk factors are missing in most cases, sufficient psychological material is gathered about the decedent's mental condition at the time of death to support a suicide determination.