Morphological and histological changes in eye lens: Possible application for estimating postmortem interval

A review study on forensic optometry: new insights in forensic science to solve crime scenes, domestic violence and sexual assaults

Forensic science has made a lot of progress in the medical field, but still ocular signs are not so well known to forensic scientists, whereas ocular signs play a very important role in forensic science. The major goal of this study to describe the importance of eye related clues in forensic science to solve the crime scenes and know the actual cause of death for the conviction of the criminals and save an innocent persons. Narrative review was done to review the articles available on the PubMed, Google Scholar, Research Gate, Web of Science and Medline related to the forensic optometry about the various methods of identification and strategies to deal with the forensic cases. The review covered studies that focused on interventions for forensic optometry and eye-related clues to the current study target. Twenty-seven of the 54 studies that met the inclusion criteria yielded good results, and all examined the significance of eye-related clues in forensic optometry. Peer reviewed articles/studies were referred to ascertain the eye related clues in the forensic science. Some authors suggest that eye related clues are very important aspects towards the forensic science and done the clinical research on that aspects. Criminal cases, domestic abuse and sexual assault affect people of all socioeconomic backgrounds. As a result, these traits would be highly valuable in determining the way of death and the chronological history of events leading up to a crime.

Interaction of βL- and γ-Crystallin with Phospholipid Membrane Using Atomic Force Microscopy

Highly concentrated lens proteins, mostly β- and γ-crystallin, are responsible for maintaining the structure and refractivity of the eye lens. However, with aging and cataract formation, β- and γ-crystallin are associated with the lens membrane or other lens proteins forming high-molecular-weight proteins, which further associate with the lens membrane, leading to light scattering and cataract development. The mechanism by which β- and γ-crystallin are associated with the lens membrane is unknown. This work aims to study the interaction of β- and γ-crystallin with the phospholipid membrane with and without cholesterol (Chol) with the overall goal of understanding the role of phospholipid and Chol in β- and γ-crystallin association with the membrane. Small unilamellar vesicles made of Chol/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (Chol/POPC) membranes with varying Chol content were prepared using the rapid solvent exchange method followed by probe tip sonication and then dispensed on freshly cleaved mica disk to prepare a supported lipid membrane. The βL- and γ-crystallin from the cortex of the bovine lens was used to investigate the time-dependent association of βL- and γ-crystallin with the membrane by obtaining the topographical images using atomic force microscopy. Our study showed that βL-crystallin formed semi-transmembrane defects, whereas γ-crystallin formed transmembrane defects on the phospholipid membrane. The size of semi-transmembrane defects increases significantly with incubation time when βL-crystallin interacts with the membrane. In contrast, no significant increase in transmembrane defect size was observed in the case of γ-crystallin. Our result shows that Chol inhibits the formation of membrane defects when βL- and γ-crystallin interact with the Chol/POPC membrane, where the degree of inhibition depends upon the amount of Chol content in the membrane. At a Chol/POPC mixing ratio of 0.3, membrane defects were observed when both βL- and γ-crystallin interacted with the membrane. However, at a Chol/POPC mixing ratio of 1, no association of γ-crystallin with the membrane was observed, which resulted in a defect-free membrane, and the severity of the membrane defect was decreased when βL-crystallin interacted with the membrane. The semi-transmembrane or transmembrane defects formed by the interaction of βL- and γ-crystallin on phospholipid membrane might be responsible for light scattering and cataract formation. However, Chol suppressed the formation of such defects in the membrane, likely maintaining lens membrane homeostasis and protecting against cataract formation.

Keep an eye on the crime – a new look at the forensic use of post-mortem eye examination to estimate time of death

Determining the time of death plays a crucial role in a forensic post-mortem examination. Many methods for the time of death (TOD) determination have been developed. However, most are not applicable during the first hours after death and produce large post-mortem interval (PMI) ranges. Eye examination makes it possible to precisely determine the time of death during the initial period after death with half-hour accuracy.. In recent years methods for estimating the time of death by measuring the changes in the eye have made great strides. Those methods use the changes in the reaction to drugs and macroscopically visible morphological changes. Experimental studies also produced equations that can estimate the post-mortem interval using biochemical, electrochemical and thermal changes within the eye.

Postmortem Interval Estimation With Corneal Endothelial Cell Density

OBJECTIVES

In the neonatal period, healthy people have the highest corneal endothelial cell density (CECD) (5000-7000 cells/mm2). Corneal endothelial cell density declines with age in adults (2500-3000 cells/mm2) and continues to decline in the postmortem period. We measured CECD in cases with different postmortem interval (PMI) and investigated its association with PMI.

METHODS

A total of 555 corneas harvested from 285 cases with a known time of death were examined using a specular microscope.

RESULTS

Postmortem corneal removal time ranged between 10 and 1395 minutes. The CECD averages were 2653 for right cornea and 2678 cells/mm2 for left cornea. An inverse but nonlinear relationship was found between age and CECD. In both men and women, there was an inverse and weak correlation between age and CECD (ρ = -0.282; P < 0.001; ρ = -0.264; P < 0.001, respectively). There was no significant relationship between postmortem corneal removal time and CECD (ρ = 0.049; P = 0.421; ρ = 0.011; P = 0.855 for right and left corneas, respectively). The highest decline in time dependent CECD was detected between the 480th and 540th minutes at -7.2%.

CONCLUSIONS

We found no significant decrease in CECD numbers according to PMI or cause of death. Experimental studies on cases with known and standardized antemortem CECD values will provide essential results in estimating PMI.

The Eye in Forensic Medicine: A Narrative Review

ABSTRACT

The eye, with its distinctive anatomy, not only reflects a wide variety of diseases in life but also undergoes a myriad of post-mortem changes. Consequently, the eye has long been an area of interest in forensic science, primarily for the estimation of post-mortem interval and therefore the time of death and also for assistance in ascertaining the cause of death. There has been significant progress in the knowledge of ophthalmic forensic science using new technologies which have allowed further possibilities to arise where understanding of this field can assist the forensic pathologist. This review aims to highlight the current knowledge which exists in this field and also to identify important avenues for further investigation. Post-mortem changes of the eye along with its current applications and challenges will be discussed. These include the important areas of post-mortem iris biometrics, pupil size correlation with post-mortem interval, use of point-of-care technology on vitreous humor, and the use of ophthalmic imaging in pediatric abusive head trauma.

Postmortem Ocular Findings in the Optical Coherence Tomography Era: A Proof of Concept Study Based on Six Forensic Cases

Postmortem analysis of the ocular globe is an important topic for forensic pathology and transplantology. Although crucial elements may be gathered from examining cadaveric eyes, the latter do not routinely undergo in-depth analysis. The paucity of quantitative and objective data that are obtainable using current, invasive necroscopic techniques is the main reason for the limited interest in this highly specialized procedure. The aim of the current study is to describe and to object for the first time the postmortem ocular changes by mean of portable optical coherence tomography for evaluating ocular tissues postmortem. The design involved the postmortem analysis (in situ, and without enucleation) of 12 eyes by portable spectral-domain Optical Coherence Tomography. The scans were performed, in corneal, retinal and angle modality at different intervals: <6 h, 6th, 12th, and 24th hour and after autopsy (25th-72nd hour). The morphological changes in the cornea, sclera, vitreous humor and aqueous humor were easy to explore and objectify in these tissues in first 72 h postmortem. On the other hand, the "in situ" observation of the retina was difficult due to the opacification of the lenses in the first 24 h after death.

Post-mortem ocular changes and time since death: Scoping review and future perspective

The forensics literature on the relationship between ocular changes and the postmortem interval (PMI) has traditionally focused on time-related variations in concentrations of metabolites and elements within the eye. However, structural changes within the eye over time deserve the same attention because there is significant evidence of their importance in determining the time since death. Therefore, we reviewed publications that provided substantial evidence on this issue. In light of our inclusion and exclusion criteria, 26 papers were eligible for review. On the basis of the ocular parameters considered, we grouped the reviewed evidence into eight thematic areas: corneal opacities, corneal thickness, drug-induced pupil diameter variations, retinal changes, segmentation of retinal vessels, intraocular pressure reduction, globe temperature and crystalline alterations. The most important and common limitations of the reviewed studies were small study populations (many were monocentric studies), absence of robust statistical methodology, use of mathematical models valid only in ideal conditions and validation only for short PMIs. Although many phenomena cannot be used to reliably estimate PMI, there is rigorous evidence suggesting that promising factors, including corneal thickness, require methodological innovations for application to forensics practice but could be used in the near future to reliably estimate the time since death.

[Problems of establishing the prescription of death]

Based on the analysis of literature data, demonstrated the relevance of further research to establish the prescription of death, including in a hot arid zone. Taking into account the climate of the seasons of Uzbekistan was stressed the importance of a comprehensive assessment of the dynamics of the development of cadaveric changes and supravital reactions, together with the results of biochemical, morphological and morphometric studies of the brain, other organs and tissues at different times of the postmortem period in certain groups. It could be used to develop additional criteria for establishing the onset of death in a hot arid zone.

A computational approach to estimate postmortem interval using opacity development of eye for human subjects

This paper presents an approach to postmortem interval (PMI) estimation, which is a very debated and complicated area of forensic science. Most of the reported methods to determine PMI in the literature are not practical because of the need for skilled persons and significant amounts of time, and give unsatisfactory results. Additionally, the error margin of PMI estimation increases proportionally with elapsed time after death. It is crucial to develop practical PMI estimation methods for forensic science. In this study, a computational system is developed to determine the PMI of human subjects by investigating postmortem opacity development of the eye. Relevant features from the eye images were extracted using image processing techniques to reflect gradual opacity development. The features were then investigated to predict the time after death using machine learning methods. The experimental results prove that the development of opacity can be utilized as a practical computational tool to determine PMI for human subjects.

Morphological, biochemical, and histopathological postmortem ocular indices following subchronic exposure to cadmium and/or lead in a rabbit model

Cadmium (Cd) and lead (Pb) are ubiquitous environmental pollutants. There is a dearth of information on the mutual interaction between the antemortem metal intoxication and the postmortem changes of the eye. Thus, this study aimed to follow the morphological, biochemical, histopathological ocular perturbations and the retinal DNA damage up to 8 h postmortem (PM) in Cd and/or Pb intoxicated rabbits. The animals orally received 5 mg Cd Cl₂/kg bw and/or 12.5 mg lead acetate/kg bw for 30 consecutive days. At time of death, eye pupil of different groups had a normal diameter except Pb-intoxicated group had marked myosis. After 8 h of death, different rabbit's eye corneas appeared wrinkled and covered with thin white cloud while the pupils were in the mydriatic stage. Up to 8 h PM, the individual exposure to Cd or Pb resulted in a significant elevation in GGT, urea, K, DNA damage and obvious retinal lesions. However, their co-exposure evoked an antagonistic outcome. The eye of Cd and/or Pb intoxicated rabbit showed mildly degenerated tissue of cornea and sclera and the presence of irregular eosinophilic droplets of variably size in the lens with a gradual degeneration and vacuolization in the different cell layers of retina especially ganglion up to 8 h PM. Also, by increasing post mortem interval (PMI), retinal DNA damage in Cd and/or Pb intoxicated group significantly decreased. It is concluded that Cd and/or Pb intoxication induced ocular alterations which retain the same trend in correlation with PMI as natural deaths except for the retinal DNA damage. Also, the simultaneous exposure to Cd and Pb evoked an antagonistic outcome in the eye. The findings of the current study should be taken into consideration when estimating PMI in areas with high Cd and/or Pb contamination.