Personal identification based on prescription eyewear

The eye in forensic practice: In the living

Eye examination plays an important role when living individuals are forensically investigated. The iris colour, retinal scans and other biometric features may be used for identification purposes while visual impairments may have legal implications in employment, driving and accidents. Ocular manifestations provide clues regarding substance abuse, poisoning and toxicity, and evidence of trauma, abuse or disease can be revealed along with psychological traits and lifestyle. Thus, the eye is a valuable tool in forensic investigations of living subjects, providing identifying characteristics along with health information. This review focuses on the medico-legal aspects of the eye's contribution when the living are subjected to forensic examination.

Tears and Eyewear in Forensic Investigation-A Review

Body fluid analysis has played a crucial role in ascertaining various characteristics and has greatly aided in reconstructing events during crime scene investigation. It is often presumed that crimes that involve violence and mental disturbances such as murder or sexual assault provide good sources of body fluids such as blood, saliva, semen, vaginal secretions, urine and tears. Tears are secreted in response to any emotional or stressful situations and may be found deposited on surfaces such as bedding, tissue paper or cloth. In the absence of the commonly noted body fluids such as blood or saliva, tears can play an important role that can lead to personal identification by examining the biochemistry and molecular aspects to obtain a full DNA profile. Additionally, identification of an individual may be done by carefully observing certain unique eye characteristics such as heterochromia which is highly individualistic. Characteristics of eyewear such as spectacles and contact lenses have unique properties and prescription criteria for correcting an individual's eyesight that can provide vital clues in understanding the visual ability of an individual. In crime scene investigation, the presence or absence of eyewear provides immense evidentiary value that has greatly aided in solving cases such as Janet Abaroa's Murder. This paper provides a systematic review of the possibility of using tears and eyewear for the purpose of forensic investigation and to statistically support the inferences with prescription databases which may be initiated across different populations. Forensic Optometry is yet to get streamlined along with the routinely followed investigative techniques and scientifically explored although no standard protocols exist to analyse eyewear. The use of behavioural optometry is gaining attention in the context of driving laws of different countries and is a simple but powerful indicator of abnormal behaviour. It is speculated that the last seen image referred to as an 'Optogram' of an individual may be captured in the retina since our eyes functions like a camera. Although this claim is considerably unexplored, it is quite possible that the last seen image of a criminal, objects or a place may be noted that can positively help in linking individuals at the scene of crime or identify the primary crime location. In this review, the potential for new insights into the analysis of tears, eye and eyewear characteristics have been explored.

Forensic application of optical correction

BACKGROUND

Prescription eyewear can be used to aid in forensic investigations. Until now, investigators and consulted eye professionals have been limited to a simple "match" or "no match" judgment. This article introduces optometry to a Web-based tool that can be used to assess the strength of a match between spectacle prescriptions and recorded patient information.

METHODS

Three databases with more than 385,000 individual prescriptions were used to create the Web tool that calculates the frequency with which a prescription occurs in various U.S. populations. A search for any prescription in the tool's database will result in a report of the number of times a given prescription occurred in the queried database(s) as well as the calculated frequency with which the combination of the given sphere power, cylinder power and axis are likely to occur.

RESULTS

Practical application of the Web tool in 2 published cases has shown matches with frequency of occurrence of 5.33 x 10(-6) and 2.66 x 10(-6), respectively. This application currently is being used by the Joint POW/MIA Accounting Command Central Identification Laboratory (JPAC-CIL) and other agencies when optical materials are available in forensic settings. Further, this application currently is contributing evidence in an active murder case.

CONCLUSION

The creation of this easy-to-use Web tool allows eye care professionals to provide strong statistical assessments when serving as consultants to forensic investigators.