Officer Candidate School physician assistant students with Blanchfield Army Community Hospital taught a class in Ophthalmology and caring for eye trauma, infection, or injury last year at Fort Campbell, KY. Photo by Justin Moeller
BETHESDA, MD — The rate of combat ocular trauma in Operations Iraqi Freedom and Enduring Freedom exceeded that of any past U.S. conflict. A new study looked at the long-term effects of the devastating battlefield injuries.
The report in the journal Ophthalmology identified higher average Disability-Adjusted Life Years (DALYs) per case ratio among U.S. servicemembers compared to the general population. “Our study provides a novel understanding of the impact of ocular injuries on active-duty service members and lays the groundwork for further research and interventions to mitigate their burden,” wrote the international researchers including participation from the Walter Reed-Uniformed Services University Department of Surgery at the Uniformed Services University and the White River Junction, VT, VAMC. The study was led by Dartmouth-Hitchcock Medical Center in Lebanon, NH.1
An earlier study from the Uniformed Services University of the Health Sciences documented the cases of injuries, explaining, “The improvised explosive device, the signature weapon of the conflicts, as well as improved personal protective equipment and combat medical care all attributed to COT being the fourth most common injury sustained by wounded U.S. servicemembers.”2
That article late last year in Military Medicine described the epidemiology, mechanisms and treatment patterns of the condition. The authors also discussed the relationship of traumatic brain injuries (TBIs) to ocular injuries.
For the more recent retrospective, observational cohort study in Ophthalmology, the research team sought to quantify the burden of ocular injuries on deployed U.S. servicemembers by calculating DALYs. Included were U.S. servicemembers with ocular injuries sustained in combat zones from 2001-2020.
The researchers used data from the Defense and Veterans Eye Injury and Vision Registry (DVEIVR) to identify health states and duration of injuries. Data described patient injury, final visual acuity, medication, procedures and history of present illness data. The study team mapped the health states to disability weights from the Global Burden of Disease (GBD) study, calculating average duration of injury/illness until remission or death. For the latter, life expectancy at age of sustaining injury, as identified from United States
Results indicated that 17,555 patients sustained ocular injury that incurred DALYs. “In total, these injuries resulted in, 11214 DALYs (average 0.64 DALYs per included patient; 20.6 DALYs per 10,000 US service members per year,” the authors explained. “Severe impairment of distance vision (77.9%) and blindness (10.6%) were the primary contributors of DALYs. While only 9.3% of patients sustained a permanent ocular injury, permanent disability accounted for 99.5% of total DALYs.”
The study determined that the average yearly incidence rate of ocular injury was 32.0 cases per 10,000 U.S. servicemembers. “Foreign body was the most frequent injury type (2,754 occurrences) followed by abrasion (2,419 occurrences) and multiple injury types (1,429 occurrences), while the most DALYs occurred in patients with multiple injury types (2,485 DALYs) followed by abrasion (accounting for 725 DALYs), and foreign body (accounting for 461 DALYs.),” the authors pointed out.
The researchers said their study “provides a novel understanding of the impact of ocular injuries on active-duty service members and lays the groundwork for further research and interventions to mitigate their burden.”
The earlier report in Military Medicine used a mixed-methods review of the literature; researchers extracted data from PubMed, Embase, and Cochrane research databases between December 15, 2020, and January 25, 2021, using the COVIDENCE review management software.
“Within the Walter Reed Ocular Trauma Database, 40% of patients with ocular trauma had concomitant TBI,” the researchers advised. “Additionally, the visual sequelae of ocular trauma ranged from 9% to 50% among reporting studies. Other ocular injury patterns receiving attention include neuro-ophthalmic and oculoplastic injuries.”
They wrote that the most common mechanism of COT was blast injury (64-84%), with improvised explosive devices (IEDs) accounting for 51-69% of ocular injuries. About 41-45% of COT required surgical treatment, with an overall enucleation rate of 12-17%.
Another Military Medicine article last year also discussed how ocular injury remains a significant source of disability for active-duty servicemembers in both deployed and training settings, as well as veterans. “Servicemembers with ocular trauma are at risk for a TBI and should be screened appropriately,” according to the study led by researchers from the Carl R. Darnall Army Medical Center at Fort Hood, TX. “Early detection results in treatment to minimize long-term sequelae, which can often be debilitating.”3
Associations With TBI
The study said it was the first to evaluate different combat-related ocular injuries and their associations with TBI.
Researchers conducted a secondary analysis of existing data from a prospective study of patients who sustained combat ocular trauma (COT) during Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) between 2006 and 2020. They reviewed clinical data of 88 participants, including patient demographics, injury-related factors, history of TBI and treatments rendered.
All cases were then categorized to compare COT (n = 13) versus COT-T (Combat Ocular Trauma associated with TBI; n = 75). The study found that, when compared to COT alone,
COT-T was significantly associated with:
- closed globe injuries (56%; OR 4.24, 95% CI 1.08-16.67),
- blast injuries (89.3%; OR 3.72, 95% CI 0.93-14.9),
- multiple surgeries (89%; OR 2.51, 95% CI 0.57-11.08),
- anterior segment injuries (69.3%; OR 1.41, 95% CI 0.42-4.79),
- optic nerve injuries (24%; OR 1.05, 95% CI 0.26-4.25),
- orbital fractures (48%; OR 2.08, 95% CI 0.59-7.34),
- enucleation (17.3%; OR 2.52, 95% CI 0.300-21.08),
- use of eye protection (68.6%; OR 2.18, 95% CI 0.57-8.32), and
- need to undergo plastic surgery (78.7%; OR 2.30, 95% CI 0.66-8.02).
The study authors reported that significant factors associated with COT included penetrating injury (30.8%; OR 0.027, 95% CI 0.07-1.08), posterior segment injuries (92%; OR 0.264, 95% CI 0.032-2.17), bilateral injuries (76.9%; OR 0.678, 95% CI 0.17-2.69) and bilateral blindness (7.7%; OR 0.857, 95% CI 0.092-7.99).
“Patients who have sustained combat-related ocular injuries, specifically blast injury, anterior segment injury, or an orbital fracture, were noted to be more likely to have also sustained a TBI,” the researchers wrote. “However, of the evaluated variables in predicting the co-occurrence of TBI, only closed globe injury was identified as statistically significant.”
They said that servicemembers with injuries requiring multiple surgical procedures, reconstructive plastic surgery or enucleation of an eye were also more likely to be diagnosed with a TBI, “but these variables were not found to be predictive of TBI among ocular trauma patients. The presence of eye protection was not protective against TBI.”
The study team called for further studies to find significant predictors of TBI in combat ocular trauma patients to assist in the early and accurate detection of TBI.
“The Global War on Terrorism saw an evolution in the types of ocular injuries sustained by U.S. servicemembers compared to previous conflicts,” authors of the USU-led study pointed out. “The widespread use of IEDs led to injury patterns not encountered in previous conflicts. Weapons of today utilize blast and shrapnel as the mechanism for destruction.”
One result is that “sequelae such as TBIs and complicated head and neck trauma have pushed innovation in the field of ophthalmology,” according to the article, which stated that “improvements in medical technology and personal protective equipment have resulted in not only survival of previously life-threatening injuries, but also a greater chance of severe loss of vision. By analyzing ocular injury data from the trauma literature, improvements in education and training can lead to improvements in point-of-injury care and eye protection for the next generation of warfighters.”
- Travor MD, Levine ES, Catomeris AJ, Purt B, et. al. Disability-Adjusted Life Years due to Ocular Injury Among Deployed Service Members, 2001-2020. Ophthalmology. 2023 Nov 24:S0161-6420(23)00863-1. doi: 10.1016/j.ophtha.2023.11.023. Epub ahead of print. PMID: 38008289.
- Lee I, Davis B, Purt B, DesRosiers T. Ocular Trauma and Traumatic Brain Injury on the Battlefield: A Systematic Review After 20 Years of Fighting the Global War on Terror. Mil Med. 2023 Aug 29;188(9-10):2916-2923. doi: 10.1093/milmed/usac226. PMID: 35869887.
- Flor R, Purt B, Sia RK, Ryan DS, et. al. Correlative Factors for Traumatic Brain Injury in Combat Ocular Trauma. Mil Med. 2022 Mar 9:usac010. doi: 10.1093/milmed/usac010. Epub ahead of print. PMID: 35260903.