Comparison of a Novel Trainer to a Traditional Swine Model for Training Providers in Lateral Canthotomy and Cantholysis.

RESEARCH OBJECTIVE: Military personnel are at greater risks of head and facial traumas and permanent blindness from orbital compartment syndrome in modern warfare. Rapid treatment must be implemented with a low-risk surgical remedy: lateral canthotomy and cantholysis (LCC). Traditional training of LCC is primarily performed using an animal tissue trainer (ATT); however, limitations to these types of trainers exist. Therefore, our research objectives were focused on highlighting the effectiveness, benefits, and vision-saving potential of learning LCC on a synthetic trainer. METHODS: Participants included 22 second-year medical students and 6 healthcare professionals. A pre-quiz assessed baseline knowledge. Next, an experienced ophthalmologist provided an overview and instruction. Subjects were randomized to either the synthetic trainer or the ATT and then switched to the other model for comparison. After performing LCC procedures on both models, a post-quiz and survey were administered. RESULTS: Participants found the synthetic trainer easier to use than the ATT model (p < 0.01). There was no statistically significant preference (p = 0.23), or preference of practical eye anatomy (p = 0.26) between the trainers. Post-quiz results demonstrated an overall improvement from pre-quiz scores for participants (p < 0.001). CONCLUSIONS: The synthetic trainer is comparable to the traditional swine model for training LCC procedures, and should be considered as a future training platform.

Optimizing Tactical Medical Performance: The Effect of Light Hue on Vision Testing.

BACKGROUND: Red and blue are the historical tactical lighting hues of choice to ensure light discipline and to preserve dark adaptation. As yet, no scientifically ideal hue for use in Special Operations medicine has been identified. We propose red/green polychromatic light as a superior choice that preserves visual function for tactical medical tasks in austere settings. METHODS: Thirty participants were enrolled in this institutional review board-approved study. Participants completed four vision tasks in low-light settings under various lighting conditions. The Pelli-Robson Near Contrast Sensitivity test (PR), tumbling E visual acuity test, Farnsworth D-15 color-vision test (FD15), and pseudoisochromatic plate (PiP) testing was performed under white, green, or red light illumination and also red/green and red/green/yellow lights. PR and tumbling E tests were performed using blue and blue/red lights. RESULTS: The test results for each light were compared against a white-light standard. Contrast sensitivity as measured by PR testing showed no statistical difference when white light was used compared with red/green or red/green/yellow light, and the differences between red, green, blue, and blue/red all were statistically different from when white light was used. When measuring visual acuity, blue light was the only color for which there was a statistically significant decrease in visual acuity in comparison with white. There was no reduction in visual acuity with any other lights compared with white. Performance on FD15 testing with all single-hue and multihue lights was significantly worse than with white light for measuring color-vision perception. Color discrimination as measured by PiP testing showed red and green light was significantly worse than with white light, whereas test results when green/red and green/red/yellow lights were used were not statistically different from white. CONCLUSION: Red/Green/yellow and red/green were superior light sources and performance results only were worse than white light on FD15 testing.

Atropine Eye Drops: A Proposed Field Expedient Substitute in the Absence of Atropine Autoinjectors.

Nerve agents are a threat to military and civilian health. The antidote, atropine sulfate, is delivered by autoinjector, which is a limited resource. We propose the use of 1% atropine ophthalmic solution (supplied commercially in 5mL or 15 mL bottles) via oral, ocular, and intranasal administration as an expedient substitute in austere environments.

Case Report of an Anthrax Presentation Relevant to Special Operations Medicine.

Special Operations Forces (SOF) medical personnel function worldwide in environments where endemic anthrax (caused by Bacillus anthracis infection) may present in one of three forms: cutaneous, pulmonary, or gastrointestinal. This report presents a rare periocular anthrax case from Haiti to emphasize the need for heightened diagnostic suspicion of unusual lesions likely to be encountered in SOF theaters.

Red-Green Versus Blue Tactical Light: A Direct, Objective Comparison.

BACKGROUND: Success in Special Operations Forces medicine (SOFMED) depends on maximizing visual capability without compromising the provider or casualty when under fire. There is no single light that has been deemed "ideal" for all SOFMED environments. METHODS: We used the Farnsworth-Munsell (FM) hue test to determine color vision of normal subjects under white, red-green, and blue flashlights to determine color discrimination. Then we used a timed color-determination visual test to determine how quickly normal subjects can identify color correctly. We had subjects perform a simulated surgery illuminated by a normal white-light source, then by red-green or blue light-emitting diode (LED) tactical light. RESULTS: The total error score for white light was 49.714, 272.923 for red/green light, and 531.4 for blue light. The subjective perception of simulated trauma wounds was not substantially different with red-green LED tactical light when compared with white LED light. However, simulated surgery under the blue LED was more difficult compared with simulated surgery under the red-green LED light. CONCLUSION: Red-green was a superior light source for SOFMED and military first responders in this study, especially, where light was required to allow accurate and efficient application of Tactical Combat Casualty Care to injured personnel.

Corneal tissue ablation depth and the Munnerlyn formula.

PURPOSE: To determine whether the error in ablation depth produced by approximations inherent in the Munnerlyn formula are clinically significant when estimating residual corneal stromal depth for the evaluation before refractive surgery. SETTING: Department of Ophthalmology, University of Texas Medical Branch, Galveston, Texas, USA. METHODS: Using identical geometric assumptions, the exact ablation depth was calculated and compared to the approximate ablation depth predicted by the Munnerlyn formula. An adjustment factor was then derived for large optical zones and corrections. RESULTS: The exact ablation depth is always larger than the ablation depth predicted by Munnerlyn's formula. Analysis found the error in ablation depth varied as the fourth power of the optical zone and linearly with correction. The initial corneal radius had little effect on the difference. The ablation depth could be reasonably approximated by adding an adjustment factor for large optical zones and refractive corrections. CONCLUSIONS: In patients with large optical zones, it may be preferable to calculate tissue ablation depth using the exact formula. Alternately, the Munnerlyn formula can be used to calculate ablation depth and then an adjustment factor can be added.

Corneal foreign body management at a role 1 flight line aid station: risks, benefits, and implications for Special Operations medicine.

Eye injuries are common in forward areas of operations. Definitive diagnosis and care may be limited not by provider skill but rather by available equipment. The ability to treat simple trauma such as corneal foreign bodies at the Role 1 level has advantages including rapid return to duty, decreased cost of treatment, and, most important, decreased risk of delayed care. We propose the device such as a hand-held portable slit lamp should be made available for appropriate Special Operations Medical Forces (SOFMED) or aviation providers.

Tactical lighting in special operations medicine: survey of current preferences.

Success in Special Operations Forces medicine (SOFMED) is dependent on maximizing visual capability without compromising the provider or casualty position when under fire. There is no single ideal light source suitable for varied SOFMED environments. We present the results of an online survey of Special Operations Medical Operators in an attempt to determine strengths and weaknesses of current systems. There was no consensus ideal hue for tactical illumination. Most Operators own three or more lights, and most lights were not night vision compatible. Most importantly, nearly 25% of respondents reported that lighting issues contributed to a poor casualty outcome; conversely, a majority (50 of 74) stated their system helped prevent a poor outcome. Based on the results of this initial survey, we can affirm that the design and choice of lighting is critical to SOFMED success. We are conducting ongoing studies to further define ideal systems for tactical applications including field, aviation, and marine settings.

Field diagnosis and treatment of ophthalmic trauma.

UNLABELLED: Identification and management of injuries to the eyes and ocular adnexa is commonly encountered by frontline medical personnel. This brief review is intended for the Special Forces Medic of all branches and describes the clinical presentation of common ophthalmic and periocular trauma with appropriate management strategies. Prompt recognition of these wounds facilitates early treatment and optimized visual outcomes for affected Soldiers and civilians alike. KEYWORDS: trauma, eye, ophthalmology, vision, open globe.