Paintball Gun Research Articles

Incidence and Outcomes of Eye Trauma Associated With Recreative Use of Nonpowder Toy Guns: A 12-Year Retrospective Study

Nonpowder toy guns (NPTGs) are responsible for many ocular traumas. This study aims to detail the outcomes of these injuries depending on the causative NPTG. Retrospective, observational case series. Cases of NPTG-associated ocular trauma managed in a Parisian eye emergency department between August 1, 2010, and January 1, 2023, were reviewed. The date of trauma, causative NPTG, patient demographics, initial and follow-up eye examinations, any surgical procedure, and visual outcomes for each ocular trauma were analyzed. Over 12 years, NPTGs were responsible for 324 eye injuries and 980 visits. Patients were mostly male (77.5%), and mean age at trauma was 16.2 years. Foam bullets or foam dart blasters accounted for 54.9% of traumas and were mainly responsible for corneal injuries and hyphema (30.9% and 27%, respectively). BB guns and airsoft guns were frequently responsible for anterior segment lesions, as well as intravitreal hemorrhages (14.7%) and commotio retinae (21.1%). Paintball guns accounted for the largest proportion of posterior segment lesions (eg, intraretinal or subretinal hemorrhages leading to macular atrophy/contusion maculopathy), and one-third of casualties had undergone ocular surgery. Among all traumas, final visual acuity was lower than 20/200 in 6.5% of cases. Phthisis occurred in 8 cases: Two were related to foam bullets or foam dart blaster injuries (1 contusion and 1 rupture), 2 other cases followed a rupture due to BB guns/airsoft guns, 1 case occurred after a rupture related to a paintball gunshot, and 3 others were due to other types of compressed air guns (1 rupture, 1 intraocular foreign body, and 1 total retinal detachment). NPTG-related ocular trauma outcomes differ according to the causative toy. Paintball guns and BB guns/airsoft gun-related traumas were more likely to be associated with severe lesions, but an increasing number of ocular injuries related to the use of foam bullets or foam dart blasters are reported in younger and younger children. Public health policies should promote the use of protective eyewear.

Proactive use of intensive aversive conditioning increases probability of retreat by coyotes

AbstractCoyotes (Canis latrans) are showing increasingly bold behaviors toward people and their pets throughout North America. Bold behavior by wildlife might be reduced by hazing and aversive conditioning, which is recommended in many management plans for coyotes, but with little information about how it is to be conducted, and few studies have tested this approach. We conducted an online search for coyote management plans across North America to review techniques and recommendations related to the implementation of hazing or aversive conditioning and reported on the implementation of a high‐intensity aversive conditioning program in Calgary, Alberta, Canada. Almost all the management plans recommended hazing coyotes, most often by using a combination of noises, lights, and movements, but only 20% of 71 plans recommended high‐intensity techniques like those used by the contractors in Calgary. Contractors there searched for coyotes in 72 public park areas where members of the public had submitted reports to a civic call center for bold coyotes, attended sites on 1917 occasions, observed coyotes on 765 occasions, and reported coyote treatments and responses on 734 occasions. The probability of coyote retreats increased by 29%–37% with each additional previous aversive conditioning event at the site and doubled with the presence of dogs and with the application of projected chalk balls prior to the event being investigated, suggesting coyotes learned to avoid contractors. During engagements with contractors, coyote retreat probability declined by 21%–25% with each additional day since the last aversive conditioning engagement, and by 97.2%–97.6% with the presence of dogs and when shots were fired from a paintball gun, presumably because these tools were used only on the boldest coyotes. We found no effect of the presence or past number of aversive conditioning events on the number of coyote reports per week by the public. Although such high‐intensity aversive conditioning is rarely recommended in management plans, our results suggest that its repeated application can reduce coyote boldness over time, but coyotes may not generalize this response to other people owing to visual cues (e.g., high‐visibility vests, consistent vehicles) associated with contractors.

Sounds produced by subsonic ballistic flow

The sounds of passing subsonic ballistic projectiles are receiving more attention yet have limited acoustic characterization. Recent accounts include buzzing sound of a rifled bullet, and the whistling sounds of spherical projectiles produced by police firing non-lethal spherical rubber bullets, paintball, and war re-enactments using muskets. Modern recording equipment with multiple simultaneous channels and high dynamic range is now available to accurately capture subsonic ballistic flow sounds. Spherical projectiles 0.69 in. in diameter were launched from smooth bore replica muskets and high pressure paintball guns, and recorded on multiple microphones. Sounds of vortex shedding at predictable frequencies were produced using smooth spherical balls with no rotation, fired at velocities between 45 and 152 m/s (150–500 fps), and with Reynolds numbers below 3.75 × 105. The paintballs shed vortices in the 500–800 Hz range (with reported whoosh sounds); while faster musket balls shed vortices in the 2000–2500 Hz range (with reported whistling sounds). Our interest originally arose from historical reports that Erastus “Deaf” Smith, a hero of the Texas Revolution, could not hear musket balls that passed near him; and recent medical speculation that he had a 2000–3000 Hz notch in his hearing spectrum.

Ocular Injuries From Drive-by Paintball Shootings

To characterize ocular injuries from drive-by paintball shootings with a focus on the severity of injuries sustained, clinical management, and visual outcomes. Retrospective, interventional case series. Setting: University practice and emergency department. Patients evaluated by the ophthalmology service for paintball injuries. Age, sex, eye laterality, mechanism of injury, initial best-corrected visual acuity (BCVA), and initial diagnosis. Clinical intervention(s), BCVA at last follow-up visit, and severity of injuries with a focus on ruptured globes. Twenty patients suffered unilateral ocular injuries from drive-by paintball shootings between January 2020 and December 2021. The median follow-up interval was 7.1 weeks (range: 3 days to 11.4 months). The average patient age at presentation was 36.6 years (range: 13-64 years). Fourteen patients (70%) had an initial BCVA of counting fingers or worse. Six patients (30%) suffered a ruptured globe injury requiring surgical repair, of whom 3 (15%) underwent subsequent evisceration. Twelve patients (60%) suffered ocular injuries requiring surgical intervention. Fifteen ocular surgeries were performed on 9 patients (45%) at our institution with 3 patients referred to outside providers for definitive surgical management due to insurance. BCVA at last follow-up visit was no light perception in 5 patients. The severity of injury after paintball-induced ocular trauma is higher in this case series than what has previously been reported in the literature. Paintball guns can cause devastating ocular injury when used as an assault weapon, and their use in unregulated settings bears further scrutiny.

Domestic Tension: Representation of Muslim artist’s body in online performance

This article investigates the relevance between body representation in online performance and Islamic art by studying Domestic Tension, an online performance by Iraqi-born artist Wafaa Bilal. Bilal lives under online participant shoots, with a paintball gun, in a gallery and broadcasts the event 24/7 on the internet. Islam and its laws, related to the body, played a central role in this performance and remained out of sight. The Qur’an mentioned the body rarely in verses; therefore, the Hadith is the most trustworthy reference to learn. Based on Hadith, figural representation between Muslims is banned, and the makers of these pictures get punished in the other world. This prohibition must be the main reason for Muslim artists’ use of symbols and signs to represent figures. In the virtual space artworks, the artist kills his own body to represent the body as a basic image, codes and sings. By analysing Domestic Tension, I argue that the connection between Muslim artists’ perception of the body and the definition of semiotics body in online performance can be a reason for artists with an Islamic background to use the internet as a medium to express themselves.

Queer Calculus, Warm Data, and Other Oxymorons

Queer Calculus, Warm Data, and Other Oxymorons

Less-Lethal Weapons Resulting in Ophthalmic Injuries: A Review and Recent Example of Eye Trauma.

IntroductionPrior reports have highlighted the dangers of crowd control weapons such as rubber bullets, paintball guns, and pepper spray. Many of these reports were written decades ago and outside of the USA. We summarize a review of the literature and discuss a contemporary case of a ruptured globe and facial trauma secondary to a projectile weapon. This case serves to highlight the severity of eye trauma caused by less-lethal weapons; severe morbidity or even mortality can occur.Clinical DescriptionA civilian presented after a projectile weapon reportedly fired by Denver law enforcement struck his face during one of the recent protests in May 2020 in Denver. Upon ophthalmic examination, we observed no light perception (NLP) vision, periorbital ecchymosis, and devastating globe trauma.Primary Diagnosis, Interventions, and OutcomesFurther examination revealed a severely ruptured globe with extensive hemorrhage and extrusion of intraocular contents. Attempts to repair the ruptured globe failed because of the lack of remaining scleral tissue and expulsion of intraocular contents. Postoperatively, the visual acuity remained NLP and the eye was unable to hold pressure. Subsequently, the patient elected for enucleation.ConclusionDespite the purported safety advancements of less-lethal weapons, we continue to see high levels of morbidity and mortality. Permanent vision loss, loss of the eye, and death caused by these weapons have been reported. We hope that this information will serve as an example to help promote judicious use of these weapons by the proper authorities. Additionally, protesters and bystanders should be aware of these dangers and utilize high-quality eye protection.

Nonpowder Firearm Injuries to Children Treated in Emergency Departments.

To investigate nonpowder firearm injuries treated in US emergency departments among children <18 years old. National Electronic Injury Surveillance System data from 1990 through 2016 were analyzed. An estimated 364 133 (95% confidence interval 314 540-413 727) children <18 years old were treated in US emergency departments for injuries related to nonpowder firearms from 1990 to 2016, averaging 13 486 children annually. From 1990 to 2016, the number and rate of nonpowder firearm injuries decreased by 47.8% (P < .001) and 54.5% (P < .001), respectively. Most injuries occurred among 6- to 12-year-olds (47.4%) and 13- to 17-year-olds (47.0%). Boys accounted for 87.1% of injured children, the most common diagnosis was foreign body (46.3%), and 7.1% of children were admitted. BB guns accounted for 80.8% of injuries, followed by pellet guns (15.5%), paintball guns (3.0%), and airsoft guns (0.6%). The rate of eye injuries increased by 30.3% during the study period. Eye injuries accounted for 14.8% of all injuries and the most common diagnoses were corneal abrasion (35.1%), hyphema (12.5%), globe rupture (10.4%), and foreign body (8.6%). Although the number and rate of nonpowder firearm injuries declined during the study period, nonpowder firearms remain a frequent and important source of preventable and often serious injury to children. The severity and increasing rate of eye injuries related to nonpowder firearms is especially concerning. Increased prevention efforts are needed in the form of stricter and more consistent safety legislation at the state level, as well as child and parental education regarding proper supervision, firearm handling, and use of protective eyewear.

Pediatric Injuries from BB Guns, Pellet Guns, and Other Nonpowder Firearms

To better understand pediatric injuries from nonpowder firearms (BB, pellet, paintball, and airsoft guns), researchers analyzed data from the National

Traumatic glaucoma due to paintball injuries: A case series

PurposeTo study the management and outcomes of patients with paintball injuries resulting in traumatic glaucoma. MethodsA retrospective review was performed, identifying four patients with a confirmed diagnosis of traumatic glaucoma secondary to paintball sports. ResultsFour male patients with paintball gun injuries presented with a mean follow-up time of 51 months after the date of injury. The mean age was 23.5 ± 18.6 years. Three patients presented with blunt trauma, while one patient had a ruptured globe. Presenting visual acuity (VA) was hand motions in three of the patients and no light perception in the fourth patient. All patients were diagnosed with traumatic glaucoma and treated with glaucoma medications during their follow-up. Two patients received tube shunts to control intraocular pressures (IOPs). At the time of most recent follow-up, three patients had elevated IOPs and were not on any medications. VA at the last follow-up was 20/400 or worse. ConclusionsTraumatic glaucoma can be managed with surgical and medical interventions, while VA usually does not return to baseline levels prior to the injury. Prognostic predictors can be used to guide treatment and identify patients who should be closely followed. Because the presentation and onset is widely variable, follow-up and screening is crucial even years after the injury.

Fantasizing about the Apocalypse: A Review of &lt;em&gt;Fallout 4&lt;/em&gt;

Fantasizing about the ApocalypseA Review of Fallout 4 Megan Condis (bio) War . . . War never changes . . . These are the words that open every installment in the postapocalyptic video game franchise Fallout. Set in the aftermath of a nuclear war between the United States and China, the games pit players against rival factions of survivors as well as the poisonous landscape and the super-mutants and irradiated ghouls that it spawned.1 The most recent entry in the series, Fallout 4, has the player choose between four possible sets of allies to guide the future of the Wasteland: the Institute, who use their futuristic technology to hide underground and who have developed (and enslaved) a robot army to do their bidding in the world above; the Railroad, a ragtag group of spies dedicated to freeing synthetic humans from the clutches of the Institute; the Minutemen, an alliance of small settlements providing safe haven and protection for residents of the area; and the Brotherhood of Steel, a militaristic group who are obsessed with gathering up and hoarding all the weaponry from the world that was. To complete the game, the player must choose a faction to align with and become its leader, working to fulfill its chosen mission, all while seeking the whereabouts of your kidnapped son. So with all these important, high-stakes paths available, why is it that Fallout 4 players spend so much time screwing around in the Wasteland, collecting Bobblehead figurines, hacking computers, decorating their houses, and searching for UFO crash sites? The answer, of course, is “because it’s fun.” Nearly everyone I know [End Page 185] who has played Fallout 4 spent some time actively avoiding progressing through the game so that they could buy themselves more time to play around in the game’s open world. And the release of extra downloadable content like the Wasteland Workshop and the Contraptions Workshop, as well as player-created mods that extend the game’s replayability, allow for even more mucking about, building, and testing Rube Goldberg machines like teddy bear catapults and paintball guns.2 In other words, the multitude of silly pleasures the game offers to the player are seemingly at odds with the player character’s very serious objectives as communicated by the game’s storyline. Click for larger view View full resolution Fig. 1. Welcome to the Wasteland. In the old world, it used to be known as “Boston.” Screenshot by Mikell Wooten. There is a name for this kind of mismatch between game mechanics and story: ludonarrative dissonance. According to Clint Hocking, who coined the term in 2007, ludonarrative dissonance is “the leveraging of the game’s narrative structure against its ludic structure,” and it “all but destroys the player’s ability to feel connected to either.”3 In the case of Fallout 4, the ludonarrative dissonance exists in the massive tonal shift between a postapocalyptic fight for the soul of the Wasteland and the temptation to abandon your narratively imposed obligations and play around. In essence the game has two different, mutually exclusive incentive structures. The narrative structure rewards forward progress [End Page 186] through the game’s story with a cinematic ending describing the fate of the Wasteland. But in a way, this reward is also a punishment in that it forecloses the game experience and marks an end to the freeform style of play that emphasizes exploration and experimentation. Click for larger view View full resolution Fig. 2. The Crater of Atom is lit by a radioactive aura visible for miles. It can only be safely explored from within the protective embrace of a suit of Power Armor. Screenshot by Mikell Wooten. But are the contradictory reward mechanisms of Fallout 4 really an example of ludonarrative dissonance? Or are they an apt expression of the competing pleasures of apocalyptic narratives more generally? In addition to the typical heroic stories about saving the oppressed and healing the world, stories of the apocalypse also offer escapist fantasies about what it would be like to be entirely free of responsibility for each other, for society, for the planet. After all, in a postapocalyptic story, the ultimate consequence has already been imposed on humanity...

Adaptive back-stepping control applied on octocopter under recoil disturbance

Unmanned air vehicles such as quadcopters are wildly being used in research and academic projects in the field of aerospace. Whether the mission is to take photos and videos, or simply fly to a given place, the problem of stabilization needs to be primarily considered. To deal with uncertainty and disturbance, traditional PID controller is a basic solution. In order to achieve better quality of robustness, sliding mode control and back-stepping control both bring great improvement to drone stabilization. This paper deals with the problem of stabilization under specific shooting disturbance. The overall system consists of a drone carrying a paintball gun via a gimbal and a servo-motor is used to pull the trigger. As the payload is quite heavy and normal quadcopter cannot afford much weight, an octocopter is considered to be used. One of the possible applications of this project is to replace policemen during a close-in gun conflict.

‘SHOOT HIM NOW!!!’ Anonymity, accountability and online spectatorship in Wafaa Bilal's Domestic Tension

This essay seeks to examine new modes of spectatorship in intermedial performance art. Using Wafaa Bilal's durational performance Domestic Tension as a case study, it explores how Internet participation reconfigures notions of presence, community and the individual. Bilal spent 31 days under video surveillance in a gallery room with a remotely controlled paintball gun. Participants of the performance could take part by either visiting the gallery or a website, from where they could steer and fire the paintball gun. The website also contained a chat room, which gave willing participants the chance to enter into a conversation with the artist and other online participants. Bilal staged his performance to draw attention to a growing disconnect between those perpetrating violence and those being subjected to it. By doing so he simultaneously created a platform for human connection and discussion to occur. This performance serves as an example to show what agency and identity look like in a digitally present society, and how they are challenged by various modes of perception resulting from different forms of presence. I analyze these online spectators’ potentiality for action within the set-up of the performance in terms of four vectors: namely, telepresence, communal spectatorship, virtual subjectivity and the posthuman. All of these respectively speak to the online participant's relationship with the performer, other participants, their own subjectivity, and the gun itself. Ultimately, I argue that action-based participation and anonymous interaction can offer the spectators a place to reflect on modern surveillance and warfare technologies.

Nonpowder firearms cause significant pediatric injuries.

We hypothesize that nonpowder firearms cause significant injuries in children, often requiring intervention. We have noted a difference in demographics of children presenting with injuries from nonpowder firearms compared with patients injured by powder firearms. We reviewed our institution's experience with patients with nonpowder firearm injuries to evaluate these aspects. A retrospective chart review was completed for all patients with a firearm injury from 2003 through February 2013 to a pediatric urban Level I trauma center. Patients were excluded if they were 18 years of age or older or readmitted. Demographics, injury circumstances, interventions, and outcomes were reviewed for 303 patients. The χ test and analysis of variance were completed with a statistical significance of p < 0.05. There were 57 nonpowder firearm injuries and 246 injuries from other firearms. Injuries occurred from BB, pellet, and paintball guns. Treatment included computed tomography scan in 39 patients, three bedside procedures, one angiography, and operative intervention in 25 patients. The most common injury locations were the eye (n = 37), head (n = 7), and neck (n = 6). Children injured by nonpowder firearms were less likely to be female (p = 0.04), more likely to be white (p < 0.01), and less likely to be injured in a violence-related event (p < 0.01). Nonpowder firearms can cause severe pediatric injuries requiring operative intervention and significant radiographic exposure from computed tomography scans. Prevention and education are important in decreasing this risk in the pediatric population and should be targeted to a different population than powder firearm prevention. Epidemiologic study, level V.

Pediatric eye injuries due to nonpowder guns in the United States, 2002-2012.

To identify epidemiologic trends in nonpowder gun-related pediatric eye injuries and to determine factors associated with severe injury requiring hospital admission. US emergency department data on pediatric eye injuries between 2002 and 2012 were reviewed using the National Electronic Injury Surveillance System. Literature review was conducted to determine trends in visual outcomes after treatment and use of eye protection. In 2012 roughly 3,161 children were treated in US emergency departments for nonpowder gun-related eye injuries. Since 2010 rates of severe nonpowder gun pediatric eye injury have increased by over 500% (P = 0.039). Specifically, while rates of hospital admission due to paintball gun eye injury have dropped precipitously (P = 0.0077), rates of admissions for air gun eye injuries have increased by over 600% since 2010 (P = 0.033). Children sustaining eye injury due to air guns are more likely to be diagnosed and admitted with foreign body or ocular puncture injury. Roughly 28% of documented cases of airsoft or BB gun-related injury had visual acuity worse than 20/50 after initial treatment. Over 98% of injuries occurred without eye protection. Air guns are rising in popularity and now account for the majority of pediatric eye injuries requiring hospital admissions. These eye injuries occur without ocular protection and may lead to permanent eye injury. Increasing regulations for eye protection, sales, and usage of air guns are needed to prevent serious pediatric eye injuries.

Insulin-like growth factor-1 binding protein 3 (IGFBP-3) promotes recovery from trauma-induced expression of inflammatory and apoptotic factors in retina

Ocular trauma affects 20% of Americans in their lifetime and can cause permanent visual system damage. We have used a mouse model of ocular trauma (exposure to an air blast from a paintball gun) to examine pathways that trigger the resulting retinal damage and to develop treatment strategies that might ameliorate the deleterious effects of trauma on retinal tissue. Our previous studies have shown that ocular blast causes an increase in protein levels of inflammatory mediators and apoptotic factors, including tumor necrosis factor alpha (TNFα) and interleukin-1-beta (IL-1β), as well as the apoptotic markers, Bax, cytochrome C, and cleaved caspase 3. Furthermore, topical treatment by eye drop application of a β-adrenergic receptor agonist, Compound 49b, was shown to decrease these inflammation/apoptosis markers and thus ameliorate the effects of blast trauma. We postulate that the protective effect of Compound 49b may be linked to its demonstrated ability to activate the β-adrenergic receptor and in turn trigger production of insulin-like growth factor binding protein 3 (IGFBP-3). In the current study, we tested this hypothesis using mice with minimal IGFBP-3 activity (IGFBP-3 knockdown mouse) vs. wildtype mice. We found that ocular blast alone did not affect IGFBP-3 levels in retinas of wild type or knockdown mice and surprisingly, the lower levels of IGFBP-3 in knockdown animals did not exacerbate the blast-induced increase in protein levels of inflammation/apoptosis markers. Nevertheless, the levels of IGFBP-3 were significantly increased in knockdown mouse retina by treatment with Compound 49b 24h post-trauma and as expected, the increase in IGFBP-3 was linked to a decrease in inflammation/apoptosis markers. We conclude that while lowered IGFBP-3 may not make the retina more vulnerable to blast injury, an increase in IGFBP-3 post-trauma may play an important role in limiting trauma-induced inflammatory and apoptotic pathways leading to retinal damage. Eye drop application of the β-adrenergic receptor agonist, Compound 49b, provides a promising treatment strategy for increasing IGFBP-3 levels to promote recovery from retinal inflammation and apoptosis after ocular blast.

Compound 49b protects against blast-induced retinal injury

AimTo determine whether Compound 49b, a novel beta-adrenergic receptor agonist, can prevent increased inflammation and apoptosis in mice after exposure to ocular blast.MethodsEyes of C57/BL6 mice were exposed to a blast of air from a paintball gun at 26 psi (≈0.18 MPa). Eyes were collected 4 hours, 24 hours, and 72 hours after blast exposure. In a subset of mice, Compound 49b eyedrops (1 mM) were applied within 4 hours, 24 hours, or 72 hours of the blast. Three days after blast exposure, all mice were sacrificed. One eye was used to measure levels of retinal proteins (TNFα, IL-1β, Bax, BcL-xL, caspase 3, and cytochrome C). The other eye was used for TUNEL labeling of apoptotic cells, which were co-labeled with NeuN to stain for retinal ganglion cells.ResultsWe found that ocular exposure to 26 psi air pressure led to a significant increase in levels of apoptotic and inflammatory mediators within 4 hours, which lasted throughout the period investigated. When Compound 49b was applied within 4 hours or 24 hours of blast injury, levels of apoptotic and inflammatory mediators were significantly reduced. Application of Compound 49b within 72 hours of blast injury reduced levels of inflammatory mediators, but not to untreated levels.ConclusionsOcular blast injury produces a significant increase in levels of key inflammatory and apoptotic markers in the retina as early as 4 hours after blast exposure. These levels are significantly reduced if a beta-adrenergic receptor agonist is applied within 24 hours of blast exposure. Data suggest that local application of beta-adrenergic receptor agonists may be beneficial to reduce inflammation and apoptosis.

Traumatic hyphema in children: A review of 137 consecutive cases

The purpose of this study is to evaluate the mechanisms of injury resulting in traumatic hyphema in children, the settings in which these injuries occur, and the outcomes of these injuries. This was a eight-year retrospective review of all patients seen at Children’s Hospital Colorado between September 1, 2003, and December 31, 2011, and diagnosed with traumatic hyphema. One hundred and thirty-seven patients were identified as having a traumatic hyphema. Eighty-eight percent of cases occurred in boys. The mean and median ages of the patients was 10 and 11 years respectively. A small number of these injuries were documented as occurring outside of the home setting (12/135). Mechanisms of injury were myriad with the most common mechanisms being horseplay (37), missiles such as ball bearing guns, airsoft pellet guns, or paintball guns (36), and sports injuries (32). Accidental trauma (14), Bungee cords (10), and assault (5) were other causes of traumatic hyphema in children. Of the patients with at least one month of follow-up (103), all but four (3.8%) recovered excellent vision. The vision loss in these four cases was due to retinal scarring, traumatic optic neuropathy, and amblyopia. The mechanisms of injury in these cases were baseball (2), paintball (1) and BB (1). This study highlights the frequency in which serious eye injuries occur in the home setting and the dangers of children using guns and participating in horseplay. The use of protective eyewear during sports, supervision of children at home, and the avoidance of children using guns could prevent the majority of the eye injuries resulting in hyphema. This study is the largest review of pediatric traumatic hyphema.

A contribution to the discussion on the safety of air weapons

Firearms legislation in the UK stems from the Firearms Act 1968 with its definition of a firearm as a lethal barrelled weapon of any description. The Act allows certain exceptions to be held without licence, most notably air weapons although these are limited by The Firearms (Dangerous Air Weapons) Rules 1969 and related regulations to below 12ft lb (16.3J) for air rifles and below 6ft lb (8.1J) for air pistols. Despite this there are occasional fatalities, typically 1 or 2 each year in the UK, from legally owned air weapons. In the USA there are over 20,000 visits each year to emergency departments due to injuries from air weapons and paintball guns. Despite this, limited research appears to have been carried out into the safety of air weapons and the present study tries to address this. Fresh samples of animal tissue were obtained from an abattoir or butcher and were embedded in ballistic gelatin. Pig heart, lung, liver and shoulder were used. By firing pellets into gelatin alone and into the combination of the gelatin and animal tissue it was possible to compare gelatin as a model for these tissues. The depth of penetration was similar but the residual track appeared to remain more open in the animal tissue. Pellets penetrated completely through the organ, with total penetration of gelatin and organ being typically around 10-15cm. Samples of pig, cow and chicken skin were placed in contact with the gelatin or embedded in the gelatin to simulate the effect of skin on penetration into a body. Chicken skin had no effect, pig skin stopped the pellet and cow skin was perforated by the pellet. If cow skin was embedded in the gelatin there was little effect on the total amount of penetration, but cow skin on the front surface of the gelatin reduced penetration by about 30%. Computed tomography was used to examine the pellet track and to calculate the volume of damage produced. However, due to the similar densities of gelatin and organ a technique had to be developed to differentiate phases. A barium salt paste was applied to outer surfaces and iodine solution or barium nitrate solution containing red food colouring was injected into the pellet track to enhance the contrast of the track. The track through the gelatin tended to enclose itself whereas the track through the organ remained more open, presumably due to the inhomogeneity of the fibrous nature of the tissue. Pellets were also fired at construction materials (wood, plasterboard and brick) and computed tomography used to determine the volume of damage created. Pellets perforated single layers of wood and plasterboard and would embed in a second layer. However, if the two layers were in contact the pellet did not penetrate the first layer. An air rifle pellet could therefore perforate house construction materials, although the resultant kinetic energy would be low and further damage would be limited. Some of the possible physical parameters are discussed that might help predict the degree of damage caused, but from this study it is not possible to define a limit which could be proposed as safe.

A mouse model of ocular blast injury that induces closed globe anterior and posterior pole damage

We developed and characterized a mouse model of primary ocular blast injury. The device consists of: a pressurized air tank attached to a regulated paintball gun with a machined barrel; a chamber that protects the mouse from direct injury and recoil, while exposing the eye; and a secure platform that enables fine, controlled movement of the chamber in relation to the barrel. Expected pressures were calculated and the optimal pressure transducer, based on the predicted pressures, was positioned to measure output pressures at the location where the mouse eye would be placed. Mice were exposed to one of three blast pressures (23.6, 26.4, or 30.4 psi). Gross pathology, intraocular pressure, optical coherence tomography, and visual acuity were assessed 0, 3, 7, 14, and 28 days after exposure. Contralateral eyes and non-blast exposed mice were used as controls. We detected increased damage with increased pressures and a shift in the damage profile over time. Gross pathology included corneal edema, corneal abrasions, and optic nerve avulsion. Retinal damage was detected by optical coherence tomography and a deficit in visual acuity was detected by optokinetics. Our findings are comparable to those identified in Veterans of the recent wars with closed eye injuries as a result of blast exposure. In summary, this is a relatively simple system that creates injuries with features similar to those seen in patients with ocular blast trauma. This is an important new model for testing the short-term and long-term spectrum of closed globe blast injuries and potential therapeutic interventions.