Ocular trauma by kinetic impact projectiles during civil unrest in Chile.

BACKGROUND: The use of kinetic impact projectiles (KIPs) for crowd-control has increased worldwide. Despite having been created as non-lethal weapons, significant damage to several organs, including the eye, has been reported. In this study, we investigated cases of ocular trauma from KIPs during the civil unrest in Chile. To our knowledge, this is the largest case series recorded in international literature. METHODS: We included all patients who sought care or were referred to the Eye Trauma Unit, a national referral centre in Santiago, Chile, during the civil unrest from October 18 to November 30, 2019. We reviewed paper medical records and extracted data on suspected cause of trauma, type of trauma, visual acuity and sociodemographic data. RESULTS: We included 259 patients, out of which in 182 cases (70.5%) KIPs were the suspected cause. Cases by KIPs were predominantly male (86.6%), young (median age 26.3, interquartile range 22.0-31.4) and living in the Metropolitan Region. Eighty-nine patients (48.9%) had severe visual impairment or were blind at the first examination. The trauma was an open-globe injury in 20.3% of cases and 13 cases required evisceration of the ocular content. Compared to other causes of ocular trauma, KIPs were related to a more severe loss of visual acuity and a higher frequency of open-globe injuries. CONCLUSIONS: The use of KIPs during a period of civil unrest in Chile resulted in severe ocular trauma, visual impairment and permanent disability. KIPs should be avoided as a method of crowd-control.

Effectiveness of sampling methods employed for Acanthamoeba keratitis diagnosis by culture.

PURPOSE: This retrospective, observational study was designed to evaluate the effectiveness of the sampling methods commonly used for the collection of corneal scrapes for the diagnosis of Acanthamoeba keratitis (AK) by culture, in terms of their ability to provide a positive result. METHODS: A total of 553 samples from 380 patients with suspected AK received at the Parasitology Section of the Public Health Institute of Chile, between January 2005 and December 2015, were evaluated. A logistic regression model was used to determine the correlation between the culture outcome (positive or negative) and the method for sample collection. The year of sample collection was also included in the analysis as a confounding variable. RESULTS: Three hundred and sixty-five samples (27%) from 122 patients (32.1%) were positive by culture. The distribution of sample types was as follows: 142 corneal scrapes collected using a modified bezel needle (a novel method developed by a team of Chilean corneologists), 176 corneal scrapes obtained using a scalpel, 50 corneal biopsies, 30 corneal swabs, and 155 non-biological materials including contact lens and its paraphernalia. Biopsy provided the highest likelihood ratio for a positive result by culture (1.89), followed by non-biological materials (1.10) and corneal scrapes obtained using a modified needle (1.00). The lowest likelihood ratio was estimated for corneal scrapes obtained using a scalpel (0.88) and cotton swabs (0.78). CONCLUSION: Apart from biopsy, optimum corneal samples for the improved diagnosis of AK can be obtained using a modified bezel needle instead of a scalpel, while cotton swabs are not recommended.