Lens Contamination Research Articles

Quantification of Acanthamoeba spp. Motility.

Acanthamoeba keratitis is a severe ocular infection that poses treatment challenges and can lead to blindness. Despite its ubiquity and potential contamination of contact lenses after water exposure, the natural behavior of this pathogen remains elusive. Understanding Acanthamoeba's movement patterns can inform us about how it colonizes contact lenses and contaminates the patient's cornea. It is fortunate that Acanthamoeba spp. are visible via brightfield microscopy starting at 4x magnification. Previous techniques have been developed to quantify Acanthamoeba motility in regard to cytopathic effects or under-exposure to the electric field. Here, we describe a method to track and quantify Acanthamoeba spp. motility long-term (hours to days), which is a protocol applicable to multiple amoeba strains, surfaces, and nutritional status of amoeba. This procedure is germane to determining many core motility quantifications, such as distance, speed, confinement, and directionality, which are necessary to monitor different stages of infection, proliferation, or behavioral change.

In situ stereomicroscopy chemical and color etching

Abstract In the field of materials analysis, chemical etching continues to play a crucial role in sample preparation, yet its approach is often more empirical. While classical metallographic methods dominate, insufficient understanding of the process creates room for innovation. To improve this situation, the development of new techniques allowing for structure observation during sample preparation is necessary. This is a critical step towards mitigating the influence of stochastic factors, thereby increasing the reliability and predictability of the outcomes. For real-time structural analysis during sample preparation, professional equipment was recently introduced. This contribution aims to verify in situ monitoring of structure during chemical etching using common laboratory equipment and a stereomicroscope with a camera and tablet. The method may encounter limitations due to the magnification and resolution capabilities of the stereomicroscope. Manipulation with a pipette and the risk of lens contamination with etchant can also be challenging. Additionally, etching in deeply dark etchants and ensuring adequate stirring of the etchant can be difficult. Nevertheless, this method offers new possibilities and can be beneficial for certain applications. To achieve a more comprehensive understanding, experiments with various materials and etchants are important to better grasp the limitations and possibilities of this innovative technique.

Microbial Contamination in Contact Lenses, Lens Care Solutions, and Accessories Among Asymptomatic Soft Contact Lens Users.

Objective This study aimed to evaluate microbial contamination of contact lenses (CL) and their accessories among asymptomatic lens users and identify behavioral risk factors that might exacerbate the said contamination. Methodology Ninety-five asymptomatic soft CL users were recruited. In total, 380 samples were collected from the inner surface of lenses, the base of lens cases, the tip of the multipurpose solution bottle, and the solution itself. All swabs with samples were inoculated onto Columbia 5% sheep blood agar, MacConkey agar, Pseudomonas agar with cetrimide, and Sabouraud dextrose agar. Blood agar, MacConkey agar, and Pseudomonas agar with cetrimide were incubated at 37 °C for 24-48 hours. Fungal growth was investigated on Sabouraud dextrose agar, incubated at 25 °C, and examined daily for three weeks. Microscopic examination, culture-based methods, and biochemical tests were used to identify isolated microorganisms. A self-administered questionnaire on compliance with care and hygiene procedures was completed by each participant. Results The overall microbial contamination of tested samples was 38.7%. The most frequently contaminated items were lens cases (59, 62.1%), followed by bottles (44, 46.3%) and lenses (35, 36.8%). Meanwhile, the lowest incidence of contamination was seen in lens multipurpose solutions (9, 9.5%). The predominant microorganisms recovered were Coagulase-negative Staphylococci (CoNS) (94, 64%) and Gram-positive rods (29, 19.7%). Other identified potential pathogens were Staphylococcus aureus(11, 7.5%), Pseudomonas aeruginosa(5, 3.4%), Escherichia coli(1, 0.7%), andCandida albicans(2, 1.4%). The questionnaire revealed that contact lens users aged 18 to 20 showed a lack of compliance with proper hygienic care for contact lens maintenance. Risk factors such as male gender, smoking, showering, or swimming while wearing CL were related to microbiological contamination in at least one of the samples (P > 0.05). Conclusions The highest degree of contamination with highly virulent pathogens was determined in lens cases owing to insufficient lens care practices among study participants. Noncompliance with the lens cleaning procedures can lead to microbial colonization of the lens and its accessories, prompting inflammatory events in the eyes in the future.

Continuous Positive-Pressure Oxygen Supply Improves Fiberoptic Intubation Efficacy and Safety in Patients With Simulated Cervical Spinal Injury: A Prospective Double-Blind Randomized Controlled Study.

Fiberoptic intubation is an important method for tracheal intubation in patients with cervical spine injury. How to effectively and safely complete fiberoptic intubation while maintaining the stability of the cervical spine is very important. This study compared the efficiency and safety of fiberoptic intubation after anesthesia induction under different types of air pressure in patients with simulated cervical spinal injury. In total, 59 adult patients who underwent fiberoptic intubation with a cervical collar for simulated cervical spinal injury were randomly allocated to continuous positive-pressure oxygen, normal-pressure, or intermittent negative-pressure suction groups. After the induction of anesthesia and adequate 100% oxygenation, which confirmed effective neuromuscular blockade, it was deemed appropriate to begin fiberoptic intubation. In the continuous positive-pressure oxygen group, the fiberoptic device was connected through the negative-pressure suction path with 5 L/min oxygen. In the intermittent negative-pressure suction group, the fiberoptic device was connected to the negative-pressure suction device. In the normal-pressure group, the flexible fiberoptic device was not connected to either the oxygen source or the negative-pressure suction device. The intubation time was recorded as the primary outcome measure. The intubation success rate, number of attempts, minimum SpO2, objective lens contamination rate, and incidence of complications were also compared among the groups. Compared with those in the other groups, the median (range) intubation time in the continuous positive-pressure group was 59 (36-181) seconds, which was significantly shorter than that in the normal-pressure group, 167 (46-181) seconds, and the intermittent negative-pressure suction group, 132.5 (38-181) seconds (P=0.04). The success rate of nasotracheal intubation was significantly greater in the continuous positive-pressure group (94.7%, 18/19) than in the normal-pressure group (50%, 10/20) and intermittent negative-pressure suction group (50%, 10/20) (P=0.004). There was a significant difference among the three groups (P=0.043). The median (range) minimum SpO2 during fiberoptic intubation was 100% (99-100%) in the continuous positive-pressure group, 100% (90-100%) in the normal-pressure group, and 99% (88-100%) in the intermittent negative-pressure suction group (P=0.029). However, no statistically significant difference was detected among the groups with complications. The continuous use of positive-pressure oxygen via the negative-pressure suction pathway can improve the efficiency and safety of fiberoptic intubation in patients with simulated cervical spinal injury after anesthesia induction.

The SRG/eROSITA All-Sky Survey

Context. Number counts of galaxy clusters across redshift are a powerful cosmological probe if a precise and accurate reconstruction of the underlying mass distribution is performed – a challenge called mass calibration. With the advent of wide and deep photometric surveys, weak gravitational lensing (WL) by clusters has become the method of choice for this measurement. Aims. We measured and validated the WL signature in the shape of galaxies observed in the first three years of the Dark Energy Survey (DES Y3) caused by galaxy clusters and groups selected in the first all-sky survey performed by SRG (Spectrum Roentgen Gamma)/eROSITA (eRASS1). These data were then used to determine the scaling between the X-ray photon count rate of the clusters and their halo mass and redshift. Methods. We empirically determined the degree of cluster member contamination in our background source sample. The individual cluster shear profiles were then analyzed with a Bayesian population model that self-consistently accounts for the lens sample selection and contamination and includes marginalization over a host of instrumental and astrophysical systematics. To quantify the accuracy of the mass extraction of that model, we performed mass measurements on mock cluster catalogs with realistic synthetic shear profiles. This allowed us to establish that hydrodynamical modeling uncertainties at low lens redshifts (z < 0.6) are the dominant systematic limitation. At high lens redshift, the uncertainties of the sources’ photometric redshift calibration dominate. Results. With regard to the X-ray count rate to halo mass relation, we determined its amplitude, its mass trend, the redshift evolution of the mass trend, the deviation from self-similar redshift evolution, and the intrinsic scatter around this relation. Conclusions. The mass calibration analysis performed here sets the stage for a joint analysis with the number counts of eRASS1 clusters to constrain a host of cosmological parameters. We demonstrate that WL mass calibration of galaxy clusters can be performed successfully with source galaxies whose calibration was performed primarily for cosmic shear experiments, opening the way for the cluster cosmological exploitation of future optical and NIR surveys like Euclid and LSST.

Deep Learning-Based Multiple Droplet Contamination Detector for Vision Systems Using a You Only Look Once Algorithm

This paper presents a practical contamination detection system for camera lenses using image analysis with deep learning. The proposed system can detect contamination in camera digital images through contamination learning utilizing deep learning, and it aims to prevent performance degradation of intelligent vision systems due to lens contamination in cameras. This system is based on the object detection algorithm YOLO (v5n, v5s, v5m, v5l, and v5x), which is trained with 4000 images captured under different lighting and background conditions. The trained models showed that the average precision improves as the algorithm size increases, especially for YOLOv5x, which showed excellent efficiency in detecting droplet contamination within 23 ms. They also achieved an average precision (mAP@0.5) of 87.46%, recall (mAP@0.5:0.95) of 51.90%, precision of 90.28%, recall of 81.47%, and F1 score of 85.64%. As a proof of concept, we demonstrated the identification and removal of contamination on camera lenses by integrating a contamination detection system and a transparent heater-based cleaning system. The proposed system is anticipated to be applied to autonomous driving systems, public safety surveillance cameras, environmental monitoring drones, etc., to increase operational safety and reliability.

Does Laparoscopic Lens Contamination Effect Operative Time? A study on the Frequency and Duration of Lens Contamination and Commonly Used Measures to Maintain Clear Vision

INTRODUCTION
 Laparoscopy surgical procedures are increasing day by day.Laparoscopic lens contamination is most common problem occurring in laparoscopic surgery. This lens fogging results in increase per operative time. Many techniques are available to improve vision during laparoscopy. These include anti fog solutions, touching a visceral organ, use of warm water or scope warmer, sterile cloth can be used which can be dry or wet.
 MATERIALS AND METHODS
 It was a cross sectional study conducted in general surgery department Gulab Devi Hospital Lahore from January 2022 to July 2022. A total of 70 patient undergoing laparoscopic surgery were recruited in this study. Operative time, duration of time lens remained cleaned or dirty, time wasted during cleaning, methods used for cleaning of lens and there time duration and causes of lens contamination were the variables of this study. 
 RESULTS
 Total operative time in all 70 laparoscopic procedures was found to equate to 53 hours and 13 minutes with a mean of 43.8 ± 8.3 minutes. A total of 288 lens contamination events were observed in all these operations with an average of 4.11 lens contamination events per case. According to study an average, 60.9% of the operational time lens remained clear, 31.2% of the operational time lens remained contaminated and 7.92% of the operative time was spent in cleaning the laparoscope. 
 CONCLUSION
 Our study demonstrates that a significant period of a laparoscopic surgery is performed with foggy display. A lot of time is wasted in lens cleaning which can be saved by reducingcontamination using perfect techniques to clean lens.

Face Detection Using a Capsule Network for Driver Monitoring Application

Bus driver distraction and cognitive load lead to higher accident risk. Driver distraction sources and complex physical and psychological effects must be recognized and analyzed in real-world driving conditions to reduce risk and enhance overall road safety. The implementation of a camera-based system utilizing computer vision for face recognition emerges as a highly viable and effective driver monitoring approach applicable in public transport. Reliable, accurate, and unnoticeable software solutions need to be developed to reach the appropriate robustness of the system. The reliability of data recording depends mainly on external factors, such as vibration, camera lens contamination, lighting conditions, and other optical performance degradations. The current study introduces Capsule Networks (CapsNets) for image processing and face detection tasks. The authors’ goal is to create a fast and accurate system compared to state-of-the-art Neural Network (NN) algorithms. Based on the seven tests completed, the authors’ solution outperformed the other networks in terms of performance degradation in six out of seven cases. The results show that the applied capsule-based solution performs well, and the degradation in efficiency is noticeably smaller than for the presented convolutional neural networks when adversarial attack methods are used. From an application standpoint, ensuring the security and effectiveness of an image-based driver monitoring system relies heavily on the mitigation of disruptive occurrences, commonly referred to as “image distractions,” which represent attacks on the neural network.

Acanthamoeba spp. aggregate and encyst on contact lens material increasing resistance to disinfection.

Acanthamoeba keratitis is often caused when Acanthamoeba contaminate contact lenses and infect the cornea. Acanthamoeba is pervasive in the environment as a motile, foraging trophozoite or biocide-resistant and persistent cyst. As contact lens contamination is a potential first step in infection, we studied Acanthamoeba's behavior and interactions on different contact lens materials. We hypothesized that contact lenses may induce aggregation, which is a precursor to encystment, and that aggregated encystment would be more difficult to disinfect than motile trophozoites. Six clinically and/or scientifically relevant strains of Acanthamoeba (ATCC 30010, ATCC 30461, ATCC 50370, ATCC 50702, ATCC 50703, and ATCC PRA-115) were investigated on seven different common silicone hydrogel contact lenses, and a no-lens control, for aggregation and encystment for 72 h. Cell count and size were used to determine aggregation, and fluorescent staining was used to understand encystment. RNA seq was performed to describe the genome of Acanthamoeba which was individually motile or aggregated on different lens materials. Disinfection efficacy using three common multi-purpose solutions was calculated to describe the potential disinfection resistance of trophozoites, individual cysts, or spheroids. Acanthamoeba trophozoites of all strains examined demonstrated significantly more aggregation on specific contact lens materials than others, or the no-lens control. Fluorescent staining demonstrated encystment in as little as 4 hours on contact lens materials, which is substantially faster than previously reported in natural or laboratory settings. Gene expression profiles corroborated encystment, with significantly differentially expressed pathways involving actin arrangement and membrane complexes. High disinfection resistance of cysts and spheroids with multi-purpose solutions was observed. Aggregation/encystment is a protective mechanism which may enable Acanthamoeba to be more disinfection resistant than individual trophozoites. This study demonstrates that some contact lens materials promote Acanthamoeba aggregation and encystment, and Acanthamoeba spheroids obstruct multi-purpose solutions from disinfecting Acanthamoeba.

Air shield system to reduce lens contamination in optical lithography based on turbulence simulation

The development of optical lithographic technology made important contributions to miniaturization. In optical lithography, it is critical to maintain high uniformity and high resolution of patterning on a silicon substrate by exposing the substrate to ultraviolet (UV) light. However, lens contamination limits the uniformity of the exposed UV light, and the effect of lens contamination on the critical dimension is increasing as electronic devices become smaller. Lens contamination can be generated by turbulence of clean air (CA) and it gradually accelerates over time. In this work, we suggest the extreme clean dry air (XCDA) shield system to reduce lens contamination in optical lithography. We have measured and analyzed the contaminants of a practical lithography lens through time-of-flight secondary mass spectrometry, and the expected contamination mechanism is also shown. Also, we simulated turbulence of CA in practical lithography based on the shield k-epsilon turbulence model. Turbulence simulations not only quantitatively showed the effects of XCDA and CA on lens contamination but also demonstrated that the lens could be directly purged with the XCDA shield system to prevent turbulence of CA. The XCDA shield system reduced the degree of contamination by 33% compared with the conventional level. We believe that the proposed system will provide high efficiency in the optical lithography industry.

Molecular and microbiological evidence of bacterial contamination of intraocular lenses commonly used in canine cataract surgery.

Inflammatory outcomes, including toxic anterior segment syndrome (TASS) and infectious endophthalmitis, are potentially painful, blinding complications following cataract surgery. In an in vitro pilot study, commercially available, sterile foldable intraocular lenses (IOLs) used during routine canine cataract surgery, and their packaging fluid were surveyed for the presence of bacterial DNA and/or viable (cultivable) bacteria. Swabs from IOLs and packaging fluid from three different veterinary manufacturers and three different production lots/manufacturer were collected for 16S ribosomal ribonucleic acid (rRNA) sequencing. Packaging fluid samples were collected for aerobic/capnophilic bacterial culture. Culture yielded one isolate, identified as Staphylococcus epidermidis. 16S rRNA sequencing revealed distinct brand-specific bacterial DNA profiles, conserved between IOLs and packaging fluid of all production lots within each manufacturer. The dominant taxonomy differentiating each manufacturer was annotated as Staphylococcus sp, and was a 100% match to S. epidermidis. Distinct mixtures of bacterial DNA are present and consistent in IOLs and packaging fluid depending on the manufacturer, and Staphylococcus is the dominant contributor to the bacterial DNA detected. Caralens products had a significantly lower amount of Staphylococcus spp. compared to Anvision and Dioptrix products.

Microbial Contamination of Soft Contact Lenses Among Medical School Students in Southern Iraq.

Contamination of CLs and accessories risks potentially devastating microbial keratitis. We aimed to explore the rate of microbial contamination and predisposing factors among a group of asymptomatic young medical students. The study included 115 healthy female medical students with a mean age of 21.64 ± 2.02 years between January and November 2021. Information about CL use, wear and care was gathered. Each participant's CL and case were swabbed for microbiological identification. Univariable and multivariable analyses were conducted to look for associations with a range of factors. Overall, 91 participants (79.13%) had at least one contaminated sample (lens and/or case). The rates of contamination of CL and their cases were 66% and 76.5%, respectively. Higher contamination rates were caused by gram-negative bacteria (60% of the contaminated samples) with P. aeruginosa being the most common contaminant both for CL and cases, whereas S. epidermidis and S. aureus were the most common contaminants for the CL and cases, respectively, regarding gram-positive contamination. Multivariable analysis showed younger age as a significant predictor of pseudomonas contamination of the lenses and cases (OR: 12.302, 6.555 for CL & cases, respectively; P = 0.001 for both). Older age was a significant predictor of K. pneumoniae contamination (OR: 4.154, P = 0.007). Pseudomonas contamination of both lenses and cases was predicted by the type of solution used (OR: 10.8 and 13.5, P = 0.001 and 0.003 for bottled and distilled water vs commercially available solutions for CL; OR: 4.5 and 5.8, P = 0.045 and 0.004, respectively, for cases). Pseudomonas case contamination was associated with low frequency of solution change. Microbial contamination rate of soft CL and their cases is high among young medical students in comparison to previously reported rates and was predisposed by several poor hygienic practices and wearing regimens.

A FINGERPRINT REMOVAL METHOD BASED ON FRACTAL–CRIMINISI TECHNOLOGY

Against the circumstance of redundant fingerprint information remaining in photographed images due to lens contamination, a fingerprint removal method is proposed by combining fractal technology and the Criminisi method. Fingerprints on an image are usually distributed in a dispersive pattern, and show statistical fractal characteristic. Therefore, based on the Criminisi method, the textural complexity of image pixel blocks expressed by box-counting fractal dimension is introduced into this method as a parameter of pixel block size and subitem of the data item with priority. On the one hand, this way of operation can select the size of the pixel blocks to be removed adaptive to the box fractal dimension; on the other hand, the box fractal dimension, as the subitem of the data item with priority, can avoid the effect of particular value and improve the reliability and stability of priority. The experimental results show that the proposed method can satisfactorily perform the fingerprint removal task and fill the information.

Antimicrobial efficacy of novel ultraviolet-C device in reducing contamination of contact lenses

Antimicrobial efficacy of novel ultraviolet-C device in reducing contamination of contact lenses

MICROBIAL BIOBURDEN OF ORTHOKERATOLOGY AND HYDROGEL CONTACT LENSES AND STORAGE CASES USING A HYDROGEN-PEROXIDE DISINFECTING SYSTEM

Background and objective: The fitting of orthokeratology (ortho-k) and multifocal soft contact lenses (SCL) is becoming increasingly popular worldwide for reducing the rate of myopia progression. However, overnight wear use of lenses and microbial contamination of contact lenses and storage vials has been shown to increase the risk of corneal inflammatory and infiltrative events (CIEs). Therefore, we conducted a pilot study to compare the rate, level, and type of microbial contamination of contact lenses and storage vialswhen participants wear ortho-k and SCL in combination with a hydrogen-peroxide disinfecting system.
 Material and Methods: A prospective, single-centre, randomized, crossover study was conducted to evalu-ate the rate and level of contact lens and storage vials contamination during the use of ortho-k and SCL along with a hydrogen-peroxide disinfecting solution over two 10 day wearing periods. Ocular signs and symptoms were assessed during lens wear at baseline and after each wearing period. In addition, contact lens and storage vials were collected, and the type and amount of microbial contamination were evaluated using viable culture and standard identification methods.Results: Twenty-five adults were enrolled, and 21 completed the study. One (5%) ortho-k lens, five (24%) ortho-k storage vials, one (5%) SCL and one (5%) SCL storage vial were contaminated (P > 0.05), predominantly with Gram-positive bacteria. None of the participants had contamination with both ortho-k and SCL. No significant differences were found between the ocular signs, including conjunctival redness and roughness, or conjunctival or corneal staining (all P > 0.05), irrespective of using ortho-k or SCL.
 Conclusion: This study provides the first data that directly compares microbial contamination of ortho-K versus SCL in patients using a hydrogen-peroxide disinfection system. However, the overall microbial contamination rate of contact lens storage vials was much lower (30%) than the previously reported study with ortho-k lens wear. The results support conducting a larger clinical trial designed to understand differences in microbial contamination with different lens materials and modalities.

Accuracy and precision of position determination in ISTEM imaging of BaTiO[formula omitted

In this paper we study the effect of lens aberrations (spherical aberration and astigmatism), beam tilt, contamination and shot noise on the accuracy and precision of position determination in imaging scanning transmission electron microscopy (ISTEM) on the example of BaTiO3. ISTEM images are simulated as a function of sample thickness and defocus starting from a nearly perfect microscope setting. A defocus range was identified, in which atom column positions were reliably visible and could be decently measured. By averaging over this defocus and thickness range a figure of merit was defined and used to study the influence of above mentioned disturbing effects as a function of their strength. It turned out that column positions might become inaccurate, but distances are measured accurately. These were used to obtain recommendations for the experimental setup to measure the atomic arrangement that induces ferroelectric switching of BaTiO3.

Raman Scattering Study on the Influence of E-Beam Bombardment on Si Electron Lens.

Microcolumns have a stacked structure composed of an electron emitter, electron lens (source lens), einzel lens, and a deflector manufactured using a micro electro-mechanical system process. The electrons emitted from the tungsten field emitter mostly pass through the aperture holes. However, other electrons fail to pass through because of collisions around the aperture hole. We used Raman scattering measurements and X-ray photoelectron spectroscopy analyses to investigate the influence of electron beam bombardment on a Si electron lens irradiated by acceleration voltages of 0, 20, and 30 keV. We confirmed that the crystallinity was degraded, and carbon-related contamination was detected at the surface and edge of the aperture hole of the Si electron lens after electron bombardment for 24 h. Carbon-related contamination on the surface of the Si electron lens was verified by analyzing the Raman spectra of the carbon-deposited Si substrate using DC sputtering and a carbon rod sample. We report the crystallinity and the origin of the carbon-related contamination of electron Si lenses after electron beam bombardment by non-destructive Raman scattering and XPS analysis methods.

Factors Affecting Microbial Contamination on the Back Surface of Worn Soft Contact Lenses.

SIGNIFICANCEThe results of this study demonstrate that Smart Touch Technology packaging, which is designed to reduce and simplify contact lens handling before insertion, is effective in reducing the frequency of bacterial contamination of the back surface of contact lenses after short-term wear.PURPOSEThe purpose of this study was to investigate the effect of lens packaging type, chelating agent, and finger contamination on microbial contamination on the back surface of worn soft contact lenses.METHODSTwenty-five subjects completed each contralateral lens wear comparison in this randomized study: Smart Touch Technology versus conventional blister packaging for (1) silicone hydrogel lenses with ethylenediaminetetraacetic acid (EDTA) and (2) hydrogel lenses without EDTA in the packaging, and (3) silicone hydrogel lenses without EDTA versus hydrogel lenses with EDTA both in Smart Touch Technology packaging. Participants washed hands, underwent finger swabs, and inserted the lenses. After 45 minutes, lenses were removed aseptically and the posterior lens surfaces cultured.RESULTSThirty-eight subjects (average age, 30.9 ± 12.5 years) participated in this study. Overall, the level of back surface contamination was low for both lens materials, ranging from 0 to 43 colony-forming unit (CFU)/lens for the silicone hydrogel and 0 to 17 CFU/lens for the hydrogel lenses. The proportion of lenses with zero back surface contamination ranged from 16 to 64% for silicone hydrogel lenses and 28 to 64% for hydrogel lenses. Contact lenses from conventional packaging containing EDTA had 3.38 times increased risk (95% confidence interval [CI], 1.02 to 11.11; P = .05) of contamination being present compared with lenses from Smart Touch packaging with EDTA. Contact lenses from conventional packaging without EDTA had 3.4 times increased risk (95% CI, 1.02 to 11.36; P = .05) of contamination being present compared with Smart Touch packaging without EDTA, and silicone hydrogel lenses had a 6.28 times increased risk (95% CI, 1.65 to 23.81; P = .007) of contamination being present compared with hydrogels. The median (interquartile range) number of bacteria isolated from fingers used to perform lens insertion after handwashing but before lens insertion was not significantly different between the silicone hydrogel and hydrogel lenses (63.7 [204.2] vs. 59 [84.5], P = .09). Finger contamination was not significantly associated with lens contamination in the presence or absence of EDTA.CONCLUSIONSSmart Touch Technology packaging was effective in reducing the proportion of contaminated lenses. Although silicone hydrogel lenses were more likely to be contaminated, the presence of EDTA ameliorated this effect. Finger contamination was not associated with lens contamination.

Ocular microbiota and lens contamination following Mel4 peptide-coated antimicrobial contact lens (MACL) extended wear

PurposeThe purpose of this study was to investigate the effect of Mel4 antimicrobial peptide-coated contact lenses (MACL) on the microbiota of the conjunctiva and lenses during three months of extended wear. MethodsOne hundred and seventy-six participants were recruited into a randomised, contralateral, double masked, biweekly extended wear MACL and uncoated control lens trial. At the one month and 3-month visit, the conjunctival microbiota was sampled using sterile cotton swabs and contact lenses were collected aseptically. Standard microbiological procedures were employed for culture of the swabs and contact lenses and identification of the isolated microorganisms. ResultsGram-positive bacteria (predominantly coagulase-negative staphylococci) were the most frequently isolated microbes from both contact lenses and conjunctiva. There was no difference in the frequency of isolation of most bacteria or fungi from the conjunctival swabs of eyes wearing either MACL or control lenses. The only exception was a higher frequency of eyes harbouring Staphylococcus arlettae when wearing control lenses (5%) versus MACL (<1%) (p = 0.002). There was no significant difference in the frequency of microbes isolated from MACL or control contact lenses. There were also no differences between lens types in the frequency of isolation of >1 microbial type per sampling occasion for either conjunctiva swabs or contact lenses. ConclusionMACL wear did not change the conjunctival microbiota during extended wear, and the types of microbes isolated from MACL were similar to those isolated from control lenses.

A laser sheet sensor (LASS) for wind-blown sand flux measurement

There is a tendency to use high-frequency piezoelectric, acoustic, and optical sensors to measure aeolian sand transport rates in the aeolian community. However, most of these sensors are particle counters with inconsistent sensitivities or low saturation limits. Here we introduce a commercial laser sheet sensor (LASS) that can be deployed streamwisely to measure local saltation flux or perpendicularly to capture the bulky character of sand streams. Our laboratory and field experiment results show that LASS sensors respond linearly to the sand flux over the range of 0–20 kg m−2 s−1, covering most saltation events in nature. The LASSes are extremely consistent. They maintain their functionality even with minor lens contamination or laser misalignment during deployment. LASSes should not be deployed in environments with poorly sorted or moist sand or non-unidirectional wind.