Microbial adherence to cosmetic contact lenses

Cosmetic Contact Lenses in the United Kingdom: Assessment of Online Regulation and Quality of Consumer Health Information

OBJECTIVES

To determine the compliance of online vendors to the UK Opticians Act 1989 Section 27 requirements and safety regulations for cosmetic contact lens (CCL) sales and the quality of online CCL health information.

METHODS

The top 50 websites selling CCLs on each three search engines, namely Google, Yahoo, and Bing, were selected. Duplicates were removed, and the remaining websites were systematically analyzed in February 2023. UK legal authorization for CCL sales was assessed using the Opticians Act Section 27 and safety regulations determined by the presence of Conformité Européene (CE) marking. The quality and reliability of online information was graded using the DISCERN (16-80) and JAMA (0-4) scores by two independent reviewers.

RESULTS

Forty-seven eligible websites were analyzed. Only six (12.7%) met the UK legal authorization for CCL sales. Forty-nine different brands of CCLs were sold on these websites, of which 13 (26.5%) had no CE marking. The mean DISCERN and JAMA benchmark scores were 26 ± 12.2 and 1.3 ± 0.6, respectively (intraclass correlation scores: 0.99 for both).

CONCLUSIONS

A significant number of websites provide consumers with easy, unsafe, and unregulated access to CCLs. Most online stores do not meet the requirements set out in the Opticians Act for CCL sales in the United Kingdom. A significant number of CCLs lack CE marking, while the average quality of information on websites selling CCLs is poor. Together, these pose a risk to consumers purchasing CCLs from unregulated websites, and therefore, further stringent regulations on the online sales of these products are needed.

A water transfer printing method for contact lenses surface 2D MXene modification to resist bacterial infection and inflammation

Contact lenses (CLs) are prone to adhesion and invasion by pollutants and pathogenic bacteria, leading to infection and inflammatory diseases. However, the functionalization of CL (biological functions such as anti-fouling, antibacterial, and anti-inflammatory) and maintaining its transparency still face great challenges. In this work, as a member of the MXenes family, vanadium carbide (V2C) is modified onto CL via a water transfer printing method after the formation of a tightly arranged uniform film at the water surface under the action of the Marangoni effect. The coating interface is stable owing to the electrostatic forces. The V2C-modified CL (V2C@CL) maintains optical clarity while providing good biocompatibility, strong antioxidant properties, and anti-inflammatory activities. In vitro antibacterial experiments indicate that V2C@CL shows excellent performance in bacterial anti-adhesion, sterilization, and anti-biofilm formation. Last, V2C@CL displays notable advantages of bacteria elimination and inflammation removal in infectious keratitis treatment.

Unregulated Decorative Lenses: A Brief Definitive Review

ABSTRACT

Contact lenses are US Food and Drug Administration-regulated medical devices that are a safe and effective method for the correction of refractive error. They are worn by an estimated 45 million Americans. Decorative contact lenses (DCLs) can be used for patients with medical conditions such as failed corneas or aniridia. However, DCLs have also gained popularity in the young, contact lens-naïve population. DCL users often buy lenses through unregulated sources without a clinical examination and education on proper use by an eye care professional. These lenses have a significantly higher risk of infection when compared with contact lenses for the correction of refractive error. To reduce the incidence of microbial keratitis, regulators and eye care professionals must make coordinated efforts to generate and disseminate prevention messages to all contact lens users. In addition, physician and patient reporting of contact lens-related complications to regulatory agencies enhances the pathway to risk reduction. This article reviews DCL use and supply, with a specific focus on the increased risk of contact lens-related complications in unsupervised DCL use.

TFOS Lifestyle: Impact of contact lenses on the ocular surface

Several lifestyle choices made by contact lens wearers can have adverse consequences on ocular health. These include being non-adherent to contact lens care, sleeping in lenses, ill-advised purchasing options, not seeing an eyecare professional for regular aftercare visits, wearing lenses when feeling unwell, wearing lenses too soon after various forms of ophthalmic surgery, and wearing lenses when engaged in risky behaviors (e.g., when using tobacco, alcohol or recreational drugs). Those with a pre-existing compromised ocular surface may find that contact lens wear exacerbates ocular disease morbidity. Conversely, contact lenses may have various therapeutic benefits. The coronavirus disease-2019 (COVID-19) pandemic impinged upon the lifestyle of contact lens wearers, introducing challenges such as mask-associated dry eye, contact lens discomfort with increased use of digital devices, inadvertent exposure to hand sanitizers, and reduced use of lenses. Wearing contact lenses in challenging environments, such as in the presence of dust and noxious chemicals, or where there is the possibility of ocular trauma (e.g., sport or working with tools) can be problematic, although in some instances lenses can be protective. Contact lenses can be worn for sport, theatre, at high altitude, driving at night, in the military and in space, and special considerations are required when prescribing in such situations to ensure successful outcomes. A systematic review and meta-analysis, incorporated within the review, identified that the influence of lifestyle factors on soft contact lens dropout remains poorly understood, and is an area in need of further research. Overall, this report investigated lifestyle-related choices made by clinicians and contact lens wearers and discovered that when appropriate lifestyle choices are made, contact lens wear can enhance the quality of life of wearers.

Was Marilyn Monroe myopic and an early adopter of colored contact lenses? A review of the evidence and the early history of colored contact lenses

Wide availability and uptake of contact lenses came with the development of the first polymethyl methacrylate corneal lenses during the late 1940s. It is less well known that colored contact lenses were developed simultaneously. These innovations allowed both a degree of spectacle independence for ametropes and an ability to vary eye color. The impact on facial and ocular cosmesis was substantial, particularly for public figures such as actors. We have obtained contact lenses and matching casts manufactured by their inventor, Kevin M. Tuohy. Measurements of these suggest they were made for a myope, and we provide indirect evidence that the lenses were made for Marilyn Monroe. We also provide evidence that Monroe is likely to have been myopic, used colored contact lenses to change her eye color and may have been an early sufferer of contact lens overwear syndrome. The importance of ocular cosmesis can be overlooked in ophthalmic practice, yet it is of great interest to and importance for patients. It appears that discomfort, and even risk, will be tolerated to achieve a particular appearance. This is reflected in current techniques aimed at achieving improved cosmesis.

Contact Lens Safety for the Correction of Refractive Error in Healthy Eyes

ABSTRACT

Contact lenses are a safe and effective method for correction of refractive error and worn by an estimated 45 million Americans. Because of the widespread availability and commercial popularity of contact lenses, it is not well appreciated by the public that contact lenses are U.S. Food and Drug Administration (FDA)-regulated medical devices. Contact lenses are marketed in numerous hard and soft materials that have been improved over decades, worn in daily or extended wear, and replaced in range of schedules from daily to yearly or longer. Lens materials and wear and care regimens have impact on the risks of contact lens-related corneal inflammatory events and microbial keratitis. This article reviews contact lens safety, with specific focus on the correction of refractive error in healthy eyes.

The role of Type III secretion system in the pathogenesis of Pseudomonas aeruginosa microbial keratitis

Pseudomonas aeruginosa is the most commonly isolated Gram-negative pathogen causing sight-threatening microbial keratitis (MK). Contact lens wear is the most significant risk factor associated with pseudomonal MK. Understanding the pathogenesis of MK due to P. aeruginosa and its interactions with contact lenses is crucial in preventing these often rapidly progressive and highly antibiotic-resistant infections. Bacterial virulence factor Type III secretion system (T3SS) has significant interplays between contact lens material, antibiotic sensitivity, disinfectant selectivity, and bacterial cell invasion. Depending on the T3SS exotoxins produced, P. aeruginosa strains are divided into cytotoxic or invasive strains. Cytotoxic strains are relatively resistant to commercial disinfectants, while invasive strains are more antibiotic resistant. Therefore, contact lens wearers are more predisposed to cytotoxic P. aeruginosa infections, and patients with trauma or previous surgery are more prone to infection by invasive strains. Previous studies with mutant P. aeruginosa strains unable to produce T3SS exotoxins were more susceptible to disinfectants and less able to adhere to soft contact lenses, indicating an essential role of T3SS in bacterial virulence. Invasion of P. aeruginosa intracellularly was found to be associated with control of scaffold protein IQ-domain GTPase-activating protein 1 (IQGAP1) and human corneal epithelial cell tight junctions. Knockdown of IQGAP1 strengthened tight junctions that prevented intracellular survival of invasive P. aeruginosa strains and enhanced corneal epithelial cell survival. These novel findings of the vital role of T3SS in the pathogenesis of pseudomonal MKs will provide new guidelines in both prevention and treatment of this common eye-blinding infection.

Influence of Contact Lens Materials and Cleaning Procedures on Bacterial Adhesion and Biofilm Formation

Purpose

The present study aimed to compare the existing soft contact lens (CL) materials regarding their influence on bacterial biofilm formation and adhesion susceptibility. Then, the study was designed to investigate the effectiveness of various disinfecting solutions and evaluate the ability of cleaning regimens in terms of anti-bacterial adhesion and biofilm removal on different soft CL materials.

Methods

Bacterial biofilm formation on CLs was evaluated by biomass assay. Adhesion assay and standard plate count were carried out at time-interval periods within 24 h. Various CL disinfecting procedures were assessed for their efficacy to remove biofilm and reduce bacterial adhesion. Scanning electron microscopy (SEM) was performed for the morphological assessment of bacterial biofilm.

Results

Printed hydroxyethyl methacrylate (HEMA) CLs significantly demonstrated more biofilm staining and bacterial attachment when compared with non-printed HEMA CLs, while the Filcon II 3 and Nesofilcon A CLs possessed less biofilm biomass and adherent cells. Staphylococcus aureus and Pseudomonas aeruginosa represented the highest biofilm producing bacteria on HEMA-based materials in this study. The disinfecting regimen with the highest efficacy was the two-step system, first using multipurpose disinfecting solution containing edetate disodium and sorbic acid (MPDS+EDSA), followed by soaking in multipurpose solution (MPS). The regimen demonstrated the greatest effect against the pre-formed biofilm and the adhesion activity of S. aureus and P. aeruginosa on the soft CLs. The SEM micrographs confirmed the morphological changes of bacterial biofilm after disinfecting and revealed that the two-step system treated CLs displayed less adherent bacteria.

Conclusion

HEMA-based soft CLs may facilitate bacterial biofilm formation and adhesion capability. The two-step system was the most effective regimen for biofilm removal, where the soaking period in the disinfecting solution of the no-rub regimen should last more than 6 h to remove pre-formed biofilm.

Monocular Diplopia: An Optical Correction Modality

Post-surgical or traumatic corectopia is among the rare causes of monocular diplopia. A 26-years-old student presented to the Institute with a complaint of monocular double vision in the left eye. He had a penetrating ocular injury in the left eye and subsequently, undergone for multiple ocular surgeries. Following the final intraocular lens implantation, he experienced a monocular double vision in his left eye. Upon contact lens clinic presentation, visual acuities were 20/20 in the right and 20/320 in the left eye (improved to 20/25 with pinhole). Slit-lamp examination on the left eye revealed scarring in the superior nasal quadrant of the cornea, irregular mid-dilated pupil with exposed aphakic and pseudophakic portions. A range of different optical management options were implemented to eliminate monocular diplopia and to correct refractive error. Finally, a combination of prosthetic soft contact lens and spectacle correction was able to remove diplopia and provide binocular single vision.

Contact Lens Use Patterns, Behavior and Knowledge Among University Students in Thailand

Purpose

Little is known about contact lens (CL) use in young generation. This study aimed to investigate the patterns, behavior and knowledge of CL wear and care in Thai university students.

Methods

A cross-sectional study using online questionnaires was conducted during July 2019 to February 2020 in two Rajabhat universities, Bangkok, Thailand. Participant characteristics, CL information, knowledge and behaviors were collected. Factors associated with poor behaviors and CL-related corneal ulcers were analyzed using logistic regression.

Results

Of 493 students participating in the survey, 336 students (66.78%) were current CL users and completed the questionnaires. Mean age was 19.2 ± 1.4 years with female predominance (80.36%). All students wore soft CL with a major replacement schedule of monthly disposable (90.18%). Good CL wear and care behaviors were found in 190 students (56.55%). The most common poor CL behavior and poor CL knowledge were CL overuse (44.64%) and sleeping with lenses (31.85%), respectively. There were no correlations between behaviors and knowledge (r = 0.03). Purchasing lens from internet, wearing experience over one year, and long wear duration (> 12 hours) were significantly associated with poor CL behavior. Male gender and swimming with lens were significantly associated with history of corneal ulcers.

Conclusion

The study pointed out a low compliance of CL wear and care in Thai university students. Good CL practices, awareness of CL-related complications and purchasing place should be carefully informed and regularly stressed to minimize preventable visual damage in young population.

TEM observation of inorganic substances distributed in gel materials for medical devices using ultra-thin cryosectioning

In this study, a method was developed for examining the distribution pattern of inorganic substances dispersed in hydrogel-filled medical devices. Transmission electron microscopy (TEM) using ultra-thin cryosectioning (owing to hydrogel's water content) was performed on contact lenses with an iris pattern in which the distribution pattern of inorganic pigments was problematic. We confirmed the depth and distribution pattern of pigments in the hydrogel. The results indicated that ultra-thin cryosectioning with TEM was effective for inspecting the distribution of inorganic substances in hydrogel-filled devices.

Transparent and UV Blocking Structural Colored Hydrogel for Contact Lenses

Usually, materials with perfect structures possess excellent properties, but it is not always the case. Here, a new approach is reported to construct structural colored hydrogel films with excellent ultraviolet (UV) blocking performance for contact lenses. The theoretical simulation predicts that with perfect periodic structures, the hydrogel films can strongly reflect incident light in a narrow visible wavelength range and thus exhibit extraordinarily brilliant colors. However, such hydrogel films cannot effectively block UV light. By slightly breaking the structural periodicity (quasi-periodic structure), strong diffuse scattering or pseudoabsorption of light can occur for all of the wavelengths shorter than a structural characteristic length, leading to perfect UV blocking. According to the theoretical prediction, a structural colored hydrogel film with nearly periodic polystyrene sphere arrays in poly(hydroxyethyl methacrylate) hydrogel matrix is fabricated; this hydrogel film possesses brilliant colors and perfect UV blocking, and the core particle composition and size have been investigated in detail for the optimized properties of contact lenses. Meanwhile, the cell proliferation assay proves the cytocompatibility of the hydrogel for real application. Regarding its unique optical characteristics, the as-prepared structural colored hydrogel shows great promise in the fields of UV-protective equipment, medical device, soft robot, sensor, and so on.

ToF-SIMS and AFM Characterization of Brown Cosmetic Contact Lenses: From Structural Analysis to the Identification of Pigments

Over the years, soft contact lenses for vision correction and cosmetic and therapeutic purposes have been greatly improved. For cosmetic contact lenses, the pigments need to be nontoxic, and the position of the pigment layer is particularly important because of the risks posed by pigment elution and the roughness of the lens surface. In this paper, we characterized the properties of brown cosmetic contact lenses made by three different manufacturers using surface analytical techniques. The surface topographies of the noncolored and colored parts were obtained by atomic force microscopy (AFM), and the position and composition of the pigment layer were determined by analyzing the cross section of the contact lenses using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The influence of pigment location on surface roughness was also examined. In addition, to find the method of the evaluation for the risk of surface elution of the pigments in the colored parts, the mass spectra and ion images of the surfaces were obtained by time-of-flight secondary ion mass spectrometry (ToF-SIMS) with a new sample preparation. From the ToF-SIMS spectra, we observed specific fragment ions of the poly(hydroxyethyl methacrylate) (PHEMA) polymer and found differences in the composition of the pigment layer depending on the manufacturers. The cross-sectioned image and 3D chemical characterizations of metallic and specific ions in the brown cosmetic contact lenses clearly indicated the spatial distribution and location of the pigment layer that can be used for the evaluation of pigment elution.

Contact Lens Technology: From Fundamentals to Applications

Contact lenses are ocular prosthetic devices used by over 150 million people worldwide. Primary applications of contact lenses include vision correction, therapeutics, and cosmetics. Contact lens materials have significantly evolved over time to minimize adverse effects associated with contact lens wearing, to maintain a regular corneal metabolism, and to preserve tear film stability. This article encompasses contact lens technology, including materials, chemical and physical properties, manufacturing processes, microbial contamination, and ocular complications. The function and the composition of the tear fluid are discussed to assess its potential as a diagnostic media. The regulatory standards of contact lens devices with regard to biocompatibility and contact lens market are presented. Future prospects in contact lens technology are evaluated, with particular interest given to theranostic applications for in situ continuous monitoring the ocular physiology.

Identifying Pigment Enclosure in Cosmetic Contact Lenses

Supplemental Digital Content is Available in the Text.

The presence of surface pigment in cosmetic contact lenses may influence possible ocular health issues and contact lens discomfort. Two in vitro test methods were developed to investigate whether a variety of cosmetic contact lenses are manufactured with a visible clear layer, indicating that the pigment bulk is enclosed within the lens matrix.

Evaluation of Pigment Distribution and Depth Analysis Methods for Decorative Soft Contact Lenses

OBJECTIVES

This study evaluates pigment component distribution and depth in decorative soft contact lenses (DSCLs) using a variety of analytical methods.

METHODS

We sampled 18 DSCLs using optical microscopy, optical coherence tomography analysis, Z-stack analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to evaluate the distribution and depth of pigment components.

RESULTS

Pigment distribution in DSCLs was easily observed with optical methods including Z-stack analysis. X-ray photoelectron spectroscopy, SEM/EDX, and TOF-SIMS were used to evaluate the level of pigment exposure on the lens surface and the results showed significant differences between the methods. Pigment components were detected in 16 samples by SEM/EDX, but not by XPS. Pigment components were only detected in eight samples using TOF-SIMS.

CONCLUSIONS

It may be necessary to show that a nanometer-thick monomolecular film does not exist on the surface of DSCLs, to demonstrate the exposure of a pigment particle. Taking into account the principle behind each of the measurement methods and the resolution and sensitivity of each of the analytical methods compared, TOF-SIMS may be the most appropriate method to accurately judge pigment exposure on DSCLs. The Z-stack method may be useful for estimating the depth of pigment components in DSCLs.

In Vitro Evaluation of Adhesion of Two Acanthamoeba Strains to Cosmetic Contact Lenses

PURPOSE

To evaluate the factors affecting the adhesion of Acanthamoeba trophozoites to the surface of cosmetic contact lenses (CCLs).

METHODS

Acanthamoeba castellanii and A. hatchetti trophozoites were inoculated onto CCLs (hema copolymer [HM] [38.5% H2O], phemfilcon [PF] [55% H2O], polymacon [PM] [38% H2O], polyhema [PH] [%42 H2O], and hema [HM55] [55% H2O]), and the number of trophozoites adhered to the lens surfaces was assessed over time, that is, at 15 min, 1, and 24 hr. In addition, scanning electron microscopy (SEM) analysis of the lens surfaces was performed to evaluate the effect of lens surface topology on adhesion.

RESULTS

The number of amoeba adhered to the contact lens surface was found lower with PF and PH production materials, than lenses with HM, PM, and HM55 production materials (P<0.05). No significant difference was detected in amoebic strains adhered in all the contact lens types (P>0.05). No significant difference was found on average amoeba adhesion between contact lenses with hema production material but with different water contents (45%, 55%), to see the effect of water content on amoebic adhesion (P>0.05). As a result of SEM analysis, surface topology showed no effect on adhesion.

CONCLUSION

(1) Chemical composition of lenses seemed to be mostly responsible for the adhesion of Acanthamoeba. (2) Different numbers of trophozoites, obtained after the adhesion experiment, could also indicate that adherence capacity can also differ among Acanthamoeba species.

Comparison of the Lubricity and Surface Roughness of 5 Cosmetic Contact Lenses

OBJECTIVES

Cosmetic contact lenses are increasingly popular because of their eye enhancing cosmetic benefits. The pigment particles used in these lenses can impact lens surface characteristics. This article examines the surface characteristics and the differences between the clear and the pigmented regions among five limbal ring design lenses.

METHODS

Scanning electron microscopy was used to determine the location and depth of the pigment particles from the lens surface. The coefficient of friction (CoF) was determined with a Basalt-MUST microtribometer at clear and pigmented regions on either the front or the back surface. Atomic force microscopy was used to determine the surface roughness of each lens in root-mean-square (RMS) units at clear and pigmented regions. A linear mixed model for repeated measures was used for the analysis of the CoF and RMS roughness to compare all lenses.

RESULTS

Four lens types had pigments exposed on the surface and one lens type had pigment fully enclosed. The CoF difference between clear and pigmented regions were similar and not statistically significant (P=0.0124) for the lens type with pigments enclosed, whereas the CoF difference for the other four lens types showed statistically significant difference (P<0.0001).

CONCLUSIONS

Of the lenses tested here, cosmetic contact lenses with pigments enclosed in the lens matrix provided a more consistent surface between clear and pigmented regions compared with lenses that had exposed pigments.

A review of cosmetic contact lens infections

This paper provides a comprehensive review of the existing literature surrounding cosmetic contact lens infections. In this paper, lens-related, dispensing-related and patient-related factors are examined in detail.

Therapeutic Contact Lenses with Polymeric Vehicles for Ocular Drug Delivery: A Review

The eye has many barriers with specific anatomies that make it difficult to deliver drugs to targeted ocular tissues, and topical administration using eye drops or ointments usually needs multiple instillations to maintain the drugs’ therapeutic concentration because of their low bioavailability. A drug-eluting contact lens is one of the more promising platforms for controllable ocular drug delivery, and, among various manufacturing methods for drug-eluting contact lenses, incorporation of novel polymeric vehicles with versatile features makes it possible to deliver the drugs in a sustained and extended manner. Using the diverse physicochemical properties of polymers for nanoparticles or implants that are selected according to the characteristics of drugs, enhancement of encapsulation efficiency and prolonged drug release are possible. Even though therapeutic contact lenses with polymeric vehicles allow us to achieve sustained ocular drug delivery, drug leaching during storage and distribution and the possibility of problems related to surface roughness due to the incorporated vehicles still need to be discussed before application in a real clinic. This review highlights the overall trends in methodology to develop therapeutic contact lenses with polymeric vehicles and discusses the limitations including comparison to cosmetically tinted soft contact lenses.

Development of uracil-DNA-glycosylase-supplemented loop-mediated isothermal amplification coupled with nanogold probe (UDG-LAMP-AuNP) for specific detection of Pseudomonas aeruginosa

Pseudomonas aeruginosa (P. aeruginosa) is an important opportunistic pathogen that causes serious infections in humans, including keratitis in contact lens wearers. Therefore, establishing a rapid, specific and sensitive method for the identification of P. aeruginosa is imperative. In the present study, the uracil-DNA-glycosylase-supplemented loop-mediated isothermal amplification combined with nanogold labeled hybridization probe (UDG-LAMP-AuNP) was developed for the detection of P. aeruginosa. UDG-LAMP was performed to prevent carry over contamination and the LAMP reactions can be readily observed using the nanogold probe. A set of 4 primers and a hybridization probe were designed based on the ecfX gene. The UDG-LAMP reactions were performed at 65°C for 60 min using the ratio of 40% deoxyuridine triphosphate to 60% deoxythymidine triphosphate. The detection of UDG-LAMP products using the nanogold labeled hybridization probe, which appeared as a red-purple color, was examined at 65°C for 5 min with 40 mM MgSO₄. The UDG-LAMP-AuNP demonstrated specificity to all tested isolates of P. aeruginosa without cross reaction to other bacteria. The sensitivity for the detection of pure culture was 1.6×10³ colony-forming units (CFU) ml⁻¹ or equivalent to 3 CFU per reaction while that of polymerase chain reaction was 30 CFU per reaction. The detection limit of spiked contact lenses was 1.1×10³ CFU ml⁻¹ or equivalent to 2 CFU per reaction. In conclusion, the UDG-LAMP-AuNP assay was rapid, simple, specific and was effective for the identification of P. aeruginosa in contaminated samples.

Adhesion of Acanthamoeba on Cosmetic Contact Lenses

BACKGROUND

This study aimed to evaluate the adhesion of Acanthamoeba trophozoites on cosmetic contact lenses (CLs) with and without CL care multipurpose solution (MPS) treatment.

METHODS

Acanthamoeba lugdunensis L3a trophozoites were inoculated onto disks trimmed from CLs: 1-day Acuvue moist, 1-day Acuvue define, Acuvue 2, and Acuvue 2 define. After 18-hour inoculation, the number of adherent trophozoites was counted under phase contrast microscopy. The effects of MPS, Opti-Free Express, soaking CLs for 6 hours, on Acanthamoeba adhesion were analyzed. Scanning electron microscopic examination was performed for assessment of Acanthamoeba attached on the lens surface.

RESULTS

Acanthamoeba trophozoites showed greater adhesion to cosmetic CL (P = 0.017 for 1-day CL and P = 0.009 for 2-week CL) although there was no significant difference between the types of cosmetic CL. On all lenses, the number of adherent Acanthamoeba was significantly reduced after treatment with MPS (P < 0.001 for 1-day Acuvue moist, P = 0.046 for 1-day Acuvue define, P < 0.001 for Acuvue 2, and P = 0.015 for Acuvue 2 define), but there was still significant difference between conventional and cosmetic CLs (P = 0.003 for 1-day CL and P < 0.001 for 2-week CL, respectively). More attachment of Acanthamoeba was observed on colored area and the acanthopodia of Acanthamoeba was placed on the rough surface of colored area.

CONCLUSION

Acanthamoeba showed a greater affinity for cosmetic CL and mostly attached on colored area. Although MPS that contained myristamidopropyl dimethylamine reduced the adhesion rate, there was a significant difference between conventional and cosmetic CLs.

Identification of Microorganisms Isolated From Counterfeit and Unapproved Decorative Contact Lenses

All contact lenses (corrective/noncorrective) are considered Class II or Class III medical devices under the Federal Food, Drug, and Cosmetic Act, which also states that contact lenses can only be obtained with a prescription. The Forensic Chemistry Center of the US Food & Drug Administration has examined over 300 decorative, noncorrective contact lenses obtained without a prescription. Our observations indicate that 60% of the counterfeit lenses and 27% of the unapproved lenses examined were positive for microbial contamination. Twenty-nine different brands of noncorrective contact lenses were examined, and 48% of them had at least one sample positive for microbial contamination. Each microorganism was further identified using DNA sequencing. Contaminated contact lenses are associated with numerous health risks, including ocular infections and conjunctivitis leading to permanent visual impairment or blindness. These results support the contention that acquiring contact lenses without a prescription is a considerable threat to consumer health and safety.

Development of ciprofloxacin-loaded contact lenses using fluorous chemistry

In this work, we developed a simple method to load drugs into commercially available contact lenses utilizing fluorous chemistry. We demonstrated this method using model compounds including fluorous-tagged fluorescein and antibiotic ciprofloxacin. We showed that fluorous interactions facilitated the loading of model molecules into fluorocarbon-containing contact lenses, and that the release profiles exhibited sustained release. Contact lenses loaded with fluorous-tagged ciprofloxacin exhibited antimicrobial activity against Pseudomonas aeruginosa in vitro, while no cytotoxicity towards human corneal epithelial cells was observed. To mimic the tear turnover, we designed a porcine eye infection model under flow conditions. Significantly, the modified lenses also exhibited antimicrobial efficacy against Pseudomonas aeruginosa in the ex vivo infection model. Overall, utilizing fluorous chemistry, we can construct a drug delivery system that exhibits high drug loading capacity, sustained drug release, and robust biological activity.

Scanning Electron Microscopy Findings With Energy-Dispersive X-ray Investigations of Cosmetically Tinted Contact Lenses

To investigate the surfaces and principal elements of the colorants of cosmetically tinted contact lenses (Cos-CLs).

Effect of the pigment-free optical zone diameter of decorative tinted soft contact lenses on visual function

AIMS

We investigated changes in visual function after wearing decorative tinted soft contact lenses with different pigment-free optical zone diameters.

METHODS

A prospective study was performed in 30 eyes of 30 healthy volunteers. Best-corrected visual acuity (BCVA), ocular higher-order aberrations (HOAs), modulation transfer function (MTF), Strehl ratio and contrast sensitivity were evaluated after wearing clear lens and tinted lenses with different pigment-free optical zone diameters (4, 5 and 6 mm).

RESULTS

BCVA decreased from 0.00 logMAR after wearing a clear lens to 0.04±0.04 logMAR after wearing 4 mm optical zone lens (p<0.001). As the optical zone diameter decreased, ocular aberrations were induced. Total HOAs, coma aberration and secondary astigmatism showed significant difference between clear lens and 5 or 4 mm optical zone lenses (p<0.050). Spherical aberration and trefoil showed significant difference between clear lens and 4 mm optical zone lens (p<0.050). The results for Strehl ratio revealed poorer optical quality for both 5 and 4 mm optical zone lens (both p=0.002). The entire ocular MTF was significantly different, corresponding to the decreased optical zone diameter. The HOAs showed a correlation with the blocked pupil covered by the tinted part (r=0.435, p<0.001). In photopic and mesopic conditions, the contrast sensitivity decreased significantly with the reduced pigment-free optical zone diameters.

CONCLUSION

Decorative tinted contact lenses significantly increased ocular aberrations and decreased optical quality and contrast sensitivity, as the pigment-free optical zone diameter decreased. Therefore, consumers of tinted lenses should be informed about the possible disturbance in visual function.

TRIAL REGISTRATION NUMBER

NCT02537275.