Epidemiology of contact lens-induced infiltrates: an updated review

The Impact of Comfort Eluting Agents and Replacement Frequency on Enhancing Contact Lens Performance

This review explores the development and clinical implications of soft contact lenses designed to elute comfort agents, emphasizing their role in enhancing user experience and ocular health. As discomfort remains one of the primary reasons for discontinuation of lens wear, this concept aims to address this challenge by gradually releasing these agents over their period of use. This review also explores the effectiveness, safety, and user satisfaction associated with frequent replacement schedules of these lenses. Clinical trials demonstrate that lenses with eluting comfort agents significantly reduce dryness and irritation, leading to improved wear-time and overall comfort. The findings suggest that frequent replacement not only enhances lens hygiene but also maximizes the therapeutic benefits of the eluted agents, promoting a healthier ocular environment. The implications for practice highlight a shift towards more patient-centered approaches in contact lens design and management, aiming to improve adherence and satisfaction among users. This research paves the way for future innovations in contact lens technology, focusing on personalized solutions that cater to individual comfort needs.

Biocidal Efficacies of Contact Lens Disinfecting Solutions Against Gram-Negative Organisms Associated with Lens Case-Associated Corneal Infiltrative Events

Background

Multi-purpose solutions (MPSs) are designed to clean, disinfect, and condition contact lenses (CLs) to reduce the risk of contact lens-related adverse events, such as corneal infiltrative events (CIEs) that are often associated with opportunistic bacteria from contaminated CLs or CL cases. This study evaluated the disinfection efficacies of six MPSs and one hydrogen peroxide solution (HPS) comparator against three lens case CIE-associated organisms.

Methods

The solutions in this study were evaluated against commonly isolated Gram-negative lens case CIE-associated organisms in the presence of organic soil, according to the International Organization for Standardization 14729 (ISO) stand-alone test protocol. Challenge organisms (Achromobacter xylosoxidans, Delftia acidovorans and Stenotrophomonas maltophilia) were inoculated into the solutions in conical tubes (for MPS) or CL cases (for HPS), and plated for organism quantification after the manufacturer-recommended minimum soak times. Disinfection efficacy for each solution is presented as mean log reduction per organism and overall disinfection across three challenge organisms (post hoc analysis).

Results

Stand-alone testing against the challenge organisms demonstrated that PAPB/Alexidine/PQ-1, Alexidine/PQ-1, and PHMB-containing MPSs, as well as HPS were significantly superior versus MAPD/PQ-1-based MPSs (all p < 0.05). While there is no ISO criteria for reduction of CIE-associated organisms, all solutions containing PAPB/Alexidine/PQ-1, Alexidine/PQ-1, and PHMB, as well as HPS, achieved greater than 3-log reductions (the primary criteria for ISO 14729 compendial bacterial organisms) for all challenge organisms. The three MAPD/PQ-1-containing MPSs achieved between 0.6 and 1.7 log reduction across the MPS/test organism combinations.

Conclusion

The PAPB, PHMB, and Alexidine-based MPSs demonstrated significantly greater disinfection efficacy than MAPD-based MPSs, and comparable disinfection efficacy to HPS, against commonly isolated Gram-negative CL case CIE-associated organisms.

Contact lenses as a potential vehicle of Candida transmission

PURPOSE

Contact lenses can be contaminated with various microorganisms, including pathogenic yeasts of the genus Candida, which are known for their ability to adhere to abiotic surfaces, including plastic materials used for various medical purposes. Microbial contamination of the lenses can lead to infection of the wearer's eyes. The purpose of this study was to simulate the contamination of contact lenses with C. albicans and C. parapsilosis, analyze the interaction of the microorganisms with the lens material, and optimize the protocol for PCR-based analysis of the microbial agents responsible for lens contamination.

METHODS

Hilafilcon lenses were exposed to C. albicans and C. parapsilosis cultures, washed, and examined for their ability to further spread the contamination. Scanning electron microscopy was used to analyze the attachment of yeast cells to the lenses. Infrared spectroscopy was used to examine the potential changes in the lens material due to Candida contamination. The protocol for DNA isolation from contaminated lenses was established to enable PCR analysis of microbes attached to the lenses.

RESULTS

Hilafilcon lenses contaminated with Candida were able to spread the contamination even after washing with saline or with a commercial cleaning solution. In the present experimental settings, the yeasts did not grow into the lenses but began to form biofilms on the surface. However, the ability of the lenses to retain water was altered. The PCR-based protocol could be used to help identify the type of contamination of contact lenses.

CONCLUSION

Once contaminated with Candida albicans or Candida parapsilosis, Hilafilcon contact lenses are difficult to clean. Yeasts began to form biofilms on lens surfaces.

Evaluating the in vitro wettability and coefficient of friction of a novel and contemporary reusable silicone hydrogel contact lens materials using an in vitro blink model

PURPOSE

To evaluate the in vitro wettability and coefficient of friction of a novel amphiphilic polymeric surfactant (APS), poly(oxyethylene)-co-poly(oxybutylene) (PEO-PBO) releasing silicone hydrogel (SiHy) contact lens material (serafilcon A), compared to other reusable SiHy lens materials.

METHODS

The release of fluorescently-labelled nitrobenzoxadiazole (NBD)-PEO-PBO was evaluated from serafilcon A over 7 days in a vial. The wettability and coefficient of friction of serafilcon A and three contemporary SiHy contact lens materials (senofilcon A; samfilcon A; comfilcon A) were evaluated using an in vitro blink model over their recommended wearing period; t = 0, 1, 7, 14 days for all lens types and t = 30 days for samfilcon A and comfilcon A (n = 4). Sessile drop contact angles were determined and in vitro non-invasive keratographic break-up time (NIKBUT) measurements were assessed on a blink model via the OCULUS Keratograph 5 M. The coefficient of friction was measured using a nano tribometer.

RESULTS

The relative fluorescence of NBD-PEO-PBO decreased in serafilcon A by approximately 18 % after 7 days. The amount of NBD-PEO-PBO released on day 7 was 50 % less than the amount released on day 1 (6.5±1.0 vs 3.4±0.5 µg/lens). The reduction in PEO-PBO in the lens also coincided with an increase in contact angles for serafilcon A after 7 days (p < 0.05), although there were no changes in NIKBUT or coefficient of friction (p > 0.05). The other contact lens materials had stable contact angles and NIKBUT over their recommended wearing period (p > 0.05), with the exception of samfilcon A, which had an increase in contact angle after 14 days as compared to t = 0 (p < 0.05). Senofilcon A and samfilcon A also showed an increase in coefficient of friction at 14 and 30 days, respectively, compared to their blister pack values (p < 0.05).

CONCLUSION

The results indicate that serafilcon A gradually depletes its reserve of PEO-PBO over 1 week, but this decrease did not significantly change the lens performance in vitro during this time frame.

Impact of COVID-19 pandemic on a world-wide private ophthalmic practice

Purpose

To assess the impact of the COVID-19 pandemic on a worldwide private ophthalmic practice.

Design

In this retrospective study, we reviewed the 2020 monthly outpatient and surgical volume of refractive, cataract, and retinal disease in Aier Eye clinics/hospitals of different regions, including the United States, Germany, Spain, Italy, and six major cities in China (Wuhan, Beijing, Shanghai, Shenyang, Urumqi and Yili). All of these data were compared to those of the same period of 2019.

Results

Overall, during the early stage (2020 January to 2020 April) of COVID-19 outbreak, the outpatient and surgical volume of three main type ocular diseases (refractive, cataract and retinal surgery) showed an obvious reduction and reached the bottom in February in China. The data from the United States, Germany, Spain and Italy revealed the same trend, but the visit count nadir occurred until April, which is consistent with the spread trend of COVID-19 disease around the world. The average change rates of surgery volume (refractive, cataract and retinal surgery) in Chinese centers are 5.59%, -26.38%, 11.76%. The change rates of refractive (REF) and cataract volumes (CAT) in the United States are -8.62% and -10.58%, in Germany are -13.71% and -20.49%, in Spain are 15.35% and 27.97%, in Italy are 30.43% and -22.64%. In addition, the optometry outpatient volumes keep going up since May, with an average increasing rate of 21.18%, ranging from 7.43% to 49.51%.

Conclusion

In conclusion, in this global chain of eye care units, the visit volumes of cataract, retinal and refractive changed significantly with the spread of COVID-19 pandemic. Among them, cataract surgery was the most affected sub-specialty, and refractive surgery and optometry volumes showed a potential growth in the near future. Therefore, medical institutions should make corresponding adjustments to the disease diagnosis and treatment strategies.

Corneal ring infiltrate- far more than Acanthamoeba keratitis: review of pathophysiology, morphology, differential diagnosis and management

OBJECTIVE

Ring infiltrates usually accompany numerous infectious and sterile ocular disorders. Nevertheless, systemic conditions, drugs toxicity and contact lens wear may present with corneal ring infiltrate in substantial part. Considering its detrimental effect on vision, detailed knowledge on etiology, pathophysiology, differential diagnosis, and management should be considered essential for every ophthalmologist.

METHODS

The PUBMED database was searched for "corneal ring infiltrate" and "ring infiltrate" phrases, "sterile corneal infiltrate" and "corneal infiltrate". We analyzed articles written in English on risk factors, pathophysiology, clinical manifestation, morphological features, ancillary tests (anterior-segment optical coherence tomography, corneal scraping, in vivo confocal microscopy), differential diagnosis and management of corneal ring infiltrate.

RESULTS

Available literature depicts multifactorial origin of corneal ring infiltrate. Dual immunological pathophysiology, involving both antibodies-dependent and -independent complement activation, is underlined. Furthermore, we found that the worldwide most prevalent among non-infectious and infectious ring infiltrates are ring infiltrates related to contact-lens wear and bacterial keratitis respectively. Despite low incidence of Acanthamoeba keratitis, it manifests with corneal ring infiltrate with the highest proportion of the affected patients (one third). However, similar ring infiltrate might appear as a first sign of general diseases manifestation and require targeted treatment. Every corneal ring infiltrate with compromised epithelium should be scraped and treat as an infectious infiltrate until not proven otherwise. Of note, microbiological ulcer might also lead to immunological ring and therefore require anti-inflammatory treatment.

CONCLUSION

Corneal ring infiltrate might be triggered not only by ocular infectious and non-infectious factors, but also by systemic conditions. Clinical assessment is crucial for empirical diagnosis. Furthermore, treatment is targeted towards the underlying condition but should begin with anti-infectious regimen until not proven otherwise.

Conjunctival microbiome changes in soft contact lens users and contact lens discomfort patients

INTRODUCTION

Contact lens discomfort (CLD) acts as a challenging problem, and the associated conjunctival microbiome changes were unclear.

MATERIAL AND METHODS

Conjunctival sac swab samples were collected from 12 eyes of nonwearers (NW), 12 eyes of asymptomatic contact lens (ACL) wearers, and 11 eyes of CLD. The V3-V4 region of the 16S rRNA gene sequencing was used to investigate differences among three groups.

RESULTS

No differences in alpha diversity were observed among the three groups. The beta diversity showed a distinct microbiome composition between ACL and CLD group (P = 0.018) with principal coordinate analysis. The relative abundance of Firmicutes was significantly higher in CLD (48.18%) than in ACL (13.21%) group (P = 0.018). The abundance of Bacillus in patients with ACL (0.05%) or with CLD (0.02%) were significantly lower than that in the NW (1.27%) group (P = 0.024, 0.028, respectively). Moreover, the abundance of Firmicutes was positively correlated with the OSDI scores in CLD patients (r = 0.817, P < 0. 01, Spearman).

DISCUSSIONS

Patients with CLD have various degrees of bacterial microbiota imbalance in the conjunctival sac, compared with NW and ACL groups.

CONCLUSION

Firmicutes may serve as a potential biomarker for the CLD patients.

Comparative Evaluation of Pseudomonas aeruginosa Adhesion to a Poly-(2-Methacryloyloxyethyl Phosphorylcholine)-Modified Silicone Hydrogel Contact Lens

Pseudomonas aeruginosa is the most common causative agent associated with microbial keratitis. During contact lens wear, pathogens may be introduced into the ocular environment, which might cause adverse events. Lehfilcon A is a recently developed contact lens with a water gradient surface composed of polymeric 2-methacryloyloxyethyl phosphorylcholine (MPC). MPC is re-ported to impart anti-biofouling properties onto modified substrates. Therefore, in this in vitro experimental study, we tested the capability of lehfilcon A to resist adhesion by P. aeruginosa. Quantitative bacterial adhesion assays using five strains of P. aeruginosa were conducted to compare the adherence properties of lehfilcon A to five currently marketed silicone hydrogel (SiHy) contact lenses (comfilcon A, fanfilcon A, senofilcon A, senofilcon C, and samfilcon A). Compared to lehfilcon A, we observed 26.7 ± 8.8 times (p = 0.0028) more P. aeruginosa binding to comfilcon A, 30.0 ± 10.8 times (p = 0.0038) more binding to fanfilcon A, 18.2 ± 6.2 times (p = 0.0034) more binding to senofilcon A, 13.6 ± 3.9 times (p = 0.0019) more binding to senofilcon C, and 29.5 ± 11.8 times (p = 0.0057) more binding to samfilcon A. These results demonstrate that, for various strains of P. aeruginosa, lehfilcon A reduces bacterial adhesion compared to other contact lens materials.

Examining daily disposable soft contact lens wearers' attitudes and beliefs using the Health Belief Model

PURPOSE

To use the Health Belief Model (HBM) to understand daily disposable (DD) soft contact lens (SCL) wearers' attitudes and beliefs.

METHODS

A convenience sample of DD SCL wearers (18-33 years) was enrolled at two sites. Participants were queried about demographics, SCL wear and HBM constructs. Rasch analysis was used to assess the psychometric properties of the survey instrument and generate scores for each HBM subscale. ANOVA was used to determine relationships among HBM constructs, subject demographics and DD SCL-related health behaviours.

RESULTS

One hundred people participated (mean ± SD), age = 24.2 ± 3.9 years, 76% female. Thirty-seven percent reported sleeping in DD SCLs and 25% reported reusing DD SCLs. Self-report of reusing DD SCLs was associated with scores on the benefits: reuse (p = 0.02) and barriers (p = 0.007) subscales, and sleeping in lenses was associated with scores on the susceptibility (p = 0.05), benefits: wear behaviours (p = 0.006) and barriers (p = 0.01) subscales. Rasch analysis showed some subscales demonstrated multidimensionality.

CONCLUSIONS

Selected health belief constructs were associated with DD SCL-related behaviours including reusing and overnight wear. Increased understanding of SCL attitudes and beliefs could inform patient education and interventions to decrease risks associated with improper SCL wear.

Akanthamöbenkeratitiden in Jugendlichen mit Orthokeratologielinsen

Hintergrund

Durch die rasant steigende Prävalenz der Myopie kommen zunehmend progressionshemmende Verfahren zum Einsatz. Auch die Orthokeratologie, basierend auf dem Ansatz des peripheren Defokus, erlebt eine Renaissance. Die gefährlichste Nebenwirkung der Orthokeratologie ist die mikrobielle Keratitis, unter ihnen eine Infektion mit Akanthamöben, welche oft spät diagnostiziert wird und potenziell visusbedrohende Verläufe nehmen kann.

Material und Methode

Diese Fallserie beschreibt die Diagnosefindung und den Behandlungsverlauf der Akanthamöbenkeratitis bei jugendlichen Patient*innen mit Orthokeratologielinsen, welche an der Spezialambulanz für Hornhauterkrankungen der Universitätsklinik für Augenheilkunde und Optometrie an der Medizinischen Universität Wien im Zeitraum eines Jahres betreut wurden.

Resultate

Vier Fälle von orthokeratologieassoziierten Akanthamöbenkeratitiden wurden mittels kornealer Konfokalmikroskopie und mikrobiologischer Verfahren zwischen August 2021 und August 2022 diagnostiziert. Die intensive Stufentherapie umfasste ein hochdosiertes, topisches Biguanid in Kombination mit einem Diamidinderivat, welches in der ersten Therapiephase mit antibakteriellen und antifungalen Augentropfen kombiniert wurde. Der Therapieverlauf und -erfolg wurde mittels der kornealen Konfokalmikroskopie beurteilt, und entsprechend angepasst.

Schlussfolgerung

Die Akanthamöbenkeratitis ist ein ernst zu nehmendes Erkrankungsbild im Zusammenhang mit Orthokeratologielinsen. Im Hinblick auf das Alter der Zielgruppe dieser myopieprogressionshemmenden Therapie sollte, neben sorgfältiger Patientenselektion, auf eine detaillierte Schulung der Kontaktlinsenträger in der Handhabung der Linsen sowie auf ein erhöhtes Bewusstsein für Zeichen einer frühen Infektion besonderes Augenmerk gelegt werden. Da alternative Möglichkeiten zur Myopieprophylaxe bestehen, müssen PatentInnen auf das Risiko der jeweiligen Methode hingewiesen werden.

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.

Topical Review: Contact Lens Eye Health and Safety Considerations in Government Policy Development

SIGNIFICANCE

As new federal or state policies are introduced in the United States to shape the evolving contact lens market, it has never been more important to amplify the importance of patient health and safety during contact lens wear and promote the value of the eye care professional-patient relationship.Within the United States, contact lenses are regulated by the Food and Drug Administration as class II or III medical devices that require additional regulatory and professional oversight to keep consumers safe. The contact lens market and broader eye health landscape are rapidly changing. Recently, the U.S. Federal Trade Commission finalized its 10-year review of the Contact Lens Rule, implementing new policies that will shape the contact lens market in the United States for years to come. The purpose of this clinical perspective was to compile and review key data regarding contact lens-related adverse events, including their economic impact on the health care system, to inform government policy development. Although contact lenses provide many benefits to the wearer, a variety of complications can occur ranging from asymptomatic events or mild discomfort to severe sight-threatening adverse events such as microbial keratitis. Patients who do not routinely visit their eye care professional or do not receive the lenses prescribed to them are at a greater risk of contact lens-related adverse events. Nearly 1 million people in the United States experience ocular infections or inflammation annually, resulting in significant health care costs. The economic burden of contact lens-related microbial keratitis in the United States has been estimated to be approximately $175 million annually. The importance of eye care professional oversight of contact lens wear cannot be emphasized enough to key stakeholders, including lawmakers, government regulators, contact lens manufacturers and distributors, and the broader eye health community.

Long Day Wear Experience with Water Surface Daily Disposable Contact Lenses

OBJECTIVE

The purpose of this study was to assess the wear experience of silicone hydrogel daily disposable contact lenses with water surface technology over a long day of lens wear.

METHODS

Thirty-five soft contact lens wearers were refit with the daily disposable study lenses and participants scored their initial impressions of comfort, vision and satisfaction using a visual analog scale (VAS). Participants used their smart phones to complete surveys of comfort and vision on a scale of 1-10 at 10, 12, 14, and 16 hours of lens wear on 5 weeknights. A participant score for each time point was calculated by averaging the evening responses. End of study VAS surveys of symptoms were also completed.

RESULTS

Median (Interquartile Range) VAS initial impression scores were 99.00 (12.00) for quality of vision, 98.00 (16.00) for comfort, and 100.00 (13.00) for satisfaction. The end of study surveys found end of day median VAS scores of 87.00 (19.00) for end of day quality of vision and 75.00 (24.50) for end of day comfort. The median score for overall quality of vision was 93.00 (14.00) and for overall comfort was 93.00 (16.50). The median score for end of day dryness was 37.00 (55.00) and overall dryness was 13.00 (34.00).

CONCLUSION

The daily disposable lenses with water surface treatment used in this study maintained high median scores for comfort and quality of vision for up to 16 hours of wear.

In Vivo Confocal Microscopy in Different Types of Dry Eye and Meibomian Gland Dysfunction

In vivo confocal microscopy (IVCM) imaging is increasingly popular in ocular surface disease diagnosis and management. We conducted a systematic review to update the use of IVCM in the diagnosis and treatment of dry eye and meibomian gland dysfunction (MGD). A literature review was conducted on IVCM studies in MGD, dry eye disease, systemic disease causing dry eye, dry eye in glaucoma patients, contact lens-associated ocular conditions, graft-versus-host disease, and Sjogren’s syndrome-related dry eye. The articles were identified through PubMed and a total number of 63 eligible publications were analyzed in detail. All primary research studies on confocal microscopy on dry eye and related conditions from 2017 onwards were included. The reports were reviewed for their contribution to the existing literature as well as potential biases and drawbacks. Despite limitations such as small field of view, lack of population-based norms, and lack of standardization of image acquisition, interpretation, and quantification, IVCM is useful as a complementary technique for clinical diagnosis in various ocular surface disorders related to dry eye. With advances in hardware and software in the near future, it has the potential for further practical impact.

Clinical and molecular diagnosis of Acanthamoeba keratitis in contact lens wearers in southern Brazil reveals the presence of an endosymbiont

Acanthamoeba keratitis (AK) is an infection that is mostly observed in contact lens wearers. It is often misdiagnosed causing delays in the administration of the correct treatment. The aim of this study was to report the outcome of clinical and molecular diagnosis of AK cases during the summer of 2019 in the southern region of Brazil. Three suspected cases of AK were discovered after an ophthalmic examination at a public hospital in the city of Porto Alegre. These cases were then confirmed through laboratory diagnosis (cell culture and molecular analysis by PCR and sequencing). In each of the three clinical sample cell cultures of corneal scraping and molecular analysis confirmed the presence of Acanthamoeba spp., all belonging to the morphological group II and to the genotype T4, which is the most common genotype associated with AK. In addition, Acanthamoeba spp. isolated from one of the clinical samples was found to harbor the Candidatus Paracaedibacter acanthamoeba, a bacterial endosymbiont. The presence of Ca. Paracaedibacter acanthamoeba in clinical isolates requires further research to reveal its possible role in the pathogenicity of Acanthamoeba infections.

Wear Experience of a Water Surface Daily Disposable Contact Lens in Existing Silicone Hydrogel Planned Replacement Lens Wearers

PURPOSE

The health benefits of silicone hydrogel lens materials and a daily replacement modality have been demonstrated in previous studies; however, existing planned replacement lens wearers may resist changing to a new lens replacement schedule. The purpose of this study is to evaluate the wear experience of satisfied planned replacement silicone hydrogel wearers when refit into a silicone hydrogel daily disposable lens.

PATIENTS AND METHODS

In this open-label, non-comparison study, satisfied wearers of two week planned replacement contact lenses were evaluated for inclusion criteria and refit with optimized prescriptions in their habitual lenses. At a follow-up visit one week later, participants were refit with the study daily disposable lenses and completed visual analog scale (VAS) surveys of initial quality of vision, comfort, and satisfaction. Participants returned for a final visit after two weeks of wearing the study daily disposable lenses. At the final visit, VAS surveys for both overall and end of day (EOD) vision, comfort, and dryness were completed. Overall median and interquartile range (IQR) were assessed for all surveys in the study.

RESULTS

Thirty individuals completed the study (29.1 ± 7.8 years old; 19 female). Median (IQR) results for the initial impression VAS surveys were 92.50(11.75) for quality of vision, 92.50(18.00) for comfort, and 93.00(18.00) for satisfaction. Final VAS survey results revealed median scores of 87.50(25.00) for EOD quality of vision and 82.50(51.25) for EOD comfort. The median overall quality of vision was 91.00(17.00) and overall comfort was 93.00(28.50). Median (IQR) overall dryness was 28.50(49.00) and median EOD dryness was 30.50(64.25).

CONCLUSION

The findings of this study suggest that providers can successfully refit satisfied wearers of early generation silicone hydrogel planned replacement lenses into a new generation silicone hydrogel daily disposable lens while maintaining satisfaction.

Addressing common myths and misconceptions in soft contact lens practice

Advances in contact lens technology over the past 50 years since the commercialisation of the first soft lenses in 1971 have been incredible, with significant changes in contact lens materials, frequency of replacement, care systems and lens designs occurring. However, despite the widespread availability of contact lenses, penetration rates for those who need vision correction remain in the low single digits and many practitioners seem to hold on to concepts around the potential value of contact lenses that appear based in the dim and distant past and are certainly no longer valid today. This review addresses 10 common 'myths and misconceptions' around soft contact lenses using an evidence-based approach that can hopefully dispel some of these incorrect assumptions.

All soft contact lenses are not created equal

Soft contact lenses that have been prescribed by eye care practitioners are sometimes substituted for alternative lenses by unqualified, unregulated and sometimes even fully regulated lens suppliers, in the mistaken belief that there is essentially no difference between different soft lens types. This review considers the implications of inappropriately substituting soft contact lens types in terms of (a) lens properties: surface treatment, internal wetting agents, material, total diameter, back optic zone radius, thickness, edge profile, back surface design, optical design, power, colour (tint) and ultraviolet protection; and (b) lens usage: wearing modality (daily versus overnight wear) and replacement frequency. Potential aspects of patient dissatisfaction and adverse events when prescribed soft lenses are substituted for lenses with different properties or intended usage are considered. Substitution of 15 of the 16 lens properties considered (i.e. except for back surface design) was found to be related to at least one - and as many as six - potential sources of patient dissatisfaction and adverse ocular events. Contact lens are medical devices which are prescribed and fitted; they should never be substituted for another lens type in the absence of a new prescription further to a full finalised fitting, for the simple reason that all soft contact lenses are not created equal. A substituted lens may have properties that results in undesirable consequences in respect of vision, ocular health, comfort and cosmetic appearance, and may be incompatible with the lifestyle of the patient.

Complications Leading to Keratoplasty among Contact Lens Users and LASIK Patients: A 10-Year Cross-Sectional Analysis

Purpose

To determine the incidence and outcomes in patients who underwent penetrating keratoplasty (PK) resulting from complications related to contact lens (CL) use and laser in situ keratomileusis (LASIK) in a metropolitan area of the United States.

Methods

Population data was obtained from the United States Census Bureau and the Centers for Disease Control. A retrospective, cross-sectional chart review was performed on all patients who underwent keratoplasty in a specific metropolitan geographic area over a ten-year period. The main outcome was best-corrected visual acuity (BCVA) at 2 years in patients who underwent PK secondary to complications related to CL use and LASIK. The secondary outcome was the relative risk of undergoing PK secondary to a complication related to CL use versus LASIK.

Results

The study's geographic area had 46,545 CL users in one or both eyes during any given year and 10,285 patients who underwent LASIK in one or both eyes during the study interval. There were 24 CL users (0.52 per 1,000) and 3 post-LASIK patients (0.29 per 1,000) who underwent PK secondary to complications during the study interval (OR 1.77 [0.53-5.87, 95% CI]; p=0.35). BCVA at 2 years was 1.45 [1.0-1.90] logMAR (20/564 Snellen) in the CL using cohort and 0.07 [-1.19-1.33] logMAR (20/23 Snellen) in post-LASIK cohort following PK (p=0.04).

Conclusions

Patients who underwent PK secondary to complications related to CL use had worse visual outcomes at 2 years compared to those related to LASIK. Complications leading to PK were rare in both cohorts, but the incidence of undergoing PK secondary to CL use trended higher than LASIK.

A web-based survey of contact lens-related adverse events among the Japanese female population

To assess the safety of cosmetic contact lenses and to identify other factors of contact lens (CL)-related complications for Japanese females. A web-based, cross-sectional, observational survey of complications related to CL use was performed. The frequencies of complications were compared between transparent and cosmetic CLs. Besides lens pigmentation, age, replacement schedule, total experience, daily wear time, location of purchase, stacking of CLs, CL exchange with friends, compliance to hygiene procedure, replacement of CLs at intervals longer than recommended, and CL wear overnight were considered as risk factors. Logistic regression analyses were performed to calculate the odds ratios. A total of 3803 Japanese females were analyzed. The frequency of adverse events was 33.4% (95%CI 31.3-35.4%) and 35.7% (95%CI 33.5-38.0%) for transparent and cosmetic CLs, respectively. In a multivariate model, statistically significant factors associated with complications included the following: quarterly schedule lenses, replacement at intervals longer than recommended, compliance to hygiene procedure, overnight wearing, purchase at physical shops and on the internet, and longer daily wearing time. Most of the risk-increasing behaviors are preventable. The role of public health ophthalmology is to increase awareness and to improve CL use behaviors.

Effect of Antimicrobial Contact Lenses on Corneal Infiltrative Events: A Randomized Clinical Trial

Purpose

To determine whether Mel4-coated antimicrobial contact lenses (MACLs) can reduce the incidence of corneal infiltrative events (CIEs) during extended wear.

Methods

A prospective, randomized, double-masked, single-center, contralateral, extended contact lens wear clinical trial was conducted with 176 subjects. Each participant was randomly assigned to wear a MACL in one eye and an uncoated control contact lens in the contralateral eye or an extended-wear biweekly disposable modality for 3 months. The main outcome measures were the incidence of CIEs per 100 eye-months, identification of the microbial types colonizing the contact lenses or eyes at the time of the CIEs, and their susceptibility to Mel4.

Results

Nine participants (5.1%) experienced unilateral CIEs; six participants had contact lens acute red eye, and three participants had infiltrative keratitis. The incidence rate for CIEs (0.4 events per 100 participant months; 1.7%) in the Mel4-coated lenses (test) was 69% less than that of the control lenses (1.3 events per 100 participant months; 3.4%; P = 0.29). All Gram-negative bacteria isolated from lenses and lids of participants with CIEs (Citrobacter diversus, Acinetobacter haemolyticus, and Acinetobacter lwoffii) were susceptible to Mel4 peptide; minimum inhibitory concentrations ranged from 15.6 to 62.5 µg/mL. Reduction of adhesion of these bacteria by Mel4-coated lenses ranged from 2.1 to 2.2 log10 colony-forming units/lens.

Conclusions

MACLs had the capacity to reduce CIEs by at least 50% compared with uncoated control lenses during extended wear over 3 months; however, due to the relatively low rates of CIEs, the reduction was not statistically different compared with control lenses.

Translational Relevance

This study provides evidence that antimicrobial contact lenses have the potential to reduce the incidence of corneal infiltrative events during extended wear.

Uptake and Release of a Multipurpose Solution Biocide (MAP-D) From Hydrogel and Silicone Hydrogel Contact Lenses Using a Radiolabel Methodology

PURPOSE

The purpose of this study was to evaluate the uptake and release of radiolabelled myristamidopropyl dimethylamine (MAP-D) on reusable daily wear contact lenses (CLs) over 7 days.

METHODS

Three silicone hydrogel (SH) CL materials (lotrafilcon B, balafilcon A, senofilcon A) and two conventional hydrogel (CH) materials (etafilcon A, omafilcon A) were tested. A short-term (experiment 1, N=4) and a longer-term (experiment 2, N=3) study was conducted. In experiment 1, the CLs were incubated in 2 mL of phosphate buffered solution (PBS) containing 14C MAP-D (5 μg/mL) for 8 hrs. The release of 14C MAP-D was measured at t=0.25, 0.5, 1, 2, 4, 8, and 24 hr in PBS. In experiment 2, the CLs were incubated in the 14C MAP-D solution for 8 hrs followed by a 16-hr release in PBS. This cycle was repeated daily for 7 days. At the end of both experiments, lenses were extracted to determine the total uptake of MAP-D. The radioactivity was measured using a beta scintillation counter.

RESULTS

In experiment 1, all three SH lenses sorbed similar amounts of MAP-D (P=0.99), all of which were higher than the two CH materials (P<0.01). However, the CH materials released a greater amount of MAP-D than the SH materials (P<0.01). In experiment 2, the uptake of MAP-D in SH materials increased over 7 days, whereas the amount of MAP-D remained constant in the CH materials (P=0.99). Similar to experiment 1, the CH lenses released more MAP-D than SH lenses after 7 days (P<0.01).

CONCLUSION

The SH materials absorbed greater amounts of MAP-D compared to CH materials. However, the CH materials released the greatest amount of MAP-D. Radioactive labelling of MAP-D offers a highly sensitive method of assessing the uptake and release profiles of biocides to CL materials.

Current understanding and therapeutic management of contact lens associated sterile corneal infiltrates and microbial keratitis

Contact lenses are widely prescribed in clinical practice with multiple applications and advantages. However, contact lenses can be associated with various complications which range from innocuous to severe. Clinicians thus not only need to possess the ability to prescribe the most appropriate contact lenses for each individual patient but also be able to recognise and manage any associated complications. This review examines the existing literature on the management of corneal infiltrative events associated with soft contact lenses, including microbial keratitis, particularly in the context of practising in Australia. The definitions and diagnosis of corneal infiltrative events, as well as the current understanding of their aetiologies, will be explored. The various aspects of a successful management will be discussed, including the applications of therapeutic agents such as antimicrobial and anti-inflammatory agents, the role of microbiological investigations, and strategies to improve long-term prognosis. The currently available evidence supporting management options will be presented, highlighting the relative abundance of high-level evidence on management protocols, antimicrobial selection and treatment duration for microbial keratitis; and the relative paucity of studies and trials for sterile corneal infiltrative events, despite this condition being much more commonly encountered in clinical practice.

The impact of patient behaviour and care system compliance on reusable soft contact lens complications

Reusable soft daily wear contact lenses (CLs) remain popular and were fit to just over half of all wearers in the most recent international CL prescribing survey. Unlike daily disposable CLs, reusables require cleaning and disinfecting after every use, along with storage in a CL case. These additional requirements add a number of steps to the daily wear and care routine, increasing the opportunities for CL wearers to exhibit non-compliant behaviour. The impact of non-compliance ranges from poor lens comfort through to potentially sight-threatening infective keratitis. The coronavirus pandemic has refocused the profession on the importance of hand hygiene in particular, and the need for promoting safe CL wear in general. This review summarises typical non-compliant behaviour related to reusable CLs, and examines strategies and opportunities to better support wearers. Patient education has a central role in encouraging compliant behaviour, although patient recall of information is low, and personal belief systems may result in continuation of non-compliant behaviour despite awareness of the risks. CL care solutions are required for the daily disinfection of lenses, however misuse of multipurpose solutions (MPS) and hydrogen peroxide (H₂O₂)-based care systems can challenge their ability to be fully efficacious. Standard efficacy testing is reviewed, with consideration of how well current protocols model real-world use of CL solutions. Although some recommendations are in place for the inclusion of additional variables such as lens cases, CL materials, organic soil and efficacy against Acanthamoeba, opportunity still exists to reevaluate global standards to ensure consistency of testing in all markets. Finally, potential future innovations are discussed which may further support increased safety in reusable lens wear through novel antimicrobial additions to both CL materials and cases.

Novel Approaches to Combat Medical Device-Associated BioFilms

Biofilms are aggregates formed as a protective survival state by microorganisms to adapt to the environment and can be resistant to antimicrobial agents and host immune responses due to chemical or physical diffusion barriers, modified nutrient environments, suppression of the growth rate within biofilms, and the genetic adaptation of cells within biofilms. With the widespread use of medical devices, medical device-associated biofilms continue to pose a serious threat to human health, and these biofilms have become the most important source of nosocomial infections. However, traditional antimicrobial agents cannot completely eliminate medical device-associated biofilms. New strategies for the treatment of these biofilms and targeting biofilm infections are urgently required. Several novel approaches have been developed and identified as effective and promising treatments. In this review, we briefly summarize the challenges associated with the treatment of medical device-associated biofilm infections and highlight the latest promising approaches aimed at preventing or eradicating these biofilms.

Orthokeratology lens-related Acanthamoeba keratitis: case report and analytical review

Acanthamoeba keratitis (AK) is a rare but severe ocular infection with a significant risk of vision loss. Contact lens use is the main risk factor for AK. The orthokeratology (OK) lens, a specially designed contact lens, has been used worldwide as an effective method of myopia control. However, the OK lens is associated with an increased risk of Acanthamoeba infection. Many primary practitioners are concerned about this infection because of its relative rarity, the lack of promising therapeutic medications, and the need for referral. We herein report two cases of AK associated with OK lenses, present a systematic review of such cases, and discuss the possible reasons for the higher incidence rate of this infection in patients who wear OK lenses. We combined the clinical knowledge and skills of corneal specialists and lens experts with the sole objective of addressing these OK lens-related AK cases. We found that the most common risk factors were rinsing the lenses or lens cases with tap water. Prompt and accurate diagnosis along with adequate amoebicidal treatment are essential to ensure desirable outcomes for OK lens wearers who develop AK. Appropriate OK lens parameters and regular checkups are also important.

Contact Lens Wear, Corneal Complications, and U.S. Service Member Readiness

INTRODUCTION

Ulcerative keratitis (UK), or corneal ulcer, is a sight-threatening and readiness-lowering medical condition that begins with a corneal infiltrative event (CIE). Contact lens (CL) wear poses a particular risk for a CIE and therefore is restricted for most active duty service members (SMs). In this study, we explored a large Department of Defense/Veterans Affairs (DoD/VA) database to estimate the prevalence of UK and CIE and their association with CL wear.

MATERIALS AND METHODS

The DoD/VA Defense and Veterans Eye Injury Vision Registry, an initiative of the DoD/VA Vision Center of Excellence, was explored using natural language processing software to search for words and diagnostic codes that might identify cornea injuries and CL wear. The effect of UK and CIE on readiness was explored by evaluating the duration between the first and final visits noted in the database.

RESULTS

A total of 213 UK cases were identified among the 27,402 SMs for whom data were recorded in Defense and Veterans Eye Injury Vision Registry. The odds ratios of UK and CIE being associated with CL wear were 13.34 and 2.20, respectively. A less specific code (superficial corneal injury) was found to be the most commonly used diagnosis in the database, and the odds ratio of CL wearers having that diagnosis was 2.25. CL-wearing patients with corneal disease also required more clinic encounters than those who did not wear CLs.

CONCLUSIONS

This study supports the current restriction on CL wear among nonpilot active duty SMs and quantifies the significantly enhanced risk of developing corneal ulcers posed by that habit.

The COVID-19 pandemic: Important considerations for contact lens practitioners

A novel coronavirus (CoV), the Severe Acute Respiratory Syndrome Coronavirus - 2 (SARS-CoV-2), results in the coronavirus disease 2019 (COVID-19). As information concerning the COVID-19 disease continues to evolve, patients look to their eye care practitioners for accurate eye health guidance. There is currently no evidence to suggest an increased risk of contracting COVID-19 through contact lens (CL) wear compared to spectacle lens wear and no scientific evidence that wearing standard prescription spectacles provides protection against COVID-19 or other viral transmissions. During the pandemic there will potentially be significant changes in access to local eyecare. Thus, it is imperative CL wearers are reminded of the steps they should follow to minimise their risk of complications, to reduce their need to leave isolation and seek care. Management of adverse events should be retained within optometric systems if possible, to minimise the impact on the wider healthcare service, which will be stretched. Optimal CL care behaviours should be the same as those under normal circumstances, which include appropriate hand washing (thoroughly with soap and water) and drying (with paper towels) before both CL application and removal. Daily CL cleaning and correct case care for reusable CL should be followed according to appropriate guidelines, and CL exposure to water must be avoided. Where the availability of local clinical care is restricted, practitioners could consider advising patients to reduce or eliminate sleeping in their CL (where patients have the appropriate knowledge about correct daily care and access to suitable lens-care products) or consider the option of moving patients to daily disposable lenses (where patients have appropriate lens supplies available). Patients should also avoid touching their face, including their eyes, nose and mouth, with unwashed hands and avoid CL wear altogether if unwell (particularly with any cold or flu-like symptoms).

Silicone hydrogel daily disposable benefits: The evidence

Daily disposable (DD) contact lenses first came to the market approximately 25 years ago and eye care professionals (ECPs) started prescribing silicone hydrogel (SiH) contact lenses, primarily for extended or continuous wear, approximately 20 years ago. It has now been over ten years since SiH DD contact lenses have been available, and while SiH materials are routinely prescribed by ECPs for reusable daily wear, hydrogel materials are still frequently selected for the DD modality of contact lens wear. This article reviews the evidence to support the benefits of both a DD modality and SiH materials and how patients' needs may be met with SiH DD contact lenses, with respect to clinical performance, health outcomes, satisfaction, compliance and convenience. Factors which may enable or constrain ECPs from prescribing SiH DD contact lenses, as opposed to hydrogel DD and reusable contact lenses, for more of their patients are discussed with the objective of providing ECPs with a greater understanding of the advantages that can be afforded by prescribing SiH DD contact lenses to both their new and existing contact lens wearers.

Prevention of Pseudomonas aeruginosa Biofilm Formation on Soft Contact Lenses by Allium sativum Fermented Extract (BGE) and Cannabinol Oil Extract (CBD)

Two natural mixtures, Allium sativum fermented extract (BGE) and cannabinol oil extract (CBD), were assessed for their ability to inhibit and remove Pseudomonas aeruginosa biofilms on soft contact lenses in comparison to a multipurpose Soft Contact Lens-care solution present on the Italian market. Pseudomonas aeruginosa (ATCC 9027 strain) and Pseudomonas aeruginosa clinical strains isolated from ocular swabs were tested. Quantification of the biofilm was done using the microtiter plate assay and the fractional inhibitory concentration index was calculated. Both forms of Pseudomonas aeruginosa generated biofilms. BGE at minimal inhibitory concentration (MIC) showed inhibition percentages higher than 55% for both strains, and CBD inhibited biofilm formation by about 70%. The care solution at MIC inhibited biofilm formation by about 50% for both strains tested. The effect of BGE on the eradication of the microbial biofilm on soft contact lenses at MIC was 45% eradication for P. aeruginosa ATCC 9027 and 36% for P. aeruginosa clinical strain. For CBD, we observed 24% biofilm eradication for both strains. For the care solution, the eradication MICs were 43% eradication for P. aeruginosa ATCC 9027 and 41% for P. aeruginosa clinical strain. It was observed that both the test soft contact lenses solution/BGE (fractional inhibitory concentration index: 0.450) and the test soft contact lenses solution/CBD (fractional inhibitory concentration index: 0.153) combinations exhibited synergistic antibiofilm activity against most of the studied bacteria. The study showed that BGE and CBD have good effect on inhibition of biofilm formation and removal of preformed biofilms, which makes them promising agents that could be exploited to develop more effective care solutions.

A study of contact lens compliance in a non-clinical setting

PURPOSE

To evaluate soft contact lens replacement, overnight (ON) wear, and contact lens case compliance in a non-clinical sample.

METHODS

Subjects (n = 297) were recruited at the Center for Science and Industry (COSI) in Columbus, Ohio. Adult (≥ 18 years) soft contact lens wearers completed a survey about contact lens replacement, ON contact lens wear, and contact lens case replacement habits.

RESULTS

Two-week replacement lenses (according to the manufacturer's replacement schedule [MRS]) were most common (45.5%), followed by monthly (34.3%) and daily replacement (20.2%). Non-compliance with replacement schedule was reported in 38.7% of subjects. Age (p = 0.02), years of lens wear (p = 0.02), and MRS (p <0.0001) affected replacement compliance. Post-hoc analysis showed daily replacement wearers were more compliant than two-week (p <0.0001) and monthly (p <0.0001) replacement wearers with prescribed lens replacement. Non-compliance with prescribed ON wear was reported in 23.9% of subjects. Subjects who were non-compliant with lens replacement were more likely to be non-compliant with ON wear (p = 0.02) and had worn contact lenses for less time (p = 0.02). Of the subjects who used contact lens cases, 74.6% were unsure when they should replace their case. Frequency of case replacement was not associated with age (p = 0.5), gender (p = 0.5), years of contact lens wear (p = 0.7), MRS (p = 0.4), replacement compliance (p = 0.3), or ON wear compliance (p = 0.7).

CONCLUSIONS

Daily replacement wearers were most likely to be compliant with contact lens replacement, but all subjects, including daily replacement wearers, had similar ON wear non-compliance. Non-compliant lens replacement was associated with non-compliant ON wear, but contact lens case replacement was not related to either compliance category. The majority of subjects had no knowledge of proper contact lens case replacement, despite compliance in other categories.

The short-term physiological impact of switching reusable silicone hydrogel wearers into a hydrogel daily disposable multifocal

Purpose: To evaluate ocular physiological responses to etafilcon A multifocal (etMF) daily disposable (DD) lenses after 4 weeks of wear, when switching from habitual silicone hydrogel (SiHy) daily wear.

Method: A single-arm, open-label, bilateral dispensing study was conducted in 39 habitual spherical SiHy wearers (14 hyperopes; 25 myopes). Clinical visits occurred with habitual SiHy (control) at baseline and after 4 weeks of etMF DD open-eye lens wear at exit. Objective limbal/bulbar hyperemia using the Oculus K5M (0–4) and subjective grading of lid wiper epitheliopathy (LWE) (0–4) were tested for non-inferiority (NI), using a margin of 1 grade. Corneal thickness along a 10 mm cord was measured using the Visante OCT and tested for NI using a 30 μm margin. Corneal staining area was graded (0–100%).

Results: The least-square mean differences (LSMD) and 95% confidence interval (95% CI) between etMF DD and habitual SiHy in central and peripheral corneal thickness (μm) were 3.64 (−2.0, 9.29) and 3.0 (−7.72, 13.72) in hyperopic, and 3.56 (−0.66, 7.78) and 6.40 (−1.62, 14.42) in myopic subjects. The LSMD (95% CI) for bulbar and limbal hyperemia were −0.08 (−0.19, 0.02) and −0.01 (−0.12, 0.09) in hyperopes, and 0.04 (−0.03, 0.12) and 0.04 (−0.04, 0.11) in myopes. The LSMD (95% CI) for LWE were 0.11 (−0.39, 0.60) and 0.30 (−0.07, 0.67) for hyperopes and myopes, respectively.

Conclusions: No clinically significant differences in a variety of physiological responses were found when habitual reusable SiHy daily wear subjects were refitted into hydrogel etMF, when the subjects were followed for 4 weeks.

Eye care professionals' perceptions of the benefits of daily disposable silicone hydrogel contact lenses

PURPOSE

To gain a better understanding of eye care professionals' (ECPs) perceptions regarding the benefits of silicone hydrogel (SiH) daily disposable contact lenses (DDCL), particularly with respect to health, comfort and patient satisfaction.

METHODS

A survey was conducted with 300 ECPs in the United States, United Kingdom and Japan during November 2017. The survey comprised 34 statements relating to SiH DDCLs, to which the ECPs provided their level of agreement using a 6 point Likert scale. A minimum of 70% agreement was set to define majority agreement. Categories of statements included Health, Comfort, Patient Experience, and Standard of Care.

RESULTS

ECPs rated the highest levels of agreement to perceptions within the Patient Experiences and Health categories. The six statements receiving the highest ratings were "Silicone hydrogel 1 day lenses satisfy today's patients' demanding lifestyles" (93% agreement); "Silicone hydrogel 1 day lenses are the best choice to safeguard my patients' eye health related to contact lens wear" (92%); "Silicone hydrogel 1 day lenses provide the best benefits to my patients" (92%); "Silicone hydrogel 1 day lenses provide better long term eye health for my patients than hydrogel 1 day lenses" (91%); "Silicone hydrogel is the healthiest lens material for my daily disposable patients" (90%); and "Silicone hydrogel 1 day lenses provide a better wearing experience for my patients than hydrogel 1 day lenses" (90%).

CONCLUSION

ECPs perceive that SiH DDCLs offer long-term eye health
and comfort for the patient and although the ECPs surveyed would not necessarily prescribe SiH DDCLs to all their patients, they would prescribe them to most of their patients. The results support the premise that while ECPs consider SiH 1 day contact lenses as the current "standard of care"; the principal barrier continues to be the perceived higher cost of these lenses.