Soft Contact Research Articles

Visual performance and quality of life in myopic adolescents with pupil-optimised multifocal versus single-vision contact lenses

ABSTRACT Clinical relevance Myopia control is a prominent area of global research, with multifocal contact lenses identified as an effective intervention for adolescents. Background This study aims to evaluate the visual performance and vision-related quality of life (QoL) of myopic adolescents when corrected with pupil-optimised multifocal soft contact lenses (MFSCLs) versus single-vision contact lenses (SVCLs), with each participant serving as their own control. Methods Thirty-five myopic adolescents, habitually wearing SVCLs and fitted with pupil-optimised MFSCL with mid-addition power, were recruited. The assessment included distance visual acuity (DVA), near visual acuity (NVA), maximum reading speed (MRS), reading acuity (RA), contrast sensitivity (CS), and stereoacuity (SA) in photopic conditions for both types of lenses. Vision-related QoL was quantified twice for both lens types using the National Eye Institute Visual Function Questionnaire (NEI VFQ-42), covering 13 vision-specific domains. Results Comparisons of visual outcomes between MFSCLs and SVCLs for the same subjects revealed statistically significant differences in DVA (p = 0.010), NVA (p = 0.014), MRS (p = 0.044), and RA (p < 0.001), with SVCLs outperforming in DVA only. No significant difference in CS and SA was observed between the two lens types. According to the NEI VFQ-42, scores for clarity of vision, far vision, glare, and satisfaction with correction were higher with SVCLs, while the score for near vision was higher with MFSCLs. When fitted with MFSCLs, no significant correlations were found between pupil size and age of the patient with any visual examination parameters. However, there was a significant negative correlation between the DVA, NVA and the spherical equivalent of the lens. Conclusion MFSCLs with mid-add power significantly improve NVA, MRS, and RA, albeit with a reduction in DVA compared to SVCLs. While SVCLs were associated with better clarity of vision, far vision, and satisfaction with correction, MFSCLs offered superior performance in near vision tasks, according to the NEI VFQ-42 scores.

Incidence of microbial keratitis associated with overnight orthokeratology: a multicenter collaborative study.

To investigate the incidence of microbial keratitis among Japanese patients wearing orthokeratology (ortho-k) lenses STUDY DESIGN: Retrospective multicenter study METHOD: This study was conducted at 4 hospitals in Japan and involved 1438 patients who had been prescribed ortho-k lenses and had worn them for at least 3 months. Data on patient demographics, lens characteristics, lens care systems, and presence of microbial keratitis were extracted from the medical records. Duration of ortho-k lens wear was calculated from the original fitting date to the patient's last visit, with the total years of lens wear used as person-years of lens wear. The incidence of microbial keratitis was calculated by dividing the number of infected cases by the total person-years of lens wear for all enrolled participants. Among the 1438 patients, 753 were male and 685 were female, with a mean age of 12.7 ± 5.4 years. The mean duration of ortho-k lens wear was 5.2 ± 4.5 years, and the mean lens power was -3.52 ± 1.41 D. The total person-years of lens wear for all enrolled patients was 7415. Four cases of microbial keratitis were identified, resulting in an overall incidence of microbial keratitis of 5.4 (95% CI: 1.0-9.8) per 10,000 patient-years among ortho-k lens wearers. This study represents the largest sample size to date for estimating the incidence of microbial keratitis associated with ortho-k lenses. The incidence was similar to or slightly lower than that of previous studies on ortho-k-related microbial keratitis and also comparable to that of daily wear soft contact lenses.

Biomechanical evaluation of different plunger size and plunger position on removing soft contact lenses and rigid gas permeable contact lenses.

To avoid risks of mucosal infection from contact lenses removal, a contact lens plunger is often used. Given various types of contact lens plungers available on the market, no study has yet been done on mechanical effects of the contact lens plunger on contact lens removal. Here, this study used finite element analysis to investigate the effects of plunger size and plunger position on the removal of soft and rigid gas permeable (RGP) contact lenses. First, we established finite element analysis models for the plunger, contact lens, cornea, and aqueous humor. The plunger is made of mostly silicone rubber, and the contact lenses are mainly made of soft and hard material. The part of the plunger used for removal was located either at the central or the edged position, with pulling 1 mm distance. The main parameters observation indicators of in this study were the reaction force at the fixed end of the cornea, aqueous humor, the von Mises stress of the plunger, the contact lenses, and the cornea. Results of this study showed that when a plunger of a larger diameter was used, the reaction force of the plunger was also larger, especially when applied to RGP lenses, which required a slightly larger force (∼0.27 N). Also, when removing a RGP lens from the edge, there was a greater stress at the edge of the contact lens (2.5799 MPa), and this caused a higher stress on both the cornea (0.0165 MPa) and the aqueous humor (0.00114 MPa). When using a plunger with a larger diameter to remove a RGP lens, although a larger force required, the relatively larger contact area likely reduced the stress on the cornea and aqueous humor, thereby reducing the risk of eye injury. In addition, when removing a RGP lens, the results of this study recommended it to be removed from the plunger edge, as that facilitated the removal of contact lens.

Non-monotonic Evolution of Contact Area in Soft Contacts During Incipient Torsional Loading

Non-monotonic Evolution of Contact Area in Soft Contacts During Incipient Torsional Loading

Extended release of ciprofloxacin from commercial silicone-hydrogel and conventional hydrogel contact lenses containing vitamin E diffusion barriers.

Vitamin E could be used as a coating with commercial silicone hydrogel lenses to extend the release of various ophthalmic drugs. This concept could provide a promising approach to improve overall ocular therapeutic outcomes for topical ocular drugs. This study aimed to develop a contact lens-based ocular drug delivery system using vitamin E as a diffusion barrier to extend the release duration of ciprofloxacin. Five commercial lenses were soaked for 24 hours in various concentrations of vitamin E dissolved in ethanol (0.0125 to 0.2 g/mL). The lenses were loaded with ciprofloxacin for 24 hours in 3 mL of 3 mg/mL of ciprofloxacin/acetic acid solution. The drug release was evaluated in 3 mL of phosphate-buffered saline solution. At t = 0.5, 1, 2, 4, 6, 8, 12, 16, and 24 hours, the amount of ciprofloxacin released was measured using a UV-VIS spectrophotometer at 270 nm. There was a decrease in ciprofloxacin loading with increasing amounts of vitamin E loaded into the silicone hydrogel lenses. For each lens type, there was an optimal amount of vitamin E loaded that extended the release duration of the drug from 1 hour (without vitamin E) to as long as 16 hours. In contrast, vitamin E loaded into hydrogel lenses had no effect on the amounts of drugs loaded or the release duration. Vitamin E can be used as a diffusion barrier with commercially available silicone hydrogel lenses to provide sustained release of ciprofloxacin. The results suggest that vitamin E may form blockages in channels within a silicone hydrogel lens material, thereby forcing a longer path for drugs to diffuse into and out of the lens material. There is an optimal amount of vitamin E that needs to be loaded to extend the release duration, and this is lens material dependent.

Multifocal Soft Contact Lenses for the Treatment of Myopia Progression in Children: A Report by the American Academy of Ophthalmology

To review the published literature assessing the efficacy of multifocal soft contact lenses for the treatment of myopia progression in children 18 years of age and younger. A literature search of the PubMed database was conducted last in March 2024 and was limited to articles published in English without date restrictions. The search yielded 76 articles, which were reviewed by the primary author in abstract form, and 28 articles were selected for full-text review. Twelve articles were deemed to have met the inclusion criteria and were assigned a level of evidence rating by the panel methodologist. Eleven studies were rated level I and 1 study was rated level II. All studies showed less myopic progression, with changes in spherical equivalent (SE) ranging from 0.22 to 0.81 diopters (D) for multifocal soft contact lenses compared with 0.50 to 1.45 D in control groups who used single-vision spectacles or single-vision contact lenses over the course of at least 1 year. Additionally, axial elongation was less in the multifocal soft contact lens group compared with control groups, with a change in axial length (AL) of 0.05 to 0.39 mm in treatment groups compared with 0.17 to 0.67 mm in control groups with at least 1 year of follow-up. The difference in change between the groups was clinically modest and statistically significant in 11 studies for SE and in all 12 studies for AL. No serious adverse events were reported in any of the studies. Level 1 evidence supports slower myopia progression and AL elongation in children who used multifocal soft contact lenses compared with spectacles or single-vision contact lenses over at least 1 year of follow-up. However, few data are available on optimal treatment duration, the progression over longer periods, or progression after discontinuation of the multifocal contact lenses. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Citicoline eluting hydrogels for therapeutic contact lenses intended to treat neurodegenerative diabetic ocular diseases

Ophthalmic neurodegenerative diseases related to diabetes, such as glaucoma and retinopathy, are among the major causes of blindness in the world. Citicoline (CIT) in the form of eye drops is currently used for the treatment/prevention of these diseases, which affect the posterior segment of the eye. To ensure the drug penetration into the back of the eye, frequent instillations of highly concentrated drug solutions are required with potential side effects. Drug-loaded soft contact lenses (SCLs) may be an effective alternative to the conventional eye drop treatment, since they may enable a sustained drug release during daily wear, ensuring a higher drug bioavailability, and avoiding drug waste. In this work, one 2-hydroxyethyl methacrylate (HEMA) based hydrogel was functionalised with N-(3-aminopropyl) methacrylamide hydrochloride (APMA), molecularly imprinted with CIT and loaded with the same drug. The material was extensively characterised, in terms of morphology, optical, mechanical, and physical–chemical properties, namely, equilibrium water content, wettability, oxygen and ionic permeability, Young’s modulus, shear deformation, transmittance and refractive index, before and after steam sterilisation. Additionally, the tendency of the material to adsorb proteins of the lachrymal fluid was evaluated and its biocompatibility was assessed by irritation and cytotoxicity assays. Comparison with the non-functionalised and non-imprinted hydrogel showed that the modified hydrogel led to a sustained in vitro release of a much higher amount of CIT than the original one, while keeping typical values for physical–chemical properties of SCLs. The drug-loaded material resisted steam sterilisation and proved to be biocompatible, demonstrating adequate properties to be used in therapeutic SCLs for the prophylaxis/treatment of neurodegenerative diabetic ocular diseases. The neuroprotective effect of the released drug was confirmed with tests using porcine retinal explants.

Efficacy of different disinfecting methods for contact lenses against Acanthamoeba castellanii

PurposeTo analyze the efficacy of different disinfecting methods for contact lenses (CL) against Acanthamoeba castellanii (AC) using quantitative PCR (qPCR) based on RNA detection. MethodsThree CL materials: rigid gas permeable (RGP), hydrogel (Hy), and silicone hydrogel (SiHy), were contaminated with 1x105 amoebae/ml and incubated for 24 h at 30 °C. After contamination, pre-cleaning steps were performed before using four maintenance solutions based on hydrogen peroxide (HP), sodium hypochlorite (SH), povidone-iodine (PI), and a multipurpose solution (MS). The pre-cleaning steps involved using a cleaner (20 % isopropyl alcohol) and rinsing the CL. Disinfection systems 1 and 2 involved no cleaner and rinsed the CL with tap water or saline solution, respectively. Systems 3 and 4 included a cleaner and rinsed with tap water or saline, respectively. After cleaning, A. castellanii was extracted and stored for qPCR analysis, using Hsp70 and TPBF genes to detect RNA A. castellanii. Results were presented as the percentage of positives or negatives (presence or absence of amoebae), with a p-value < 0.05 considered statistically significant. ResultsDisinfection system 1 with MS resulted in 56 % positives for RGP lenses and 100 % positives for both hydrogel materials. When MS was combined with a cleaner, 12.5 % positives were found for SiHy and 100 % negatives for Hy and RGP lenses (p < 0.05). PI solution alone yielded 38 % and 12 % positives for hydrogel and silicone hydrogel lenses, respectively, but was 100 % effective when combined with a cleaner. HP and SH, whether combined with a cleaner or not, were effective against AC for all CL materials, except HP without a cleaner for Hy lenses. ConclusionAll disinfection methods showed some efficacy against Acanthamoeba on any CL material. The most effective solutions were those based on hydrogen peroxide and sodium hypochlorite. Using a cleaner enhanced the final disinfecting efficacy, especially with the multipurpose solution.

Subjective Wearing Experience of Lehfilcon A Among Satisfied Comfilcon A Toric Lens Wearers.

To evaluate the subjective wearing experience of lehfilcon A toric lenses among subjects who were already satisfied with their comfilcon A toric lenses. This was an open-label, single arm study of currently satisfied comfilcon A soft toric contact lens (Biofinity Toric, CooperVision, Pleasanton, CA) wearers that were refit with lehfilcon A soft toric lenses (Total30® for Astigmatism; Alcon Vision LLC, Fort Worth, TX). Subjects were administered a questionnaire about satisfaction with comfort, visual performance, end of day comfort, and ease of handling with lehfilcon A toric lenses. A total of 40 subjects completed the study. After one month of wear the median and interquartile range (IQR) was 8 (2) for overall satisfaction with lehfilcon A comfort, 8 (1.25) for visual performance, 7 (3.25) for end of day comfort, 9 (2) for ease of handling, and finally 8 (2) for overall satisfaction. A high proportion of subjects were satisfied with the subjective wearing experience with lehfilcon A toric lenses, including satisfaction with comfort, visual performance, end of day comfort, and ease of handling.

Comfort advantages demonstrated with a novel soft contact lens: A randomized clinical trial

PurposeTo compare comfort outcomes between a novel daily disposable contact lens – designed to maximize comfort – and an established control. The hypothesis was that the test lens would be superior to the control for four key comfort questionnaire items: end-of-day comfort, all-day comfort, visual comfort while driving at night, and reduction of ocular fatigue from digital device use. MethodsThis randomized, controlled, subject-masked, parallel-arm study enrolled young (18–39 years), healthy, myopic, contact lens wearers with an up-to-date prescription at 19 investigational sites in the United States. Subjects wore either the test (ACUVUE® OASYS MAX 1-Day, senofilcon A) or control (Dailies Total1®, delefilcon A) lens for 2 weeks of bilateral, daily disposable wear before completing comfort questionnaire items, each of which had 5 or 6 response options. For each item, the odds ratio for positive (top-two-box) responses was estimated from a binomial generalized linear mixed model. A gatekeeping approach combined with the truncated Hochberg procedure was used for multiplicity adjustment. ResultsOf 344 enrolled subjects, 342 subjects were randomized and dispensed lenses, with 171 subjects per lens group. Among the 342 subjects, 68.4% were female, 83.6% were White, and the average age was 29.7 (±5.53) years. The test lens was statistically superior to the control for all four comfort questions: odds ratios (test vs. control) were 2.01 (95% CI: 1.25, 3.22) for end-of-day comfort, 2.17 (alpha-adjusted CI: 1.30, 3.64) for all-day comfort, 2.00 (alpha-adjusted CI: 1.18, 3.41) for reducing ocular fatigue from digital device use, and 1.77 (95% CI: 1.04, 3.02) for comfortable vision while driving at night. ConclusionThe test lens demonstrated statistically superior physical and visual comfort, as measured by the four comfort endpoints, compared to the control. The test lens had significantly greater odds of favorable responses for all comfort items compared to the control.

Literature review and evaluation of methods relating to the surface friction of soft contact lenses

Purpose. Numerous reports have hypothesised that there is a strong correlation between the contact lens (CL) comfort and its on-eye friction. Hence many methods had been developed, to measure coefficients of friction (CoF) of soft CL. The aim of this work is the review, evaluation and discussion of these methods. Material and Methods. From the relevant literature, 15 methods published between 1995 and 2021 have been chosen based on their frequency of citation or because of their new or unusual approach. The evaluation focuses on the requirement that the method should closely mimic the CL on-eye situation. Moreover, it has been examined if these methods produce comparable results. Results. None of the methods meet the requirements in every aspect and many show large differences in the used techniques. That includes the often used tribometer, a rheometer, a pendulum, an inclined glass plate and fingers. Moreover, it has been shown that the methods create a wide range of CoFs. For example, the material nelfilcon A, measured by five different methods, show values between 0.013 and 0.474. That is a difference of 0.461. On the other side, for narafilcon A the difference between CoFs is only 0.143. Conclusion. To ensure that results from CoF measurements are valid and comparable between and within studies, a standardised method needs to be defined or developed. Choosing methods and parameters that simulate on-eye conditions would be beneficial in predicting wearing comfort and the effect of lubricating eyedrops. Thus, a more suitable method must be developed in the future.

Enhancing Performance of Silicone Hydrogel Contact Lenses with Hydrophilic Polyphenolic Coatings.

This study explores the application of a dopamine-assisted co-deposition strategy to modify the surface of daily disposable silicone hydrogel contact lenses. Aiming to enhance the hydrophilicity of these typically hydrophobic lenses, we developed an industry-friendly process using simple dip coating in aqueous solutions. By co-depositing tannic acid, dopamine and chitosan derivative and employing periodate oxidation, we achieved a rapid and efficient coating process. High-molecular-weight branched polyethylene imine was introduced to promote surface reactions. The resulting lenses exhibited extreme hydrophilicity and lipid repellency without compromising their intrinsic properties or causing cytotoxicity. While the coating demonstrated partial antimicrobial activity against Gram-positive Staphylococcus aureus, it offers a foundation for the further development of broad-spectrum antimicrobial coatings. This versatile and efficient process, capable of transforming hydrophobic contact lenses into hydrophilic ones in just 15 min, shows significant potential for improving comfort and performance in daily disposable contact lenses.

Effects of Rebamipide for Dry Eye on Optical Quality and Efficacy: A Systematic Review and Meta-Analysis.

Purpose: To evaluate the effects of rebamipide ophthalmic suspension on optical quality and efficacy of patients with dry eye under different conditions. Methods: A comprehensive search across five databases (PubMed, Cochrane Library, Web of Science, China National Knowledge Infrastructure, and Wan Fang) was conducted for studies published through May 13, 2024, focusing on rebamipide for dry eye treatment. Results: A total of 11 studies including 334 patients with dry eye were included. Tear breakup time (TBUT) values of patients with dry eye increased significantly after 2 weeks (standardized mean difference [SMD] =1.07, 95% confidence interval [CI] = [0.05, 2.09]), 4 weeks (SMD = 1.26, 95% CI = [0.77, 1.75]), and 12 weeks (SMD = 1.04, 95% CI = [0.37, 1.71]) of rebamipide treatment. Subgroup analysis revealed that patients with dry eye wearing soft contact lens (SCL) exhibited higher TBUT values after 4 weeks of rebamipide treatment compared with those who received rebamipide alone. In addition, rebamipide significantly improved fluorescein staining score of patients with dry eye after 4 weeks of treatment (SMD = -0.34, 95% CI = [-0.63, -0.06]). However, 4 weeks of rebamipide treatment showed no significant effect on Schirmer I test values (SMD = -0.04, 95%, CI = [-0.43, 0.35]) and higher-order aberrations (SMD = -0.73, 95% CI = [-1.77, 0.30]). Conclusions: These results indicate a significant improvement in the efficacy of rebamipide treatment for patients with dry eye, particularly for those wearing SCL. The effect of rebamipide on visual quality was found to correlate with the underlying dry eye status.

Keratoconus.

Keratoconus is a progressive eye disorder primarily affecting individuals in adolescence and early adulthood. The ectatic changes in the cornea cause thinning and cone-like steepening leading to irregular astigmatism and reduced vision. Keratoconus is a complex disorder with a multifaceted aetiology and pathogenesis, including genetic, environmental, biomechanical and cellular factors. Environmental factors, such as eye rubbing, UV light exposure and contact lens wearing, are associated with disease progression. On the cellular level, a complex interplay of hormonal changes, alterations in enzymatic activity that modify extracellular membrane stiffness, and changes in biochemical and biomechanical signalling pathways disrupt collagen cross-linking within the stroma, contributing to structural integrity loss and distortion of normal corneal anatomy. Clinically, keratoconus is diagnosed through clinical examination and corneal imaging. Advanced imaging platforms have improved the detection of keratoconus, facilitating early diagnosis and monitoring of disease progression. Treatment strategies for keratoconus are tailored to disease severity and progression. In early stages, vision correction with glasses or soft contact lenses may suffice. As the condition advances, rigid gas-permeable contact lenses or scleral lenses are prescribed. Corneal cross-linking has emerged as a pivotal treatment aimed at halting the progression of corneal ectasia. In patients with keratoconus with scarring or contact lens intolerance, surgical interventions are performed.

Hand-Washing Habits in a Sample of Spanish Soft Contact Lens Wearers.

Contact lens (CL) wear is a safe method for the correction of refractive errors. However, rare, severe ocular complications may occur which may lead to visual loss. As most of these complications are related to poor patient compliance with care and maintenance instructions, resulting in the contamination of hands, CLs and accessories, it was the purpose of this study to assess hand-washing habits in a sample of Spanish soft CL wearers. Hand hygiene was explored through a self-reported online survey and via an in-office practical demonstration in a subset of those users answering the survey. A total of 198 surveys were analyzed, and 18 CL users participated in the practical demonstration. Overall, hand-washing habits were not adequate, with 35 (17.8%) and 103 (52.2%) participants reporting not always washing their hands prior to CL or storage case manipulation, respectively. While 161 (81.3%) participants dried their hands after washing, 132 of these (82.1%) used non-disposable cloth towels. Participants receiving specific hand-washing information from their practitioners (141, or 71.1%) had better hand hygiene (p < 0.05). During the practical demonstration, 13 (72.2%) participants used water and soap to wash their hands, but only 3 (16.7%) displayed correct hand washing routines. Complete patient education, as well as practical reminders at all follow-up visits, are essential to ensure better hand hygiene in order to reduce the probability of ocular complications and to guarantee safe and satisfactory CL use.

The relationship between contact lens ultraviolet light transmittance and myopia progression: a large-scale retrospective cohort study.

The prevalence of myopia is increasing dramatically around the world, and many studies have suggested the possibility that ultraviolet (UV) light is effective to prevent the onset and progression of myopia. However, UV is a risk factor for diseases that cause refractive errors such as cataract and pterygium. In this study, we evaluated the relationship between UV exposure and myopia progression. The dataset consisted of a total of 337 396 eyes of patients in the 12-to-29-year age range, who were prescribed soft contact lenses (SCL) for refractive error at Okada Eye Clinic in Japan between 2002 and 2011. They were tracked over a five-year period and did not change the type of SCL. In this retrospective cohort study based on medical records, we divided patients into two groups, one prescribed SCL with UV protection (UV-SCL), and another prescribed SCL without UV protection (UV+SCL). Change in refractive power over five years was measured and results compared. It was -0.413 diopter (D) in the UV-SCL group and -0.462 D in the UV+SCL group. Thus, the progression of myopia was slower in the UV-SCL group. The results were also analyzed separately by gender and degree of myopia at the time of initial prescription, which all showed significant differences (P<0.001). Results suggest that UV exposure may advance myopia. Further research is needed to investigate the underlying mechanisms that could explain this.

Efficacy in myopia control-The impact of rebound.

When myopia control treatment is discontinued, progression will increase, but does it revert to expected values based on the age and race of the child or does it accelerate further? The latter scenario is considered a rebound. A PubMed search was conducted with the words 'rebound' and 'myopia control', identifying further papers from reviews. Inclusion was limited to prospective studies with ≥6 months of treatment, ≥3 months of data following cessation and with axial length data, which allowed calculation of rebound. Nineteen studies were identified, comprising 24 treatment groups. In 10 studies, untreated control children were followed both throughout the treatment and cessation periods, allowing for a concurrent comparison group. In three studies, a control group was followed for 1 or 2 years and thereafter received the treatment under evaluation. Later, treatment ceased in the originally treated children. Finally, six studies were cross-over designs. For these latter two study designs, initial axial elongation and myopia progression in the control group were extrapolated to the cessation period, accounting for annual slowing. Values from durations of <1 year were annualised. The mean annualised rebound was +0.05 ± 0.10 mm and -0.09 ± 0.24 D for axial length and myopia progression, respectively, and these were correlated (r2 = 0.59, p < 0.001). Rebound was associated with 1-year treatment efficacy (r2 = 0.43, p < 0.001). The mean annualised rebound with optical corrections was -0.01 ± 0.03 mm. Five of the six highest rebound values (≥0.14 mm) were from red light therapy and atropine studies. Rebound ranged from +0.03 to +0.14 mm for overnight orthokeratology. Consistent with previous statements, no evidence for rebound was found for myopia control spectacles and soft contact lenses. Future research should explore the influence of age and magnitude of treatment efficacy on rebound.

Innovations in Silicone Hydrogels: Achieving High Oxygen Permeability with Maintained Equilibrium Water Content

Silicone hydrogels are pivotal materials used in contact lenses, biomedicine, and electronic devices, where oxygen permeability and equilibrium water content (EWC) are essential attributes. Generally, an increase in silicone content boosts oxygen permeability but diminishes EWC, presenting a notable trade‐off challenge. In this study, a solvent incorporation method that significantly elevates oxygen permeability without markedly affecting EWC is introduced. Among various solvents, isopropanol incorporation notably enhances oxygen permeability (101 barrer) while maintaining an EWC of 56.0%. This improvement is attributed to enhanced connectivity within the silicone network. Additionally, it is discovered that incorporating siloxane nanoparticles (SNPs) further increases the connectivity of the silicone network, offering a more pronounced improvement in oxygen permeability than solvent alone. However, excessive SNP addition can lead to large phase separation, resulting in decreased transmittance, lower EWC, and increased mechanical strength. Optimizing a transmittance of over 99%, SNP addition achieves a silicone hydrogel with an oxygen permeability of 125 barrer and an EWC of 49.5%, surpassing many advancements reported in the literature.

Corneal endothelial density and morphology in long-term soft contact lens users in Japan: a retrospective cross-sectional study of 17,732 eyes

Purpose There is a lack of long-term and large-scale studies on the adverse effects of soft contact lenses (SCLs) on the corneal endothelia of Asian populations. Here, we aimed to examine the effects of long-term SCL use on corneal endothelial density and morphology. Materials and Methods This retrospective study involved consecutive patients at the Miyata Eye Hospital (Miyazaki, Japan), who had used SCLs for more than 1 year. Patients with ophthalmological disorders without refractive errors were excluded. The period of SCL use, SCL type, corneal endothelial cell density (ECD), appearance rate of hexagonal cells (HEX), and coefficient of variation of cells (CV) were analyzed. Results In total, 17,732 eyes of 8866 patients were included in the analysis (age, 26.0 ± 8.8 years). The mean period of SCL use was 6.3 ± 5.4 years. Multivariate regression analysis revealed that ECD and HEX were significantly negatively correlated with the period of SCL use, age, and sex (p < 0.001 for all). The CV was significantly positively correlated with the period of use (p < 0.001), sex (p = 0.002), and age (p < 0.001). Conclusions Corneal ECD, HEX, and CV were significantly associated with the period of SCL use in long-term users. It is essential to regularly check the corneal endothelium in patients with a history of long-term SCL use.

A Comparison of Subjective Symptoms of Two Types of Silicone Hydrogel One-Day Disposable Contact Lenses.

This study aimed to evaluate the comfort and discomfort of two types of soft contact lenses (SCLs) by comparing their quality of vision, fit, subjective dryness, and handling. A total of 62 SCL wearers with contact lens (CL) discomfort were recruited. They were fitted with narafilcon A and verofilcon A for two weeks each by crossover. The comfort of the two types of SCLs was compared by having each participant answer a modified 5-Item Dry Eye Questionnaire (m-DEQ5, scores for vision, wearing comfort, and handling: the total score of the five items is a maximum of 25, higher being better) and modified Japanese version of the 8-item Contact Lens Dry Eye Questionnaire (m-J-CLDEQ-8: scores for discomfort and dry eye symptoms: the total score of the eight items is a maximum of 44; lower is better) survey forms. Results: Overall, the m-DEQ5 and m-J-CLDEQ-8 scores for the two SCLs of narafilcon A and verofilcon A were higher than the median of 3.0 points. Scores for 4 of 5 items and total scores in m-DEQ5 (18.7 ± 3.4 vs. 21.6 ± 2.5) were significantly higher and better in verofilcon A than in narafilcon A (p<0.01). Scores for 8 of 8 items and total scores on the m-J-CLDEQ-8 (15.2 ± 7.9 vs. 8.4 ± 4.9) were also significantly lower and better in verofilcon A than in narafilcon A (p<0.05). Verofilcon A provided excellent vision, comfort, and ease of handling and was less likely to cause dry eye symptoms or eye discomfort. These results suggest that verofilcon A is an excellent option for patients with dry eye symptoms and CL discomfort.