Soft Contact Research Articles

Drug-impregnated contact lenses via supercritical carbon dioxide: A viable solution for the treatment of bacterial and fungal keratitis

Keratitis is a corneal infection caused by various bacteria and fungi. Eye drop treatment of keratitis involves significant challenges due to difficulties in administration, inefficiencies in therapeutic dosage, and frequency of drug applications. All these are troublesome and result in unsuccessful treatment, high cost, time loss, development of drug resistance by microorganisms, and a massive burden on human health and the healthcare system. Most of the antibacterial and antifungal medications are non-water-soluble and/or include toxic drug formulations. Here, the aim was to develop drug-loaded contact lenses with therapeutic dosage formulations and extended drug release capability as an alternative to eye drops, by employing supercritical carbon dioxide (ScCO2) as a drug impregnation solvent to overcome inefficient ophthalmic drug use. ScCO2, known as a green solvent, has very low viscosity which provides high mass transfer power and could enhance drug penetration into contact lenses much better with respect to drug loading using other solvents. Here, moxifloxacin (MOX) antibiotic and amphotericin B (AMB) antifungal medicines were separately loaded into commercially available silicone hydrogel contact lenses through 1) drug adsorption from the aqueous solutions and 2) impregnation techniques via ScCO2 and their efficacies were compared. Drug impregnation parameters, i.e., 8–25 MPa pressure, 310–320 K temperature, 2–16-hour impregnation times, and the presence of ethanol as polar co-solvent were investigated for the optimization of the ScCO2 drug impregnation process. The highest drug loading and long-term release kinetic from the contact lenses were obtained at 25 MPa and 313 K with 2.5 h impregnation time by using 1 % ethanol (by volume). Furthermore, antibacterial/antifungal activities of the MOX- and AMB-impregnated contact lenses were effective against in vitro Pseudomonas aeruginosa (ATCC 10145) bacteria and Fusarium solani (ATCC 36031) fungus for up to one week. Consequently, the ScCO2 method can be effectively used to impregnate commercial contact lenses with drugs, and these can then be safely used for the treatment of keratitis. This offers a sustainable delivery system at effective dosage formulations with complete bacterial/fungal inhibition and termination, making it viable for real animal/human applications.

Silicone hydrogel versus hydrogel soft contact lenses for differences in patient-reported eye comfort and safety: A Cochrane systematic review summary.

This work is significant because it is the first Cochrane systemic review that compares the comfort and safety of hydrogel and silicone hydrogel soft contact lenses (SCL). This study aimed to conduct a systemic review of randomized trials comparing the comfort and safety of silicone hydrogel and hydrogel SCLs. CENTRAL, MEDLINE Ovid, EMBASE.com , PubMed, LILACS, ClinicalTrials.gov , and World Health Organization International Clinical Trials Registry Platform were searched on or before June 24, 2022, to identify randomized clinical trials that compared silicone hydrogel and hydrogel SCLs. Seven trials were identified and evaluated. One trial reported Ocular Surface Disease Index results, with the evidence being very uncertain about the effects of SCL material on Ocular Surface Disease Index scores (mean difference, -1.20; 95% confidence interval, -10.49 to 8.09). Three trials reported visual analog scale comfort score results, with no clear difference in comfort between materials, although results were of low certainty; trial results could not be combined because the three trials reported results at different time points. None of the included trials reported Contact Lens Dry Eye Questionnaire 8 or Standard Patient Evaluation of Eye Dryness scores. There was no evidence of a clinically meaningful difference (>0.5 unit) between daily disposable silicone hydrogel and hydrogel SCLs in corneal staining, conjunctival staining, or conjunctival redness (very low certainty evidence). The overall evidence for a difference between all included silicone hydrogel and hydrogel SCL trials was of very low certainty, with most trials judged as having a high overall risk of bias. There was insufficient evidence to support recommending one SCL material over the other. Future well-designed trials are needed to generate high certainty evidence to further clarify differences in SCL material comfort and safety.

Scoping review: Reporting characteristics for the safety of contact lenses in the pediatric population.

Contact lenses are an increasingly popular option for correcting pediatric refractive error due to increased awareness of interventions to slow myopia progression. With limited information on the safety profiles of contact lenses in children, it is important to characterize the current understanding and promote this device's safe and effective use. This scoping review evaluates characteristics of the current literature that have examined the safety of contact lenses in pediatric patients. It provides future directions for systematic reviews and identifies any gaps in the current literature or areas for future research. Literature searches in MEDLINE via PubMed, EMBASE, The Cochrane Library, trial registries, and U.S. Food and Drug Administration clinical trial documentation were performed. Included studies (i.e., experimental and quasi-experimental studies; observational studies including prospective and retrospective cohort, case-control, and analytical cross-sectional studies, and case series of 30 or more participants) reported safety and/or complications of the use of any contact lens for correcting refractive error in children (0 to 18 years). Two independent reviewers first screened the titles and abstracts, and then full-text reports for eligibility. Conflicts in eligibility were resolved by discussions with a third reviewer. Two independent reviewers extracted data, including details about the participants, context, study methods, and key findings relevant to the review question. This scoping review included 73 studies from 10 countries using different contact lens modalities, primarily orthokeratology and soft contact lenses, in children (6 to 18 years). The most common adverse event reported by the studies was corneal staining (60% orthokeratology, 45% soft contact lens). The need for uniform reporting standards for adverse events poses challenges for comprehensive data synthesis. However, this scoping review identified a sufficient number of studies for a future systematic review to quantify the risks associated with orthokeratology and soft contact lens use in children.

International trends in prescribing toric soft contact lenses to correct astigmatism (2000–2023): An update

PurposeThere have been significant advancements in toric soft contact lens design and manufacturing technology, and increased product availability, over the past half a century. The purpose of this work is to update earlier surveys by describing international trends in toric soft lens fitting between 2000 and 2023, inclusive. MethodAn annual contact lens prescribing survey was sent to eye care practitioners in up to 71 countries between 2000 and 2023, inclusive. Data relating to 220,934 standard soft daily wear single vision lens fits undertaken in 20 countries returning reliable longitudinal data were analysed in respect of toric soft lens fitting. ResultsOverall, toric soft lens prescribing almost doubled over the time-course of this survey, from 24.4 % of standard soft daily wear single vision lens fits in 2000 to 46.2 % in 2023 (p < 0.0001). There were significant differences between countries in toric soft lens prescribing (p < 0.0001). Of all standard soft daily wear single vision contact lenses prescribed to males, 32.0 % were toric soft lenses, compared with 28.7 % for females (p < 0.0001). The mean age of toric soft lens wearers was 30.5 ± 12.5 years, compared to 27.9. ± 12.1 years for spherical soft lens wearers (p < 0.0001). Analysis of 13,582 recent toric soft lens fits (2019–2023, inclusive), in terms of material type and replacement frequency, revealed the following proportions: reusable silicone hydrogel – 51 %; daily disposable silicone hydrogel – 27 %; daily disposable hydrogel – 12 %; and reusable hydrogel – 10 %. ConclusionThere has been a substantial increase in toric soft lens fitting throughout the 24 years of this survey, to a point whereby almost all clinically significant astigmatism is being corrected among those wearing standard soft daily wear single vision lenses.

The induced defocus by Defocus Incorporated Soft Contact lenses is dependent on visual distance and ambient illuminance.

Defocus Incorporated Soft Contact (DISC) lenses, a commonly used type of multifocal lens in clinical practice, may slow down myopia progression by inducing myopic retinal defocus. The purpose of this study was to explore whether the induced defocus across the retina could be affected by visual environments encountered in the real world, such as differences in viewing distance and ambient illuminance. In this cross-over trial, 30 myopic adults wore both DISC lenses and single vision contact (SVC) lenses in random order. An open-view Hartmann-Shack scanning wavefront sensor was used to measure defocus at different retinal locations along the horizontal meridian under four experimental conditions: far target (3 m) and near targets (0.33 m) under scotopic (<1 lux) or photopic (~300 lux) conditions. The results showed that DISC lenses induced more myopic retinal defocus than SVC lenses in all conditions (all p < 0.05), except for the scotopic near target. In addition, for DISC lenses, the defocus was greater in the photopic than the scotopic conditions for both the far and near targets (both p < 0.05). In conclusion, the retinal defocus induced by these multifocal lenses was dependent on both visual distance and ambient illuminance, indicating that the visual conditions might affect the anti-myopia efficacy of these devices.

Comparative study of transepithelial versus alcohol-assisted photorefractive keratectomy

Aim The aim of this study was to compare the clinical, refractive, and visual outcome of transepithelial photorefractive keratectomy (T-PRK) to the alcohol-assisted photorefractive keratectomy (AA-PRK). Patients and methods This is a prospective randomized controlled trial that included 60 myopic patients (120 eyes). They were randomized into two groups, 60 eyes each: group I (AA-PRK) and group II (T-PRK). The operation was performed in both groups by the same Excimer laser machine (EX 500 Excimer laser WaveLight). In the alcohol-assisted group, the corneal epithelium was removed by 20% ethyl alcohol followed by Excimer laser to correct the amount of ametropia. In the T-PRK group, the Streamlight PRK software (WaveLight EX 500) was used, which incorporated Excimer laser stromal ablation and epithelial removal in a single step. After completion of each procedure in both groups, mitomycin C with a concentration of 0.02% was used for 30 s, followed by copious irrigation with a cold balanced salt solution. A soft bandage contact lens was applied until epithelial healing was complete for 5 days and changed after 48 h. The patients were evaluated postoperatively on the first, third, and fifth day, then after 1 week, 1 month, and 3 months. On the first visit, uncorrected visual acuity (UCVA), epithelial healing, and postoperative pain were evaluated. At 1-week and 1-month follow-up visits, UCVA, best-corrected visual acuity (BCVA), manifest refraction spherical equivalent (MRSE), Schirmer’s I, and tear break-up time (TBUT) tests were evaluated. The corneal haze was evaluated using a slit lamp biomicroscope and subjectively graded. At the 3-month follow-up, UCVA, BCVA, MRSE, Schirmer’s I test, TBUT test, and root mean square (RMS) assessment for total higher-order aberration were evaluated. Results There was an insignificant difference between the studied groups regarding all baseline ophthalmological assessments including UCVA, BCVA, MRSE, central corneal thickness, RMS, TBUT, and Schirmer’s test (P=0.839, 0.057, 0.187, 0.537, 0.219, 0.013, and 0.151, respectively). After 3 months, the median UCVA was the same in both groups (1.0), while the MRSE did not differ significantly between the two groups (P=0.126), with a median (interquartile range) of −0.25 D (−0.75 to 0.25 D) in the AA-PRK group compared to −0.25 D (−0.50 to 0.3125 D) in the T-PRK group. The healing duration was significantly shorter in the T-PRK group (median=3.0 days) than in the AA-PRK group (5.0 days, P&lt;0.001). The median postoperative pain was also significantly higher in the AA-PRK group (4.0) than in the T-PRK group (3.0, P&lt;0.001). The RMS was significantly lower in the T-PRK group (median=0.35) than in the AA-PRK group (median=0.65, P&lt;0.001). The corneal haze did not differ significantly between the two groups after 1 month (P=0.783). After 3 months, the Schirmer’s test was significantly lower in the AA-PRK group (median=18.0 mm) than in the T-PRK group (19.0 mm, P&lt;0.001), while the TBUT test showed no significant difference (P=0.055). Conclusion The T-PRK technique provided a faster visual recovery with a better refractive outcome, faster healing response, less pain score, and less dryness than the AA-PRK.

Study of Influence of Various Methods of Intraoperative Keratoprotection on Morphological and Functional State of Ocular Surface System in Early Period after Phacoemulsification in Senile Cataract

Purpose: to study the effect of various methods of intraoperative keratoprotection on morphological and functional state of ocularsurface system (OSS) in early period after phacoemulsification (PE) in senile cataract (SC). Patients and methods. 240 patients (240 eyes) who applied for surgical treatment of SC. Age: 65 ± 4 years. 109 men, 131 women. All patients were divided into three observation groups according to the method of intraoperative keratoprotection: 1st group — 60 patients, corneal irrigation with balanced solution; 2nd group — 60 patients, ophthalmic viscosurgical device was applied to the cornea; 3rd group: 3a subgroup — 60 patients, soft contact lens (SCL) was applied to the cornea; subgroup 3b — 60 patients, SCL impregnated with riboflavin solution was applied to the cornea. In addition to the standard ophthalmological examination, Schirmer I test, OCT-scanning were performed, and tear breakup time (TBUT) was determined. Results. Operations were performed without complications. On the 1st day after the operation, the parameters of the Schirmer I test were higher in the eyes of 1st and 2nd groups. On the 5th day after the operation, tear production decreased sharply in all eyes. On the 10th day, an increase in tear production was observed in all groups, the maximum increase — in 3b subgroup. On the 1st day after the operation, TBUT decreased in all examined eyes. The largest significant TBUT decrease was noted in 1st group, the smallest — in 3b subgroup. On 1st day, corneal epithelial thickness (CET) decreased in all eyes, the maximum decrease was detected in 1st group. On the 5th day, CET continued to decrease in all eyes, the minimum decrease occurred in the 3b subgroup. On the 10th day — a decrease in CET in all groups with minimal significant dynamics in 3b subgroup. Conclusion. The study showed that the state of OSS in the early period after PE in SC depends on the method of intraoperative keratoprotection. The most optimal method of intraoperative protection of corneal epithelium and prevention of negative morphological and functional state of OSS after PE in SC is using of SCL impregnated with riboflavin.

Tear Film Break-Up Time before and after Watching a VR Video: Comparison between Naked Eyes and Contact Lens Wearers

The impact of viewing VR videos using a head-mounted display (HMD) on tear film dynamics is examined by comparing the viewing experience of individuals using their naked eyes with that of viewers wearing contact lenses. While the impact of VR on eye dryness has been studied, there is limited research on the risks for contact lens wearers. This study aims to investigate eye dryness associated with VR use in individuals wearing soft contact lenses. Seventeen adults in their 20s (7 male, 10 female) with uncorrected visual acuity of 0.8+ participated. The non-invasive tear film break-up time (NIBUT) was assessed before and after a 20 min VR video session under two conditions: with and without soft contact lenses. The results indicated a decrease in the initial tear film break-up time and an increase in the average tear film break-up time when viewing with naked eyes, whereas viewing with contact lenses led to decreases in both parameters, with statistically significant changes observed. Although the alteration in the tear film break-up time was insignificant during VR video viewing with naked eyes, the tear film stability of individuals wearing soft contact lenses tended to decrease. Caution is advised when using soft contact lenses during VR video sessions to mitigate potential eye dryness.

Effect of antihistamine-releasing contact lenses on ocular symptoms and treatment behavior in patients with seasonal allergic conjunctivitis: A retrospective study

PurposeThis study aimed to compare subjective allergic conjunctivitis symptoms and anti-allergic eye drop use patterns between antihistamine-releasing contact lens users and daily disposable soft contact lens users during Japan's hay fever season. MethodsThis web-based retrospective cohort study included daily disposable soft contact lens or antihistamine-releasing contact lens users with a history of seasonal allergic conjunctivitis who regularly used daily disposable soft contact lenses since the previous year. The total ocular symptom score (range 0–20) based on 5-item questionnaire scores and time from the start of the hay fever season to the initiation of anti-allergic eye drop treatment were compared between antihistamine-releasing contact lens users and daily disposable soft contact lens users. ResultsThe study included 24 participants: 17 using daily disposable soft contact lenses and 7 using antihistamine-releasing contact lenses. Antihistamine-releasing contact lens users experienced a greater reduction in total ocular symptom score from 2021 to 2022 compared with daily disposable soft contact lens users (mean total ocular symptom score [standard deviation]: daily disposable soft contact lens: −0.65 [1.4], antihistamine-releasing contact lens: −4.7 [3.6]; n = 24; Mann–Whitney U test, P = 0.010). Fourteen daily disposable soft contact lens users and five antihistamine-releasing contact lens users eventually required anti-allergic eye drops. Kaplan–Meier analysis revealed a significant delay in the initiation of anti-allergic eye drop treatment among those using antihistamine-releasing contact lenses compared with those using daily disposable soft contact lenses (median days, daily disposable soft contact lenses: 19 days, antihistamine-releasing contact lens: 57 days; n = 24; log-rank test, P = 0.045). ConclusionsAntihistamine-releasing contact lenses can potentially mitigate worsening ocular allergic responses during the hay fever season when used appropriately as a preventive measure.

The role of peripheral retinal defocus in myopia progression

The increasing incidence of myopia has become a global public health concern. Exploring the mechanisms underlying the onset and progression of myopia is crucial for prevention and control. This paper reviews the role of peripheral retinal defocus mechanisms in the development of myopia, with particular emphasis on the interaction between accommodation lag and peripheral retinal defocus, as well as the impact of optical intervention on myopia control effectiveness. In recent years, researchers have developed various optical tools for myopia prevention and control based on the peripheral retinal defocus theory, such as peripheral defocus spectacle lenses, orthokeratology lenses, and peripheral defocus soft contact lenses. This paper aims to provide clinicians with the latest research findings to deepen their understanding of the mechanisms involved in myopia development and to guide the future development and clinical application of myopia prevention and control products.

Effect of Light Sources on Transmittance of Commercially Available Contact Lenses.

Previous studies have suggested that light rays may interact with contact lenses, potentially affecting their transmittance. This study aimed to investigate the effects of visible and ultraviolet (UV)-A light sources on the transmittance of some commercially available daily, weekly, and monthly contact lenses. Nine commercially available soft contact lenses were irradiated with a solar simulator, light-emitting diode (LED) source, laser source, and UV-A source. The average transmittance of the tested lenses before and after irradiation in the UV, visible, and infrared light wavelength ranges was determined using an Agilent UV-visible spectrophotometer, model 8453. The results showed a partial or complete block of UV transmission at the UV-B region (300 nm) and the UV-A region (355 nm) by the Bio true daily contact lens, as well as the Acuvue Oasys, Avaira, and Biomedics 55 weekly lenses. At the visible region (555 nm), irradiation of the contact lenses by different light sources resulted in reduced light transmittance. At the infrared region (900 nm), the weekly and monthly contact lenses partially blocked infrared transmission, while the daily lenses showed either increased or decreased infrared transmission. Solar and artificial lighting, as well as high-powered lasers, constitute a major concern on the contact lenses' light transmission and optical properties. It is essential to develop soft contact lenses that have photoprotective properties while maintaining visible light transmittance.

Subjective Symptoms of First-Time Wearers of Verofilcon A Silicone Hydrogel One-Day Disposable Contact Lenses: A First Time Use of Verofilcon A (FTVeA) Study.

Purpose: Verofilcon A, a new daily disposable silicone hydrogel soft contact lens (SCL), is expected to be more comfortable to wear due to its smooth surface. This study aims to compare the comfort level of verofilcon A with eyeglasses in first-time SCL wearers. Methods: A total of 58 new SCL wearers participated in this study. Participants' comfort scores while wearing glasses or verofilcon A were examined at baseline (glasses) and one and four weeks after starting to wear the SCLs. Results: At the end of the one-month study period, no participants had abandoned wearing the SCLs due to discomfort. The vision scores (1-10) for glasses (baseline) and SCLs (week one, week four) were better withSCLs than glasses in the morning (7.9 ± 1.9 vs 8.9 ± 1.3, 9.0 ± 1.2, p<0.01), during the day (8.0 ± 1.6 vs 9.0 ± 1.1, 8.9 ± 1.2, p<0.01), at the end of the day (7.2 ± 2.1 vs 8.5 ± 1.5, 8.7 ± 1.4, p<0.01), and the entire day (7.7 ± 1.7 vs 8.9 ± 1.2, 8.7 ± 1.3, p<0.01). The percentages of participants who agreed that wearing SCLs at week four was as good as or better than glasses in terms of overall vision, peripheral vision, vision at the end of the day, comfort during the day, comfort at the end of the day, less fatigue during the day, and less fatigue at the end of the day were 91.4%, 100.0%, 91.4%, 89.7%, 82.8%, 87.9%, and 89.7%, respectively. Of the participants, 93.1%, 100.0%, and 93.1% felt that the SCLs were easy to wear, more comfortable than expected, and would like to purchase the same lenses in the future, respectively. Conclusion: These findings suggest that verofilcon A is more comfortable than glasses and is effective as an introductory lens for first-time SCL wearers.

Physical properties of soft contact lens multipurpose solutions commercially available in Ghana

PurposeTo investigate the physical properties of commercially available multipurpose soft contact lens solutions in Ghana. MethodspH (Kelilong ICL-099 pH meter, China), osmolality (OSMOMAT 3000, GONOTEC, Germany), surface tension (Sigma 700 Tensiometer, Sweden), and viscosity (CFOC-200 Viscometer, Cannon Company, USA) of various soft contact lens multipurpose solutions (MPS) were measured in triplicates at room temperature. Viscosity measurements were also taken at 34 °C ocular surface temperature. The solutions examined were Opti-Free Replenish (OFR), Trufresh (TF), Avizor (AV), Freshlook (FL), and Refresh (RF). ResultsSeveral solutions were largely hypo-osmotic in the range of 108–231 mOsm/kg, the exception being Avizor, which had osmolality values that were closer to human tears (301 ± 0.58 mOsm/kg). The range of pH values of the solutions (6.33–8.24, mean (SD) = 7.53 ± 0.18) fell within the reported tolerable range for the ocular surface (6.20–9.00). Surface tension values ranged from 35.86 to 42.27 mNm with a mean of 38.49 ± 2.32 mNm. The average viscosity of most solutions at room temperature (25 °C) was 1.44 ± 0.49 cP with a range of 1.04–2.15 cP. Significantly lower values ranging from 0.79 to 1.58 cP were obtained at ocular surface temperature (34 °C), p = 0.0001). ConclusionsThe physical properties of many of the solutions used as MPS in Ghana are markedly variable. Nevertheless, pH, surface tension, and viscosity fall within the acceptable limits of ocular physiological tolerance; except for osmolality, which majority were outside the reported tolerable range for the ocular surface. This information may partly explain the reason some patients exhibit strong preferences for certain care systems and should aid clinical decision-making when prescribing eye care systems to patients.

Possibilities of using neural network analysis in the diagnosis of dry eye syndrome

The prevalence rate of dry eye syndrome varies from 6.5 to 95 %. Diagnostic criteria are based on different methods and/or their combinations and are characterized by heterogeneity.The aim of the study. To identify the risk factors for the development of dry eye syndrome in order to create a technology for early diagnosis of the degree of the disease in young people without concomitant ocular and general somatic pathology.Materials and methods. Fifty patients aged 24 [22; 27] years were examined. We carried out an ophthalmological examination, including autorefractometry, visometry, biomicroscopy, the Norn test, a survey using the author’s questionnaire, and an assessment of the degree of dry eye syndrome using the Ocular Surface Disease Index (OSDI). Three study groups were formed: control group (OSDI = 0–13 points); group 1 – patients with OSDI = 14–22 points; group 2 – patients with OSDI &gt; 22 points.Results. When examining presented independent variables, screen time had the highest normalized importance (100 %), followed by tear film breakup time (58.4 %), smoking (24.3 %), night shifts (22.5 %) and using soft contact lenses (11.1 %). The technology for early diagnosis of the degree of dry eye syndrome is implemented on the basis of a multilayer perceptron, the percentage of incorrect predictions during its training process was 8.0 %. The structure of the trained neural network included 8 input neurons (the value of screen time and tear film breakup time, the presence or absence of smoking, night shifts and/or the use of soft contact lenses), two hidden layers containing 3 and 2 units, respectively, and 3 output neurons.Conclusion. The proposed neural network has no difficulties in assessing the early diagnosis of the severity of dry eye syndrome and can be used in clinical practice.

Drug-Modified Contact Lenses-Properties, Release Kinetics, and Stability of Active Substances with Particular Emphasis on Cyclosporine A: A Review.

The following review focuses on the manufacturing and parameterizing of ocular drug delivery systems (DDS) using polymeric materials to create soft contact lenses. It discusses the types of drugs embedded into contact lenses, the various polymeric materials used in their production, methods for assessing the mechanical properties of polymers, and techniques for studying drug release kinetics. The article also explores strategies for investigating the stability of active substances released from contact lenses. It specifically emphasizes the production of soft contact lenses modified with Cyclosporine A (CyA) for the topical treatment of specific ocular conditions. The review pays attention to methods for monitoring the stability of Cyclosporine A within the discussed DDS, as well as investigating the influence of polymer matrix type on the stability and release of CyA.

42‐2: Self‐Scalable UV Blocking Artificial Iris Operated by Radially Controlled Crosslinking Density with Fast Switching Dynamics

In the anatomy of human eye, the role of iris is crucial since it controls the light level entering the eye and enhances the visibility. Here, we propose a soft contact lens type artificial iris actuated by eternal UV (ultra‐violet) light source, self‐regulating its effective aperture size by varying the crosslinking density of bio‐compatible polymer matrix doped with photochromic dye. For its self‐regulating characteristic, we cured HEMA‐based polymer matrix gradually from center to edge. Since the polymer matrix is polymerized by heat, we utilized NIR (near infra‐red) lamp and gradient grayscale patterned photomask for its gradual characteristic. Thereby, the crosslinking density of central position is higher compared to that of peripheral, causing slow switching dynamics. The gradient difference in switching dynamics leads to artificial iris gaining self‐regulation dynamics of effective aperture. The manufactured artificial iris shows advantage in blocking UV light, self‐regulating, and fast switching dynamics. The switching dynamics of artificial iris under bright and dim light adaptation are less than 50 seconds and 120 seconds, showing similar property with human iris.

Influence of Face Mask on the Use of Soft Contact Lenses in Saudi Arabia

The COVID-19 pandemic is broadly streaked by face masks utilization. Face mask application has been believed as a potent reason of dry eye. We pursued to esteem the effectiveness of masks application on the visual quality of patients. Online questionnaire was carried to detect alterations happened with soft contact lenses usage during the pandemic relative to face masks employment. A total of 515 subjects participated in the study. Statistical analysis was performed with Microsoft Excel version 28 and proved that the use of contact lenses increased compared with before the pandemic (p ≥0.05). Subsequently, it was concluded that dry eye sensation was worse in monthly, weekly and daily contact lens wearers where p value was 0.037, 0.032 and 0.007 consecutively. Hence contact lens wearers, using a mask suffered from dry eye symptoms and reduced vision quality.

Soft Contact Lens Engraving Characterization by Wavefront Holoscopy.

Permanent engravings on contact lenses provide information about the manufacturing process and lens positioning when they are placed on the eye. The inspection of their morphological characteristics is important, since they can affect the user's comfort and deposit adhesion. Therefore, an inverted wavefront holoscope (a lensless microscope based on Gabor's principle of in-line digital holography) is explored for the characterization of the permanent marks of soft contact lenses. The device, based on an in-line transmission configuration, uses a partially coherent laser source to illuminate the soft contact lens placed in a cuvette filled with a saline solution for lens preservation. Holograms were recorded on a digital sensor and reconstructed by back propagation to the image plane based on the angular spectrum method. In addition, a phase-retrieval algorithm was used to enhance the quality of the recovered images. The instrument was experimentally validated through a calibration process in terms of spatial resolution and thickness estimation, showing values that perfectly agree with those that were theoretically expected. Finally, phase maps of different engravings for three commercial soft contact lenses were successfully reconstructed, validating the inverted wavefront holoscope as a potential instrument for the characterization of the permanent marks of soft contact lenses. To improve the final image quality of reconstructions, the geometry of lenses should be considered to avoid induced aberration effects.

Acrylamide‐Based Aramid‐Reinforced Soft Contact Lenses

In this study, manufacturing of acrylamide‐based soft contact lenses is attempted with high elastic modulus, tensile strength, water content, and oxygen transmissibility. For this purpose, colorless and transparent aramids are prepared using diamine monomers with strong electron‐withdrawing groups such as CF3 and sulfone groups. These aramids are used as reinforcing agents. These compounds are not only thermally and thermodynamically stable but also colorless, transparent, and mechanically very robust. They are very soluble in N,N‐dimethylacrylamide. Subsequently, reactive liquid resins are prepared simply by dissolving aramids in N,N‐dimethylacrylamide, and lenses are manufactured by the bulk polymerization of the liquid resins to which an appropriate amount of a crosslinking agent is added. Mechanically enhanced soft contact lenses are thus easily produced by the conventional manufacturing method. Some of the synthesized lenses maintain their original shape without phase separation even after hydration. These lenses have remarkably higher elastic modulus (up to 8.13 MPa) and tensile strength (up to 1.62 MPa) than the conventional lenses made of 2‐hydroxyethyl methacrylate (HEMA). The synthesized lenses also have a high water content (up to 83.0%) and oxygen transmissibility (up to 26.8 Dk t−1).

Assessment of large-diameter and small-diameter SoftK specialty contact lenses for early-stage keratoconus.

Soft contact lenses may be a good alternative for early-stage keratoconus (KC) patients who do not tolerate rigid gas permeable (RGP) lenses due to ocular discomfort or complications. This prospective study compared outcomes obtained after 2 weeks of wearing two types of soft silicone hydrogel contact lenses for keratoconus that varied in their diameter and central thickness (cc). Patients with Amsler-Krumeich grades I or II KC were fitted with small-diameter (14.2 or 14.8 mm) SoftK (SD-SoftK, cc = 0.48 mm) and large-diameter (17 mm) SoftK (LD-SoftK, cc = 0.60 mm) lenses, each worn for 2 weeks in a crossover design. Low (10%;10VA) and high (100%;100VA) contrast visual acuity, contrast sensitivity (CS, Pelli-Robson), higher order aberrations (HOAs, Visionix Vx130), the number of trial lens modifications during fitting and the subjectively preferred lens were compared using Friedman tests with post-hoc analysis. Forty eyes (N = 20, 10 males, mean age: 39.0 ± 9.9 years, range: 23-55 years) were examined. Their habitual median (interquartile1, interquartile3) 10VA (LogMAR), 100VA (LogMAR) and CS (LogCS) were 0.52 (0.30, 0.50), 0.14 (0.10, 0.15) and 1.35 (1.35, 1.50), respectively. For the SD-SoftK condition, the values were 0.23 (0.17, 0.30), 0.02 (0.00, 0.05) and 1.50 (1.50, 1.65), respectively. For the LD-SoftK condition, the respective values were 0.36 (0.27, 0.44), 0.09 (0.05, 0.13) and 1.50 (1.50, 1.60). SD-SoftK lenses significantly improved 10VA compared with habitual and LD-SoftK. SD-SoftK also significantly improved CS compared with habitual, but not LD-SoftK. LD-SoftK significantly improved spherical aberration compared with uncorrected (0.03 ± 0.10 μ vs. 0.07 ± 0.13 μ) but not SD-SoftK (0.04 ± 0.07 μ). Both lenses required a mean of 1.5 modifications prior to final lens fitting. Fewer adverse events were seen with SD-SoftK (N = 3) compared with LD-SoftK (N = 8), and 75% of participants preferred SD-SoftK lenses. SD-SoftK lenses were preferred by 75% of subjects, were associated with fewer adverse events and significantly improved 10VA compared with LD-SoftK lenses. SD-SoftK lenses also significantly improved CS compared with the habitual correction, but this did not differ significantly from the LD-SoftK lenses.