Soft Lenses Research Articles

Contact lenses in dry eye disease and associated ocular surface disorders.

Dry eye disease (DED) is prevalent in all age groups and is known to cause chronic ocular discomfort and pain, and greatly affects the quality of life. Patients with ocular surface disease (OSD) may also have reduced tear secretion due to lacrimal gland damage, thus leading to aqueous deficient DED. Even with conventional management modalities such as lubricating eyedrops, topical corticosteroids, autologous serum eyedrops, or punctal plugs, many patients continue to suffer from debilitating symptoms. Contact lenses are increasingly being used in OSD providing surface hydration, protection from environmental insults, mechanical damage from abnormal lids, and as a modality for constant drug delivery to the ocular surface. This review describes the role of soft lenses and rigid gas-permeable scleral lenses in the management of DED associated with OSD. The efficacy of contact lenses, lens selection, and optimal lens fit are reviewed for specific indications.

Incidence of Corneal Adverse Events in Children Wearing Soft Contact Lenses.

There is increasing interest in fitting children with soft contact lenses, in part due to the increase in prescribing of designs to slow the progression of myopia. This literature review summarizes large prospective and retrospective studies that include data on the incidence of microbial keratitis and corneal infiltrative events (CIEs) in children wearing soft contact lenses. Peer-reviewed prospective and retrospective studies that report contact lens-related complications in children with at least one year of wear and at least 100 patient years of wear were identified. Seven prospective studies published between 2004 and 2022 were identified representing 3,752 patient years of wear in 1,756 children, nearly all of whom were fitted at age 12 years or younger. Collectively, they report one case of microbial keratitis and 53 CIEs, of which 16 were classified as symptomatic. The overall incidence of microbial keratitis was 2.7 per 10,000 patient years (95% CI: 0.5-15), and the incidence of symptomatic CIEs was 42 per 10,000 patient years (95% CI: 26-69). Two retrospective studies were identified representing 2,545 patient years of wear in 1,025 children, fitted at age 12 years or younger. One study reports two cases of microbial keratitis giving an incidence of 9.4 per 10,000 patient years (95% CI: 0.5-15). Accurate classification of CIEs is challenging, particularly in retrospective studies. The incidence of microbial keratitis in children wearing soft lenses is no higher than in adults, and the incidence of CIEs seems to be markedly lower.

Biomimetic human eyes in adaptive lenses with conductive gels

To investigate the imaging effect, adaptive robust lenses are prepared by sealing transparent liquid or gel. Lenses are fabricated using the negative-pressure method, which is a benefit for a stable biconvex shape. Under the action of an electric field, the soft lens deforms following the dielectric elastomer actuator (DEA). DE (dielectric elastomer) membranes expand in the plane perpendicular to the electric field lines. The toroidal driving area leads to a decrease in lens diameter and an increase in convex curvature. Therefore, the focal length of the lens becomes shorter. The experimental measurement utilizes the double focal length method. As a result, the largest focal length change that could be achieved was 44.7% (190 mm→105 mm) of the soft lens using a DEA with carbon grease electrodes. Furthermore, the ECG (electrocardiogram) conductive gel could replace traditional carbon grease for DEA electrodes in optics. This type of transparent electrode is creatively applied to a biomedical lens. Under the same conditions, the electrostriction rate in a DEA with ECG gel was achieved at 33%, which was greater than that of 28% in a DEA coupled with carbon grease electrode. Adaptive lenses have characteristics such as easy fabrication, low cost, and strong operability, and they possess great potential application value in biomedical feild.

Harnessing Soft Elasticity of Liquid Crystal Elastomers to Achieve Low Voltage Driven Actuation

AbstractDielectric elastomers (DE) are soft electromechanical transducers that can generate large, rapid, and reversible deformation under an electric field. Despite being one of the leading candidates for soft actuators, the widespread applications of dielectric elastomers are restricted by the high voltage requirement (1–10 kV) for thin film DEs, which increases the system complexity and pose a potential safety threat for humans. In this work, a new class of dielectric elastomer actuators using liquid crystal elastomers (DLCEs) is reported. Soft elasticity of DLCEs and the high dielectric constant are utilized to reduce the actuation voltage. Freestanding DLCE thin film actuators (≈20 µm) are fabricated, which can generate large actuation strains (≈88%) at 400 V, an input voltage almost one order of magnitude lower compared to typical dielectric elastomers actuators. This allows to develop a soft tunable bilayer DE lens, which can achieve a 21% focal length variation at 500 V.

Efficacy of custom-made soft keratoconus lenses on corneal aberrations and photic phenomena in patients with keratoconus: a corneal topography imaging based study.

To evaluate the efficacy of custom-made soft keratoconus (KC) lenses on corneal aberrations and photic phenomena in two different optical zones in patients with KC. Sixty eyes of 42 patients with KC were examined at baseline and after fitting HydroCone (Toris K) soft silicone hydrogel lenses. Best spectacle-corrected visual acuity (BSCVA) and contact lens-corrected visual acuity (CLCVA) were recorded. Lower- and higher-order corneal aberrations (LOAs and HOAs) were measured with and without Toris K lenses and compared in central 4.5 mm and 7 mm zones. Mesopic pupil diameter and subjective photic phenomena were also assessed. Mean CLCVA was significantly improved compared to BSCVA (P<0.0001). Corneal curvature and refractive measurements were found to be significantly reduced by the use of Toris K lenses, except for posterior corneal curvature values. In the 4.5 mm central optical zone, all wavefront aberrations decreased significantly after lens fitting (P<0.0001). In contrast, in the 7 mm (peripheral) optical zone, values for HOAs, spherical and residual aberrations, and optical path differences were increased, while LOAs, trefoil, and quadrifoil coefficients were decreased. The rate of photic phenomena was significantly higher in participants with a pupil size >6.00 mm (85.7%). Toris K lenses provide good visual results and a significant reduction in central corneal aberrations in patients with KC but could cause an increase in peripheral aberrations. This practical and nonsurgical approach appears to be an effective method for the visual management of KC.

Minding the gap between the front and back offices: A systemic analysis of the offshore oil and gas upstream supply chain for framing digital transformation

AbstractThe offshore oil and gas upstream supply chain operations are part of a complex system with many stakeholders and intricate relationships. Traditionally, these operations are managed manually, which leads to inefficiencies. Despite the innovative and engineering‐orientated approaches adopted in other technical operations of the industry, the supply chain activities remain unchanged, relying heavily on legacy systems. However, cutting‐edge technology opportunities are available for adoption in supply chain management systems in the oil and gas industry. Such a transformative upgrade relies on first understanding the operational inefficiencies and preparing an accurate picture for how these operations should be performed. This study adopts a systemic approach to examine the oil and gas offshore supply chain operations of a case company to identify areas for improvement. The objective is to address the following research questions: (1) what is the current “AS‐IS” supply chain operations support; and (2) what is the desired “TO‐BE” state for these operations. This research adopts a soft systems lenses applied in an action research project to capture and analyze existing operations. The research revealed that information exchange is a major barrier, and that technology and organizational gaps are the primary hindrance for a digital transformation. The conclusion is that there is a need for a higher level of data exchange and increased data quality in any proposed transformation.

Peripheral defocus as it relates to myopia progression: A mini-review

Myopia is the most common refractive error in the world and has reached a pandemic level. The potential complications of progressive myopia have inspired researchers to attempt to understand the sources of myopia and axial elongation and to develop modalities to arrest progression. Considerable attention has been given over the past few years to the myopia risk factor known as hyperopic peripheral blur, which is the focus of this review. It will discuss the primary theories believed to be the cause of myopia and the parameters considered to contribute to and influence the effect of peripheral blur, such as the surface retinal area of blur or the depth of blur. The multitude of optical devices designed to provide peripheral myopic defocus will be mentioned, including bifocal and progressive addition ophthalmic lenses, peripheral defocus single-vision ophthalmic lenses, orthokeratology lenses, and bifocal or multifocal center distance soft lenses, as well as their effectivity as discussed in the literature to date.

The impacts of contact lenses on the short- and long-term biochemical parameters of tear films and corneal thickness

Introduction: To investigate the effects of long- and short-term use of different types of contact lenses on corneal metabolism and corneal thickness. Materials and Method: The participants were divided into two groups in the study. In the first group, 20 of the 42 patients were administered a rigid gas-permeable lens (RGPL) with a Dk value of 92x10-11, while the remaining wore a soft contact lens with a water content of 38%. We then explored their Lactate Dehydrogenase (LHD) levels to evaluate the hypoxic effect on tear films in short- (8 hours) and long-term (2nd, 3rd, 5th months) and albumin levels to assess mechanical trauma. In the second group, the corneal thickness was measured using a Haag-Streit optical pachymeter before and at the 8th hour and 2nd month following the first set of lenses, and LDH and albumin values were simultaneously evaluated in tear film. Results: The results yielded no significant increase in tear film LDH and albumin levels in the short- and long-term in both the RGPL and the soft contact lens groups with similar age and sex distribution. In the second part, the corneal thickness measurements resulted in an increase of 5.5% in the RGPL group and 3.63% in the soft lens group at the 8th hour of lens use. However, the groups did not significantly differ by baseline corneal thickness at the 2nd-month follow-up. Similarly, there was no significant increase in LDH and albumin levels in the tear film samples of the same group. Conclusion: The absence of a long-term increase in corneal thickness and no elevated levels of albumin and LDH in tear films indicate that contact lenses fit corneal physiology.

Characteristics and Complications of Cosmetic Contact Lens

Cosmetic contact lenses are soft lenses dyed for cosmetic enhancement. Their use has increased over time in Korea, especially among adolescents, but they are associated with certain complications. We compared the characteristics of cosmetic and conventional soft contact lenses, as well as the complications and treatments therefor.

Rigid Gas Permeable Contact Lens Management of Infantile Aphakia Status-Post Cataract Extraction

Infants born with congenital cataracts require cataract extraction to prevent lifelong visual impairment resulting from deprivational amblyopia. After lensectomy, two optimal corrective treatment options exist: intraocular lens implantation or contact lens correction. This case presentation describes the etiology, treatment, and successful management of a patient with unilateral infantile aphakia with a rigid contact lens. The seven-week-old patient with a congenital cataract of the right eye was referred to our clinic for a contact lens fitting prior to cataract extraction. Surgeons often do not elect to manage aphakia with artificial lens implantation because the correct intraocular lens parameter is difficult to infer in a rapidly growing child, and surgical complications may occur. While glasses are important for when contact lens wear is not indicated, the high prescription required by these aphakic individuals results in significant visual distortion and aniseikonia. Contact lens correction has shown to be a safe and visually effective alternative to treating infantile aphakes. Various material options exist, including rigid gas permeable and soft lenses. While soft hydrogel lenses may appear more comfortable and less intimidating to a parent, limitations exist including restricted parameter availability for commercially produced lenses and reduced oxygen permeability for custom soft lenses. Rigid contact lenses provide optimal visual correction due to their extensive customizability while also offering high oxygen permeability. This lens modality, in conjunction with proper follow-up monitoring and ophthalmological co-management, provided for successful aphakia treatment in our patient. &lt;br&gt;CE Notification: This article is available as a COPE accredited CE course. You may take this course for 1-hour credit. Read the article and take the qualifying test to earn your credit. Click here to Enroll. (https://www.crojournal.com) Please check COPE course expiry date prior to enrollment. The COPE course test must be taken before the course expiry date.

Role of Corneal Collagen Cross Linking in Halting the Progression of Keratoconus: A Contralateral Eye Study

Objective: To assess the efficacy of Corneal Collagen Cross-Linking in preventing the progression of Keratoconus by comparing changes in Maximum Simulated Keratometry (K-max) in treated and untreated eye of the same patient. Methodology: All the cases, that met the inclusion/exclusion criteria (with complete pre-operative examinations), were enrolled in the study. Patients gave informed permission. In each patient, a computerized random number table was used to pick one eye for treatment and the other as a control. Patients were told to stop wearing hard contact lenses 3 weeks before the treatment and soft lenses 1 week before. After pre-op assessment, the selected eye underwent CXL. To control bias, only one experienced surgeon carried out the procedure and a thorough examination was done at 1st post-op day, 01 week, 01, 03 and 4 months after CXL. Main outcome measure during follow up was K-max as measured by Corneal Topography using Galilei G4. One experienced person performed corneal topography for all eyes to control bias. Results: In our study, mean age was 20.55+6.27 years, 60.61%(n=20) were male while 39.39%(n=13) were females. Comparison of the efficacy of corneal collagen cross-linking in preventing the progression of keratoconus by comparing changes in maximum simulated keratometry (K-max) in treated and untreated eyes of the same patient shows that 96.97%(n=32) in CXL and 3.03%(n=1) in control group showed efficacy whereas remaining 3.03%(n=1) in CXL and 96.97%(n=32) in control group had no efficacy, p value was 0.000. Conclusion: We concluded that Corneal Collagen Cross Linking is significantly effective in preventing increase in K-max when compared with the control group. Keywords: Keratoconus, Maximum Simulated Keratometry, Corneal Collagen Cross-Linking, Efficacy

Print Media Portraying Pak-China Education Collaboration Through Soft Power lens

The study examines the connection between Pakistan and China in education through an evaluation of print media. The purpose is to discover how Pakistani media portray the relationship between Pakistan and China from a soft-power perspective. The Down, News and Educationists, three press outlets, have been followed (2010-2019). The data was divided into four streams. Pakistani students moving to China to study in China are included. The second wave studied publications citing Chinese schooling news in Pakistan. In the third flow, the researcher examined articles on the movement of Pakistani education into China. In the fourth flow, the researcher looked at articles on how China improves its education system, policies, and what Pakistan may learn. China and Pakistan have partnered in research and technology, according to the article. The Chinese Government supports Chinese education through several bursaries and bourses and the introduction of numerous technology-based programs for Pakistani students. This study evaluated how China used Soft power to promote Pakistan-China relations and how the print media depicted it.

Contact Lens Prescribing Patterns in a University Clinic in Trinidad and Tobago.

The study assessed the contact lens prescribing patterns and associated factors in a university optometry clinic in Trinidad and Tobago. The data relating to habitual or new contact lens (CL) prescribing patterns among wearers over a two-year period were reviewed. Pearson’s chi-squared test and logistic regression models were used to analyze the findings. The Hosmer–Lemeshow goodness-of-fit test was used to examine the model calibration. A total of 243 CL fits were analyzed, and the Homeshow–Lemeshow goodness-of-fit test indicated a good fit (χ2 (7) = 7.296, p = 0.399). The mean age of lens wearers was 29.6 ± 12.4 (mean ± SD); the majority, 155 (63.8 %) of whom, were 21 to 40 years old. Most lenses were fitted on females (64.2% of fits overall) and about half of the wearers (n = 122, 50.2%) were prescribed lenses for cosmetic purposes. Conventional soft CL were the most prescribed modality of wear, accounting for 129 (53.1%) of the fits. Age from 21 to 40 years was the predictor of lens type prescribed, and those in that age range were four times more likely to be prescribed soft lenses compared to other ages. The patterns of CL prescribing in a university optometry clinic in Trinidad and Tobago are similar to the global market trends with slight variations.

Acanthamoeba Keratitis Risk Factors for Daily Wear Contact Lens Users: A Case–Control Study

This study was designed to establish risk factors for the development of Acanthamoeba keratitis (AK) for daily disposable (DD) contact lens (CL) users compared with daily wear (DW) reusable lens users and for risks unique to DD users. This is important because, in many major economies, CL use is the principal cause of microbial keratitis, of which AK accounts for approximately 50% of cases with sight loss. Determining these AK risks informs practitioner advice and consumer behavior. Case-control study. Cases and controls were recruited from an Accident and Emergency Department serving South-East England. Cases were new CL users with AK recruited retrospectively from January 2011 to February 2013 and prospectively thereafter until August 2014. Controls were recruited prospectively from February 2014 to June2015. Analysis of a self-administered questionnaire. Independent risk factors and population attributable risk percentage (PAR%) for AK. A total of 83 AK cases and 122 controls were recruited; DD use was reported by 20 (24%) cases and 66 (54%) controls. In multivariable analyses adjusted for potential confounders, the odds of AK was higher for DW reusable soft lenses (odds ratio [OR], 3.84; 95% confidence interval [CI], 1.75-8.43) and rigid lenses (OR, 4.56; 95% CI, 1.03-20.19) than for DD lenses. Within the DD-using subset, AK was associated with the following modifiable risk factors: less frequent professional follow-up visits (OR, 10.12; 95% CI, 5.01-20.46); showering in lenses (OR, 3.29, 95% CI, 1.17-9.23); lens reuse (OR, 5.41; 95% CI, 1.55-18.89); and overnight wear (OR, 3.93; 95% CI, 1.15-13.46). The PAR% estimated that 30% to 62% of cases could be prevented by switching from reusable soft lens to DD lens use. Acanthamoeba keratitis risks are increased > threefold in DW reusable lens users versus DD lens use. Acanthamoeba keratitis risks for DD lens users can be minimized by adherence to safe use guidelines (no reuse, overnight wear, or contamination by water). Safe CL use can be improved by increasing the prominence of risk avoidance information from manufacturers and regulators. Because AK accounts for half of severe keratitis in CL users, these measures can be expected to have public health benefits.

Effect of poly(ethylene glycol) methacrylate on the ophthalmic properties of silicone hydrogel contact lenses

In this study, silicone hydrogels were synthesized via the photoinitiated free radical polymerization of 3-(methacryloyloxy)propyltris(trimethylsiloxy) silane (TRIS), 1-vinyl-2-pyrrolidinone (NVP), methacrylic acid (MAA), and poly(ethylene glycol) methacrylate (PEGMA), with ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2-hydroxy-2-methylbenzene acetone (D-1173) as the photoinitiator. The equilibrium water content (EWC) and oxygen permeability (Dk) of the synthesized silicone hydrogel polymers were linearly proportional to the hydrophilic PEGMA content. The high PEGMA content of the polymers led to a higher EWC, lower Dk, and lower contact angle. The highest Dk value of the soft lens was 73 barrers, which corresponded with the lowest EWC (31 %) value of the hydrogel without PEGMA. The stiffness of the hydrogel decreased with increasing PEGMA content. The silicone hydrogel adsorbed low amounts of lysozymes and human serum albumin (HSA) due to the anti-fouling properties of PEG moiety. In addition, the synthesized silicone hydrogels were non-cytotoxic as determined by an in vitro L929 fibroblast assay. Therefore, the TRIS-NVP-MAA-PEGMA hydrogel can be potentially used as a contact lens material with adjustable EWC, Dk, and low protein adsorption.

Stepless shape morphing polymer

AbstractTo change the situation of shape memory polymers (SMPs) that can only remember very few shapes and enable discretional morphing for practical application, the authors report a reversible stepless multiple SMP derived from ultrahigh molecular weight polyethylene (UHMWPE). As the crystals of semi‐crystalline polymers are assembled by those with slightly different melting temperatures, and each type of crystal can remember a single shape, the crystalline region of UHMWPE is allowed to remember plenty of temporary shapes after programming. Changing the temperature of the programmed polymer within the melting/crystallization temperature ranges would lead to releasing/recovery of the memorized temporary shapes. Accordingly, multiple shape memory effects can be easily realized without an elaborate design of material structure and training process in advance as before. The temperature‐dependent adjustability of the analog capacitor and soft lens with embedded programmed UHMWPE as actuators, characterized by the continuous/random/proportional responsivity, further reveals the utilization prospects of the controllable reversible stepless discretionary morphing effect. Moreover, the maximum work density of the programmed UHMWPE is found to be 210 kJ/m3, which is more than 10 times of piezoelectric ceramics, so that it can serve as a proof‐of‐concept mechanical driver for reversibly pumping of ethanediol‐droplet upon heating/cooling.

The Use of Soft Contact Bandage Lenses for Corneal Ulcer in Dogs and Cats: A Review

A corneal ulcer is the characteristic of the destruction of the corneal epithelium layer and loss of the stroma layer at various depths. At present time, soft bandage contact lenses are used in many countries for corneal ulcers in dogs and cats to protect their cornea, increase contact time with topical eyes solutions, and support corneal reepithelialization. This article aimed to review information on the use of soft contact bandage lenses to treat corneal ulcers in dogs and cats interms of their efficacy and precaution. The results of the present review have revealed that soft contact bandage lenses are used to protect the cornea, enhance contact time with topical eye treatments, reduce median healing time, and provide comfort in dogs and cats with corneal ulcers. In the case of serious infections and dry eyes, soft contact bandage lenses are not recommended. Keywords: Corneal ulcer, Incidence, Soft contact bandage lenses, Treatment

The impact of a rub and rinse regimen on removal of human coronaviruses from contemporary contact lens materials

PurposeTo assess the influence of contemporary contact lens (CL) materials on human coronavirus attachment and the influence of a rub and rinse step to remove these viruses. MethodsThe binding rates of HCoV-229E and HCoV-OC43 to eight soft CL materials and four rigid gas permeable materials were analyzed. The impact of a rub and rinse step to remove these viruses from all materials was examined. The efficacy of Biotrue (Bausch & Lomb), OPTI-FREE Puremoist (Alcon), Clear Care (Alcon) and cleadew (Ophtecs) to remove virus contamination from two representative soft lens materials (etafilcon A and lotrafilcon B) was also determined. ResultsApproximately 102 to 103 infectious viral particles were recovered from each CL material. Although some materials were more prone to coronavirus adhesion, contamination of both viral types was reduced to below the limit of quantification (LQ) from all materials using a simple saline rinse step. Exposure to Clear Care and cleadew reduced the number of infectious viral particles from both etafilcon A and lotrafilcon B to below the LQ, while for Biotrue and OPTI-FREE Puremoist, infectious viral particles were reduced to below the LQ only when additional rub and rinse steps were included. ConclusionHuman coronavirus contamination can be easily removed from CL surfaces. Although CL care products containing hydrogen peroxide and povidone-iodine efficiently removed virus contamination from CL surfaces without the need for a rub and rinse step, a full regimen including rub and rinse steps is crucial when using CL care products based on non-oxidative systems.

Miniature and tunable high voltage-driven soft electroactive biconvex lenses for optical visual identification

Soft electroactive materials including dielectric elastomer (DE) and polyacrylamide (PAM) hydrogel have recently been investigated, which can provide exciting opportunities for optical imaging and biomedical engineering. We propose a tunable liquid lens based on PAM hydrogels, and the miniature lens is also composed of a dielectric elastomer actuator (DEA) and an ionic liquid enclosed. When a biconvex lens is fabricated, a bubble needs to be voided by controlling the pressure. The lens DEA based on PAM electrodes has various resistances that decrease with the stretch. However, it is a constant of 0.49 Ω for the DEA coupling carbon grease electrodes. In a high voltage-driven state, the curvature radius of the lens increased. As a result, the focal length was tuned and enlarged. Computational models are derived for the soft-actuated liquid lens, which improves the existing related theory by detail. Especially, the relationship between voltage and focal length is deduced and verified by experiments. The computational models and experimental phenomena are consistent. Moreover, an increase in pre-stretch and voltage produces a wider tenability range. This study opens the soft electroactive biconvex lenses in potential optical healthcare rehabilitation and optical visual identification applications.

Pengelompokan Barang Menggunakan Metode K-Means Clustering Berdasarkan Hasil Penjualan Di Toko Widya Bengkulu

The Widya shop sells various kinds of hijab products that are tailored to the needs of fashion development. The Widya Bengkulu store also sells various kinds of women's needs such as clothes, accessories, bags, wallets, soft lenses, cosmetics and other fancy items. So far, Widya Store has not used computers as a data processing medium. All processes of selling goods and inventory of goods are still carried out with book records, and do not yet have an application that can help the process of managing the data of these goods. In addition, in managing inventory, Toko Widya only sees stock based on sales results, if the stock on one of the items runs out, an order will be made to the supplier.&#x0D; Implementation of the K-Means Clustering Method in Grouping Goods Based on Sales Results at the Widya Bengkulu Store was made using the Visual Basic .Net programming language and SQL Server 2008 database. In the Grouping of Goods Based on Sales Results at the Widya Bengkulu Store, it will be processed to seek knowledge from chunks of data, namely goods sales data. Cluster I is a Very Selling Item, Cluster II is a Self Selling Item, and Cluster III is a Less Selling Item. Based on the results of the tests that have been carried out, the application of Grouping Goods Based on Sales Results at the Widya Bengkulu Store can provide information on the best-selling items sold at the Widya Store.&#x0D;