Binocular vision parameters and visual performance in bilateral keratoconus corrected with spectacles versus rigid gas-permeable contact lenses / Parámetros de visión binocular y rendimiento visual en queratocono bilateral corregido con gafas versus lentes de contacto rígidos permeables al gas

Purpose: To analyze binocular vision of individuals aged 18 to 35 years diagnosed with keratoconus, utilizing spectacles and rigid gas-permeable (RGP) contact lenses. Research was led by the Universidad Autónoma de Aguascalientes, México and Fundación Universitaria del Área Andina Pereira, Colombia. Methods: A single center, prospective non-randomized, comparative, interventional, open-label study, in which the differences in binocular vision performance with both spectacles and RGP contact lenses was carried out from December 2018 to December 2019. Sampling was performed according to consecutive cases with keratoconus that met the inclusion criteria until the proposed sample size was reached. Results: Rigid gas-permeable (RGP) contact lenses notably enhanced distance and near visual acuity in keratoconus patients compared to spectacles. Visual alignment analysis shows exophoria at both distances and is slightly higher with RGP contact lenses. The difference was statistically significant (p<0.05), with 82.5 % presenting compensated phoria with spectacles and pnly 42.50% with RGP contact lenses. Stereoscopic vision improved while wearing RGP contact lenses (42.59 %), although accommodation and accommodative flexibility remained within normal ranges. Conclusions: Patients with keratoconus fitted with RGP contact lenses have improved binocular vision skills such as visual acuity, stereopsis, and accommodative flexibility. However, even when the vergence and motor system is decompensated with respect to normal ranges, the range between break and recovery points for both fusional reserves and the near point of convergence (NPC) improves with the use of RGP contact lenses, giving indications of an adaptive condition of the motor system from the medium to the long term.(AU)

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

BACKGROUND: To avoid risks of mucosal infection from contact lenses removal, a contact lens plunger is often used. OBJECTIVE: 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. METHODS: 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: 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). CONCLUSIONS: 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.

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.

Scleral Lenses for Managing Dry Eye Disease in the Absence of Corneal Irregularities: What Is the Current Evidence?

Scleral lenses (SLs) are large-diameter rigid contact lenses that are a mainstay treatment for eyes with corneal irregularities. In recent years, there has been increased interest in the role of managing dry eye disease (DED) with SLs, as many patients with DED have reported symptomatic relief with SL wear. The role of SLs for DED management when there are associated corneal irregularities is supported by individual case reports and studies. This has prompted practitioners to begin advocating using SLs in DED cases, even in the absence of associated corneal irregularities and other ocular surface diseases (OSDs). There have also been discussions on potentially placing SLs earlier in the treatment hierarchy of DED, where it currently sits at a more advanced level of intervention (Step 3) in the TFOS DEWS II Report. This review will present the currently available, albeit sparse, evidence that supports and suggests this practice, as well as ancillary evidence supporting the purported benefits of SL wear in DED. The advantages of SL wear, such as corneal healing, absence of tear evaporation and contact lens dehydration, and improved visual acuity with associated increased wear comfort, and how this will benefit DED patients will be explored. Conversely, the challenges associated with fitting SLs in DED patients, including increased midday fogging, poor wettability, and subjective patient satisfaction, will also be presented, as well as a discussion on the key considerations for SL fitting in this population. Overall, while more research is needed to support the use of SLs in DED patients without associated corneal irregularities and other forms of OSD, the use of these lenses may prove to have a potentially wider role given their reported ancillary benefits in these populations.

Sustained descemetocele management with Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) treatment.

Purpose: To report a case of a 67-year-old male who was successfully managed over a 7-year period for descemetocele secondary to ocular graft versus host disease (oGVHD) using Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) treatment. Observations: We previously reported on a patient managed with a PROSE device for severe dry eyes secondary to oGVHD, who subsequently developed a central corneal descemetocele. The patient was deemed a poor surgical candidate due to limbal stem cell deficiency secondary to oGVHD. Therefore, we elected to closely monitor the descemetocele as the patient continued PROSE therapy. The patient's descemetocele has been managed successfully without perforation throughout a 7-year follow-up period with corrected distance visual acuity remaining stable at 20/50 in the affected eye. Conclusions and importance: Descemetoceles are an uncommon complication of ocular graft versus host disease. This is the longest published report of a corneal descemetocele managed with PROSE. Our report suggests that in appropriate patients who are at high-risk for post-surgical complications, PROSE in conjunction with other medical management should be considered as an alternative to corneal transplantation.

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

BACKGROUND: Previous studies have suggested that light rays may interact with contact lenses, potentially affecting their transmittance. AIM: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Contact lenses as a potential vehicle of Candida transmission.

PURPOSE: Contact lenses can be contaminated with various microorganisms, including pathogenic yeasts of the genus Candida, which are known for their ability to adhere to abiotic surfaces, including plastic materials used for various medical purposes. Microbial contamination of the lenses can lead to infection of the wearer's eyes. The purpose of this study was to simulate the contamination of contact lenses with C. albicans and C. parapsilosis, analyze the interaction of the microorganisms with the lens material, and optimize the protocol for PCR-based analysis of the microbial agents responsible for lens contamination. METHODS: Hilafilcon lenses were exposed to C. albicans and C. parapsilosis cultures, washed, and examined for their ability to further spread the contamination. Scanning electron microscopy was used to analyze the attachment of yeast cells to the lenses. Infrared spectroscopy was used to examine the potential changes in the lens material due to Candida contamination. The protocol for DNA isolation from contaminated lenses was established to enable PCR analysis of microbes attached to the lenses. RESULTS: Hilafilcon lenses contaminated with Candida were able to spread the contamination even after washing with saline or with a commercial cleaning solution. In the present experimental settings, the yeasts did not grow into the lenses but began to form biofilms on the surface. However, the ability of the lenses to retain water was altered. The PCR-based protocol could be used to help identify the type of contamination of contact lenses. CONCLUSION: Once contaminated with Candida albicans or Candida parapsilosis, Hilafilcon contact lenses are difficult to clean. Yeasts began to form biofilms on lens surfaces.

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.

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.

Visual rehabilitation with mini scleral contact lenses in scarred corneas.

PURPOSE: To present a case series of patients with corneal scars who were successfully fitted with mini scleral contact lenses (mSCL). METHODS: Case series study. RESULTS: Six eyes of six patients with corneal scars were fitted with mSCLs. All scars were situated in the visual axis within the scotopic pupillary zone. The sizes of the scars varied, with the smallest being confined to a central corneal area (case 5) and the largest covering the entire visual axis (case 2). In addition to compromising corneal transparency, these scars also induced significant corneal irregularities, especially in cases 1, 3, and 4. The average corrected distance visual acuity (CDVA) with spectacles was 20/80, with a range of 20/200 to 20/40. With the use of mSCLs, CDVA improved to an average of 20/25, ranging from 20/40 to 20/16. The mean visual acuity improvement observed was five optotype lines, with a range of 3 to 7 lines. CONCLUSION: Corneas with scars often exhibit increased higher-order aberrations (HOA), and affected patients not only experience reduced vision but also suffer from seriously reduced optical quality and optical phenomena such as photophobia. Utilizing mSCLs in such individuals can significantly enhance visual acuity and improve optical side effects resulting from corneal opacity and irregularity.

Compatibility of a New Ocular Surface Dye with Disposable and Bi-Weekly Soft Contact Lenses: An Experimental Study.

Ocular surface staining for assessing corneal and conjunctival epithelium integrity is typically conducted using fluorescein, lissamine green, or rose Bengal dyes. Recently, a novel vital dye, REmark®, based on riboflavin, has been proposed for ocular surface examination. In the management of corneal and ocular surface diseases (OSD), the use of contact lenses is integral to therapeutic strategies. This study explores the compatibility of REmark® with four different types of disposable or bi-weekly soft contact lenses. Morphological variations observed under stereomicroscopy and ultraviolet (UV) ray transmittance in the visible spectrum (VIS) were evaluated at 2 and 4 h post-immersion of the contact lenses in both the original fluid and the new dye. The findings indicate no significant differences between the group treated with the original liquid and those immersed in REmark®, except for a yellow hue observed in the latter group, which dissipates after 8 h in physiological solution. This study highlights the potential of utilizing the new vital dye for ophthalmologic examinations even in the presence of applied soft contact lenses, offering a promising avenue for improved diagnostic practices and patient comfort.

[Comparative analysis of clinical and functional parameters in patients with stable stage II-III keratoconus after implantation of corneal segments and fitting of scleral rigid contact lenses]. / Sravnitel'nyi analiz kliniko-funktsional'nykh pokazatelei u patsientov so stabil'nym keratokonusom II­III stadii posle implantatsii rogovichnykh segmentov i podbora skleral'nykh zhestkikh kontaktnykh linz.

The modern treatment strategy for keratoconus (KC) involves sequential application of medical technologies aimed at stabilizing pathological changes in the cornea and restoring visual acuity. PURPOSE: This study compares the effect of implantation of intrastromal corneal ring segment (ICRS) and fitting of individual scleral rigid contact lenses (RCLs) on visual functions in patients with stage II-III KC after previously performed corneal collagen cross-linking. MATERIAL AND METHODS: The Helmholtz National Medical Research Center of Eye Diseases examined and treated 34 patients (69 eyes) aged 18 to 33 years with stage II-III KC. The study included patients who had previously undergone standard corneal collagen cross-linking. Depending on the type of optical correction, the patients were divided into two groups: patients in group 1 underwent ICRS implantation using a femtosecond laser; patients in group 2 were fitted with individual scleral RCLs. RESULTS: Improvement in clinical and functional parameters was observed in both groups. A higher clinical and functional result was achieved in group 2. CONCLUSION: For patients with stable stage II-III KC, it is advisable to recommend fitting of individual scleral RCLs for visual rehabilitation.

Assessing neophyte response to daily disposable silicone hydrogel contact lenses: A randomised clinical trial investigation over one month.

OBJECTIVE: This randomised clinical trial assessed the impact on symptoms, tear film dynamics and ocular surface integrity of daily disposable silicone-hydrogel contact lenses (CLs) over a month, paying special attention to lid wiper epitheliopathy (LWE) and its implications for CL discomfort. METHODS: Neophyte CL wearers (n = 44, 21.09 ± 5.00 years old) were randomly assigned to either the experimental (n = 24) or control group (n = 20). Participants assigned to the experimental group were required to wear daily disposable CLs for 1 month for at least 8 h/day and 6 days/week. All participants were healthy subjects (no history of ocular surgery or active ocular disease) with spherical refractive errors between -8.00 and +5.00 D and cylindrical power <0.75 D. At the baseline and 1-month sessions, the Dry Eye Questionnaire 5 (DEQ-5) was completed, together with the measurement of tear film osmolarity with the TearLab osmometer, tear meniscus height (TMH) and lipid layer pattern (LLP) using a slit-lamp with Tearscope Plus attached, fluorescein break-up time (FBUT), maximum blink interval (MBI), corneal staining with fluorescein under cobalt blue light and LWE with lissamine green under slit lamp and halogen white light. RESULTS: At the baseline session, LWE showed a negative correlation with DEQ-5 (r = -0.37, p = 0.02). Significant differences in FBUT and LWE (p = 0.04) and a positive correlation between LWE and DEQ-5 (r = 0.49, p = 0.007) were observed at 1 month. Intrasession analysis at 1 month showed significant differences between the experimental and control groups in DEQ-5, FBUT and LWE (all p ≤ 0.02). Intersession analysis in the experimental group showed variations in DEQ-5, FBUT and LWE (all p ≤ 0.02) but no significant variation in the control group (all p ≥ 0.11). CONCLUSION: The presence of LWE was significantly correlated with higher symptom values in the DEQ-5. Also, participants in the experimental group presented higher values of LWE after 1 month of CL wear, in comparison with the control group.

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

INTRODUCTION: 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). METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Refractive surgical approaches to keratoconus: A systematic review and network meta-analysis.

Advancements in diagnostic methods and surgical techniques for keratoconus (KC) have increased non-invasive treatment options. Successful surgical planning for KC involves a combination of clinical science, empirical evidence, and surgical expertise. Assessment of disease progression is crucial, and halting the progression should be the focus if it is progressive. While surgeons used to rely on experience alone to decide the surgical method, comparing the network of primary factors, such as visual acuity, across studies can help them choose the most appropriate treatments for each patient and achieve optimal outcomes. Meticulous tabulation methods facilitate interpretation, highlighting the importance of selecting the correct surgical and rehabilitation approach based on each patient's condition and stage of the disease. We detail the outcomes of a comprehensive network meta-analysis comparing the effectiveness of various combined therapeutic refractive treatments for KC at identical stages of the disease, spanning 4 distinct follow-up intervals. Additionally, the comprehensive analysis suggests that for corneas with optimal best corrected visual acuity (BCVA) preoperatively (classified as regular), combining phakic intraocular lenses with intracorneal ring segments (ICRS) and corneal cross-linking (CXL) could offer the best therapeutic approach provided the disease stage does not exceed stage 3. For irregular corneas, although initial follow-ups show a significant difference in BCVA with surface ablation, longer-term follow-ups recommend combining surface ablation with ICRS and CXL, especially at higher stages.

Contact lenses as novel tear fluid sampling vehicles for total RNA isolation, precipitation, and amplification.

The tear fluid is a readily accessible, potential source for biomarkers of disease and could be used to monitor the ocular response to contact lens (CL) wear or ophthalmic pathologies treated by therapeutic CLs. However, the tear fluid remains largely unexplored as a biomarker source for RNA-based molecular analyses. Using a rabbit model, this study sought to determine whether RNA could be collected from commercial CLs and whether the duration of CL wear would impact RNA recovery. The results were referenced to standardized strips of filtered paper (e.g., Shirmer Strips) placed in the inferior fornix. By performing total RNA isolation, precipitation, and amplification with commercial kits and RT-PCR methods, CLs were found to have no significant differences in RNA concentration and purity compared to Schirmer Strips. The study also identified genes that could be used to normalize RNA levels between tear samples. Of the potential control genes or housekeeping genes, GAPDH was the most stable. This study, which to our knowledge has never been done before, provides a methodology for the detection of RNA and gene expression changes from tear fluid that could be used to monitor or study eye diseases.

Potential of a laser pointer contact lens to improve the reliability of video-based eye-trackers in indoor and outdoor conditions.

Many video-based eye trackers rely on detecting and tracking ocular features, a task that can be negatively affected by a number of individual or environmental factors. In this context, the aim of this study was to practically evaluate how the use of a scleral contact lens with two integrated nearinfrared lasers (denoted CLP) could improve the tracking robustness in difficult lighting conditions, particularly outdoor ones. We assessed the ability of the CLP (on a model eye) to detect the lasers and to deduce a gaze position with an accuracy better than 1° under four lighting conditions (1 lx, 250 lx, 50 klux and alternating 1lx /250 lx) on an artificial eye. These results were compared to the ability of a commercial eye tracker (Pupil Core) to detect the pupil on human eyes with a confidence score equal to or greater than 0.9. CLP provided good results in all conditions (tracking accuracy and detection rates). In comparison, the Pupil Core performed well in all indoor conditions (99% detection) but failed in outdoor conditions (9.85% detection). In conclusion, the CLP presents strong potential to improve the reliability of video-based eyetrackers in outdoor conditions by providing easy trackable feature.

Infectious keratitis associated with contact lens wear: REGINFECOR multicenter study.

This 32-centre multicentre study addresses the lack of knowledge about the prevalence and significance of microbial keratitis (MK) associated with contact lens (CL) wear in Spain. A total of 304 cases recruited from 32 hospitals were studied and showed that infectious keratitis associated with contact lens wear mainly affects young women during the summer months. In this study, soft lenses with monthly replacement and single solution cleaning were most commonly used, purchased and fitted in opticians' shops. Common risk factors were identified among users, such as topping off solutions, prolonging the life of lenses, and frequently sleeping, swimming and showering with lenses. Overnight lens wear was significantly associated with a higher incidence of corneal opacities, and the presence of Pseudomonas aeruginosa in bacterial cultures was associated with more severe sequelae and a greater need for corneal transplantation. Although most cases were benign, the time taken to heal was long, which poses a problem for working patients. This study provides valuable epidemiological, microbiological and risk factor information and estimates the incidence of CL related MK in Spain to be approximately 1 case per 30,000 inhabitants per year.

Wearable smart contact lenses: A critical comparison of three physiological signals outputs for health monitoring.

Smart contact lenses (SCLs) have been considered as novel wearable devices for out-of-hospital and self-monitoring applications. They are capable of non-invasively and continuously monitoring physiological signals in the eyes, including vital biophysical (e.g., intraocular of pressure, temperature, and electrophysiological signal) and biochemical signals (e.g., pH, glucose, protein, nitrite, lactic acid, and ions). Recent progress mainly focuses on the rational design of wearable SCLs for physiological signal monitoring, while also facilitating the treatment of various ocular diseases. It covers contact lens materials, fabrication technologies, and integration methods. We also highlight and discuss a critical comparison of SCLs with electrical, microfluidic, and optical signal outputs in health monitoring. Their advantages and disadvantages could help researchers to make decisions when developing SCLs with desired properties for physiological signal monitoring. These unique capabilities make SCLs promising diagnostic and therapeutic tools. Despite the extensive research in SCLs, new technologies are still in their early stages of development and there are a few challenges to be addressed before these SCLs technologies can be successfully commercialized particularly in the form of rigorous clinical trials.

Wear Experiences with Two Soft Contact Lenses for Astigmatism of Different Modalities.

Introduction: Patients expect to have excellent vision and comfort when wearing soft contact lenses. The purpose of this study was to compare the wear experiences of participants with astigmatism when wearing a daily disposable soft toric lens to an established, commonly used reusable toric lens. Methods: In this crossover study, habitual soft toric lens wearers were fit with a daily replacement soft toric lens (delefilcon A) and a reusable, 1-month replacement soft toric lens (comfilcon A) in a randomized order. After 30 days of wear, Visual analog scale (VAS) surveys were used to assess wear experience, including vision and comfort, for overall wear and end-of-day wear. Scores were compared statistically with mixed-effects linear models. Participants also responded to questions about convenience, ease of use, and satisfaction with both lenses and preference questions based upon comfort, vision, and overall performance. Results: Fifty-nine participants completed the multi-site crossover study. VAS scores [mean(std dev)] for overall quality of vision for the delefilcon A [80.4(16.4)] and comfilcon A [66.8(27.7)] lenses were statistically significant (P=0.002). The difference in the mean overall comfort scores for the delefilcon A lenses [71.6(26.3)] and comfilcon A lenses [63.2(28.9)] was 8.4, which exceeds the establish criteria for clinical significance, although not statistically significant (P=0.08). Overall satisfaction scores were 68.8(26.9) for the delefilcon A and 59.7(30.3) for the comfilcon A lenses (P=0.08). Both lenses provided mean binocular visual acuities better than 20/20 Snellen equivalent. Over half of the participants preferred the delefilcon A lenses based upon comfort, vision, and overall performance. Convenience, ease of use, and satisfaction all scored higher with delefilcon A lenses. Conclusion: The results of this study show that wear experience with delefilcon A lenses for astigmatism can meet or exceed that of comfilcon A toric lenses while also providing healthy, daily disposable lens wear.