Evaluation of Pollen Adhesion to Verofilcon-A Soft Contact Lenses

Purpose: A new 1-day disposable soft contact lens (SCL), verofilcon-A, constructed of silicone hydrogel material, has recently become available in Japan. This SCL has a very smooth surface produced by using the SMARTSURFACE ® Technology, and it was expected that pollen particles and protein components would not adhere easily to its surface. We examined the degree of pollen adhesion to the surface of the verofilcon-A material SCL and compared the results with those of other 1-day disposable SCLs (1DSCL). Methods: To determine the number of pollen grains attached to the surface of different types of SCLs, 0.01 mg/ml of cedar pollen solution was dropped onto the surface of 13 types of 1DSCL. After 24 h, each 1DSCL was rinsed in a shaker and washed five times with saline (n = 10 for each 1DSCL type). The number of pollen particles adhered to the 1DSCL and the percentage of surface area occupied by pollen was determined. Results: The number of pollen particles on the 1DSCLs ranged from 0 to 185 in the 200 × 200 µm area. The number of particles was lowest in the delefilcon-A and verofilcon-A SCLs with 0 particles, and the number was higher in the other 11 1DSCLs. The number of pollen particles was negatively correlated with the water content (r = −0.48), oxygen permeability (Dk; r = −0.43), oxygen transmissibility (r = −0.42), and center thickness (r = −0.33) of the 1DSCLs. The pollen adhesion area ranged from 0.0% to 3.1% and was lowest in the delefilcon-A and verofilcon-A 1DSCLs. There were significant differences in the pollen adhesion area between colored 1DSCLs (2.73 ± 1.97%) and clear 1DSCLs (1.03 ± 1.01%, P<0.001) and between hydroxyethyl methacrylate-based 1DSCLs (1.84 ± 1.45%) and silicone hydrogel-based 1DSCLs (0.05 ± 0.16%, P<0.001). Conclusion: These findings indicate that the verofilcon-A 1DSCL processed with SMARTSURFACE™ Technology is an excellent option for SCL users with allergic conjunctivitis during the high pollen season.

Acanthoamoeba Keratitis Induced by a Therapeutic, Soft Contact Lens: Diagnosis via Gram Staining

Purpose: We report two cases of Acanthamoeba keratitis diagnosed by Gram staining in patients who had recently worn therapeutic, soft contact lenses and had no history of lens use for visual correction.Case summary: The first patient was initially diagnosed with suspected mixed bacterial or fungal keratitis before a final diagnosis of Acanthamoeba keratitis was confirmed by Gram staining of a corneal smear. The second patient was initially diagnosed with a persistent epithelial defect caused by an earlier lid injury inflicted by a metallic foreign body, and then with a suspected mixed infection combined with herpetic uveitis. The patient was finally diagnosed with Acanthamoeba keratitis by Gram staining of a corneal smear. Both cases were treated with polyhexamethylene biguanide and chlorhexidine.Conclusions: Therapeutic, soft contact lenses are used to enhance corneal, epithelial wound healing in conjunction with antimicrobial prophylaxis. However, application of such a lens to a diseased cornea may predispose to the development of microbial keratitis caused by microorganisms resistant to the usual, prophylactic, antimicrobial eye drops. Therapeutic, soft contact lenses are associated with a risk of Acanthamoeba keratitis; early diagnosis is important. Gram staining of a corneal smear is useful in this context. Acanthamoeba is not eradicated by empirical broad-spectrum antimicrobials.

Safe Contact Lens Practices during Coronavirus (COVID-19) Pandemic

World is threatened by different variants of Coronavirus to an extent that life has been jeopardized in all services including eye care facility. Contact lenses which are one of the preferred modes of vision correction are not an exception to COVID-19 infection. Recently there is confusion among practitioners and patients regarding the safety of contact lens use during COVID-19. This review article summarizes the current recommendations and findings regarding contact lens use during COVID-19. Though eye health professionals and contact lens users are at risk to contract Coronavirus, with proper care, maintenance and disinfection techniques, it would be safe to continue wearing contact lenses. There is currently no strong evidence to suggest that contact lenses are not safe to wear during COVID 19 times. Eye care practitioners responsible for contact lens application must wear special surgical masks, protective glasses or visors and disposable waterproof gloves. Regarding soft contact lenses, preferably daily disposable lenses should be used from the sterile packages. Similarly for rigid gas permeable lenses, lenses made up of fluoropolymer contained in sealed packages must be motivated for the individuals. Since the infected hands can bring the virus to the eyes, contact lens users should avoid touching the nose, mouth and eye unnecessarily. Contact lens after each use must be disinfected with hydrogen peroxide solutions with a special catalyst container. In the case of eye redness and Flu like symptoms, contact lens trial and wearing practices should be suspended or postpone till the condition becomes normal. To minimize the contact time between the patient and examiner soft copy of the instruction sheet, teleconsultation should be motivated. Though the eye is an unlikely site for Coronavirus infection, eye doctors should warn the contact lens wearers to follow scrupulous contact lens hygiene rules.

Myopiekontrolle: aktuelle Strategien

Purpose. The prevalence of myopia is increasing worldwide and its long-term effects can have major impacts on eye health. Paediatric onset of myopia leads to a higher risk for developing high levels of myopia in adulthood. Slowing down or stopping myopia progression is an important task for the future. Material and Methods. Based on a literature review, the latest developments in the field of myopia control for children were summarized. The current study situation for orthokeratology, soft contact lenses, atropine therapy and spectacle lenses for the management of myopia is discussed in detail. Results. Results on the safety and effectiveness of orthokeratology and modified soft contact lenses are exceedingly consistent. Soft multifocal contact lenses, as well as newer spectacle lenses, recently received regulatory approval for myopia control. Studies on the administration of atropine recommend a dosage of 0.01 - 0.05 %. All methods slow down myopia progression and decrease axial length growth of the eye. Side effects, adverse events or discontinuation of treatment only occur in the rarest of cases. Orthokeratology and atropine continue to deliver the best results. Conclusion. From today’s perspective, carrying out myopia control can be recommended with great certainty. The choice of method depends on the individual requirements of each patient, with all methods offering success in reducing myopia progression. In the future, even more advanced contact lens geometries, more precise atropine dosages or improved optics of spectacle lenses will further increase the success of the treatment. Keywords. Progressive myopia, myopia control, children, contact lenses, atropine, spectacle lenses

Molecular Identification of Pathogenic Free-Living Amoeba from Household Biofilm Samples in Iran: A Risk Factor for Acanthamoeba Keratitis

Free-living amoeba (FLA) are ubiquitously distributed in the environment. However, they are also the causative agents of opportunistic infections in humans and other animals. A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. Moreover, FLA have been detected in various biofilms around the world. Therefore, the present study aimed to check for presence of FLA in samples from household biofilms in Iran and to characterize them at the molecular level. A total of 69 biofilm samples collected from showerheads, kitchen areas, and bathroom sinks were analyzed. Positive samples for FLA were characterized at the morphological and molecular levels. Furthermore, the results of morphology analysis indicated that 26.08% (18/69) of biofilm samples were positive for Acanthamoeba spp., Vermamoeba genus, and Vahlkampfiids. According to sequence analysis, five strains of Acanthamoeba isolates related to the T4 genotype and two strains belonged to the T2 genotype. In addition, the pathogenic potential of Acanthamoeba-positive isolates was conducted using the tolerance ability test. The results of BLASTn of Vermamoeba sequences were similar to what was expected for Vermamoeba vermiformis. The above-mentioned reasons revealed that the relative high contamination of household biofilm samples with FLA may pose a risk for people using soft contact lenses and for patients with traumatic cataract. Our finding proposes that filtration should be performed in shower heads and indicates the need to monitor people at increased risk of Acanthamoeba keratitis.

Cosmetics and Contact Lenses: Influence on Safety

The article describes the effect of decorative cosmetics on the material of soft contact lenses and studies specific features that can be observed in SCL wearers who use cosmetics extensively. Examples of complications associated with the use of various cosmetic products that may occur in contact lens wearers are given. Conclusion: in cases when patients have complaints about discomfort and dry eyes, doctors should pay attention to the amount of decorative cosmetics used as well as study the effect it can have on the surface of the contact lenses.

Development of Environmentally Friendly Cellulose Derivative-Based Hydrogels for Contact Lenses Using a Radiation Crosslinking Technique

Although they have potential environmental pollution issues, soft contact lenses are value-added biodevices for medical use. Thus, it is important to reconsider starting materials and production methods to achieve sustainable development. In this study, hydrogels composed of hydroxypropyl cellulose (HPC) as an environmentally friendly material were produced by radiation and investigated for use in disposable soft contact lenses. HPC-based hydrogels with good mechanical properties and transparency were prepared by irradiation of electron beams on highly concentrated aqueous solutions containing HPC, polyethylene glycol #1000 dimethacrylate (23G), and 2-hydroxyethyl methacrylate (HEMA). The addition of 23G to HPC aqueous solutions resulted in an increase in the gel fraction as well as improved mechanical properties, such as tensile strength and elongation at break. The tensile strength and the elongation at break of HPC/HEMA/23G hydrogel obtained by the further addition of HEMA with HPC/23G aqueous solutions exhibited 0.2 MPa and 124%, which were approximately 2.0 and 1.8 times larger than these of the pure HPC hydrogel, respectively. The evaluation of the properties of the HPC/HEMA/23G hydrogel demonstrated its potential as a soft contact material with improved mechanical properties.