AEROMEDICAL ASPECTS OF CONTACT LENSES (SOFT AND SEMISOFT).
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ABSTRACT:
SUBMITTER: Prasad G
PROVIDER: S-EPMC5530011 | biostudies-other | 1995 Jul
REPOSITORIES: biostudies-other
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Project description:In this study, we synthesized three novel acrylic monomers with a cinnamate group. We then mixed each monomer with 2-hydroxyethyl methacrylate (HEMA) to prepare soft contact lenses through bulk polymerization. Fourier transform infrared (FT-IR) and UV spectral analyses confirmed that the cinnamate group in the polymer undergoes a photodimerization reaction via UV irradiation. After UV curing, the present lenses stably maintained their shapes even in a water-swollen state and showed significantly improved mechanical properties compared to conventional lenses manufactured using a cross-linking agent. These lenses showed slightly lower water contact angles than the conventional lenses, although the water content was slightly reduced. The present photodimerization cross-linking method was found to be useful in reducing the tearability of soft lenses.
| S-EPMC10515589 | biostudies-literature
Project description:Contact lens-related ocular surface complications occur more often in teenagers and young adults. The purpose of this study was to determine changes in tear proteome of young patients wearing glasses (GL), orthokeratology lenses (OK), and soft contact lenses (SCL). Twenty-two young patients (10-26 years of age) who were established (> 3 years) GL (n=10), OK (n=6), and SCL (n=6) wearers were recruited. Tears were collected via Schirmer strips. Proteomic data were collected using a data-independent acquisition-parallel accumulation serial fragmentation (diaPASEF) workflow. Tear proteome composition and abundance were compared across different correction groups and between the children (age <18 years) and young adults (age 18 years) GL wearers. We identified 3406 protein groups in tears. Among proteins identified in 80% of tear samples, 8 proteins were upregulated, and 11 proteins were down-regulated in the SCL group compared to the OK group. Eighty-two proteins were differentially expressed in children and young adults GL wearers, among which 67 proteins were upregulated, and 15 proteins were downregulated in children. These 82 proteins were involved in 1 inflammation, 9 immune, and 1 glycoprotein metabolic biological processes. As teenagers and young adults have the highest risk of developing contact lens-related complications, this work highlights the importance of understanding ocular responses to contact lens wear across different ages.
2022-11-07 | PXD029188 | Pride
Project description:Background:It is unclear whether multifocal soft contact lenses (MFSCLs) affect visual quality when they are used for myopia control in juvenile myopes. The aim of this study was, therefore, to investigate the effect of MFSCLs on visual quality among juvenile myopia subjects. Methods:In a prospective, intervention study, thirty-three juvenile myopes were enrolled. Visual perception was assessed by a quality of vision (QoV) questionnaire with spectacles at baseline and after 1 month of MFSCL wear. At the one-month visit, the high (96%) contrast distance visual acuity (distance HCVA) and low (10%) contrast distance visual acuity (distance LCVA) were measured with single vision spectacle lenses, single vision soft contact lenses (SVSCLs) and MFSCLs in a random order. Wavefront aberrations were measured with SVSCLs, with MFSCLs, and without any correction. Results:Neither distance HCVA (p?>?0.05) nor distance LCVA (p?>?0.05) revealed any significant difference between MFSCLs, SVSCLs and single vision spectacle lenses. The overall score (the sum of ten symptoms) of the QoV questionnaire did not show a statistically significant difference between spectacles at baseline and after 1 month of MFSCL wear (p?=?0.357). The results showed that the frequency (p?<?0.001), severity (p?=?0.001) and bothersome degree (p?=?0.016) of halos were significantly worse when wearing MFSCLs than when wearing single vision spectacle lenses. In contrast, the bothersome degree caused by focusing difficulty (p?=?0.046) and the frequency of difficulty in judging distance or depth perception (p?=?0.046) were better when wearing MFSCLs than when wearing single vision spectacle lenses. Compared with the naked eye, MFSCLs increased the total aberrations (p?<?0.001), higher-order aberrations (p?<?0.001), trefoil (p?=?0.023), coma aberrations (p?<?0.001) and spherical aberrations (SA) (p?<?0.001). Compared with the SVSCLs, MFSCLs increased the total aberrations (p?<?0.001), higher-order aberrations (p?<?0.001), coma aberrations (p?<?0.001) and SA (p?<?0.001). The direction of SA was more positive (p?<?0.001) with the MFSCLs and more negative (p?=?0.001) with the SVSCLs compared with the naked eye. Conclusions:Wearing MFSCLs can provide satisfactory corrected visual acuity (both distance HCVA and distance LCVA). Although the lenses increased the aberrations, such as total aberrations and higher-order aberrations, there were few adverse effects on the distance HCVA, distance LCVA and visual perception after 1 month of MFSCL use. Trial registration:Chinese Clinical Trial Registry: ChiCTR-OOC-17012103. Registered 23 July 2017, http://www.chictr.org.cn/usercenter.aspx.
| S-EPMC7368986 | biostudies-literature
Project description:To examine safety and efficacy of bandage soft contact lenses (BSCLs) for ocular chronic graft-versus host disease (GVHD), we conducted a phase II clinical trial. Extended-wear BSCLs were applied under daily topical antibiotic prophylaxis. Patients completed standardized symptom questionnaires at enrollment and at 2 weeks, 4 weeks, and 3 months afterward. Ophthalmologic assessment was performed at enrollment, at 2 weeks, and afterward as medically needed. Assessments at follow-up were compared with baseline by paired t-test. Nineteen patients with ocular GVHD who remained symptomatic despite conventional treatments were studied. The mean Lee eye subscale score was 75.4 at enrollment and improved significantly to 63.2 at 2 weeks (P = .01), to 61.8 at 4 weeks (P = .005), and to 56.3 at 3 months (P = .02). The ocular surface disease index score and 11-point eye symptom ratings also improved significantly. According to the Lee eye subscale, clinically meaningful improvement was observed in 9 patients (47%) at 2 weeks, in 11 patients (58%) at 4 weeks, and in 9 patients (47%) at 3 months. Visual acuity improved significantly at 2 weeks compared with enrollment values. Based on slit lamp exam at 2 weeks, punctate epithelial erosions improved in 58% of the patients, showed stability in 16%, and worsened in 5%. No corneal ulceration or ocular infection occurred. BSCLs are a widely available, safe, and effective treatment option that improves manifestations of ocular GVHD in approximately 50% of patients. This study was registered at www.clinicaltrials.gov as NCT01616056.
| S-EPMC4604037 | biostudies-literature
Project description:PURPOSE:To evaluate the impact of soft contact lens eye-fit on optical power by computational modelling and to produce correction maps for reversing this impact during the design process. METHODS:Finite element models of spherical and toric hydrogel contact lenses at varying nominal powers of -20 D to +20 D, base curves radii (R1b) of 8.2, 8.5, 8.8 mm, and overall diameters (d3) of 14.5, 15.0, 15.5 mm were generated. Lenses were fitted to computational eye models generated with human eyes' topography data. Combined eye-lens simulations were run under the boundary conditions of the tears' surface tension between the contact lens and the eye in addition to the eyelid blink pressure. Lens optical zone power changes were calculated through computational light-ray tracing methods following each simulation. RESULTS:Effective power changes (EPC) were affected negatively for all toric simulated lenses with power varying from -20 D to +20 D. Spherical lenses demonstrated similar behaviour, however with some positive EPC over the power range from -20 D to -10 D for spherical power (SPH) lenses. EPC assessment was between +0.25 D and -0.5 D for most lenses, however, lenses with prescriptions from +10 D to +20 D incurred EPC outside this range. The spherical lenses showed a maximum effective power change of +1.046 ± 0.338 D (Average Eye), and a minimum of -3.278 ± 0.731 D (Steep Eye). Similarly, the toric lenses showed a maximum of +1.501 ± 0.338 D (Average Eye), and a minimum of -3.514 ± 0.731 D (Steep Eye). EPC trends, along with minimum and maximum power, generally increased negatively as nominal lens prescription increased positively. Contact lens base curve selection affected the assessed effective power change for both spherical and toric lenses. The effect from lens total diameter for spherical lenses was less substantial than that for toric lenses. CONCLUSIONS:This study considered the impact of soft contact lens design parameters on effective optical power changes (EPC) after eye-fit. Spherical lenses experienced more EPC of clinical significance (>0.25 D) than toric lenses. Both types of lenses, spherical and toric (simple astigmatism), demonstrated similar trends in EPC on fitting from -20 D to +20 D, with lenses in the extremely positive and the extremely negative prescriptions demonstrating the highest EPCs. The lens base curve impacted the extent of EPC observed, with flatter base curves experiencing less power change. Diameter proved to impact toric lenses more than spherical ones, however generally the diameter has less effect on power change than base curve selection.
| S-EPMC6516737 | biostudies-literature
Project description:Purpose To investigate changes in tear film surface quality after commencing soft contact lens wear. Methods Tear film surface quality (TSQ) was assessed during the interblink period using dynamic videokeratoscopy at 25 Hz. A quantitative value of TSQ is derived for each raw Placido ring image. Eleven young subjects with normal tear characteristics participated in the study. Dynamic videokeratoscopy was taken three times per day; in the morning, at lunchtime, and in the afternoon. This was done on two baseline days (bare eye) and on the first and seventh days of lens wear for a conventional hydrogel lens and following a week of no lens wear, for a further week of silicone hydrogel lens wear. Additionally clinical tests to assess TSQ were conducted and subjects were also asked to rate the subjective dryness of their eyes. Results All lens wear measurements showed a significant worsening of TSQ compared to bare eye measurements (repeated measures ANOVA, P<0.01). A significant diurnal change was found on the first day of silicone hydrogel contact lens wear, where TSQ improved during the day (P=0.045). However, no diurnal changes were found in TSQ for the other lens wearing days or for the bare eye condition (P>0.05). The subjective rating of dryness correlated with TSQ values (Pearson's r=0.62, P<0.05) for the bare eye condition, but not during contact lens wear. TSQ derived from the right and left bare eyes of the same individuals showed a significant correlation (Pearson's r=0.61, P<0.05). Conclusions The measurement of TSQ using dynamic videokeratoscopy differentiates between bare eye and lens wearing conditions. It also shows a small systematic improvement in tear surface quality during the first day of silicone hydrogel lens wear and a significant association with subjective dryness for the bare eye condition.
| S-EPMC3972648 | biostudies-literature
Project description:Aim: The purpose of this study was to compare the changes in relative peripheral refractive error produced by two different designs of progressive soft contact lenses in myopic schoolchildren. Methods: Twenty-seven myopic schoolchildren age between 13 to 15 years were included in this study. The measurements of central and peripheral refraction were made using a Grand-Seiko WR-5100K open-field autorefractometer without correction (baseline), and two different designs of progressive contact lenses (PCLs) (Multistage from SEED & Proclear from Cooper Vision) with an addition power of +1.50 D. Refractive power was measured at center and at eccentricities between 35º temporal to 35º nasal visual field (in 5º steps). Results: Both PCLs showed a reduction in hyperopic defocus at periphery. However, this reduction was only significant for the Multistage PCL (p= 0.015), (Proclear PCL p= 0.830). Conclusion: Multistage PCLs showed greater reduction in peripheral retinal hyperopic defocus among myopic schoolchildren in comparison to Proclear PCLs.
| S-EPMC5247792 | biostudies-literature
Project description:PurposeTo compare the visual performance of soft contact lenses reported to reduce myopia progression.MethodsIn a double-blind, randomized, crossover trial, 30 non-presbyopic myopes wore MiSight™, center-distance Proclear® Multifocal (+2.00 D add), and two prototype lenses for 1 week each. High- and low-contrast visual acuities at 6 m, and 70 and 40 cm; stereopsis at 40 cm; accommodative facility at 33 cm; and horizontal phoria at 3 m and 33 cm were measured after 1 week. Subjective performance was assessed on a numeric rating scale for vision clarity, lack of ghosting, vision stability, haloes, overall vision satisfaction, and ocular comfort. Frequency of eye-strain symptoms and willingness to purchase lenses were also reported with categorical responses. Participants reported wearing times (total and visually acceptable). Linear mixed models and chi-square tests were employed in analysis with level of significance set at 5%. Theoretical optical performance of all lenses was assessed with schematic myopic model eyes (-1.00, -3.00, and -6.00 D) by comparing the slope of the edge spread function (ESF), an indicator for optical performance/resolution and the blur patch size of the line spread function, an indicator for contrast, between the lenses.ResultsProclear Multifocal and MiSight provided the best distance acuities. However, the prototype lenses were rated significantly higher for many subjective variables, and there were no subjective variables where commercial lenses were rated significantly higher than the prototypes. Theoretical optical performance showed steeper slopes of the ESF and greater blur patch sizes of the LSP with commercial lenses, supporting the clinical findings of better visual acuities but reduced subjective performance. Participants wore prototypes longer and reported their vision acceptable for longer each day compared to MiSight. Both prototypes had the highest willingness-to-purchase rate.ConclusionsThe prototypes were better tolerated by myopes compared to the commercial soft contact lenses currently used for slowing myopia progression.
| S-EPMC6181805 | biostudies-literature
Project description:Recent advances in wearable electronics combined with wireless communications are essential to the realization of medical applications through health monitoring technologies. For example, a smart contact lens, which is capable of monitoring the physiological information of the eye and tear fluid, could provide real-time, noninvasive medical diagnostics. However, previous reports concerning the smart contact lens have indicated that opaque and brittle components have been used to enable the operation of the electronic device, and this could block the user's vision and potentially damage the eye. In addition, the use of expensive and bulky equipment to measure signals from the contact lens sensors could interfere with the user's external activities. Thus, we report an unconventional approach for the fabrication of a soft, smart contact lens in which glucose sensors, wireless power transfer circuits, and display pixels to visualize sensing signals in real time are fully integrated using transparent and stretchable nanostructures. The integration of this display into the smart lens eliminates the need for additional, bulky measurement equipment. This soft, smart contact lens can be transparent, providing a clear view by matching the refractive indices of its locally patterned areas. The resulting soft, smart contact lens provides real-time, wireless operation, and there are in vivo tests to monitor the glucose concentration in tears (suitable for determining the fasting glucose level in the tears of diabetic patients) and, simultaneously, to provide sensing results through the contact lens display.
| S-EPMC5787380 | biostudies-literature
Project description:SignificanceThe results of this study demonstrate that Smart Touch Technology packaging, which is designed to reduce and simplify contact lens handling before insertion, is effective in reducing the frequency of bacterial contamination of the back surface of contact lenses after short-term wear.PurposeThe purpose of this study was to investigate the effect of lens packaging type, chelating agent, and finger contamination on microbial contamination on the back surface of worn soft contact lenses.MethodsTwenty-five subjects completed each contralateral lens wear comparison in this randomized study: Smart Touch Technology versus conventional blister packaging for (1) silicone hydrogel lenses with ethylenediaminetetraacetic acid (EDTA) and (2) hydrogel lenses without EDTA in the packaging, and (3) silicone hydrogel lenses without EDTA versus hydrogel lenses with EDTA both in Smart Touch Technology packaging. Participants washed hands, underwent finger swabs, and inserted the lenses. After 45 minutes, lenses were removed aseptically and the posterior lens surfaces cultured.ResultsThirty-eight subjects (average age, 30.9 ± 12.5 years) participated in this study. Overall, the level of back surface contamination was low for both lens materials, ranging from 0 to 43 colony-forming unit (CFU)/lens for the silicone hydrogel and 0 to 17 CFU/lens for the hydrogel lenses. The proportion of lenses with zero back surface contamination ranged from 16 to 64% for silicone hydrogel lenses and 28 to 64% for hydrogel lenses. Contact lenses from conventional packaging containing EDTA had 3.38 times increased risk (95% confidence interval [CI], 1.02 to 11.11; P = .05) of contamination being present compared with lenses from Smart Touch packaging with EDTA. Contact lenses from conventional packaging without EDTA had 3.4 times increased risk (95% CI, 1.02 to 11.36; P = .05) of contamination being present compared with Smart Touch packaging without EDTA, and silicone hydrogel lenses had a 6.28 times increased risk (95% CI, 1.65 to 23.81; P = .007) of contamination being present compared with hydrogels. The median (interquartile range) number of bacteria isolated from fingers used to perform lens insertion after handwashing but before lens insertion was not significantly different between the silicone hydrogel and hydrogel lenses (63.7 [204.2] vs. 59 [84.5], P = .09). Finger contamination was not significantly associated with lens contamination in the presence or absence of EDTA.ConclusionsSmart Touch Technology packaging was effective in reducing the proportion of contaminated lenses. Although silicone hydrogel lenses were more likely to be contaminated, the presence of EDTA ameliorated this effect. Finger contamination was not associated with lens contamination.
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