In-vitro dewetting properties of planned replacement and daily disposable silicone hydrogel contact lenses

AimTo compare the in-vitro videokeratoscopic surface dewetting properties of new-generation silicone hydrogel (SiH) planned replacement contact lenses (CL) with those of daily disposable CLs.MethodA chrome coated cornea model was used for the in-vitro evaluation of surface dewetting. Pre-lens and post-lens film layers were formed by instilling a normal preservative-free normal saline solution (PFNs) (0.9 %) before and after the placement of the CL on the model cornea. The tests were carried out on fanfilcon A, lotrafilcon B, samfilcon A, and senofilcon A lenses, as well as such daily disposable lenses as delefilcon, nesofilcon A and senofilcon one day. Using videokeratoscopic methods, images were obtained at 30-second intervals up to 180 s in the lens and control groups and were analyzed by the ImajeJ® program.ResultsThe mean measured area of the keratoscopic rings was largest in the fanfilcon group (67.56 mm²), followed by 61.53 mm² in the lotrafilcon A group and 64.60 mm² in the samfilcon group, while the smallest area was measured in the senofilcon A group, at 56.90 mm². The area was measured as 64.33, 63.09 and 68.39 mm² for the delefilcon, nesofilcon and Senofilcon one day CLs, respectively. The dewetting patterns and properties differed in the CL groups (p < 0.05), while no significant differences were found between the measured areas of the planned replacement and daily disposable CL groups (p > 0.05).DiscussionVideokeratoscopy using in-vitro cornea models has been identified as a reproducible and reliable method for the analysis of the surface dewetting of CLs. The dewetting characteristics of CL groups have been found to differ from each other, despite all being produced from SiH materials. The surface wetting coating has been shown to affect CL dewetting performance.     

The influence of surface treatment on hydrophobicity, protein adsorption and microbial colonisation of silicone hydrogel contact lenses.

PURPOSE: To evaluate the influence of surface treatment of silicone-hydrogel CL on lens hydrophobicity, protein adsorption and microbial colonisation by studying several silicone hydrogel contact lenses (CL) with and without surface treatment. The lenses used in this study were Balafilcon A, Lotrafilcon A, Lotrafilcon B and Galyfilcon A. A conventional hydrogel CL (Etafilcon A) was also tested. METHODS: Hydrophobicity was determined through contact angle measurement using the advancing type technique on air. The type and quantity of proteins adsorbed were assessed through SDS-PAGE and fluorescence spectroscopy, respectively. Microbial colonisation was studied by removing the microbes from the lenses through sonication, and counting the colony-forming units on agar plates. RESULTS: Regarding hydrophobicity, both surface and non-surface-treated silicone hydrogel CL were found to be hydrophobic, and the conventional hydrogel CL was found to be hydrophilic. Concerning protein adsorption, different protein profiles were observed on the several lenses tested. Nevertheless, the presence of proteins with the same molecular weight as lysozyme and lactoferrin was common to all lenses, which is probably related to their abundance in tears. In terms of total protein adsorption, silicone hydrogel CL did not exhibit any differences between themselves. However, the conventional hydrogel Etafilcon A adsorbed a larger amount of proteins. Regarding microbial colonisation, Balafilcon A exhibited the greatest amount of colonising microbes, which can be due to its superior hydrophobicity and higher electron acceptor capacity. CONCLUSION: This study suggests that silicone hydrogel lenses adsorb a lower amount of proteins than the conventional hydrogel lenses and that this phenomenon is independent of the presence of surface treatment. Concerning microbial colonisation, the surface treated Balafilcon A, exhibited a greater propensity, a fact that may compromise the lens wearer's ocular health.     

Efficacy of two silicone-hydrogel contact lenses for bandage use after photorefractive keratectomy

PurposeTo evaluate the efficacy of two silicone hydrogel (SiH) contact lenses, approved for continuous wear for one week, following photorefractive keratectomy (PRK).MethodsForty seven myopic patients (94 eyes) undergone bilateral PRK were enrolled in this prospective, double-masked, comparative study. One eye of each patient was fitted with a Lotrafilcon B lens (Ciba Vision, Duluth, US; 30-day recommended replacement) whereas the fellow eye was fitted with an Asmofilcon A lens (Menicon, Nagoya, Japan; 14-day recommended replacement). Epithelial defect size was assessed using slit lamp biomicroscopy on the day of surgery and at days 1–4 post-operatively. Uncorrected and best-corrected visual acuity and retinal straylight (C-Quant, Oculus Optigerate, Germany) were evaluated pre-operatively and one month post-operatively.ResultsAverage epithelial defect size for Asmofilcon A and Lotrafilcon B was 25.5 ± 11.0 mm² vs. 27.1 ± 9.9 mm² at day 1 (p = 0.007) and 6.3 ± 7.0 mm² vs. 9.2 ± 9.5 mm² at day 2 (p = 0.012) post-operatively. Re-epithelialization at day 3 was completed in 87.2% of the eyes fitted with Asmofilcon A lenses, compared to 74.5% with Lotrafilcon B lenses (p = 0.012). At the 3rd post-operative day 29.8% of re-epithelialized eyes showed irregular suture with Lotrafilcon B, compared to 12.8% eyes with Asmofilcon A lenses (p < 0.001). Finally, no statistically significant differences were found post-operatively between the two lenses retinal straylight (p = 0.98) and best-corrected visual acuity (p = 0.68).ConclusionsSiH lenses can be used as an effective bandage after PRK due to the limited time requested for achieving complete corneal re-epithelialization. Faster and smoother epithelial healing is provided with Asmofilcon A over Lotrafilcon B lenses.     

Improving your spectacle patients’ in-practice experience with contact lenses during frame selection

PurposeA market research survey was conducted to assess the impact of offering complimentary contact lenses (CLs) to spectacle-only wearing patients during frame selection with regards to their in-office experience, the transaction amount for their eyewear purchase and the likelihood of proceeding with a comprehensive contact lens fitting.MethodsFive optometry offices in the US participated. An initial interviewing phase served as a control during which optometrists treated spectacle-only wearing patients in the usual manner for frame selection. After this, the offices transitioned into a test phase where patients were offered the opportunity to wear CLs while selecting new spectacle frames. Only patients 18 or older who had not expressed an interest in CLs were invited to participate. A brief survey was completed on an iPad following the visit by all patients in both control and test phases.Results410 patients (205 test, 205 control) participated. 63% of the test group elected to wear CLs (40% spherical, 20% toric, 35% multifocal, 5% monovision). Patients wearing CLs spent more on their eyewear purchase ($708 vs $593, p = 0.04), were greater than 2.5X more likely to have received or scheduled a CL fit (p = 0.01), and were greater than 3X more likely to consider scheduling a CL fitting in the future (p = 0.0003). Additionally, 93% reported that they were highly satisfied with the experience and 86% said they would wear CLs to select frames again (86%).ConclusionsOffering CLs to spectacle-only patients positively impacts eyewear selection and purchase and can grow the overall CL business.     

Contact lens prescribing pattern in India—2011

PurposeTo understand the pattern of prescribing contact lenses (CL) among Indian practitioners.MethodsSurvey forms were sent to 257 practitioners across the country to collect information about their last 10 CL fits, location and type of practice, years of experience and educational qualification. A logistic regression analysis was performed to determine any association of various factors to the lens fitting pattern and chi-square test was used to compare proportions. The data were analyzed using SPSS v.16.ResultsCL fitting details from 227 practitioners were acquired representing a total of 2270 fits. The mean age of patients was 26.8 ± 7.4 years and 67% of them were females. Ninety-eight percent of patients wore soft CL comprising 24% toric lenses. Ninety percent patients preferred disposable modality with 65% of these opting for monthly disposable lenses. Twenty-eight percent of the lenses dispensed were silicone hydrogel (SiH) lenses. Optometry practices located in metropolitan cities dispensed significantly higher numbers of disposable (p < 0.001) and SiH lenses (p < 0.001). Logistic regression analysis showed Fellowship of International Association of Contact Lens Educators (FIACLE) (OR: 13.79, 95% CI: 2.61–72.70), post graduate degree (OR: 3.87, 95% CI: 0.87–17.12) and years of experience were directly associated with fitting of advanced CL.ConclusionThe CL prescribing patterns in India elicited from this survey suggest the dominance (90%) of prescribing of disposable soft CL. Higher level of education, greater experience and a FIACLE status were significantly associated with advanced fitting.     

Improved contact lens fitting after corneal cross-linking in eyes with progressive keratoconus

ObjectivesThe study aimed to assess the possible effects of corneal cross-linking (CXL) on contact lens (CL) fitting in patients with progressive keratoconus who initially had CL intolerance.MethodsA retrospective review was performed of the medical records of patients who had stopped CL wear due to discomfort prior to CXL and who were fitted with CLs after CXL. All eyes were evaluated pre- and 1, 6, 12, 24 months postoperatively. Data collected included pre- and post-CXL refraction, corneal topographic data, uncorrected visual acuity, and best-corrected visual acuity (BCVA). CL comfort was evaluated using the Likert scale post-CXL.ResultsA total of 20 eyes from 14 patients were included in the study. Preoperative Kmax values significantly decreased by 2.8 D at 6 months and by 4.1 D at 12 months after CXL (p < 0.001 for both). CLs were prescribed on average 12 ± 2.5 months after CXL. The mean duration of successful CL wear was 10.4 ± 2.8 months during the follow-up period. Subjective CL comfort scores were satisfactory post-CXL.ConclusionCXL not only halts the progression of keratoconus but may also improve CL tolerance by providing a more regular shaped cornea in these patients. Ongoing corneal topographic changes in the late postoperative period after CXL may have a positive effect on CL fitting.     

Rigid gas permeable contact lenses for visual rehabilitation of unilateral aphakic children in China

PurposeTo investigate the effectiveness, safety and tolerance of rigid gas-permeable contact lenses (RGP CLs) in the visual rehabilitation of unilateral aphakic children in China.MethodsRecords of 36 children (36 eyes) with RGP CLs to unilateral aphakia between 2014 and 2018 were evaluated. Each enrolled child underwent vision assessment (visual acuity, fixation, and deviation) at each follow-up visit and their caregivers completed a questionnaire designed to find out the reasons for RGP CLs dropout. The fit characteristics and adverse events were also evaluated.ResultsThe mean age was 7.0 months (interquartile range, 5.0–12.8 months). The final mean logMAR visual acuity (VA) of the treated eyes was 1.2 ± 0.7 for 12 patients who cooperated in visual assessments and 6 out of these subjects had a VA of better than 1.0 logMAR. The proportion of treated eyes which could be recorded the visual results increased significantly after RGP CLs intervention (5.6% vs. 33.3%, P < 0.001). The final VA assessed for the fellow eyes and both eyes were 0.7 ± 0.4 and 0.6 ± 0.3, respectively. Of the 36 patients, 24 had strabismus. There was no severe lens-related adverse event except only one patient had mild conjunctivitis. At the end of the follow-up it was found that 25 eyes are still using RGP CLs (69%). Indications to discontinue contact lens wear included difficult manipulation of RGP CL, loss of motivation, unstable lens, and eye irritation.ConclusionsRGP contact lenses provide an effective and safe alternative method for visual rehabilitation and can be well tolerated in pediatric aphakia.     

Computational analysis of retinal image quality with different contact lens designs in keratoconus

PurposeTo determine 1) the relative differences in optical quality of keratoconic eyes fitted with four routinely used CL designs and 2) the Zernike coefficients in the residual wavefront aberration map that may be responsible for differences in the optical quality of keratoconic eyes fitted with these CLs.MethodsWavefront aberrations over a 3-mm pupil diameter were measured without and with Kerasoft IC®, Rose K2®, conventional spherical Rigid Gas Permeable (RGP), and Scleral CLs in 15 mild to moderate keratoconic eyes (20 – 28 years) and under unaided viewing in 10 age-similar non-contact lens wearing controls. The resultant through-focus curves constructed for the logarithm of Neural Sharpness (logNS) Image Quality (IQ) metric were quantified in terms of peak value, best focus, and depth of focus. Sensitivity analyses determined the impact of the residual Zernike coefficients of keratoconic eyes fitted with CLs on the IQ of controls at emmetropic refraction.ResultsThe peak IQ and depth of focus were similar with Rose K2®, conventional RGP, and Scleral CLs (p > 0.05, for all) but significantly better than Kerasoft IC® CLs (p < 0.01 for all). Best focus was similar across all four CLs (p > 0.2 for all). However, the IQ parameters of all the lenses remained significantly poorer than the controls (p < 0.01, for all). The IQ of the controls dropped to keratoconic levels with induced residual lower-order Zernike terms and 3rd-order coma across all lenses in the sensitivity analysis (p < 0.001).ConclusionsIQ of keratoconic eyes remain suboptimal with routinely dispensed CL designs, largely due to residual lower-order aberrations and coma, all relative to the controls. The performance drop appears greater for the Kerasoft IC® CL relative to the other CL designs. These results may provide the optical basis for psychophysical spatial visual performance reported earlier across these four CL designs for keratoconus.     

Quantification of accommodative response and visual performance in non-presbyopes wearing low-add contact lenses

PurposeDigital eye strain encompasses a range of ocular and visual symptoms across all age groups. Recently, symptoms associated with accommodative or binocular vision stress have become a major problem, especially in young individuals. The purpose of this prospective, single-blinded study was to objectively quantify the accommodative response and visual performance of low-add soft contact lenses (CLs) in young non-presbyopic individuals.MethodsA daily disposable low-add bifocal design lens (low-add CL) was tested. It employs a centre-distance optical zone and peripheral zone with the added power of +0.50 D to support near vision. Sixteen subjects aged 20–39 years were enrolled in the study. Refractive state and accommodation were measured using an open-field autorefractor with three target vergences, namely, −0.20 D, −2.5 D, and −4.0 D. Binocular visual acuity at high (100%) and low (40%, 20%) contrast and reading ability were assessed. Monofocal soft CLs were used as controls.ResultsAccommodative response with low-add CLs was significantly smaller than those with two monofocal CL wearing conditions, i.e., at 40 cm (2.5 D of stimulus) and 25 cm (4.0 D of stimulus) (all p < 0.05). The 20% contrast visual acuity at distance was significantly better with low-add CLs and second-time monofocal CLs compared to first-time monofocal CLs (all p < 0.05). The reading ability was not significantly different.ConclusionsQuantification of accommodative response and visual performance demonstrated that using low-add CLs alleviated the accommodation under the near-vision condition, without sacrificing distance vision, in non-presbyopes.     

UV–vis light transmittance through tinted contact lenses and the effect of color on values

PurposeTo assess the transmittance, in the 200–700 nm electromagnetic radiation spectrum, by popularly used tinted soft contact lenses (CLs).MethodThe spectra transmittances of ultraviolet (UV)-blocking (I Day Acuvue Define, Freshlook ONE DAY) and non-UV-blocking (Durasoft 3, Tutti, and NeoCosmo) tinted soft CLs were tested. The transmittance of each lens, including nine different colors of Freshlook CL was recorded on spectrophotometer, and the data used to also calculate a UV protection factor (PF) for each lens brand tested, with a higher value indicating a higher level of protection.ResultsThe UV-blocking CLs significantly reduced UVC, UVB & UVA transmission and thereby meet the American National Standards Institution standard for class 2 UV blockers: a maximum of 30% transmittance of UVA and 5% transmittance of UVB wavelengths. In contrast, the Durasoft 3, Tutti, and NeoCosmo CLs demonstrated negligible UV-blockage. The Acuvue Define CL offered the greatest protection from UVC (PF = 69) and UVB (PF = 55), but with only 35% luminous transmittance, while the Freshlook CL (especially gemstone green) offered the best protection from UVA (PF = 24) and showed about 55% translucency. Overall, the UV-blocking CLs performed equally well across the UV spectrum. Different colors of Freshlook CL transmitted statistically and clinically significantly different amounts of visible light but similar amounts of UVR.ConclusionFreshlook and Acuvue Define CLs which are designated as UV-blockers significantly reduced UVR transmission to safe levels whereas Tutti, NeoCosmo and Durasoft 3 did not. Transmission within the Freshlook CL family was more dependent on color in the visible light spectrum, but not in the UV-spectrum, where the gemstone green performing best among the tested colors.     

An investigation into disposal and recycling options for daily disposable and monthly replacement soft contact lens modalities

PurposeTo examine the annualised waste and end-of-life disposal options with two representative soft contact lens (CL) modalities.MethodsThe component parts of two representative soft CL modalities were catalogued, separated, weighed and inspected for material identification: somofilcon A soft CLs (clariti elite, CooperVision Inc.) used with multi-purpose solution (MPS) (All in one Light, CooperVision Inc.) and somofilcon A CLs (clariti 1 day, CooperVision Inc). Using a model that assumed compliant wear and care of CLs, the mass of material solid waste generated by CL use over a year was calculated. Disposal options were explored using household and specialist recycling streams in order to develop recommendations for responsible disposal of CL waste.ResultsFull-time daily disposable (DD) CL wear generates 1.06 kg of waste annually compared to 0.83 kg generated by reusable-monthly replacement daily wear (‘reusable’) CLs. Plastic was the dominant material in both modalities. With full-time use of DD CLs, 64% of waste by mass was plastic blister trays. For full-time use of reusable CLs, where figures from lens and MPS packaging are combined, plastics accounted for 67% of waste by mass. MPS bottles alone made up almost half the waste (45%) associated with full-time reusable CL wear.ConclusionFull-time DD wear generates 27% more waste annually than full-time reusable lens wear. Reusable CL wearers can recycle 78% of waste at home. DD lens wearers have access to recycling options that allow them to recycle 100% of CL related waste. Full-time CL lens wear represents just 0.20–0.26% of the 412 kg of household waste generated per person, per year in the United Kingdom. Worn CLs should never be disposed of down the sink or lavatory. CL wearers should be aware of responsible end-of-life recycling and disposal options for all CL waste.     

Long-term effect of corneoscleral contact lenses on refractory ocular surface diseases

PurposeTo report the therapeutic effect of corneoscleral contact lenses (CLs) with a diameter of 14.0 mm on the refractory ocular surface diseases.MethodsMedical records of 13 eyes (of nine patients) attempted for fitting with corneoscleral CLs for the management of the severe refractory ocular surface diseases were retrospectively reviewed including Stevens-Johnson syndrome (SJS; eight eyes) and chronic ocular graft-versus-host disease (GVHD; five eyes). Lenses were fitted to improve refractory punctate epithelial erosions (PEE, ten eyes) and persistent epithelial defect (PED, three eyes with SJS) despite the proper medical management. Short-term (1 month) and long-term (12 months) changes in the best corrected visual acuity (BCVA), corneal fluorescein staining (CFS) score, mean wearing time, and National Eye Institute’s Visual Function Questionnaire-25 (VFQ-25) were evaluated.ResultsOf the 13 eyes, ten eyes were successfully fitted with the corneoscleral CLs. The fitting was failed in three eyes due to small palpebral fissure and shortened fornices (two eyes) and handling difficulty (one eye). At one-month follow-up after successful fitting in ten eyes, mean wearing time was 12.6 h (6.5–17, all day long) and BCVA improved from 0.56 ± 0.59 to 0.27 ± 0.46 in logMAR (P = .018). For the eight well-fitted eyes with refractory PEE, CFS score improved from 7.38±2.20 to 5.13±2.48 (P = .024). PED improved in all two eyes which were successfully fitted with corneoscleral CLs (Of the three eyes with PED, one eye failed fitting). At 12-month follow-up, mean wearing time was 11.4 h and the improved BCVA and CFS score were maintained. Furthermore, no adverse events attributable to corneoscleral CLs use occurred.ConclusionThe corneoscleral CLs with a diameter of 14.0 mm were successfully fitted in ten out of 13 eyes with severe refractory ocular surface diseases and demonstrated therapeutic benefits in the well-fitted eyes. The corneoscleral CL can be an option in the management of severe refractory ocular surface diseases.     

Exploring non-adherence to contact lens wear schedule: Subjective assessments and patient related factors in children wearing single vision and myopia control contact lenses

PurposeTo determine factors associated with non-adherence to contact lens wear schedule involving single vision and myopia control contact lenses in children.MethodsData from 379 children enrolled in a prospective, double masked, randomized clinical trial, aged 8–13 years, cycloplegic spherical equivalent of -0.75 to -3.50D and wearing either: single vision silicone hydrogel (SiH) CL (control lens); two anti-myopia SiH CL that incorporated relative plus in the central and periphery in a stepped manner (test lens I and II); and two extended depth of focus hydrogel CL (test lens III and IV) was considered. A questionnaire was administered to the participants at every scheduled visit and gathered information on days of wear/week and subjective assessments of ocular comfort and visual quality on an analog scale of 1–10.Participants were categorized as “Adherent” when lens wear was ≥ 6 days/week or “Non-adherent” when lens wear ≤ 5 days/week. Categorized adherence data was summarized as a percentage across visits for each CL type. Differences between the two groups were analyzed using linear mixed model.ResultsFor the control lens, 79.6 % participants were adherent as compared to 63.7%–74.6% with test lenses (p=0.026). Non-adherence was greater in those that discontinued (p<0.001). Subjective ratings of visual quality for static and dynamic tasks were lower with non-adherent wearers and more variable between visits. Ocular comfort was also poorer in non-adherent wearers irrespective of lens material or lens design. Male gender, lower baseline myopia, lower high contrast visual acuity and esophoria were associated with a higher risk of non-adherence.ConclusionsThe study identified a wide range of factors associated with non-adherence to lens wear schedule. Paying specific attention to these factors when evaluating patients for CL wear and taking steps to ensure satisfaction in lens wear may promote longer term continuation of wear.     

Presbyopia correction with multifocal contact lenses: Evaluation of silent reading performance using eye movements analysis

PurposeMany activities of daily living rely on reading, thus is not surprising that complaints from presbyopes originate in reading difficulties rather in visual acuity. Here, the effectiveness of presbyopia correction with multifocal contact lenses (CLs) is evaluated using an eye-fixation based method of silent reading performance.ΜethodsVisual performance of thirty presbyopic volunteers (age: 50 ± 5 yrs) was assessed monocularly and binocularly following 15 days of wear of monthly disposable CLs (AIR OPTIX™ plus HydraGlyde™, Alcon Laboratories) with: (a) single vision (SV) lenses – uncorrected for near (b) aspheric multifocal (MF) CLs. LogMAR acuity was measured with ETDRS charts. Reading performance was evaluated using standard IReST paragraphs displayed on a screen (0.4 logMAR print size at 40 cm distance). Eye movements were monitored with an infrared eyetracker (Eye-Link II, SR Research Ltd). Data analysis included computation of reading speed, fixation duration, fixations per word and percentage of regressions.ResultsAverage reading speed was 250 ± 68 and 235 ± 70 wpm, binocularly and monocularly, with SV CLs, improving statistically significantly to 280 ± 67 (p = 0.002) and 260 ± 59 wpm (p = 0.01), respectively, with MF CLs. Moreover, fixation duration, fixations per word and ex-Gaussian parameter of fixation duration, μ, showed a statistically significant improvement when reading with MF CLs, with fixation duration exhibiting the stronger correlation (r = 0.79, p < 0.001) with improvement in reading speed. The correlation between improvement in VA and reading speed was moderate (r = 0.46, p = 0.016), as was the correlation between VA and any eye fixation parameter.ConclusionAverage silent reading speed in a presbyopic population was found improved with MF compared to SV CL correction and was faster with binocular compared to monocular viewing: this was mainly due to the faster average fixation duration and the lower number of fixations. Evaluating reading performance using eye fixation analysis could offer a reliable outcome of functional vision in presbyopia correction.     

Assessment of contact lens wearers’ attitude toward contact lens wear and care during Coronavirus Disease 2019 (COVID-19) pandemic: A cross-sectional online survey

AimCOVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several reports have provided conflicting recommendations regarding contact lenses (CL) use during COVID-19, causing confusion among CL wearers. The aim of this study is to assess CL wearers’ attitudes toward CL wear and care during COVID-19 pandemic.MethodsA web-based cross-sectional online survey was used to assess the participants’ attitude toward CL wear and care during the COVID-19 pandemic. The survey layout was based on Google form® specifically developed for CL wearers. Demographic characteristics and CL history and profile were also collected for each participant.ResultsA total of 196 CL wearers completed the online survey with an average age was 26 (± 4.1) and 90.8 % of participants were females. As reported by the participants, social media was the main source of information about COVID-19. 38.8 % of the study population reported stopping CL wear during the pandemic. The main stated reason for lens discontinuation was decreased social activities during the pandemic. 61.2 % of participants continued lens wear, with the majority reported considerable changes in their behaviors toward CL wear and care during the pandemic. This includes reinforced hands cleaning before and after lens wear, disinfecting of CLs and CL case and less frequent CL aftercare visits.ConclusionThe majority of the study population have continued CL wear during the pandemic. Contact lens wearers reported profound changes in attitudes toward CL wear including improved care and maintenance. Additionally, changes in CL purchase habit have been reported with more tendency for online purchase. CL cessation has been associated with several perceived reasons mainly attributed to reduced outdoor activity and fear of ocular infection. Levels of compliance among CL wearers should be assessed and reinforced during the current pandemic and similar lockdown situation to reduce possible CL-related complications and dropout.     

Does blue-violet filtering in contact lenses improve contrast sensitivity?

PurposeThe work is aimed at (i) comparing photopic contrast sensitivity (CS) of healthy subjects in an indoor environment with either blue-violet filtering (BVF) or clear contact lenses (CLs) and (ii) investigating a possible dependence of the CS variation on the subjects' intrinsic CS, measured with clear CLs.MethodsOptical transmittance of BVF and clear CLs was measured by a spectrophotometer. Photopic CS was measured monocularly on forty-one subjects (nineteen in the age range 20–36 years and twenty-two in the age range 44–66 years) by a digital optotype system at spatial frequencies from 1.5 to 18 cpd, wearing either clear or BVF CLs. The results are indicated as CS_clear and CS_BVF, respectively.ResultsTransmittance curves in the visible range of the two CLs are very similar, despite an absorption band in the BVF CL spectrum with the minimum of transmittance at 428 ± 4 nm equal to about 79%. For both CS_clear and CS_BVF, no significant CS difference was found between younger and older adults. The difference [log(CS_BVF) ? log(CS_clear)] showed a decreasing trend and changed sign from positive to negative as a function of log(CS_clear) with correlation Spearman’s Rho coefficients ranging from 0.80 to 0.88 (p < 0.01 at all spatial frequencies).ConclusionIn the choice of a BVF CL, practitioners should take into consideration that it can influence photopic CS, improving it for subjects who have a relatively low CS with clear CLs, and worsening it for subjects who have a relatively high CS with clear CLs. BVF can affect positively the CS by reducing intraocular scattering. However, it can also cause a reduction in light intensity, which contributes to the formation of the retinal image. The positive or negative influence of BVF CLs compared to clear ones on CS is attributed to a balance among these effects.     

Multifocal contact lens vision simulated with a clinical binocular simulator

PurposeThe purpose of this study is to compare the binocular visual perception of participants wearing multifocal contact lenses and these same lens designs viewed through a temporal multiplexing visual simulator.MethodsVisual performance and perceived visual quality at various distances were obtained in 37 participants wearing soft M?CLs and through the SimVis Gekko programmed with the same lenses. In a pilot study (n = 10) visual performance was measured in terms of LogMAR visual acuity (VA) at far (4 m), intermediate (64 cm) and near (40 cm) distances and through-focus VA (TFVA) curves with the simulated M?CLs. In the follow-up study (n = 27), LogMAR VA at far, intermediate and near distances were measured both with the actual and simulated M?CLs. Perceived visual quality was measured in both studies using the Multifocal Acceptance Score (MAS-2EV), and a Participants Reported Outcomes Vision questionnaire. Differences between the metrics obtained with simulated and actual lenses were obtained.ResultsBoth actual and simulated M?CLs increased depth-of-focus by a similar amount. Mean LogMAR VA differences with actual and simulated M?CLs ranged between 4 and 6 letters (0.08 ± 0.01, 0.12 ± 0.01 and 0.10 ± 0.01, for far, intermediate and near distances, respectively). MAS-2EV average score differences with actual and simulated M?CLs ranged between ?1.00 and + 4.25. Average MAS-2EV scores were not correlated significantly with VA. However, MAS-2EV (average and individual scores) were highly correlated to visual quality questionnaire responses (p < 0.005).ConclusionsA simultaneous vision simulator accurately represented vision with M?CLs both VA at various distances and perceived visual quality, as measured in a clinical setting. The MAS-2EV metric accurately captured participant reported outcomes of standard vision questionnaires. The combination of SimVis Gekko and MAS-2EV has the potential to largely reduce chair time in M?CLs fitting.     

Clinical factors associated with contact lens dropout

PurposeContact lens (CL) dropout is estimated to be approximately equal to the number of new wearers per year, resulting in virtually no growth in the global CL market. The purpose of this study was to determine ocular and CL factors associated with CL dropout.MethodsThis five-site study recruited subjects 18–45 years of age who had ceased CL wear within the past 6–12 months due to discomfort. Dropout subjects were compared to age- and sex-matched currently successful CL wearers. Each subject was administered a symptoms survey and a study-specific survey that queried general CL history and compliance. Clinical testing included non-invasive tear break-up time, tear meniscus height, blepharitis assessment, meibum quality and expression, and meibography.ResultsA total of 56 matched-pairs were recruited. Dry eye was found to significantly increase a subject’s odds of dropping out of CLs. The odds of dropping out of CLs was also significantly increased with each worsening grade of upper or lower eyelid meibomian gland (MG) plugging, upper eyelid meibum quality, and upper eyelid MG tortuosity. No other factors analyzed increased a subject’s odds of dropping out of CLs.ConclusionsCL dropout may be precipitated by underlying dry eye symptoms, though most dry eye signs, with the exception of MG structure and function, had minimal predictive value for CL dropout. Nevertheless, evidence suggests that practitioners should screen for and educate CL patients about the importance of maintaining healthy MGs, which may potentially allow them to maintain comfortable CL use and increase their CL longevity.