Topical Review: Contact Lens Eye Health and Safety Considerations in Government Policy Development.

SIGNIFICANCE: As new federal or state policies are introduced in the United States to shape the evolving contact lens market, it has never been more important to amplify the importance of patient health and safety during contact lens wear and promote the value of the eye care professional-patient relationship.Within the United States, contact lenses are regulated by the Food and Drug Administration as class II or III medical devices that require additional regulatory and professional oversight to keep consumers safe. The contact lens market and broader eye health landscape are rapidly changing. Recently, the U.S. Federal Trade Commission finalized its 10-year review of the Contact Lens Rule, implementing new policies that will shape the contact lens market in the United States for years to come. The purpose of this clinical perspective was to compile and review key data regarding contact lens-related adverse events, including their economic impact on the health care system, to inform government policy development. Although contact lenses provide many benefits to the wearer, a variety of complications can occur ranging from asymptomatic events or mild discomfort to severe sight-threatening adverse events such as microbial keratitis. Patients who do not routinely visit their eye care professional or do not receive the lenses prescribed to them are at a greater risk of contact lens-related adverse events. Nearly 1 million people in the United States experience ocular infections or inflammation annually, resulting in significant health care costs. The economic burden of contact lens-related microbial keratitis in the United States has been estimated to be approximately $175 million annually. The importance of eye care professional oversight of contact lens wear cannot be emphasized enough to key stakeholders, including lawmakers, government regulators, contact lens manufacturers and distributors, and the broader eye health community.

Analysis of polyvinyl alcohol release from commercially available daily disposable contact lenses using an in vitro eye model.

The purpose of this work was to determine the release of polyvinyl alcohol (PVA) from etafilcon A, omafilcon A, and nelfilcon A daily disposable hydrogel contact lenses using a novel in vitro model. PVA is an ocular lubricant that can be found in multiple formulations of artificial tears. Nelfilcon A innately contains PVA, so only the release of PVA from this lens was evaluated. Etafilcon A and omafilcon A lenses were incubated in a PBS solution containing PVA. The release of PVA was evaluated using a novel in vitro blink platform with Milli-Q water and PBS under various blink conditions and flow rates. Nelfilcon A lenses significantly released more PVA than other lenses at 0.5 and 1.5 h in both PBS and Milli-Q water (p < 0.001). For nelfilcon A, there was no statistical significance between the release profiles of PVA between the blink and no-blink conditions, or for the various flow rates (p > 0.05). All tested groups and lenses showed a burst release within the first 4.5 h and rapidly plateaued thereafter. The current study demonstrates that releasable PVA (whether through uptake or through being inherently available from the material) is loosely bound on hydrogel lenses, and the majority is released within 4.5 h. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1662-1668, 2019.

A Randomized Trial to Evaluate the Effect of Toric Versus Spherical Contact Lenses on Vision and Eyestrain.

OBJECTIVES: To compare the effect of toric versus spherical soft contact lenses on objective measures of visual performance using visual acuity and electromyography of the orbicularis oculi muscle. METHODS: Current soft contact lens wearers with -0.75 to -1.75 D astigmatism in each eye were binocularly fitted with toric (1-Day ACUVUE MOIST for astigmatism) and spherical (1-Day ACUVUE MOIST) contact lenses in random order. After each fitting and at 1-week follow-up, high- and low-contrast visual acuities were measured. Electromyography was used to objectively evaluate eyestrain. Linear mixed models were used to assess differences between toric and spherical contact lenses. RESULTS: The mean age (±SD) of the 60 participants was 27.5±5.0 years, spherical refractive error was -3.68±2.01 D, and cylinder was -1.28±0.36 D. High- and low-contrast visual acuities with toric lenses were better than with spherical lenses at both fitting (toric high-contrast: -0.065±0.078 and low-contrast: 0.133±0.103 vs. spherical high-contrast: 0.001±0.104 and low-contrast: 0.224±0.107) and follow-up (toric high-contrast: -0.083±0.087 and low-contrast: 0.108±0.107 vs. spherical high-contrast: -0.015±0.095 and low-contrast: 0.211±0.104) (all P<0.0001). Electromyography-measured eyestrain was less with toric versus spherical contact lenses at fitting (least-square ratio of toric over spherical=0.72; P=0.0019) but not at follow-up (ratio=0.86; P=0.11). CONCLUSION: These results suggest that toric contact lenses provided improved objective measures of vision in a low-to-moderate astigmatic population.

Efficacy of Toric Contact Lenses in Fitting and Patient-Reported Outcomes in Contact Lens Wearers.

OBJECTIVES: To assess whether patient-reported measures are improved with soft toric contact lenses (TCLs) compared with soft spherical contact lenses (SCLs) and whether clinical time needed to fit TCL is greater than SCL. METHODS: Habitual contact lens wearers with vertexed spherical refraction +4.00 to +0.25 D or -0.50 to -9.00 D and cylinder -0.75 to -1.75 DC were randomly assigned to be binocularly fitted into a TCL or SCL, and masked to treatment assignment. Time to successful fit was recorded. After 5 days, the National Eye Institute Refractive Error Quality of Life Instrument (NEI-RQL-42) and modified Convergence Insufficiency Symptom Survey (CISS) were completed. After washout, subjects were fit into the alternative lens design (TCL or SCL). Outcomes were evaluated using linear mixed models for the time to fit and CISS score, generalized linear model for the successful fit, and Wilcoxon tests for the NEI-RQL-42. RESULTS: Sixty subjects (71.7% women, mean age [±SD] = 27.5±5.0 years) completed the study. The mean time to fit the TCL was 10.2±4.3 and 9.0±6.5 min for the SCL (least square [LS] mean difference (TCL-SCL)=1.2, P=0.22). Toric contact lens scored better than SCL in global NEI-RQL-42 score (P=0.006) and the clarity of vision (P=0.006) and satisfaction with correction subscales (P=0.006). CISS showed a 15% reduction in symptoms (LS mean difference [TCL-SCL]=-2.20, P=0.02). CONCLUSION: TCLs are a good option when trying to improve the vision of patients with low-to-moderate astigmatism given the subjective improvements in outcomes.

Corneal Swelling with Cosmetic etafilcon A Lenses versus No Lens Wear.

PURPOSE: To determine if the use of pigments or adding polyvinyl pyrrolidone during the fabrication of 1-DAY ACUVUE DEFINE (AD) brand contact lenses impacts open-eye corneal swelling compared with no lens wear (NLW). METHODS: A partial double-masked, randomized, bilateral crossover study was conducted in 24 Asian subjects using AD, 1-DAY ACUVUE DEFINE with Lacreon (ADL), NLW, and a control lens with no tint (1-DAY ACUVUE MOIST [AM]). Central corneal thickness was measured before insertion and immediately after removal after 8 ± 1 h of open-eye wear using an optical pachymeter in one eye. Corneal thickness along a 10-mm cord was measured in the contralateral eye using the Visante optical coherence tomographer (OCT). Corneal swelling was tested for noninferiority using a 5% margin. The endothelial bleb response was measured at baseline and 20 min after lens insertion using specular microscopy. Subjective grading of corneal staining and limbal/bulbar hyperemia were also monitored. RESULTS: After 8 ± 1 h of open-eye wear, central corneal swelling across the study lenses with either optical pachymeter or OCT methods was negligible. Peripheral corneal swelling least-square mean differences with OCT were -0.03% (95% confidence interval [95% CI], -0.65 to 0.58%) and -0.26% (95% CI, -0.87 to 0.36%) between AD and ADL and the control lens (AM), respectively, and 1.67% (95% CI, 1.06 to 2.29%) and 1.45% (95% CI, 0.84 to 2.06%) between AD and ADL and NLW, respectively. No endothelial blebs were observed. No clinically significant differences were distinguished between the lenses and NLW for corneal staining and limbal/bulbar hyperemia. CONCLUSIONS: After 8 ± 1 h of open-eye wear, central and peripheral corneal swelling along the horizontal meridian with AD, ADL, AM, and NLW were equivalent. These results confirm that the addition of polyvinyl pyrrolidone or pigments to etafilcon A to obtain a limbal ring design have no impact on corneal swelling or limbal/bulbar hyperemia during normal open-eye wear.

Resultant vertical prism in toric soft contact lenses.

PURPOSE: Rotational stability of toric soft contact lenses (TSCLs) is achieved using a range of designs. Designs utilising prism or peripheral ballast may result in residual prism in the optic zone. This study quantifies the vertical prism in the central 6mm present in TSCLs with various stabilisation methods. METHOD: Vertical prism was computed using published refractive index and vertical thickness changes in the central optic zone on a full lens thickness map. Thickness maps were measured using scanning transmission microscopy. Designs tested were reusable, silicone hydrogel and hydrogel TSCLs: SofLens(®) Toric, PureVision(®)2 for Astigmatism, PureVision(®) Toric, Biofinity(®) Toric, Avaira(®) Toric, clariti(®) toric, AIR OPTIX(®) for ASTIGMATISM and ACUVUE OASYS(®) for ASTIGMATISM; with eight parameter combinations for each lens (-6.00DS to +3.00DS, -1.25DC, 90° and 180° axes). RESULTS: All TSCL designs evaluated had vertical prism in the optic zone except one which had virtually none (0.01Δ). Mean prism ranged from 0.52Δ to 1.15Δ, with three designs having prism that varied with sphere power. Vertical prism in ACUVUE OASYS(®) for ASTIGMATISM was significantly lower than all other TSCLs tested. CONCLUSIONS: TSCL designs utilising prism-ballast and peri-ballast for stabilisation have vertical prism in the central optic zone. In monocular astigmats fitted with a TSCL or those wearing a mix of toric designs, vertical prism imbalance could create or exacerbate disturbances in binocular vision function. Practitioners should be aware of this potential effect when selecting which TSCL designs to prescribe, particularly for monocular astigmats with pre-existing binocular vision anomalies, and when managing complaints of asthenopia in monocular astigmats.

Atomic force microscopy and scanning electron microscopy analysis of daily disposable limbal ring contact lenses.

BACKGROUND: Limbal ring (also known as 'circle') contact lenses are becoming increasingly popular, especially in Asian markets because of their eye-enhancing effects. The pigment particles that give the eye-enhancing effects of these lenses can be found on the front or back surface of the contact lens or 'enclosed' within the lens matrix. The purpose of this research was to evaluate the pigment location and surface roughness of seven types of 'circle' contact lenses. METHODS: Scanning electron microscopic (SEM) analysis was performed using a variable pressure Hitachi S3400N instrument to discern the placement of lens pigments. Atomic force microscopy (Dimension Icon AFM from Bruker Nano) was used to determine the surface roughness of the pigmented regions of the contact lenses. Atomic force microscopic analysis was performed in fluid phase under contact mode using a Sharp Nitride Lever probe (SNL-10) with a spring constant of 0.06 N/m. Root mean square (RMS) roughness values were analysed using a generalised linear mixed model with a log-normal distribution. Least square means and their corresponding 95% confidence intervals were estimated for each brand, location and pigment combination. RESULTS: SEM cross-sectional images at 500× and 2,000× magnification showed pigment on the surface of six of the seven lens types tested. The mean depth of pigment for 1-DAY ACUVUE DEFINE (1DAD) lenses was 8.1 µm below the surface of the lens, while the remaining lens types tested had pigment particles on the front or back surface. Results of the atomic force microscopic analysis indicated that 1DAD lenses had significantly lower root mean square roughness values in the pigmented area of the lens than the other lens types tested. CONCLUSIONS: SEM and AFM analysis revealed pigment on the surface of the lens for all types tested with the exception of 1DAD. Further research is required to determine if the difference in pigment location influences on-eye performance.

Clinical evaluation of fitting toric soft contact lenses to current non-users.

PURPOSE: To evaluate the ease with which astigmats from three groups of current non-wearers of toric contact lenses can be fitted with current toric soft lenses, and to determine toric lens-wearing success. METHODS: This was a 1-month, randomized, bilateral, open-label, daily wear study involving 200 subjects and 16 investigational sites in the UK. Three groups of astigmatic subjects aged from 16 to 60 and with a mean age of 36 years (67 spherical soft contact lens users, SW; 72 contact lens drop-outs, DO; and 61 neophytes, Neo) were fitted with one of two toric soft lens types: a daily disposable toric soft lens (1 Day Acuvue Moist for Astigmatism, Johnson & Johnson Vision Care) or a 2-weekly replacement, re-usable toric soft lens (Acuvue Oasys for Astigmatism, Johnson & Johnson Vision Care). Subjects were evaluated after 1 month of wear and success rates calculated according to pre-set criteria for acceptable fit, orientation stability, visual acuity, quality of vision, and overall comfort. RESULTS: Eighty-eight percent of lenses were fitted at the first attempt. Of 198 subjects dispensed with lenses, 182 (92%) completed the study. When analysed by subject group, the success rates according to the pre-set criteria were 80% (53/66), 74% (52/70), and 70% (39/56) for the SW, DO and Neo groups respectively. Comfort was the most common reason for failure with all three groups; however, visual problems were more common in the DO and Neo groups (13% vs 6%). VA with the study lenses was significantly better in the SW group compared to their habitual lenses. For the DO and Neo groups combined (i.e. spectacle wearers), visual acuity was comparable to their habitual spectacles. CONCLUSIONS: A high proportion of astigmats who are not using toric soft contact lenses can be fitted with current lenses. Previous contact lens drop-outs and neophyte wearers achieve visual acuity comparable to spectacles when fitted with toric soft lenses. Spherical contact lens wearing astigmats achieve superior visual acuity when refitted with toric soft lenses. These findings suggest that many astigmats who are not currently using toric soft contact lenses could do so successfully.