1-DAY ACUVUE Research Articles

Optical edge effects create conjunctival indentation thickness artefacts.

Conjunctival compression observed in ultrahigh resolution optical coherence tomography (UHR-OCT) images of contact lens edges could be actual tissue alteration, may be an optical artefact arising from the difference between the refractive indexes of the lens material and the conjunctival tissue, or could be a combination of the two. The purpose of this study is to image the artefact with contact lenses on a non-biological (non-indentable) medium and to determine the origins of the observed conjunctival compression. Two-dimensional cross-sectional images of the edges of a selection of marketed silicone hydrogel and hydrogel lenses (refractive index ranging from 1.40 to 1.43) were acquired with a research grade UHR-OCT system. The lenses were placed on three continuous surfaces, a glass sphere (refractive index n = 1.52), a rigid contact lens (n = 1.376) and the cornea of a healthy human subject (average n = 1.376). The displacement observed was analysed using ImageJ. The observed optical displacement ranged between 5.39(0.06) μm with Acuvue Advance and 11.99(0.18) μm with Air Optix Night & Day when the lens was imaged on the glass reference sphere. Similarly, on a rigid contact lens displacement ranged between 5.51(0.03) and 9.72(0.12) μm. Displacement was also observed when the lenses were imaged on the human conjunctiva and ranged from 6.49(0.80) μm for the 1-day Acuvue Moist to 17.4(0.22) μm for the Pure Vision contact lens. An optical displacement artefact was observed when imaging a contact lens on two rigid continuous surfaces with UHR-OCT where compression or indentation of the surface could not have been a factor. Contact lenses imaged in situ also exhibited displacement at the intersection of the contact lens edge and the conjunctiva, likely a manifestation of both the artefact and compression of the conjunctiva.

Assessment of corneal morphological changes induced by the use of daily disposable contact lenses.

To assess the effect of different disposable soft contact lenses upon corneal thickness, and upon anterior and posterior corneal curvatures using a dual-Scheimpflug imaging based device. Twenty-eight young, healthy subjects wore four different types of daily disposable soft contact lenses on four different days: Dailies Total1, Proclear 1 Day, Clariti 1-Day and 1-Day Acuvue Moist. The lenses had different material and water content. Pachymetry maps and keratometry values were obtained using the Galilei G4 twice a day: one before putting the lens on and one after an eight-hour period of contact-lens wear. Measurements were also recorded without any contact lenses being worn during a day. Clariti 1-Day lens caused the greatest thickening in the central (8.9±2.8 μm; p<0.01) and in the peripheral cornea (10.1±4.6 μm; p<0.01), whereas Dailies Total1 was the lens that had the most similar behaviour to the non-contact lens scenario. All the lenses caused a slight flattening in the anterior corneal curvature, except Clariti 1-Day, which induced a very slight steepening. The four lenses caused a steepening of different magnitude in the posterior corneal curvature. The magnitude of the changes introduced by the use of soft contact lenses over the eight-hour wearing period was rather small. Thus it is probable it will not influence the vision nor the comfort of the subject. Also, variations on corneal parameters seem to depend on the type of contact lens used.

The effect of tinted soft contact lens wear on functional visual acuity and higher-order aberrations

To investigate the differences of functional visual acuity (FVA) and high order aberrations (HOAs) in relation to tinted and clear hydrogel soft contact lens (SCL) wear. A prospective comparative study was performed in 16 eyes of 16 healthy volunteers. Dynamic visual acuity (using a FVA measurement system) and higher-order aberrations (using a wavefront sensor) were compared in subjects wearing two types of soft contact lenses: 1-day Acuvue(®) (Vistakon, Jacksonville, FL) clear and the 1-day Acuvue(®) Define(TM) (Vistakon, Jacksonville, FL) tinted lens. The blink rates were recorded during FVA testing. The correlation between the difference of HOAs and differences in FVA values was analyzed. The mean LogMAR FVA scores with clear and tinted SCLs were 0.07 ± 0.13 and 0.14 ± 0.17 (P<0.05). The mean blink frequencies with clear and tinted SCL wear were 18.4 ± 8.3 and 25.3 ± 4.7 blinks/min (P<0.05). Both 3rd-order aberrations and total HOAs showed statistically significant differences between the two types of soft contact lenses for 6mm pupil measurements (P<0.05). A significant positive linear correlation was observed between ΔHOAs and ΔLogMAR FVA for 6mm pupil measurements (R=0.53, P=0.04). Tinted contact lens wear appears to induce a reduction in optical quality. Functional visual acuity measurement is a useful procedure to study the changes of visual performance and quality in tinted contact lens wear.

Differences in daily disposable circle lens performance characteristics

Differences in daily disposable circle lens performance characteristics Jeffery M Schafer, William T Reindel, Marjorie J Rah, Osbert Chan, Lening Zhang Bausch &amp; Lomb Incorporated, Rochester, NY, USA Purpose: The purpose of this evaluation was to compare the performance characteristics of two cosmetically tinted contact lenses in the circle lens category that differ in lens design, lens material, and pigment print pattern: etafilcon A (1-Day Acuvue Define; Johnson &amp; Johnson Vision Care) and hilafilcon B (Naturelle; Bausch &amp; Lomb Incorporated). Methods: Two hundred Asian subjects (400 eyes) were enrolled in this 1-month parallel, bilateral, randomized study at ten investigative sites. Study lenses were dispensed at a screening/dispensing visit, and follow-up visits occurred at 2 weeks and 1 month. Lenses were worn on a daily disposable basis. Fit characteristics were evaluated at each visit, and slit-lamp evaluations were completed at each follow-up visit. Results: Of the 200 patients enrolled, 172 (344 eyes) completed the study. The proportion of eyes with fully centered lenses was statistically significantly higher for the hilafilcon B group at the 2-week and 1-month visits, P&lt;0.05. Over all visits, 0.6% of hilafilcon B eyes demonstrated incomplete corneal coverage, whereas for the etafilcon A group, 8.5% of eyes demonstrated incomplete corneal coverage and/or edge lift. The proportion of eyes with adequate lens movement was statistically significantly higher for the hilafilcon B group, P&lt;0.05. Over all visits, none of the hilafilcon B eyes was reported to have excessive movement, whereas for etafilcon A lenses, 10.2% of eyes were reported to have excessive movement. Conclusions: Etafilcon A lenses were significantly less likely to be fully centered and significantly more likely to have incomplete corneal coverage and/or edge lift compared with the hilafilcon B lenses. Keywords: cosmetic contact lens, circle contact lens

Contact Lens In Vitro Wettability by Interferometry Measures of Drying Dynamics

To develop with a thin film interferometer new parameters to describe the drying properties of contact lenses; these are: time to first break-up (onset latency), duration of lens surface drying (drying duration), maximum speed of increase in the drying area (maximum speed), and the time to reach maximum drying speed (peak latency). These new parameters were compared with the contact angle (CA) measurement of contact lenses by the captive bubble (CB) technique. A thin film interferometer was connected to a digital camera, which captured images of the pre-lens liquid film of seven soft contact lenses in vitro: 1-Day Acuvue Moist, ACUVUE Oasys (Johnson & Johnson Vision Care); SofLens 38, PureVision (Bausch & Lomb); AirOptix Night & Day, AirOptix Aqua (CIBA Vision, Corp); and Proclear (Cooper Vision). The images were obtained from the lens surface when it was wet until it became dry (7 images per second) to generate video clips. A program was created in MATLAB to analyze the results. The CAs of the lens surfaces were measured by the CB technique with an OCA-20 contact angle analyzer (Data Physics Instruments). There were no significant relationships found between the CA and the new drying parameters (P > 0.05). Analysis of the results using analysis of variance and post hoc tests showed that the surface drying dynamics measures effectively differentiated between more of the soft lenses than the CA. A new technique is described for assessing the drying characteristics of contact lenses by observations of the pattern, size, and speed of pre-lens liquid film break-up observed by a thin film interferometry. The interferometry method allowed evaluation and differentiation between lens materials. This new technique has the major advantage that it can be applied to evaluate contact lens wettability in vivo and in vitro.

Comfort Response of Three Silicone Hydrogel Daily Disposable Contact Lenses

To evaluate subjective ocular comfort across the day with three silicone hydrogel daily disposables (SHDDs) in a group of adapted lens wearers. Masked subjects (asymptomatic or symptomatic of end-of-day (EOD) dryness with habitual lenses) wore three SHDDs: DAILIES TOTAL1 (DT1), Clariti 1day (C1D), or 1-DAY ACUVUE TRUEYE (AVTE), each for 3 days. On day 2, wearing time (WT) and comfort ratings after insertion, at 4, 8, and 12 hours, and at EOD were recorded. Because not all subjects wore lenses for 12 hours, comfort was analyzed across the day (up to 8 hours, 8 to 12 hours), and a new variable ("cumulative comfort" [CC]) was calculated for EOD. One hundred four subjects completed the study (51 asymptomatic, 53 symptomatic). The two groups had different WTs (mean WT, 14.0 and 12.7 hours, respectively; p < 0.001). Ocular comfort was rated higher in the asymptomatic group throughout the day (p < 0.001). One hundred four subjects wore all three SHDDs for at least 8 hours, whereas 74 (45 asymptomatic, 29 symptomatic) subjects wore them for 12 hours or longer. Comfort ratings were higher with DT1 (least square means [LSM] = 91.0) than with C1D (LSM = 86.5; p < 0.001) and AVTE (LSM = 87.7; p = 0.011) for the first 8 hours and lower with C1D compared with DT1 (p = 0.012) from 8 to 12 hours. Mean EOD (± SD) comfort with the C1D lens was 72 ± 21, lower than both DT1 (mean, 79 ± 17; p = 0.001) and AVTE (mean, 78 ± 21; p = 0.010). Mean CC was higher in the asymptomatic group (mean, 1261 ± 59) compared with that in the symptomatic group (mean, 1009 ± 58; p < 0.001) and higher for DT1 (mean, 1184 ± 258) than C1D (mean, 1094 ± 318; p = 0.002) and AVTE (mean, 1122 ± 297; p = 0.046). All three SHDDs had average WTs of 12 hours or longer for 1 day. Comfort during the first 12 hours was highest with DT1 (similar to AVTE between 8 and 12 hours) and lowest with C1D. End-of-day comfort was lowest with C1D, and CC was highest for DT1. Cumulative comfort may be a valuable new metric to assess ocular comfort during the day.

Release of N-acetylcysteine and N-acetylcysteine Amide From Contact Lenses

To investigate the use of contact lenses to release N-acetylcysteine (NAC) and N-acetylcysteine amide (NACA) that have frequently used for the treatment of some eye diseases. Three commercial contact lenses were used: Soflens Multi-Focal, 1-Day ACUVUE TruEye, and Frequency 55. All contact lenses were individually kept for 3 days in 10 mL of 3 mM NAC or NACA solutions in phosphate-buffered saline (PBS). After the loading period, the lenses were removed from the solution and put into 5 mL of PBS for 3 days (static mode). During this period, samples were taken at specified times and analyzed by high-pressure liquid chromatography. From the release profiles of NAC and NACA, it was found that both NAC and NACA could be released from the lenses within 72 hours. Frequency 55 released 95.9%±2.7% of loaded NAC and 60.0%±2.1% of loaded NACA in 24 hours, whereas 1-Day ACUVUE TruEye released 80.9%±1.2% of loaded NAC and 54.0%±1.9% of loaded NACA and Soflens Multi-Focal released 72.8%±2.8% of loaded NAC and 51.9%±2.3% of loaded NACA during that same period. The lenses could achieve the appropriate delivery of drugs during their intended time of wear. The amount of released NACA was less than that of NAC because of the more hydrophobic structure of NACA. According to the power law, the values of the exponential constant n were found to be below 0.5, indicating that the behavior observed was "less Fickian".

Diurnal Variations in Visual Performance for Disposable Contact Lenses

The purpose of this study is to compare the visual performance provided by different daily disposable contact lenses and to analyze its variation over time. Visual performance was evaluated in terms of visual acuity (VA) and contrast sensitivity (CS) in 15 myopic subjects (-0.50 to -4.00 diopters) who had been previously fitted with each one of the following seven types of soft contact lenses: DAILIES TOTAL1 (Alcon, Forth Worth, TX), DAILIES AquaComfort Plus (Alcon), 1-DAY ACUVUE TruEye (Johnson & Johnson Vision Care, Jacksonville, FL), 1-DAY ACUVUE MOIST (Johnson & Johnson Vision Care), SofLens daily disposable (Bausch & Lomb, Rochester, NY), Proclear 1 Day (CooperVision, Fairport, NY), and Clariti 1-Day (Sauflon, Twickenham, United Kingdom). We measured VA at three contrast levels (10%, 50%, and 100%) and CS for three spatial frequencies (10, 20, and 25 cycles/degree). These measurements were performed at 2-hr intervals during a 12-hr period of continuous wearing. Measurements were also performed with ophthalmic lenses before contact lens fitting. Two-way analysis of variance (ANOVA) results revealed significant differences across the lens types and over time for low-contrast VA only. For high- and medium-contrast VA, ophthalmic lens performed better than the contact lenses after 12 hr of use (without statistical differences among the contact lenses). Contrast sensitivity values also showed differences across lenses for the three spatial frequencies under analysis. For each particular lens type, no CS variations were observed with wearing time. Although some of the differences were not statistically significant, we found that, for many of the VA and CS measures, ophthalmic lens and DAILIES TOTAL1 yielded better values than the 1-DAY ACUVUE TruEye and Clariti 1-Day. Assessing VA at different contrasts and CS measurements allowed us to perform a visual function evaluation. Contact lens characteristics such as material and water content, among others, may be the cause of the differences in visual performance that emerged from this study. Our findings provide useful information for contact lens practitioners.

In vitro power profiles of daily disposable contact lenses

To evaluate and compare the distribution of refractive power within the optic zone of different soft contact lenses and to investigate the effect of lens decentration on the power profiles. The Nimo TR1504 instrument was used to measure the optical power across different aperture diameters (from 1.5mm to 5.5mm in steps of 0.5mm) of four daily disposable contact lenses: DAILIES TOTAL1, Proclear 1-Day, SofLens daily disposable and 1-DAY ACUVUE MOIST. Measurements were performed using a wet cell. Power data were evaluated when contact lenses were in its centered position and after inducing different amounts of lens decentration (from 0.2mm to 1.0mm in steps of 0.2mm). All contact lenses showed an increase - more negative - in lens power with distance from the lens center. The amount of change varied depending on the lens. It was about 10% of lens power for DAILIES TOTAL1 (-0.29diopters (D)), SofLens daily disposable (-0.36D), and Proclear 1-Day (-0.32D) whereas 1-DAY ACUVUE MOIST showed a percentage variation of 3.3% (-0.10D). After inducing a lens decentration up to 1mm, the power curves were shifted in the negative direction. However, the change obtained in lens power compared with well-centered position was always lower than a quarter of diopter both for all the lenses and aperture diameters. Our results showed a variation of the refractive power from the lens center, becoming more negative toward the periphery, with a negligible effect of the decentration for all disposable contact lenses studied.

Influence of decorative lenses on higher-order wavefront aberrations

To investigate the influence of decorative lenses on ocular wavefront aberrations. A wavefront analyzer was used to measure higher-order aberrations (HOAs) in 20 right eyes of 20 participants while they were wearing Vistacon contact lenses of different designs, namely, clear 1-day Acuvue, ring-design circle 1-day Acuvue Define (Accent style), or spoke-design circle 1-day Acuvue Define (Vivid style). All of these lenses are made of the same materials and have the same lens parameters, except for the tinted design. HOAs induced by each contact lens were measured for 4- and 6-mm pupils. The coma-like, spherical-like, and total HOAs of each lens type were compared. HOAs of well- and poorly fitting lenses were also compared. For a 4-mm pupil, the HOAs of the three lens types did not differ significantly. For the 6-mm pupil, coma-like and total HOAs were significantly larger with decorative lenses than with clear lenses (P < 0.05, Bonferroni test). No significant differences were observed between the two types of decorative lenses. Poorly fitting decorative lenses showed significantly larger HOAs than did well-fitting decorative lenses. Poorly fitting decorative lenses may reduce the quality of vision. Consequently, care should be taken that these lenses are properly centered.

On‐eye optical quality of daily disposable contact lenses for different wearing times

To quantify the optical quality of various daily disposable contact lenses in vivo and to ascertain its variation in terms of wearing time by means of objective non-invasive determination of wavefront patterns. The crx1 adaptive-optics system was used to measure the wavefront aberrations in 15 myopic eyes before and at 2-h intervals after contact lens fitting, over a 12-h wearing period. Seven types of contact lenses having different material, water content and lens design were evaluated in this study: Dailies Total1, Dailies AquaComfort Plus, Proclear 1 Day, 1-Day Acuvue TruEye, 1-Day Acuvue moist, SofLens daily disposable and Clariti 1-Day. The aberration data were analysed by fitting Zernike polynomials up to the 5th-order for 3 and 5-mm pupils. The optical quality under each condition and at each point in time was described by means of the Root-Mean-Square (RMS) value of wavefront aberration, Modulation Transfer Function (MTF), Point Spread Function and cut-off spatial frequency. A RMS increase was observed after contact lens fitting as well as over time, both for a 3-mm and a 5-mm pupil. Each type of lens induced a different amount of wavefront aberrations, which vary over time also in a different manner. Dailies Total1 showed the lowest RMS values both at baseline and at the end of the day. In addition, Dailies Total1 provided the best MTF out of all the contact lenses that were assessed. These observations were reflected in higher cut-off spatial frequencies and visual resolution both at baseline and after 12h of wearing time. Aberrometry makes it possible to analyse accurately and in vivo the optical quality of contact lenses and to assess how lenses having different characteristics - such as material or water content - behave for different wearing times. These variations across contact lenses may result in differences in visual performance.

Extended delivery of an anionic drug by contact lens loaded with a cationic surfactant

Drug eluding contact lenses can be very effective vehicles for ophthalmic drug delivery, but are incapable of releasing drug for more than a few hours. We propose to optimize the interactions of the polymer matrix of the contact lens with the hydrophobic tails of ionic surfactants to adsorb the surfactant molecules on the polymer with high packing and thus create a high surface charge. Ionic drugs can then adsorb on the charged surfactant coated surfaces with high affinity to reduce the transport rates, leading to extended release. Specifically, we show control release of an anionic drug dexamethasone 21-disodium phosphate from poly-hydroxyethyl methacrylate (p-HEMA) contact lenses by utilizing cationic surfactant (cetalkonium chloride). The partition coefficient of the drug increase exponentially with surfactant loading in the gel in at least qualitative agreement with the Debye-Hückel theory. The drug adsorbs on the surfactant covered polymer, and can also diffuse along the surface with diffusivity lower than that for the free drug, leading to a reduction in the effective diffusivity, which is the weighted combination of the free and surface diffusivities. The addition of surfactant did not impact transparency of lenses, and had additional benefits of increase in wettability and significant reduction in protein absorption. With a surfactant loading of about 10%, the drug release duration was increased from about 2 h to 50 h in 1-day ACUVUE® contact lenses, proving the viability of using surfactant for increasing drug release durations.

Comparing on eye dehydration and corneal staining of three daily disposable contact lenses in a low humidity environment

Purpose: The objective was to evaluate water loss and corneal response of a novel, 78% water investigational lens compared to a 58% water etafilcon A [1-Day Acuvue Moist] lens and a 48% water narafilcon B [1-Day Acuvue TruEye] lens in a controlled 6% relative humidity environment.

Extended cyclosporine delivery by silicone–hydrogel contact lenses

Cyclosporine A (CyA) is effective in treating chronic dry eyes and contact lens mediated dry eyes. CyA is delivered through eye drops of an oil-in-water emulsion, which has a small residence time in the eyes, leading to low bioavailability. Here we explore delivery of CyA from contact lenses to provide controlled and extended drug delivery with an increased bioavailability due to enhanced ocular residence time. Loading and release profiles of CyA from commercial contact lenses are presented to show that 1-DAY ACUVUE® releases CyA for about a day and extended wear silicone hydrogel (SiH) lenses release CyA for about 2-weeks. The longer duration from SiH lenses compared to the 1-DAY ACUVUE®lens is due to larger partition coefficients in the gel. A novel approach is presented for increasing release duration from the SiH lenses to the desired 1-month through incorporation of Vitamin E. The results show that Vitamin E loaded lenses can provide CyA release within the therapeutic window for a period of about a month. This pilot study demonstrates the promising potential of delivering CyA from contact lens for treatment of chromic dry eyes and contact lens mediated dry eyes.

Contact Lenses in Pediatrics Study in Singapore

Previous studies in the United States have evaluated the benefits of soft contact lenses (CLs) in 8- to 12-year-old children and 13- to 17-year-old teens. This study was undertaken in Singapore and evaluated the safety, efficacy, and physiologic performance of daily disposable soft lenses in a population of children. In this open-label, bilateral, 3-month dispensing study, 59 children (8-11 years) were fit with etafilcon A spherical or toric daily disposable lenses (1-DAY ACUVUE or 1-DAY ACUVUE for ASTIGMATISM, Vistakon, Jacksonville, FL). All subjects were neophytes requiring visual correction in both eyes. The refractive inclusion criteria were plano to -9.00 diopter (D) with astigmatism of < or =2.00DC in both eyes, or hyperopia of +0.50 to +6.00D with astigmatism of 0.75D or less. The subjects underwent follow-up evaluations, which included a questionnaire for parents and subjects, at 1 week, 1 month, and 3 months. Of the 59 subjects enrolled, 53 (90%) completed the study successfully. Six subjects were discontinued because of lens handling difficulties (four), unacceptable lens fit (one), and an adverse event (one). Adverse events were reported in three subjects, including the discontinuation, and in each case were due to a chalazion. Overall vision quality, overall comfort, and end-of-day comfort were graded significantly better at each of the follow-up visits compared with baseline with spectacles (P< or =0.0001). Both handling and reported symptoms improved during the course of the study. The questionnaire results indicated that most of both parents and subjects preferred CLs to spectacles across a wide variety of aspects including vision, comfort, handling, and appearance. Significantly, more limbal and bulbar hyperemia was noted at follow-up visits than at baseline (P=0.0001); however, no instances of hyperemia greater than grade 2 were noted at any visit. Significantly, more corneal staining was also noted at the 1- and 3-month follow-up visits than at baseline (21% at 3 months). A high proportion of Singaporean children requiring vision correction are able to successfully wear daily disposable soft CLs over a 3-month period. Overall, slit lamp findings showed the prevalence of corneal staining in this study to be 21% at 3 months, which is lower than that previously reported in adults, but higher than that reported in the US Contact Lenses in Pediatrics study (6%).

Influence of cosmetically tinted soft contact lenses on higher-order wavefront aberrations and visual performance

To investigate the influence of cosmetically tinted soft contact lenses on ocular higher-order aberrations and visual performance, and to analyze the relationship between these parameters after the lens wear. In 44 eyes of 22 subjects, visual acuity, contrast sensitivity under photopic and mesopic conditions, and ocular higher-order aberrations were evaluated before and after wearing the tinted soft contact lenses (1-day Acuvue Colours; Vistakon, Jacksonville, FL). Contrast sensitivity under a photopic condition was determined at 3, 6, 12, and 18 cycles per degree, and the area under the log contrast sensitivity function (AULCSF) was calculated. Mesopic contrast sensitivity with and without glare was assessed. Ocular higher-order aberrations for a 4-mm pupil were measured, and coma-like, spherical-like, and total higher-order aberrations were determined. The tinted contact lens wearing resulted in significant decreases in log contrast sensitivity at all spatial frequencies (P < 0.05) and AULCSF (P < 0.0001), although 100% contrast visual acuity did not change. Log mesopic contrast sensitivity with and without glare was also reduced significantly by the lens wear (P < 0.0001). The contact lens wear significantly increased coma-like, spherical-like, and total higher-order aberrations (P < 0.0001). The induced changes in higher-order aberrations were analyzed in relation to the changes in contrast sensitivity function. Although the changes in coma-like and spherical-like aberrations did not correlate significantly with those in AULCSF (P > 0.05), the changes in total higher-order aberrations showed a significant correlation with those in AULCSF (P < 0.05). On the other hand, there was no significant relationship between the changes in higher-order aberrations and the changes in log mesopic contrast sensitivity with and without glare (P > 0.05). Cosmetically tinted contact lenses increase ocular higher-order aberrations and worsen contrast sensitivity under both photopic and mesopic conditions. Increases in higher-order aberrations are responsible for decreased contrast sensitivity under the photopic condition. Tinted contact lens wearers should be sufficiently informed about the possible reduction in optical quality of the eye and quality of vision.

Multi-centre evaluation of two daily disposable contact lenses

Purpose To evaluate the clinical performance of two daily disposable contact lenses: 1-DAY ACUVUE ® (1DA) (etafilcon A, Johnson & Johnson Vision Care) and FOCUS ® DAILIES ® with AquaComfort™ (FD) (nelfilcon A, CIBA Vision, Inc.), which contains a quickly released moisture enhancing agent, polyvinyl alcohol (PVA). Methods This was a 1-week, daily wear, subject-masked, bilateral, parallel group study with subjects randomly assigned to one of two daily disposable soft contact lenses. Subjects were existing soft contact lens wearers in the age range 18–39 years with a spherical refraction between −0.50 and −6.00D. Subjects were assessed at baseline and after 1 week. Assessments included both subjective (symptoms, wearing time, vision) and objective (lens fit and ocular health) outcomes. Results Twenty clinical sites enrolled 282 subjects (74% female) of whom 276 (98%) successfully completed the study. Significantly more 1DA wearers reported higher mean comfort scores than with FD (3.95 versus 3.41, respectively, P < 0.0001). End-of-day comfort means were also significantly higher with the 1DA group compared to the FD group (3.3 versus 3.0, P = 0.03). The 1DA group reported significantly longer mean overall wearing time (1DA was worn on average 0.66 ± 0.30 h longer than FD, P = 0.03) and longer mean comfortable wearing time (1DA was worn on average 1.73 ± 0.35 h longer than FD, P < 0.0001). The 1DA lens generally showed significantly better on-eye fitting in terms of movement in primary ( P < 0.0001) and upgaze ( P < 0.0001) and ease of removal from the eye (92% versus 63%, P < 0.0001) compared to FD. There was significantly less corneal staining observed with the 1DA wearing eyes compared with the FD wearing eyes (23% versus 45%, respectively, P < 0.0001). Finally, there was a weak correlation between corneal staining and comfort for FD ( r = 0.27, P = 0.002, n = 136), but not for 1DA ( r = −0.11, P = 0.18, n = 140). Conclusion Subjective and objective clinical performance differences between two commonly used daily disposable lenses highlight that, although both lenses may be considered as clinically acceptable, these lenses should not be regarded as interchangeable.

Case report: the occurrence of fibrillary lines in overnight orthokeratology

To report the occurrence of concentric fibrillary lines in the central corneas of a 13-year-old girl during overnight orthokeratology. Observational case report. The initial refractive errors and keratometric readings (flattest/steepest meridians) of the patient were -6.00/-0.50 x 180 and 45.25/46.20 D, respectively, in the right eye and -5.50 DS and 44.90/45.80 D, respectively in the left eye. She underwent orthokeratology for myopic control, with a target reduction of 4.00 D myopia. A pair of DreimLens lenses was prescribed to be worn on a nightly basis and spectacles were worn by day. The same orthokeratology lenses were used throughout the monitoring period. Corneal topography showed well-centred treatment zones but persistent peripheral corneal staining due to trichiasis. A faint, peripheral pigmented brownish corneal arc and bundles of fine concentric fibrillary lines were observed in the central cornea about 12 months after commencing lens wear. In view of the persistent corneal staining due to trichiasis, she was advised to stop the orthokeratology treatment after 16 months of lens wear and was prescribed 1-Day Acuvue daily disposable contact lenses. The pigmented line disappeared after 2 months of hydrogel lens wear, while the fibrillary lines took 10 months to resolve. Fibrillary lines are a feature of the normal cornea thought to represent the arrangement of the subbasal, epithelial nerve plexus. We hypothesize that orthokeratology lens wear stimulates an altered epithelial migration pattern and a structural reorganisation of the subbasal nerve plexus in relation to this. This is assumed to account for the concentric pattern of fibrillary lines seen in our patient. The lines had no effect on vision and resolved over a period of 10 months following cessation of orthokeratology lens wear.

Corneal Innervation in the Pathogenesis of Dry Eye following Refractive Surgery or related to other Conditions Compromizing Ocular Surface

The ultraviolet (UV) transmittance spectra of daily wear hydrogel and disposable silicone hydrogel contact lenses were measured. Average transmittance percentages were calculated for each lens for the entire UV spectrum and individually for the UVC, UVB and UVA portions of the spectrum. The significance of the differences in transmittance spectra obtained for the lenses was analysed using a one-way ANOVA planned comparisons test (α = 0.05). The transmittance data were then used to calculate a UV protection factor (PF) for each contact lens brand tested. The PFs for 1-DAY ACUVUE® MOIST™ (6.22), ACUVUE® ADVANCE™ (10.02) and ACUVUE® OASYS™ (11.96) contact lenses show that these contact lenses have superior UV-blocking capabilities. The PFs for Focus® DAILIES® (1.79), SofLens™ 1-day disposables (1.72), NIGHT & DAY™ (1.84), O2 Optix™ (1.99) and Purevision™ (2.62) show that these contact lenses posses more modest UV-blocking characteristics. This paper reviews the importance of protection of the anterior ocular surface from UV damage and quantifies the protection afforded by selected commercially available disposable contact lenses.

Drying methods for XPS analysis of PureVision?, FocusS Night&amp;Day? and conventional hydrogel contact lenses

The surface composition of hydrogel contact lenses that contain silicon-based monomers, PureVision™ (balafilcon A) and Focus ® Night&Day™ (lotrafilcon A), were investigated by X-ray photoelectron spectroscopy (XPS). Conventional and daily disposable hydrogel lenses based on hydroxyethyl methacrylate (HEMA) were also studied, with the commonly prescribed 1-day Acuvue ® lens (etafilcon A) used as a control. All the lenses were pre-washed and dehydrated by three different methods, including drying in air, drying in nitrogen or freezing with subsequent freeze-drying, before the XPS analysis. The lenses dried in air had more impurities on the surface, and the lenses that were freeze-dried lost transparency, suggesting that drying lenses in nitrogen is the preferred preparation method for XPS analysis. Surface compositions for all lens materials were obtained and this data can be used as a control/base-value for future analysis of the interactions of soft contact lens materials with chemicals such as drugs or tear components.