Jones,L., Downie,L. E., Korb,D., Benitez-del-Castillo,J. M., Dana,R., Deng,S. X., Dong,P. N., Geerling,G., Hida,R. Y., Liu,Y., Seo,K. Y., Tauber,J., Wakamatsu,T. H., Xu,J., Wolffsohn,J. S., Craig,J. P. TFOS DEWS II Management and Therapy Report Ocular Surface 2017;15(3):575-628 [ Show Abstract ]

The members of the Management and Therapy Subcommittee undertook an evidence-based review of current dry eye therapies and management options. Management options reviewed in detail included treatments for tear insufficiency and lid abnormalities, as well as anti-inflammatory medications, surgical approaches, dietary modifications, environmental considerations and complementary therapies. Following this extensive review it became clear that many of the treatments available for the management of dry eye disease lack the necessary Level 1 evidence to support their recommendation, often due to a lack of appropriate masking, randomization or controls and in some cases due to issues with selection bias or inadequate sample size. Reflecting on all available evidence, a staged management algorithm was derived that presents a step-wise approach to implementing the various management and therapeutic options according to disease severity. While this exercise indicated that differentiating between aqueous-deficient and evaporative dry eye disease was critical in selecting the most appropriate management strategy, it also highlighted challenges, based on the limited evidence currently available, in predicting relative benefits of specific management options, in managing the two dry eye disease subtypes. Further evidence is required to support the introduction, and continued use, of many of the treatment options currently available to manage dry eye disease, as well as to inform appropriate treatment starting points and understand treatment specificity in relation to dry eye disease subtype.

Jones,L., Drobe,B., González-Méijome,J. M., Gray,L., Kratzer,T., Newman,S., Nichols,J.J., Ohlendorf,A., Ramdass,S., Santodomingo-Rubido,J., Schmid,K. L., Tan,D., Tan,K. O., Vera-Diaz,F. A., Wong,Y. L., Gifford,K. L., Resnikoff,S. IMI - Industry Guidelines and Ethical Considerations for Myopia Control Report Invest Ophthalmol Vis Sci 2019;60(3):M161-M183 [ Show Abstract ]

PURPOSE:
To discuss guidelines and ethical considerations associated with the development and prescription of treatments intended for myopia control (MC).

METHODS:
Critical review of published papers and guidance documents was undertaken, with a view to carefully considering the ethical standards associated with the investigation, development, registration, marketing, prescription, and use of MC treatments.

RESULTS:
The roles and responsibilities of regulatory bodies, manufacturers, academics, eye care practitioners, and patients in the use of MC treatments are explored. Particular attention is given to the ethical considerations for deciding whether to implement a MC strategy and how to implement this within a clinical trial or practice setting. Finally, the responsibilities in marketing, support, and education required to transfer required knowledge and skills to eye care practitioners and academics are discussed.

CONCLUSIONS:
Undertaking MC treatment in minors creates an ethical challenge for a wide variety of stakeholders. Regulatory bodies, manufacturers, academics, and clinicians all share an ethical responsibility to ensure that the products used for MC are safe and efficacious and that patients understand the benefits and potential risks of such products. This International Myopia Institute report highlights these ethical challenges and provides stakeholders with recommendations and guidelines in the development, financial support, prescribing, and advertising of such treatments.

Jones,L., Efron,N., Bandamwar,K., Barnett,M., Jacobs,D. S., Jalbert,I., Pult,H., Rhee,M. K., Sheardown,H., Shovlin,J. P., Stahl,U., Sranila,A., Tan,J. Tavazzi,S., Ucakhan,O. O., Willcox,M. D. P., Downie,L. TFOS lifestyle: Impact of contact lenses on the ocular surface Ocular Surface 2023;29(July):175-219 [ Show Abstract ]

Several lifestyle choices made by contact lens wearers can have adverse consequences on ocular health. These include being non-adherent to contact lens care, sleeping in lenses, ill-advised purchasing options, not seeing an eyecare professional for regular aftercare visits, wearing lenses when feeling unwell, wearing lenses too soon after various forms of ophthalmic surgery, and wearing lenses when engaged in risky behaviours (e.g., using tobacco, alcohol or recreational drugs). Those with a pre-existing compromised ocular surface may find that contact lens wear exacerbates ocular disease morbidity. Conversely, contact lenses may have various therapeutic benefits. The coronavirus disease-2019 (COVID-19) pandemic has impinged upon the lifestyle of contact lens wearers, introducing challenges such as mask-associated dry eye, contact lens discomfort with increased use of digital devices, inadvertent exposure to hand sanitizers, and reduced use of lenses. Wearing contact lenses in challenging environments, such as in the presence of dust and noxious chemicals, or where there is the possibility of ocular trauma (e.g., sport or working with tools) can be problematic, although in some instances lenses can be protective. Contact lenses can be worn for sport, theatre, at high altitude, driving at night, in the military and in space, and special considerations are required when prescribing in such situations to ensure successful outcomes. A systematic review and meta-analysis, incorporated within the review, identified that the influence of lifestyle factors on soft contact lens dropout remains poorly understood, and is an area in need of further research. Overall, this report investigated lifestyle-related choices made by clinicians and contact lens wearers and discovered that when appropriate lifestyle choices are made, contact lens wear can enhance the quality of life of wearers.

Jones,L., Hui,A., Phan,C-M., Read,M. L., Azar,D., Buch,J., Ciolino,J. B., Naroo,S. A., Pall,B., Romond,K., Saknaridurg,P., Schnider,C. M., Terry,L., Willcox,M. CLEAR - Contact lens technologies of the future Contact Lens Anterior Eye 2021;44(2):398-430 [ Show Abstract ]

Contact lenses in the future will likely have functions other than correction of refractive error. Lenses designed to control the development of myopia are already commercially available. Contact lenses as drug delivery devices and powered through advancements in nanotechnology will open up further opportunities for unique uses of contact lenses.

This review examines the use, or potential use, of contact lenses aside from their role to correct refractive error. Contact lenses can be used to detect systemic and ocular surface diseases, treat and manage various ocular conditions and as devices that can correct presbyopia, control the development of myopia or be used for augmented vision. There is also discussion of new developments in contact lens packaging and storage cases.

The use of contact lenses as devices to detect systemic disease has mostly focussed on detecting changes to glucose levels in tears for monitoring diabetic control. Glucose can be detected using changes in colour, fluorescence or generation of electric signals by embedded sensors such as boronic acid, concanavalin A or glucose oxidase. Contact lenses that have gained regulatory approval can measure changes in intraocular pressure to monitor glaucoma by measuring small changes in corneal shape. Challenges include integrating sensors into contact lenses and detecting the signals generated. Various techniques are used to optimise uptake and release of the drugs to the ocular surface to treat diseases such as dry eye, glaucoma, infection and allergy. Contact lenses that either mechanically or electronically change their shape are being investigated for the management of presbyopia. Contact lenses that slow the development of myopia are based upon incorporating concentric rings of plus power, peripheral optical zone(s) with add power or non-monotonic variations in power. Various forms of these lenses have shown a reduction in myopia in clinical trials and are available in various markets.

Jones,L., Macdougall,N., Sorbara,L. G. Asymptomatic corneal staining associated with the use of balafilcon silicone-hydrogel contact lenses disinfected with a polyaminopropyl biguanide-preserved care regimen Optometry and Vision Science 2002;79(12):753-761 [ Show Abstract ]

PURPOSE: To compare subjective symptoms and signs in a group of individuals who wear silicone-hydrogel lenses on a daily wear basis while they sequentially used two differing care regimens. METHODS: Fifty adapted soft-lens wearers were fitted with a silicone-hydrogel lens material (PureVision, Bausch & Lomb). The lenses were worn on a daily wear basis for two consecutive 1-month periods, during which the subjects used either a Polyquad (polyquaternium-1) -based system or a polyaminopropyl biguanide (PHMB) -based system, using a double-masked, randomized, crossover experimental design. RESULTS: Significant levels of relatively asymptomatic corneal staining were observed when subjects used the PHMB-based system, with 37% of subjects demonstrating a level of staining consistent with a classical solution-based toxicity reaction. Only 2% of the subjects exhibited such staining when using the Polyquad-based system. These results were significantly different (p < 0.001). Significant symptoms were not correlated with the degree of staining, with no differences in lens comfort or overall preference being reported between the regimens (p = NS). The only statistically significant difference in symptoms related to minor differences in stinging after lens insertion being reported, with the Polyquad-based system demonstrating less stinging (p < 0.008). CONCLUSIONS: Practitioners who fit silicone-hydrogel contact lenses on a daily wear basis should be wary of the potential for certain PHMB-containing multipurpose care systems to invoke corneal staining. Switching to non-PHMB based regimens will eliminate this complication in most instances.

Jones,L., May,C., Nazar,L., Simpson,T. In vitro evaluation of the dehydration characteristics of silicone hydrogel and conventional hydrogel contact lens materials Contact Lens and Anterior Eye 2002;25(3):147-156 [ Show Abstract ]

Purpose: This study investigated the in vitro dehydration performance of silicone hydrogel and conventional hydrogel contact lens materials. Methods: In vitro dehydration was assessed using a gravimetric method. The mass loss over time of Focus Night&Day, PureVision, Optima, Acuvue and Proclear Compatibles was measured as the ambient temperature increased from room temperature to 34°C under varying airflow and humidity conditions. Results: Dehydration data demonstrated a typical ogival form. The results were best fitted with a double exponential, non-linear regression model, which accounted for at least 99% of the variance. Regardless of material, increased airflow had a greater impact on dehydration rate than increased humidity (P < 0.05). Relative dehydration amounts were strongly correlated with initial water content (r2 = 0.92), with higher water content materials dehydrating to a greater extent. Conclusions: In vitro dehydration studies of conventional and novel silicone-containing hydrogel materials indicated that evaporation rates from materials are predominantly water content related, with only subtle differences between materials of similar water contents being seen. Environmental conditions have a significant impact on in vitro dehydration, with increased airflow having a greater impact than reduced humidity on increasing dehydration rates. In vitro dehydration is closely related to bulk water diffusion rates and, as a result of their low water content, silicone-containing hydrogel materials exhibit low levels of dehydration compared with high water content hydrogel contact lens materials. Further, in vivo studies are necessary to see if the in vitro dehydration behaviour of silicone hydrogel materials is predictive of in-eye performance. © 2002 British Contact Lens Association. Published by Elsevier Science Ltd. All rights reserved.

Jones,L., Powell,C. H. Uptake and release phenomena in contact lens care by silicone hydrogel lenses Eye and Contact Lens 2013;39(1):29-36 [ Show Abstract ]

Contact lens solutions are highly complex mixtures of biocides (preservatives), surfactants, and other agents designed to disinfect, clean, and wet contact lenses. The commercialization of silicone hydrogel (SiHy) lenses has resulted in unique challenges to the manufacturers of contact lens solutions, because the properties of these materials differ markedly from those seen previously with poly-hydroxyethyl methacrylate-based hydrogels. Historically, hydrogel lens uptake and release of low-molecular weight preservatives such as chlorhexidine and thimerosal were known to result in allergic reactions, resulting in corneal irritation, stinging, conjunctival hyperemia, development of corneal infiltrates, palpebral lid changes, and corneal staining. However, little is known about the interaction of modern care systems with modern soft lens materials. Factors to be considered when evaluating the uptake and release of care components include the water content, charge, relative hydrophobicity, surface treatment, and porosity of the lens material, in conjunction with the concentration, charge/molecule, ionicity in the product matrix, molecular weight, and hydrophobicity of the care component in question. These factors control the sorption of the solution components by lenses, resulting in a variety of differences in the amount of the component taken up into the lens material and the amount and rate of subsequent release onto the ocular surface. Because both natural (ocular) and environmental biota become part of the solution-lens system during regimen use of any lens care product, these extraneously introduced substances should also be considered regarding their potential for uptake and either subsequent release onto the ocular surface or functioning as a scaffold for the adhesion of microbes. This article will review current knowledge concerning these interactions and investigate what clinically observable complications may arise from these interactions. It also reviews whether current methods to determine these interactions could be improved on. © 2013 Lippincott Williams & Wilkins.

Jones,L., Senchyna,M., Glasier,M. A., Schickler,J., Forbes,I., Louie,D., May,C. Lysozyme and lipid deposition on silicone hydrogel contact lens materials. Eye Contact Lens 2003;29(1 Suppl):S75-79; discussion S83-84, S192-194 [ Show Abstract ]

PURPOSE: We sought to determine whether there were differences in lysozyme (quantity and conformation) and lipid deposition on in vivo worn conventional (etafilcon) and silicone hydrogel (balafilcon and lotrafilcon) contact lenses. METHODS: After extraction, lysozyme concentration in each extract was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Lysozyme activity was determined by the rate of lysis of Micrococcis lysodeikticus cells. Lipid deposition was determined by high-performance liquid chromatography. RESULTS: Lysozyme deposition on etafilcon lenses was significantly greater than that measured on silicone hydrogel (SH) lenses (985 microg per lens versus 10 and 3 microg per lens for balafilcon and lotrafilcon materials, respectively; P<0.001). The degree to which lysozyme was denatured was influenced by the lens material, with the lowest degree of denaturation (22%) seen on the conventional lens material, as compared with 50% for balafilcon and 80% for lotrafilcon (P<0.001). Lipid deposition was greatest on the SH materials, with up to 600 microg per lens of certain lipid classes being deposited on balafilcon, as compared with 20 microg per lens on etafilcon (P<0.001). CONCLUSION: The quantity and conformation of lysozyme and the quantity of lipid deposited on hydrogel contact lenses is significantly influenced by the composition of the lens material. SH contact lens materials deposit low levels of lysozyme and high levels of lipid deposition compared with ionic contact lens materials. Although SH materials deposit only small amounts of lysozyme, the degree of lysozyme denaturation that occurs is higher relative to that seen on ionic lens materials.

Jones,L., Walsh,K., Willcox,M., Morgan,P., Nichols,J. The COVID-19 pandemic: Important considerations for contact lens practitioners Cont Lens Anterior Eye 2020;43(3):196-203 [ Show Abstract ]

A novel coronavirus (CoV), the Severe Acute Respiratory Syndrome Coronavirus - 2 (SARS-CoV-2), results in the coronavirus disease 2019 (COVID-19). As information concerning the COVID-19 disease continues to evolve, patients look to their eye care practitioners for accurate eye health guidance. There is currently no evidence to suggest an increased risk of contracting COVID-19 through contact lens (CL) wear compared to spectacle lens wear and no scientific evidence that wearing standard prescription spectacles provides protection against COVID-19 or other viral transmissions.

During the pandemic there will potentially be significant changes in access to local eyecare. Thus, it is imperative CL wearers are reminded of the steps they should follow to minimise their risk of complications, to reduce their need to leave isolation and seek care. Management of adverse events should be retained within optometric systems if possible, to minimise the impact on the wider healthcare service, which will be stretched. Optimal CL care behaviours should be the same as those under normal circumstances, which include appropriate hand washing (thoroughly with soap and water) and drying (with paper towels) before both CL application and removal. Daily CL cleaning and correct case care for reusable CL should be followed according to appropriate guidelines, and CL exposure to water must be avoided. Where the availability of local clinical care is restricted, practitioners could consider advising patients to reduce or eliminate sleeping in their CL (where patients have the appropriate knowledge about correct daily care and access to suitable lens-care products) or consider the option of moving patients to daily disposable lenses (where patients have appropriate lens supplies available). Patients should also avoid touching their face, including their eyes, nose and mouth, with unwashed hands and avoid CL wear altogether if unwell (particularly with any cold or flu-like symptoms).

Kao,E. C. Y., McCanna,D. J., Jones,L. W. Utilization of in vitro methods to determine the biocompatibility of intraocular lens materials Toxicology in Vitro 2011;25(8):1906-1911

Kao,E. C. Y., Seo,J., McCanna,D. J., Subbaraman,L. N., Jones,L. In vitro assessment of the biocompatibility of chemically treated silicone materials with human lens epithelial cells Nature - Scientific Reports 2022;12(1):Article 4649 [ Show Abstract ]

Cytotoxicity testing is a regulatory requirement for safety testing of new ocular implants. In vitro toxicity tests determine whether toxic chemicals are present on a material surface or leach out of the material matrix. A method of evaluating the cytotoxicity of ocular implants was developed using fluorescent viability dyes. To assess the assay’s sensitivity in detecting toxic substances on biomaterials, zinc diethydithiocarbamate (ZDEC) and benzalkonium chloride (BAK) were deposited on silicone surfaces at different concentrations. Human lens epithelial cells (HLEC) were added to the surface of these treated silicone surfaces and were assessed for viability. The viability of both the adherent and non-adherent cells was determined using confocal microscopy with, annexin V, ethidium homodimer, and calcein. Cell metabolism was also evaluated using resazurin and the release of inflammatory cytokines was quantified using a multiplex Mesoscale Discovery platform. Confocal microscopy was shown to be a sensitive assay for evaluating material toxicity, as significant toxicity (p < 0.05) from ZDEC and BAK-treated surfaces compared to the untreated silicone control was detected. Patterns of cytokine release from cells varied depending on the toxin evaluated and the toxin concentration and did not directly correlate with the reduction in cell metabolic activity measured by alamarBlue.

Kapadia,W., Qin,N., Zhao,P., Phan,C.-M., Haines,L., Jones,L. Ren,C. L. Shear-Thinning and Temperature-Dependent Viscosity Relationships of Contemporary Ocular Lubricants Translational Vision Science & Technology 2022;11(3):Article 1 [ Show Abstract ]

Purpose: To evaluate the shear viscosity of contemporary, commercially available ocular lubricants at various shear rates and temperatures and to derive relevant mathematical
viscosity models that are impactful for prescribing and developing eye drops to treat dry eye disease.

Methods: The shear viscosity of 12 ocular lubricants was measured using a rheometer and a temperature-controlled bath at clinically relevant temperatures at which users may experience exposure to the drops (out of the refrigerator [4.3°C]; room temperature [24.6°C]; ocular surface temperature [34.5°C]). Three replicates for each sample at each temperature were obtained using a standard volume (0.5 mL) of each sample. The viscosity of each ocular lubricant was measured over the full range of shear rates allowed
by the rheometer.

Results: The shear viscosity of the same ocular lubricant varied significantly among the three temperatures. In general, a higher temperature resulted in smaller viscosities than a lower temperature (an average of −48% relative change from 4.3°C to 24.6°C and −21% from 24.6°C to 34.5°C). At a constant temperature, the viscosity of an ocular lubricant over the studied shear rates can be well approximated by a power-law model.

Conclusions: Rheological analysis revealed that the ocular lubricants exhibited shear-thinning behavior at the measured temperatures. Differences in the ocular lubricants’ formulations and measured temperatures resulted in different viscosities.

Translational Relevance: When prescribing eye drops, eye care professionals can select the optimal one for their patients by considering a variety of factors, including its
rheological property at physiologically relevant shear rates and temperatures, which can improve residence time on the ocular surface, while ensuring appropriate comfort and vision. However, care must be taken when using the derived mathematical models in this study because the in vivo shear behavior of the ocular lubricants has not been examined and might show deviations from those reported when placed on the ocular surface.

Karlgard,C. C. S., Jones,L. W., Moresoli,C. Ciprofloxacin interaction with silicon-based and conventional hydrogel contact lenses Eye and Contact Lens 2003;29(2):83-89 [ Show Abstract ]

Purpose. Hydrogel contact lenses can be used as bandage lenses to protect the corneal surface after injury. The use of novel silicon-based hydrogel lens materials as bandage lenses has not gained widespread acceptance. As a first step toward advocating their usefulness as bandage lenses, their interaction with ocular pharmaceuticals must be understood because topical agents are often administered in conjunction with bandage lenses. Methods. The in vitro uptake and release of ciprofloxacin from silicone-based hydrogel (SH) and conventional pHEMA-based (CH) hydrogel contact lenses was examined by spectrophotometric evaluation of the drug concentration in saline solution. Results. The hydrogel contact lenses tested showed similar drug uptake (average 1800 μg/lens) but different levels of drug release. Multiphoton laser microscopy indicated that ciprofloxacin was distributed throughout the lens thickness, with higher levels of drug at the surface owing to drug precipitation. The drug adsorption onto the lenses was partially reversible. The SH lenses released a lower amount of drug than CH lenses (72 vs. 168 μg/lens). Ionic lenses released less drug than non-ionic lenses (127 vs. 151 μg/lens). Conclusions. The differences in ciprofloxacin uptake and release between SH and CH materials may not be clinically significant because the amount of drug released from all lenses would be above the MIC90 of ciprofloxacin for common ocular pathogens. These results indicate that material properties have a significant impact on drug-lens interactions. © 2003 Contact Lens Association of Ophthalmologists, Inc.

Karlgard,C. C. S., Sarkar,D. K., Jones,L. W., Moresoli,C., Leung,K. T. Drying methods for XPS analysis of PureVision™, Focus® Night&Day™ and conventional hydrogel contact lenses Applied Surface Science 2004;230(1-4):106-114 [ Show Abstract ]

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. © 2004 Elsevier B.V. All rights reserved.

Karlgard,C. C. S., Wong,N. S., Jones,L. W., Moresoli,C. In vitro uptake and release studies of ocular pharmaceutical agents by silicon-containing and p-HEMA hydrogel contact lens materials International journal of pharmaceutics 2003;257(1-2):141-151 [ Show Abstract ]

The in vitro uptake and release behaviour of cromolyn sodium, ketotifen fumarate, ketorolac tromethamine and dexamethasone sodium phosphate with silicon-containing (lotrafilcon and balafilcon) and p-HEMA-containing (etafilcon, alphafilcon, polymacon, vifilcon and omafilcon) hydrogel contact lenses indicated that both drug and material affected the uptake and release behaviour. Rapid uptake and release (within 50min) was observed for all drugs except ketotifen fumarate which was more gradual taking approximately 5h. Furthermore, the maximum uptake differed significantly between drugs and materials. The highest average uptake (7879±684μg/lens) was cromolyn sodium and the lowest average uptake (67±13μg/lens) was dexamethasone sodium phosphate. Partial release of the drug taken up was observed for all drugs except dexamethasone sodium phosphate where no release was detected. Sustained release was demonstrated only by ketotifen fumarate. Drug uptake/release appeared to be a function of lens material ionicity, water and silicon content. The silicon-containing materials released less drug than the p-HEMA-containing materials. The lotrafilcon material demonstrated less interactions with the drugs than the balafilcon material which can be explained by their different bulk composition and surface treatment. © 2003 Elsevier Science B.V. All rights reserved.

Keech,A., Flanagan,J., Simpson,T., Jones,L. Tear meniscus height determination using the OCT2 and the RTVue-100 Optometry and Vision Science 2009;86(10):1154-1159 [ Show Abstract ]

PURPOSE: To compare anterior segment spectral-domain optical coherence tomography (SOCT) tear meniscus height (TMH) measures with those from the more commonly used time-domain OCT (TOCT). METHODS: The right eye of 50 healthy subjects had images of their TMH captured with TOCT (OCT2) and SOCT (RTVue-100). Data were acquired using two different anterior segment lenses, the cornea/anterior module-short (CAM-S) and long (CAM-L), on the SOCT. Images were then analyzed for differences in their derived TMH. RESULTS: The average TMH for TOCT was 0.280 ± 0.139 mm, whereas the mean TMH measured using the SOCT was 0.354 ± 0.163 mm and 0.345 ± 0.167 mm for the CAM-S and CAM-L, respectively. There was a significant difference (p < 0.001) when comparing TOCT with either of the SOCT lenses. There was no statistically significant difference between the CAM-L and CAM-S (p = 1.0). Bland-Altman analysis showed poor agreement between TOCT and SOCT (95% limits of agreement -0.138 to + 0.285 mm for the CAM-S and -0.185 to +0.315 mm for the CAM-L). CONCLUSIONS: The RTVue-100 produces TMH measurements that are significantly higher than OCT2 in a normal patient population. However, the RTVue-100 showed a number of other advantages over the OCT2 in the measurement and analysis of images. Future work needs to determine the causative factors behind the observed differences.

Keech,A., Senchyna,M., Jones,L. Impact of time between collection and collection method on human tear fluid osmolarity Current eye research 2013;38(4):428-436 [ Show Abstract ]

Aim: To generate data on the variability of tear osmolarity in a control (normal, non-dry eye) and symptomatic dry eye population (Ocular Surface Disease Index: OSDI ≥20). A secondary outcome is the determination of the effect that tear collection technique has on the osmolarity of the sample. Materials and methods: This was a two-phase study that recruited 20 subjects (n = 10 normal, n = 10 dry eye) to evaluate the influence of time between measurements (Phase I) and 30 subjects (n = 15 normal, n = 15 dry eye) to evaluate the influence of collection technique (Phase II). As part of Phase I, serial tear osmolarity measurements were performed on each eye; four separated by 15min followed by four separated by lmin, at each of three visits. Phase II compared the consecutive measurement of four in vivo tear samples to four in vitro measurements on tears collected and dispensed from a glass capillary tube. Results: During Phase I, the dry eye group had a significantly higher maximum osmolarity (334.2 ± 25.6 mOsm/L) compared to the normal group (304.0 ± 8.4mOsm/L, p = 0.002). No significant differences were observed whether collections were performed at 15 or 1 min intervals. During Phase II, the in vivo osmolarity was equivalent to in vitro measurements from glass capillary tube samples for both the dry eye group (323.0± 16.7mOsm/L versus 317.7±24.8, p = 0.496), and for the normal subjects (301.2±7. 2mOsm/L versus 301.9 ± 16.0 mOsm/L, p = 0.884). Conclusion: Symptomatic dry eye subjects exhibited a significantly higher tear osmolarity and variation over time than observed in normal subjects, reflecting the inherent tear film instability of dry eye disease. There was no change in the distribution of tear osmolarity measurements whether tears were collected in rapid succession or given time to equilibrate, and collection method had no impact on tear osmolarity. © Informa Healthcare USA Inc.

Keech,A., Simpson,T., Jones,L. Repeatability of pachymetry and thinnest point localization using a Fourier-domain optical coherence tomographer Optometry and Vision Science 2010;87(10):736-741

Keir,N. J., Simpson,T., Hutchings,N., Jones,L., Fonn,D. Outcomes of wavefront-guided laser in situ keratomileusis for hyperopia Journal of cataract and refractive surgery 2011;37(5):886-893 [ Show Abstract ]

Purpose: To determine the impact of wavefront-guided laser in situ keratomileusis (LASIK) for hyperopia on corrected distance visual acuity (CDVA), contrast sensitivity, and higher-order aberrations (HOAs). Setting: Centre for Contact Lens Research, University of Waterloo, Waterloo, Ontario, Canada. Design: Case series. Methods: This study comprised patients who had LASIK for hyperopia. The HOAs up to the 4th order (5.0 mm pupil) in right eyes were analyzed. Results: The study enrolled 31 patients. The preoperative mean values were sphere, +2.60 diopters (D) ± 1.15 (SD) (range +1.00 to +5.00 D); astigmatism, -0.87 ± 0.74 D (range 0.00 to -3.75 D); and spherical equivalent (SE), +2.16 ± 1.00 D (range +0.63 to +4.50 D). The postoperative refractive SE was within ±0.50 D in 71.0% of eyes. The uncorrected distance visual acuity was 20/20 or better in 87.2% of eyes. There was no significant change in CDVA or contrast sensitivity (all P>.05). There was a significant change in Zernike coefficients Z(0,4), Z(-1,3), Z(-3,3), and Z(3,3) (range of mean absolute change ± SEM: 0.092 ± 0.013 μm to 0.208 ± 0.018 μm; all P<.001). Coefficients Z(-1,3) and Z(3,3) increased and Z(0,4) and Z(-3,3) decreased in magnitude; each had a reversal of sign. The only significant postoperative association was between low-contrast CDVA and Z(0,4) (r = 0.617, P<.001). Conclusions: Low-contrast CDVA after LASIK surgery for hyperopia was correlated with Z(0,4). There were no significant changes in CDVA or contrast sensitivity. The relative risk for losing low-contrast CDVA increased if more than 1 Zernike term had a sign change. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. © 2011 ASCRS and ESCRS.

Keir,N. J., Simpson,T., Jones,L. W., Fonn,D. Wavefront-guided LASIK for myopia: Effect on visual acuity, contrast sensitivity, and higher order aberrations Journal of Refractive Surgery 2009;25(6):524-533 [ Show Abstract ]

PURPOSE: To determine the impact of wavefrontguided LASIK for myopia with or without astigmatism on high and low contrast best spectacle-corrected visual acuity (BSCVA), photopic and mesopic contrast sensitivity, and higher order aberrations. METHODS: Bilateral wavefront-guided LASIK (LADARVision4000; Hansatome microkeratome) was performed on 324 eyes (162 patients) with a mean spherical manifest refraction of -2.84±1.35 diopters (D) (range: -0.25 to -6.50 D) and astigmatism of -0.81±0.74 D (range: 0 to -4.00 D). Mean age was 37.7±9.3 years (range: 20 to 60 years). Best spectacle-corrected visual acuity and contrast sensitivity were assessed using ETDRS charts and vertical sinusoidal gratings, respectively. Higher order aberrations were measured using a Shack-Hartmann wavefront sensor, analyzed across a 5-mm pupil. Repeated measures and post hoc analyses determined statistical significance (P<.0025). Only right eyes were analyzed. RESULTS: One hundred thirty-six eyes (84%) had uncorrected visual acuity of 20/20 or better 6 months postoperative; 80.9% (131 eyes) were within ±0.50 D of attempted correction. Statistically significant postoperative improvements were noted in high and low contrast BSCVA (both P≤.001); in photopic contrast sensitivity at 3, 6, and 12 cycles per degree (cpd); and in mesopic contrast sensitivity at 12 and 18 cpd (all P<.001). With respect to higher order aberrations, a statistically significant change was seen in Zernike coefficients Z 3 -1, Z 3 1, Z 3 -3, Z 3 3, and Z 3 4 following surgery (range of mean absolute change: 0.042 to 0.142 μm; all P<.001). All increased in magnitude except for Z 3 -3, which decreased. CONCLUSIONS: Despite an increase in higher order aberrations, wavefront-guided LASIK yields excellent visual acuity and contrast sensitivity. Spherical aberration, which increases the most following non-wavefront-guided LASIK, showed no significant change.

Keir,N., Jones,L. Wettability and silicone hydrogel lenses: A review Eye and Contact Lens 2013;39(1):100-108 [ Show Abstract ]

One of the major breakthroughs in the development of silicone hydrogel contact lenses has related to the ability of manufacturers to overcome the surface hydrophobicity that occurred with silicone elastomer lenses. However, the wettability of silicone hydrogel lenses continues to be of interest as a potential link between in vivo lens performance and contact lens-related comfort. This article will review some of the knowledge we have gained in the area of contact lens wettability over the past decade and will discuss some of the challenges related to its measurement. © 2013 Lippincott Williams & Wilkins.

Keir,N., Luensmann,D., Woods,C.A., Bergenske,P., Fahmy,M., Fonn,D. Effect of Masking on Subjective Responses to Daily Disposable Contact Lenses Optom Vis Sci 2016;93(8):828-35 [ Show Abstract ]

PURPOSE: To explore the effect of masking on subjective responses when wearing daily disposable (DD) contact lenses.
METHODS: In an adaptation phase, habitual wearers of Manufacturer-A (MFA) (n = 43) and Manufacturer-B (MFB) (n = 53) wore MFA-brand 1 or MFB-brand 1 DDs, respectively, for 30 days, open-label. Subjects were then randomly assigned to one of two experiments. Each experiment included two, 3-day crossover phases. An enhanced version of MFA and MFB lenses (MFA-brand 2 and MFB-brand 2) were worn contralaterally to evaluate potential differences in masking result between manufacturers. Experiment 1: subjects were fully masked to lens and packaging (FM) then unmasked (UM). Experiment 2: subjects were FM then partially masked using an over-label (PM). Comfort ratings (0-100) were recorded for each lens daily and preference between lenses was recorded on day 3 for each crossover phase. The mean difference between 0-100 ratings or preference when FM or PM versus UM for the same lens was considered a measurement of the effect associated with masking. The purpose of the study was withheld from subjects to minimize bias.
RESULTS: The effect associated with masking for habitual wearers of MFA and MFB lenses was less than 1 out of 100 (0 ± 2.5) in both experiments. Fifty-eight subjects (60%) expressed no preference when FM. This decreased to 29 (30%) when UM or PM (proportion test, p < 0.001). Approximately half the subjects had a change in lens preference when they were UM or PM, primarily in favor of their habitual lens manufacturer.
CONCLUSIONS: Masking did not have a measurable impact on 0-100 ratings with the DD lenses used in this study but did have an impact on lens preference. Subjects were more likely to express a preference when they handled the lenses and were exposed to the lens packaging and, in some cases, able to read the lens brand and lens manufacturer.

Keir,N., Simpson,T., Fonn,D. Visual and optical performance of silicone hydrogel contact lenses for moderate myopia Journal of Optometry 2010;3(3):149-157 [ Show Abstract ]

Purpose: To compare the short-term visual and optical performance of silicone hydrogel contact lenses for myopia = -3.00D. Methods: This was a short-term, non-dispense, double-masked, randomized study investigating Night&Day (ND), PureVision (PV), O2 Optix (O2), Biofinity (BF), Acuvue Advance (AA) and Acuvue OASYS for myopia = -3.00D. Testing was conducted under scotopic conditions. Measures (one eye only) included: high- and low-contrast visual acuity (HCVA/LCVA), contrast sensitivity, subjective clarity of vision ratings (0-100 scale using reference images, with test image representing grade 50) and ocular aberrations (up to the 4th order, analyzed across individual scotopic pupil sizes). Results: Three males and 27 females participated, with a mean (± SD) age of 24.9 ± 7.7 yrs (range 19 to 53 yrs), sphere of -5.30 ± 1.73D (range -3.00 to -10.75D) and cylinder -0.36 ± 0.23D (range 0 to -0.75D). Mean (± SEM) logMAR HCVA ranged from 0.06 (PV) to 0.10 (AA) (± 0.02), LCVA from 0.33 (BF) to 0.40 (AA) (± 0.02) and contrast sensitivity from 2.33 (BF) to 2.53 (ND) (± 0.15) (differences not statistically significant; all p > 0.05). Subjective ratings for the test image ranged from 59 (PV) to 64 (ND) (± 4) and 56 (AA) to 65 (ND) (± 4), for monochromatic and polychromatic reference images, respectively (all p > 0.05). There was a statistically significant impact on ocular aberrations with all study lenses compared to no lens. Between-lens differences were statistically significant for defocus (Z 0 2), horizontal coma (Z 1 3) and spherical aberration (Z 0 4). Conclusions: Despite some differences in ocular aberrations, there were no significant differences in HCVA, LCVA, contrast sensitivity or subjective ratings across lenses. © 2010 Spanish General Council of Optometry. Published by Elsevier España, S.L. All rights reserved.

Keir,N., Woods,C. A., Dumbleton,K., Jones,L. Clinical performance of different care systems with silicone hydrogel contact lenses Contact Lens and Anterior Eye 2010;33(4):189-195

Khanal,S., Bai,Y., Ngo,W., Nichols,K. K., Wilson,L., Barnes,S., Nichols,J. J. Human meibum and tear film derived cholesteryl and wax esters in meibomian gland dysfunction and tear film structure: Cholesteryl and wax esters in meibomian gland dysfunction Ocular Surface 2022;23(January):12-23 [ Show Abstract ]

Purpose
This study evaluated the presence and roles of cholesteryl esters (CEs) and wax esters (WEs) from human tear film and meibum in meibomian gland dysfunction (MGD).

Methods
Out of 195 enrolled subjects, 164 and 179 subjects provided tear and meibum samples, respectively. Subjects were classified into normal, asymptomatic MGD, MGD, and mixed (MGD & aqueous deficient). The precorneal tear film (PCTF) thinning rate (evaporation) was measured using optical coherence tomography. Lipids extracted from tear and meibum samples were infused into a SCIEX 5600 TripleTOF mass spectrometer. CE and WE intensities quantified with Analyst 1.7 TF and LipidView 1.3 were compared across disease groups in MetaboAnalyst 5.0 and correlated with PCTF thinning rates.

Results
The numbers of unique CEs and WEs identified in the samples were 125 and 86, respectively. Unsupervised Principal Component (PC) analysis and supervised Partial Least Square Discriminant analysis exhibited little separation among groups for both CEs and WEs in tears and meibum. Spearman's correlation analyses showed no association between either the first or second PC scores with PCTF thinning rates.

Conclusion
The abundances of human PCTF and meibum-derived CEs and WEs were independent of MGD disease status and PCTF thinning (evaporation). CEs and WEs alterations do not contribute to alterations in tear film dynamics in MGD, such as has been demonstrated by the (O-acyl) ω-hydroxy fatty acids (OAHFAs).