Haque,S., Simpson,T., Jones,L. Corneal and epithelial thickness in keratoconus: A comparison of ultrasonic pachymetry, Orbscan II, and optical coherence tomography Journal of Refractive Surgery 2006;22(5):486-493 [ Show Abstract ]

PURPOSE: To compare corneal thickness measurements in individuals with keratoconus using optical coherence tomography (OCT), Orbscan II, and ultrasonic pachymetry and to measure epithelial and stromal thickness in these individuals using OCT. METHODS: Twenty individuals with keratoconus and 20 controls (without keratoconus) were enrolled. The Orbscan II was used to locate the steepest area of the cornea, which was taken to represent the cone apex. Each instrument was used to obtain four total corneal thickness measurements-from the cone apex, corneal center, mid-nasal, and mid-temporal cornea. Optical coherence tomography scans were analyzed to provide epithelial and stromal thickness readings. RESULTS: In individuals with keratoconus, mean central corneal thickness (CCT) measured by ultrasonic pachymetry, Orbscan, and OCT was 494.2±50.0 μm, 438.6±47.7 μm, and 433.5±39.7 μm, respectively. The central keratoconic cornea was 57.7 μm thinner than the normal cornea (post-hoc P.05). CONCLUSIONS: Ultrasonic pachymetry produced the highest corneal thickness readings in the center and apex, compared to Orbscan II and OCT. Centrally, the total cornea, epithelium, and stroma were thinner in individuals with keratoconus than in normal individuals.

Henderson,L., Bond,D., Simpson,T. The association between eye color and corneal sensitivity measured using a Belmonte esthesiometer Optometry and Vision Science 2005;82(7):629-632 [ Show Abstract ]

Purpose. The purpose of this study is to determine the association between corneal sensitivity measured using a pneumatic esthesiometer and eye color quantified objectively. Methods. Twenty subjects had ocular surface sensitivity measured using a Belmonte esthesiometer. An ascending method of limits followed by the method of constant stimuli were used to estimate 1) cold detection thresholds, 2) discomfort detection thresholds (both using pneumatic stimuli at 20°C, 3) mechanical detection thresholds using pneumatic stimuli at 50°C (ocular surface temperature approximately 33°C), and 4) percent CO2 chemical detection thresholds using 50°C pneumatic stimuli at flow rates set at half of each subject's pneumatic detection threshold (therefore detected by the chemical content and not the mechanical content). Eye color was estimated 1) clinically by two observers ranking the color (light to dark) of digital images of each subject's iris, 2) photometrically by measuring iris luminance, and 3) using chromaticity obtained from a Photo Research 650 spectroradiometer with controlled illumination. Correlation and linear and nonlinear regression analyses were used to examine relationships between variables. Results. There were no associations between eye color (determined clinically or objectively) for mechanical and chemical detection thresholds (best r2 = 0.15, all p > 0.05). There was a significant linear association between 20° detection thresholds and eye color (r2 = 0.39), which was substantially improved with a two-line function (part level and part increasing linearly, r2 = 0.65). Conclusions. We were generally unable to demonstrate the relationship between eye color and sensitivity reported previously using a Cochet-Bonnet esthesiometer. However, for a subset of subjects with palest irises, there appears to be a linear association between eye color and sensitivity to cooling stimuli. Copyright © 2005 American Academy of Optometry.

Heynen,M., Babaei Omali,N., Fadli,Z., Coles-Brennan,C., Subbaraman,L. N., Jones,L. Selectivity and localization of lysozyme uptake in contemporary hydrogel contact lens materials Journal of Biomaterials Science, Polymer Edition 2017;28(13):1351-1364 [ Show Abstract ]

The purpose of this study was to investigate the early and selective uptake of lysozyme and the location of deposited lysozyme on contemporary hydrogel contact lens (CL) materials after exposure to an artificial tear solution (ATS) for 16 h. Seven different hydrogel CL materials [polymacon, omafilcon A, nelfilcon A, nesofilcon A, ocufilcon B, etafilcon A (Acuvue Moist), and etafilcon A (Acuvue Define)] were incubated in an ATS for various times. Total protein deposition was determined using a modified Bradford technique. Lysozyme, lactoferrin, and albumin deposition on CLs were determined using 125I-radiolabeling method. A confocal laser scanning microscopy (CLSM) technique was utilized to map the location of lysozyme uptake in an asymmetric environment. All lens materials had significant amounts of lysozyme after 1 min of exposure to ATS. After 16 h of incubation, higher levels of total protein deposited on the two etafilcon A-based lenses (Moist and Define), followed by ocufilcon B and both were significantly higher than all other CLs tested (p = 0.0001). The two etafilcon A materials (Moist and Define) also deposited the highest amounts of lysozyme (514.8 ± 28.4 and 527.1 ± 14.7 µg/lens respectively) when compared to other test CLs (p = 0.0001). The CLSM technique revealed that the non-ionic CLs tended to have symmetric distribution of lysozyme throughout the lens materials, while the ionic CLs had an asymmetric distribution, with the highest concentration of lysozyme on and near the exposed surface. The quantity and nature of proteins deposited on CLs varies, depending upon the chemical composition of the material. Among the various lenses tested, etafilcon A deposited the highest amount of total protein, most of it represented by lysozyme, which was largely located near the surface of the lens. © 2017 Informa UK Limited, trading as Taylor & Francis Group.

Heynen,M., Lorentz,H., Srinivasan,S., Jones,L. Quantification of non-polar lipid deposits on senofilcon A contact lenses Optometry and Vision Science 2011;88(10):1172-1179

Heynen,M., Ng,A., Martell,E., Subbaraman,L. N., Jones,L. Activity of Deposited Lysozyme on Contemporary Soft Contact Lenses Exposed to Differing Lens Care Systems Clinical Ophthalmology 2021;15(April):1727-1733 [ Show Abstract ]

Purpose: The amount of protein deposition on soft contact lenses and to what extent the proteins are denatured may have an impact on comfortable wearing times of contact lenses. The purpose of this study was to evaluate the effects of two lens care systems on total protein and the quantity and activity of lysozyme deposited on worn senofilcon A, silicone hydrogel contact lenses.

Participants and Methods: Thirty symptomatic soft contact lens wearers were enrolled into a 4-week prospective, randomized, bilateral eye, daily-wear, crossover, double-masked study. Participants were fitted with biweekly senofilcon A lenses and were assigned either a polyquaternium-1 and myristamidopropyl dimethylamine-containing system (OPTI-FREE RepleniSH) or a peroxide-based system (CLEAR CARE). After each wear period, proteins were extracted from the lenses and analyzed for total protein, total lysozyme quantity and activity.

Results: The use of either the peroxide-based system or the polyquaternium-1 and myristamidopropyl dimethylamine-containing system resulted in no difference (P> 0.05) to the amount of total protein deposited on the lenses (6.7 ± 2.8 micrograms/lens versus 7.3 ± 2.8 micrograms/lens, respectively) or to the amount of denatured lysozyme deposits (0.8 ± 0.7 versus 0.9 ± 0.7 micrograms/lens), respectively. The total amount of lysozyme deposited on the lenses was significantly lower when using the peroxide-based system (1.3 ± 0.9 micrograms/lens) compared to the polyquaternium-1 and myristamidopropyl dimethylamine-containing system (1.7 ± 1.0 micrograms/lens) (P=0.02).

Conclusion: The inactivation of lysozyme deposited on senofilcon A lenses when disinfected with the peroxide-based or the polyquaternium-1 and myristamidopropyl dimethylamine-containing systems were neither statistically nor clinically significant and the overall amounts of denatured lysozyme recovered from the lenses were low (< 1 microgram/lens).

Holland,E. J., Darvish,M., Nichols,K. K., Jones,L., Karpecki,P. M. Efficacy of topical ophthalmic drugs in the treatment of dry eye disease: A systematic literature review Ocul Surf 2019;17:412-423 [ Show Abstract ]

Dry eye disease (DED) is a multifactorial and complex disease of the ocular surface, with a high prevalence in adults. We systematically reviewed efficacy and safety data from published articles reporting results from prospective, controlled trials of topical ophthalmic drugs for DED. PubMed was searched from January 1997 to October 2017. Twenty-six unique trials investigating 13 ophthalmic drugs were identified, including trials of the approved drugs cyclosporine A, cyclosporine A cationic emulsion, diquafosol, rebamipide and lifitegrast. All identified studies provided level 1 evidence. None of the large (N > 100) studies demonstrated statistical significance of primary endpoints for both a sign and a symptom endpoint versus a control treatment in the same published trial. Publications on lifitegrast reported statistical superiority in a symptom or sign endpoint versus the control group in a large (N > 200), multicenter trial, with results repeated in trials of similar design. The most common adverse events associated with the approved drugs related to ocular discomfort upon instillation, especially burning/stinging and ocular irritation. The trial design and endpoints used across the studies varied considerably, highlighting the importance of standardization in clinical trials for DED. Recent advances in drug delivery and improved understanding of DED should contribute to new ophthalmic drug approvals.

Hrynchak,P., Hutchings,N., Jones,D., Simpson,T. A comparison of cup-to-disc ratio evaluation in normal subjects using stereo biomicroscopy and digital imaging of the optic nerve head Ophthalmic and Physiological Optics 2003;23(1):51-59 [ Show Abstract ]

The cup-to-disc (CD) ratio evaluated using stereoscopic biomicroscopy was compared with that evaluated by viewing a non-stereo digital image of the optic nerve head. Twenty normal subjects (mean age 26 +/- 4 years) were evaluated by two observers. The average CD ratio was 0.29 with a range of 0-0.80. The intra-class correlations between the observers ranged from 0.82 to 0.96, when comparing horizontal and vertical CD ratios for both evaluation techniques. The mean CD ratio was significantly smaller when viewing the digital image (0.25 +/- 0.01) compared with stereoscopic observation (0.33 +/- 0.03, p < 0.0001). Although the mean differences between the two techniques were small, the percentage of CD ratios that differed by >or=0.2 were between 5 and 25% of evaluations. Caution should be exercised when using stereoscopic and non-stereo digital evaluations of CD ratio interchangeably to assess longitudinal progression in a multi-clinician setting.

Hrynchak,P., Simpson,T. Optical coherence tomography: An introduction to the technique and its use Optometry and Vision Science 2000;77(7):347-356 [ Show Abstract ]

This report describes the new optical imaging technique of optical coherence tomography (OCT). OCT is capable of high-resolution, micrometer-scale, cross-sectional imaging of biological tissue. The OCT for ophthalmic application uses 843-nm, near-infrared light, which produces a longitudinal resolution of 10 to 20 μm and a penetration depth of a few millimeters. The scans are displayed in a false color representation scale on which warm colors represent areas of high optical reflectivity and cool colors represent areas of minimal or no reflectivity. A cross-sectional view similar to a histology section is obtained. The cornea, iris, and lens may be visualized as well as the retina and optic nerve. OCT has been used to investigate several ocular diseases. These include macular disease, genetic retinal disease, retinal detachment and retinoschisis, choroidal tumors, optic nerve disorders, and glaucoma.

Hui,A., Bajgrowicz-Cieslak,M., Phan,C. -M, Jones,L. In vitro release of two anti-muscarinic drugs from soft contact lenses Clinical Ophthalmology 2017;11:1657-1665 [ Show Abstract ]

The purpose of this study was to investigate the release of the anti-myopia drugs atropine sulfate and pirenzepine dihydrochloride from commercially available soft contact lenses. Standard ultraviolet (UV) absorbance-concentration curves were generated for atropine and pirenzepine. Ten commercially available contact lenses, including four multifocal lenses, were loaded by soaking in atropine or pirenzepine solutions at two different concentrations (10 mg/mL and 1 mg/mL). The release of the drugs into phosphate-buffered saline was determined over the course of 24hours at 34°C using UV absorbance. Materials with surface charge released the greatest amount of atropine when loaded with either concentration when compared to the other lens types (p<0.05), releasing upward of 1.026±0.035mg/lens and 0.979±0.024mg/lens from etafilcon A and ocufilcon A, respectively. There were no significant differences in the amount of atropine or pirenzepine released from the multifocal and non-multifocal lenses made from the same lens materials. Narafilcon A material demonstrated prolonged release of up to 8 hours when loaded with pirenzepine, although the overall dose delivered from the lens into the solution was among the lowest of the materials investigated. The rest of the lenses reached a plateau within 2 hours of release, suggesting that they were unable to sustain drug release into the solution for long periods of time. Given that no single method of myopia control has yet shown itself to be completely effective in preventing myopia progression, a combination of optical and pharmaceutical devices comprising a drug delivering contact lens presents a novel solution that warrants further investigation. © 2017 Hui et al.

Hui,A., Boone,A., Jones,L. Uptake and release of ciprofloxacin-HCl from conventional and silicone hydrogel contact lens materials. Eye & contact lens 2008;34(5):266-271 [ Show Abstract ]

OBJECTIVES: To investigate the uptake and release characteristics of the antibiotic ciprofloxacin-HCl in conventional and silicone hydrogel lenses, and evaluate their potential as therapeutic drug delivery devices. METHODS: Nine differing soft contact lens materials were soaked in a 0.3% ciprofloxacin-HCl solution at 34 degrees C. The uptake of the drug into the lenses was measured by the change in concentration over 24 hours using fluorescence spectrophotometry. The lenses were then placed in a buffered saline solution, and the release of the drug from the lenses was also measured using spectrophotometry. RESULTS: The release of drug varied from 0.016 +/- 0.004 mg/lens for lotrafilcon A lenses to 0.42 +/- 0.03 mg/lens for etafilcon A lenses, with an average of 0.133 mg/lens. The 3 conventional lenses used in the study released a statistically significantly different amount of drug when compared with the silicone hydrogels. The release of drug was very rapid, with drug release reaching a plateau after no more than 10 minutes for the majority of the lenses. The majority of the lenses were able to release enough drug to achieve minimum inhibitory concentration 90 for most resistant ocular pathogens. Ciprofloxacin was found to heavily precipitate on the etafilcon A lenses during the release phase at physiologic pH. CONCLUSION: While balafilcon A released the most drug from the silicone hydrogel materials, all materials released the drug too quickly to be effective as drug delivery devices.

Hui,A., Sheardown,H., Jones,L. Acetic and acrylic acid molecular imprinted model silicone hydrogel materials for ciprofloxacin-HCL delivery 2012;5(1):85-107 [ Show Abstract ]

Contact lenses, as an alternative drug delivery vehicle for the eye compared to eye drops, are desirable due to potential advantages in dosing regimen, bioavailability and patient tolerance/compliance. The challenge has been to engineer and develop these materials to sustain drug delivery to the eye for a long period of time. In this study, model silicone hydrogel materials were created using a molecular imprinting strategy to deliver the antibiotic ciprofloxacin. Acetic and acrylic acid were used as the functional monomers, to interact with the ciprofloxacin template to efficiently create recognition cavities within the final polymerized material. Synthesized materials were loaded with 9.06 mM, 0.10 mM and 0.025 mM solutions of ciprofloxacin, and the release of ciprofloxacin into an artificial tear solution was monitored over time. The materials were shown to release for periods varying from 3 to 14 days, dependent on the loading solution, functional monomer concentration and functional monomer:template ratio, with materials with greater monomer:template ratio (8:1 and 16:1 imprinted) tending to release for longer periods of time. Materials with a lower monomer:template ratio (4:1 imprinted) tended to release comparatively greater amounts of ciprofloxacin into solution, but the release was somewhat shorter. The total amount of drug released from the imprinted materials was sufficient to reach levels relevant to inhibit the growth of common ocular isolates of bacteria. This work is one of the first to demonstrate the feasibility of molecular imprinting in model silicone hydrogel-type materials.

Hui,A., Willcox,M., Jones,L. In vitro and in vivo evaluation of novel ciprofloxacin-releasing silicone hydrogel contact lenses Investigative Ophthalmology and Visual Science 2014;55(8):4896-4904 [ Show Abstract ]

PURPOSE. The purpose of this study was to evaluate ciprofloxacin-releasing silicone hydrogel contact lens materials in vitro and in vivo for the treatment of microbial keratitis. METHODS. Model silicone hydrogel contact lens materials were manufactured using a molecular imprinting technique to modify ciprofloxacin release kinetics. Various contact lens properties, including light transmission and surface wettability, were determined, and the in vitro ciprofloxacin release kinetics elucidated using fluorescence spectrophotometry. The materials then were evaluated for their ability to inhibit Pseudomonas aeruginosa growth in vitro and in an in vivo rabbit model of microbial keratitis. RESULTS. Synthesized lenses had similar material properties to commercial contact lens materials. There was a decrease in light transmission in the shorter wavelengths due to incorporation of the antibiotic, but over 80% light transmission between 400 and 700 nm. Modified materials released for more than 8 hours, significantly longer than unmodified controls (P 0.05), which is significantly less than corneas treated with unmodified control lenses or those that received no treatment at all (P < 0.05). CONCLUSIONS. These novel contact lenses designed for the extended release of ciprofloxacin may be beneficial to supplement or augment future treatments of sight-threatening microbial keratitis. © 2014 The Association for Research in Vision and Ophthalmology, Inc.

Huynh,C. B., Nagaarudkumaran,N., Kalyaanamoorthy,S., Ngo,W. In Silico and In Vitro Approach for Validating the Inhibition of Matrix Metalloproteinase-9 by Quercetin Eye & Contact Lens 2023;49(5):193-198 [ Show Abstract ]

Purpose:
To validate the mechanism and inhibitory activity of quercetin against matrix metalloproteinase-9 (MMP-9) using a hybrid in silico and in vitro approach.

Methods:
The structure of MMP-9 was obtained from the Protein Data Bank, and the active site was identified using previous annotations from the Universal Protein Resource. The structure of quercetin was obtained from ZINC15. Molecular docking was performed to quantify the binding affinity of quercetin to the active site of MMP-9. The inhibitory effect of various concentrations of quercetin (0.0025, 0.025, 0.25, 1.0, and 1.5 mM) on MMP-9 was quantified using a commercially available fluorometric assay. The cytotoxicity of quercetin to immortalized human corneal epithelial cells (HCECs) was quantified by obtaining the metabolic activities of the cells exposed to various concentrations of quercetin for 24 hr.

Results:
Quercetin interacts with MMP-9 by binding within the active site pocket and interacting with residues LEU 188, ALA 189, GLU 227, and MET 247. The binding affinity predicted by molecular docking was −9.9 kcal/mol. All concentrations of quercetin demonstrated significant inhibition of MMP-9 enzyme activity (all P0.99).

Conclusions:
Quercetin inhibited MMP-9 in a dose-dependent manner and was well-tolerated by HCECs, suggesting a potential role in therapy for diseases with upregulated MMP-9 as part of its pathogenesis.

Huynh,C. B., Ngo,W. Quantifying the Effect of Spectacle Frame Dimensions on Wind-Induced Ocular Plane Evaporation Using an in Vitro Model Eye & Contact Lens 2021;47(347):351 [ Show Abstract ]

Purpose: To quantify the effect of spectacle frame dimensions on wind-induced ocular plane evaporation.

Methods: A drop of 0.5 μL water was pipetted onto an eye of a mannequin head. The face was fitted with a spectacle frame. A fan positioned 10 cm away directed air (185 CFM) toward the face and the time required for the drop to evaporate was recorded. This procedure was repeated with 31 different frames to obtain evaporation times for various eye sizes, vertical heights, vertex distances, temperature, and humidity. This was also repeated 30 times without spectacle wear to obtain evaporation times for various temperature and humidity conditions.

Results: Spectacle wear increased evaporation times compared with nonspectacle wear, in both high (>35%) and low humidity (<30%) conditions (both P<0.01). Humidity was correlated with evaporation time, regardless of spectacle and nonspectacle wear (both P<0.01). Evaporation time did not correlate with spectacle eye size, vertical height, or vertex distance (all P≥0.21).

Conclusion: This study showed that spectacle wear guarded against wind-induced evaporation at the ocular plane compared with nonspectacle wear. However, once spectacles were worn, eye size, vertical height, and vertex distance were not correlated with evaporation times. Humidity drove evaporation independent of spectacle wear.

Jabeen,A., Luensmann,D., Woods,J., Hill,J., Jones,L. Evaluation of Lag of Accommodation with Full-Field Diffusion Optics Technology™ (DOT) Contrast Management Spectacle Lenses in Emmetropic Children Clinical Ophthalmology 2024;18(May):1181-1190 [ Show Abstract ]

Purpose: To evaluate the impact on the lag of accommodation (LOA) in emmetropic children after short-term wear of full-field Diffusion Optics TechnologyTM (DOT) spectacle lenses, designed to modulate retinal contrast to control myopia progression.

Patients and methods: This was a single-visit, prospective, randomized, subject-masked study of emmetropes (ametropes ±1.00D or less in each meridian) with no history of myopia control treatment. Unaided logMAR visual acuity was measured, and ocular dominance was determined using the sighting method. In a randomized order, participants wore plano full-field contrast management (DOT) spectacles (no clear central aperture) or control spectacles (standard single vision spectacle lenses). Each participant was given 5 minutes for adaptation to the respective lenses before open field autorefraction measurements were taken at 6 meters and 40 cm. Ten measurements were taken for each eye. Data were evaluated from the right eye and the dominant eye separately.

Results: A total of 30 participants (20 females and 10 males) with a mean age of 10.4 ± 2.8 (7 to 17) years completed the study. There was no significant difference in right eye mean LOA with contrast management spectacles 0.57 ± 0.39D versus control spectacles 0.62 ± 0.34D; Wilcoxon test, p = 0.37. For dominant eyes, LOA values were 0.60 ± 0.40D and 0.68 ± 0.33D with contrast management spectacles and control spectacles, respectively (p = 0.14). Additionally, no significant difference was observed in mean LOA between males and females or between age groups (7-11 years vs 12-17 years) for either right or dominant eyes with contrast management or control spectacles (all p > 0.05).

Conclusion: Full-field contrast management spectacle lenses had no significant effect on LOA compared to standard single vision spectacle lenses, indicating no differential impact on accommodative response over the short period of lens wear tested.

Jadi,S., Heynen,M., Luensmann,D., Jones,L. Composition of incubation solution impacts in vitro protein uptake to silicone hydrogel contact lenses Molecular Vision 2012;18337-347 [ Show Abstract ]

Purpose: To determine the impact of incubation solution composition on protein deposition to silicone hydrogel (SH) contact lenses using a simplistic and a complex model of the tear film. Methods: Three SH materials - senofilcon A (SA), lotrafilcon B (LB), and balafilcon A (BA) - were incubated in two different solutions; Solution A was a simplistic augmented buffered saline solution containing a single protein, whereas Solution B was a complex artificial tear solution (ATS), containing the augmented buffered saline solution in addition to proteins, lipids, and mucins (pH=7.4). The proteins of interest (lysozyme, lactoferrin, albumin) were radiolabeled with Iodine-125 (2% protein of interest) and the accumulation of the conjugated protein to the lens materials was determined after 1, 7, 14, and 28 days of incubation. Protein deposition was measured using a gamma counter and the raw data were translated into absolute amounts (μg/lens) via extrapolation from standards. Results: After 28 days, lysozyme uptake was significantly lower on BA lenses when incubated in Solution A (33.7 μg) compared to Solution B (56.2 μg), p0.05. LB lenses also deposited similar amounts of lysozyme for both solutions (Solution A: 5.0 μg, Solution B: 4.7 μg, p>0.05). After 28 days, BA lenses accumulated approximately twice the amount of lactoferrin than the other lens materials, with 30.3 μg depositing when exposed to Solution A and 22.0 μg with Solution B. The difference between the two solutions was statistically significant (p0.05. LB lenses also deposited similar amounts of lysozyme for both solutions (Solution A: 5.0 μg, Solution B: 4.7 μg, p>0.05). After 28 days, BA lenses accumulated approximately twice the amount of lactoferrin than the other lens materials, with 30.3 μg depositing when exposed to Solution A and 22.0 μg with Solution B. The difference between the two solutions was statistically significant (p0.05). After 28 days, albumin deposition onto BA lenses was significantly greater when lenses were incubated in Solution B (1.7 μg) compared to Solution A (0.9 μg), p0.05). LB lenses incubated in Solution A deposited more albumin compared to Solution B (0.9 μg versus 0.6 μg), p=0.003. Discussion: Protein deposition onto SH materials varied when contact lenses were incubated in either a complex ATS compared to a single protein solution. More lysozyme accumulated onto BA lenses incubated in a complex analog of the human tear film, whereas lactoferrin deposited onto SA lenses independent of incubation solution composition. To better mimic the ex vivo environment, future studies should use more appropriate analogs of the tear film. © 2012 Molecular Vision.

Jiang,Q., Zhang,Z., Niu,L., Wang,B., Fadel,D., Wei,R., Chen,Z. Changes in anterior segment after short-term scleral lens wear in healthy Chinese population Contact Lens Anterior Eye 2024;Online ahead of print [ Show Abstract ]

Purpose
To evaluate the impact of short-term scleral lens (SL) wear on anterior chamber (AC) dimension and central corneal thickness (CCT) in healthy Chinese people.

Methods
This is a prospective, daily wear study. Eligible participants were dispensed SLs to correct refractive errors. Anterior segment (AS) parameters were measured by AS optical coherence tomography (AS-OCT) before, during, and after 2 and 4 hours of lens wear. Repeated-measures analysis of variance (ANOVA) was used to analyze the changes in AS parameters over time.

Results
Twelve subjects (10 females and 2 males) with a mean age of 25.3 ± 3.8 years (ranging from 21 to 34 years) were recruited. The AC parameters, including anterior chamber depth (ACD) from the endothelium (endo-ACD), angle opening distance at 500 μm (AOD500), and trabecular-iris space area at 500 μm (TISA500), significantly decreased after wearing SLs for 4 hours (P<0.05). CCT increased by 12 μm (2.29 %) after wearing SLs for 4 hours (P=0.013).

Conclusion
This study suggests that SL wear has a significant impact on AS dimensions in patients with healthy corneas in the short term with SL in situ, but tend to recover quickly after SL removal. Further research is needed to determine whether the change in AS dimensions during SL wear affects aqueous humor (AH) outflow and causes changes in intraocular pressure (IOP).

Jin,Y., Dixon,B., Jones,L., Gorbet,M. The Differential Reactive Oxygen Species Production of Tear Neutrophils in Response to Various Stimuli In Vitro International Journal of Molecular Sciences 2021;22(23):12899 [ Show Abstract ]

A large number of polymorphonuclear neutrophils (PMNs) invade the ocular surface during prolonged eye closure (sleep); these leukocytes are commonly referred as tear PMNs. PMNs contribute to homeostasis and possess an arsenal of inflammatory mediators to protect against pathogens and foreign materials. This study examined the ability of tear PMNs to generate reactive oxygen species (ROS), an essential killing mechanism for PMNs which can lead to oxidative stress and imbalance. Cells were collected after sleep from healthy participants using a gentle eye wash. ROS production in stimulated (phorbol-12-myristate-13-acetate (PMA), lipopolysaccharides (LPS) or N-Formylmethionyl-leucyl-phenylalanine (fMLP)) and unstimulated tear PMNs was measured using luminol-enhanced chemiluminescence for 60 min. A high level of constitutive/spontaneous ROS production was observed in tear PMNs in the absence of any stimulus. While tear PMNs were able to produce ROS in response to PMA, they failed to appropriately respond to LPS and fMLP, although fMLP-stimulated tear PMNs generated ROS extracellularly in the first three minutes. Higher ROS generation was observed in isolated tear PMNs which may be due to priming from the magnetic bead cell separation system. The differential responses of tear PMNs in ROS generation provide further evidence of their potential inflammatory roles in ocular complications involving oxidative stress.

Jin,Y., Jones,L., Gorbet,M. Investigation of the response of tear-film neutrophils to interleukin 8 and their sensitivity to centrifugation, fixation, and incubation Scientific report 2020;10(1):19690 [ Show Abstract ]

During eye closure, a large number of neutrophils (polymorphonuclear neutrophils, PMNs) invade the ocular surface and are often referred to as tear-film PMNs. While immunophenotyping experiments have been performed on tear-film PMNs, the impact of commonly used experimental procedures on their phenotype as well as their response to interleukin-8 (IL-8), a physiological inflammatory mediator, have not yet been investigated. A gentle eye wash method was used to collect cells at home. In the morning upon awaking, participants washed their eyes with sterile phosphate buffer saline (PBS) and collected the runoff into a sterile polypropylene tube. The cell collection was then delivered to the lab within two hours. The effects of centrifugation, incubation and fixation with paraformaldehyde (PFA) before (pre-fixed staining) or after (post-fixed staining) incubation with antibodies were characterized. Tear-film PMNs as well as blood PMNs (used for comparison) were also stimulated with IL-8. To assess the reproducibility of cell collection and variability in receptor expression over time, participants were also asked to collect cells three times over a period of a month. The change in expression of surface receptors, CD11b, CD16, CD55, CD66b, important inflammatory and activation markers, and CD45 (PAN leukocyte marker) was assessed by flow cytometry. Fixing tear-film PMNs prior to the staining with antibodies resulted in a significant (fivefold or more) reduction in the expression of CD11b, CD16 and CD45 when compared to unfixed samples, while CD16 was the only receptor to undergo significant downregulation upon post-staining fixation. Furthermore, additional centrifugation step prior to antibody incubation as well as long (4 h) incubation at 37 °C resulted in significant reductions in expression of CD11b, CD16 and CD55 when compared to control samples. As opposed to blood PMNs, stimulating tear-film PMNs with IL-8 did not induce any significant changes in expression of CD11b, CD16, CD55 and CD66b. When working with collected tear-film PMNs, our results suggest that any additional centrifugation and incubation step should be avoided, or at least limited, and post fixation staining is recommended in order to preserve cell phenotype and cell integrity of tear film PMNs. Our study also adds further information on the reproducibility of the gentle eye wash as well as the inability of tear-film PMNs to modulate their surface receptors upon stimulation with IL-8. The latter may be due to prior exposure to IL-8, activation in the closed-eye environment, or a reduced ability to respond to inflammatory stimulus. Further mechanistic studies will be needed to gain a better understanding of the tear-film neutrophil phenotype.

Jin,Y., Minten,C., Jenkins,M., Jones,L., Gorbet,M. Investigation of the rhythmic recruitment of tear neutrophils to the ocular surface and their phenotypes Scientific Reports 2024;147061 [ Show Abstract ]

Hundreds of thousands of polymorphonuclear neutrophils (PMNs) are collected from the ocular surface upon waking, while few are harvested during daytime. This study aimed to investigate potential factors contributing to the circadian infiltration of tear PMNs, including changes in IL-8 and C5a in tears, and their phenotypes across different time points in a 24-h cycle. Tear PMNs were collected using a gentle eyewash after 2-h and 7-h of sleep (eye closure, EC) at night, after 2-h EC during the day, and towards the end of the afternoon. Significantly fewer cells were collected after 2-h EC during the day compared to 2-h EC at night. A positive correlation between IL-8 and PMN numbers existed, but not with C5a. Tear PMNs collected after 2-h EC at night were less degranulated and possessed a larger activation potential compared to 7-h EC. Tear PMNs from 7-h EC at night exhibited hyper-segmented nuclei and more NETosis compared to 2 h EC night, indicating an aged and activated phenotype. The diurnal-nocturnal recruitment pattern of tear PMNs may be driven by increased IL-8 in nighttime tears. Higher degranulation and NETs point to the significant activation of tear PMNs on the ocular surface during prolonged eye closure at night.

Jones,D., Woods,C., Jones,L., Efron,N., Morgan,P. A sixteen year survey of Canadian contact lens prescribing Contact Lens and Anterior Eye 2016;39(6):402-410 [ Show Abstract ]

Purpose To understand long-term contact lens prescribing habits of Canadian optometrists. Methods One thousand optometrists were surveyed annually from 2000 to 2015. Information was requested on the first ten patients examined after receiving the survey. Results Over the 16-year survey period, 1987 optometrists provided information on 19,143 patients. Mean age of the patients was 32.7 ± 14.4 years. Ratio of females to males was 2:1, the ratio of new fits to refits was 2:3. Soft contact lenses represented 94.5% of all fits. Rigid lenses were more often used as a refit compared to a new fit. Over the 16 years, market share for silicone hydrogel materials grew from 0% to 69.6%, mid-water content materials declined from 75.7% to 14.1%. The multifocal market share grew at the expense of spherical designs, with no change in toric lens fitting. Monthly soft lens replacement remained the preferred option at 48.2%, followed by daily disposable at 40.8%; two-weekly replacement declined to less than10% of patients by 2015. Extended wear was likely used to refit and only to a small proportion of wearers, representing 2.6% of SCL by 2015. The lens care system of choice throughout the period was multipurpose solutions, although the proportion for peroxide systems more than doubled by 2015 from 9.6%, to 21.1%. Conclusions Over the 16-year period, SCL material preference changed to silicone hydrogels with monthly replacement being preferred; daily disposables replacing 2-weekly as the alternate. Lens care preference continued to be multipurpose solutions. Rigid lenses appear to be sustained for specialist fitting. © 2016 British Contact Lens Association

Jones,L. W., Byrne,M., Ciolino,J. B., Legerton,J., Markoulli,M., Papas,E., Subbaraman,L. Revolutionary future uses of contact lenses Optometry and Vision Science 2016;93(4):325-327

Jones,L. W., Jones,D. A. Non-inflammatory corneal complications of contact lens wear Contact Lens and Anterior Eye 2001;24(2):73-79 [ Show Abstract ]

Contact lenses can induce changes in the epithelium, stroma and endothelium of the cornea, all of which can be observed clinically using the slit-lamp biomicroscope. These complications include epithelial microcysts, vacuoles and staining, stromal oedema and vascularization, and endothelial polymegethism and blebs. Each complication can be attributed to one or more aetiological factors such as hypoxia, hypercapnia, tissue acidosis, trauma, hypersensitivity and toxicity. This review outlines the way in which these complications manifest clinically, and consideration is given to management strategies and likely prognoses. Early detection of these conditions and appropriate action can usually prevent more serious ocular complications.

Jones,L., Brennan,N. A., González-Méijome,J., Lally,J., Maldonado-Codina,C., Schmidt,T. A., Subbaraman,L., Young,G., Nichols,J. J. The TFOS International Workshop on Contact Lens Discomfort: Report of the contact lens materials, design, and care subcommittee Investigative Ophthalmology and Visual Science 2013;54(11):TFOS37-TFOS70

Jones,L., Chauhan,A.,DiGirolamo,N., Sheedy,J., Smith III,E. Expert views on innovative future uses for contact lenses Optometry and Vision Science 2016;93(4):328-35 [ Show Abstract ]

Over the past 10 to 15 years, the availability of new materials and technologies has resulted in revolutionary concepts for contact lenses being proposed that go well beyond correcting vision. These novel uses include their prescribing to deliver topical ocular and systemic drugs, assist with ocular surface disease management, and limit the progression of myopia and novel methods to display visual information. How likely are these concepts to become commercially available, how successful will they be, and what are the potential issues to consider for them to come to market? To answer these questions, a panel of four experts were invited to discuss the benefits and pitfalls of these technologies and what challenges lay ahead of these concepts before their availability. Their responses provide a fascinating insight for the clinician into the likelihood of such revolutionary contact lenses being available in a clinical setting.