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Purpose: The purpose of this study was to assess the immediate ocular immune response to soft contact lens (CL) wear by examining presumed epithelial immune cell (EIC) density and morphology at the central, peripheral, limbal cornea, and conjunctiva., Methods: Fifty-four participants naïve to CL wear (mean age = 24.8 ± 9.8 years, 44% female participants), were examined using in vivo confocal microscopy at baseline and after 2 hours of CL wear (1-Day ACUVUE MOIST). Images were captured at the central, temporal far peripheral and limbal cornea, and bulbar conjunctiva. EIC density was counted manually and morphology was graded. Differences in EIC parameters pre- and post-CL wear were examined using a generalized estimating equation model with appropriate post hoc analyses., Results: After 2 hours of soft CL wear, there was a significant increase in EIC density in all regions other than the central cornea (all P < 0.001). Cell body size was significantly larger, and a higher proportion of participants exhibited EIC with long dendrites after lens wear at the central and peripheral cornea (both P < 0.001). There was a significant increase in the number of participants displaying EIC with thick dendrites at the peripheral (P = 0.04) and limbal cornea (P < 0.001) after lens wear., Conclusions: EICs were primarily recruited to the peripheral regions, whereas the central cornea shows no significant recruitment after short-term CL wear. Both central and peripheral corneas exhibited an enhanced antigen capture capacity, whereas migratory capacity was increased in the peripheral corneal regions suggesting EIC activation following a short period of CL wear.

Purpose: To investigate the effect of long-term extended soft contact lens wear on limbal and central corneal cell morphology, and limbal architecture., Methods: Each participant attended a study visit involving in vivo confocal microscopy of central corneal and limbal epithelium. Scans were graded by five masked graders for three features: central epithelial irregularity, limbal epithelial irregularity and the prominence of palisades of Vogt. The variability of grades between different graders and the difference of grades between extended wearers and daily soft/non-contact lens wearers were assessed., Results: Nineteen participants (9 extended soft contact lens wearers and 10 daily soft/non-contact lens wearers) aged 31-65 years were enrolled in this study. Scans from 37 eyes were included in the analysis. Agreement between graders for each feature was moderate to good with inter class correlation >0.7. While there were no significant differences in central epithelial cell irregularity (p = 0.527) and the prominence of palisade of Vogt (p = 0.182) between extended or daily soft/non-contact lens wearers, limbal epithelial cell irregularity showed a trend with increased irregularity in extended soft contact lens wearers (p = 0.091)., Conclusions: While no differences in limbal cell morphology and structureor central epithelial cell wasfound in thissubjective grading study of extended wearers compared to daily soft/non-contact lens wearers, further studies using a larger sample size or a longitudinal study design are warranted., (Crown Copyright © 2021. Published by Elsevier Ltd. All rights reserved.)

This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia). However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation. In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience., (Copyright © 2021 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Significance: Established reusable contact lens (CL) wearers show higher tear inflammatory cytokine concentrations and greater conjunctival metaplasia in the region covered by standard soft CLs. The balance of proinflammatory to anti-inflammatory cytokines, but not individual tear cytokine concentrations, was associated with self-reported CL discomfort., Purpose: Daily disposable (DD) lenses are often used to improve CL discomfort, but the effect on ocular inflammatory responses has not been fully investigated. This study aimed to compare the concentrations of tear cytokines and conjunctival cell morphology in healthy habitual DD and reusable soft CL wearers., Methods: Thirty-six established daily CL wearers, including 14 DD and 24 reusable wearers, were enrolled. Symptoms and ocular surface integrity were evaluated. The concentration of tear cytokines (interleukin 1β [IL-1β], IL-6, IL-10, IL-12(p70), IL-17A, and tumor necrosis factor α) were determined using Multiplex assays. The ratios of proinflammatory and anti-inflammatory cytokines were calculated. Impression cytology was performed on the conjunctiva, and goblet cell density and epithelial squamous metaplasia were quantified. Differences in variables by CL replacement schedules and the associations between variables were analyzed., Results: Reusable CL wearers had higher concentrations (in pg/mL) of IL-1β (26 ± 7 vs. 16 ± 11), IL-6 (42 ± 14 vs. 25 ± 20), IL-10 (83 ± 23 vs. 49 ± 36), IL-12(p70) (145 ± 44 vs. 91 ± 68), IL-17A (93 ± 26 vs. 54 ± 44), and tumor necrosis factor α (312 [171 to 468] vs. 189 [6 to 447]) (all P < .01) and greater conjunctival metaplasia in the region covered by CLs (0.7 [0.2 to 1.6] vs. 0.4 [0.04 to 1.2], P = .01) compared with DD wearers. There was a positive association between CL discomfort and ratios of IL-1β to IL-10 and IL-12(p70) to IL-10 (ρ = 0.42 and ρ = 0.33, P < .05)., Conclusions: Higher ocular inflammatory responses, as indicated by higher tear cytokine concentrations and higher conjunctival epithelial metaplasia, were found in reusable CL wearers than in DD CL wearers. The balance of proinflammatory and anti-inflammatory cytokines may be helpful to assess the inflammatory status of the eye.

Purpose: This study investigated changes in selected tear cytokine concentrations (IL-1β, IL-1Ra, IL-6, IL-10, IL-12 (p70), and TNF-α) after a 1-week washout from soft contact lens wear (CLW), and the repeatability of cytokine measurements using custom multiplex assays., Methods: A total of 10 subjects completed this 6-visit (immediately following contact lens removal, and after 1, 2, 3, 4, and 7 [±1] days without CLW) pilot study. Approximately 20 to 30 μL of pooled basal tears were collected from both eyes at each visit. Two custom multiplex assays were used by two operators to quantify the concentration of tear cytokines. Tear samples from subjects 1 to 6 were analyzed using the first kit by operator 1. Tear samples from subject 7 to 10 plus additional tear samples from subjects 1 to 5, which were used to determine the between-kit per operator repeatability, were analyzed using the second kit by operator 2. Linear mixed models were used to determine changes in tear cytokine concentrations over time. Between-kit per operator and within-kit per operator repeatabilities were assessed using the Bland and Altman analysis., Results: There were no significant changes in tear cytokine concentrations over a 1-week washout of CLW. More than 99% of the tear samples had detectable levels of cytokines using custom multiplex assays. Within-kit per operator repeatability was good, but between-kit per operator repeatability was poor; likely due to protein degradation, differences in operator experience, and operating procedures., Conclusion: A washout period may not be necessary when evaluating changes in tear cytokines with new contact lenses or lens care products. A well-trained operator using standardized operating procedures can produce repeatable measurements using custom multiplex assays.

Purpose: To establish whether increased end-of-day discomfort during soft contact lens wear is associated with short-term changes occurring to the lens itself., Methods: Twenty-seven subjects wore hydrogel lenses (Focus Dailies; Alcon) bilaterally for 10 hours on two separate days. Comfort was reported using 1-100 numerical rating scales (1 = intolerable discomfort, 100 = lens cannot be felt). Day 1 ratings were taken before lens insertion and at 0.05, 5, and 10 hours post-insertion. Day 2 ratings occurred at similar times, but lenses were removed after the 5-hour assessment and either reinserted (n = 14) or newly replaced (n = 12). An additional rating was taken 5 minutes after re-insertion. Wear then continued to the 10-hour point. In a separate study, 24 different subjects repeated these procedures using a silicone hydrogel lens (AirOptix Aqua; Alcon) with wear taking place on 3 days to permit lens replacement to be with existing as well as new lenses in all subjects., Results: For hydrogel lenses, comfort scores (mean ± 95% CI) reported after 10 hours were 79.4 ± 8.3 when lenses were worn un-replaced, compared with 73.2 ± 9.2 for replacement with the existing lens. When replacement was with a brand new lens, the corresponding values were 72.9 ± 10.9 (un-replaced) versus 69.2 ± 12.8 (new lens replacement). For silicone hydrogel lenses, 10-hour comfort was 90.3 ± 3.2 (un-replaced) versus 92.2 ± 2.9 (replacement with existing lens) versus 90.0 ± 3.3 (replacement with new lens). Differences between replacement conditions were not significant in any case (analysis of variance, p > 0.05)., Conclusions: Final comfort was not influenced by replacing lenses midway through the wearing period. Comfort decrements experienced by users of these daily contact lenses towards the later part of the wearing period are not caused by changes occurring to the lenses on this time scale. Possible alternative etiological factors include a fatigue-like response in one or more ocular tissues or stimulation of ocular surface nociceptors induced by the presence of the contact lens.