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1.
《Contact lens & anterior eye》2021,44(2):192-219
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. 相似文献
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《Contact lens & anterior eye》2021,44(6):101388
PurposeTo investigate the relationship between the real contact lens imprint into the conjunctival tissue, observed by optical coherence tomography (OCT) and conjunctival staining and contact lens wearing comfort.Methods17 participants (mean age = 26.6 SD ± 3.6 years; 7 females) were fitted with three different contact lenses base curves of the same silicone hydrogel custom lens type (Visell 50; Hecht Contactlinsen, Au, Germany) in a randomised order. One lens was optimally fitted according to the manufacturer's recommendation, one fitted 0.4 mm flatter and one fitted 0.4 mm steeper. After 4 h of lens wear the contact lens edge in the area of the conjunctiva was imaged nasally and temporally using OCT (Optovue iVue SD-OCT). To correct the artefact due to optical distortion with OCT, the imprint of all worn lenses was measured on a glass plate afterwards. Conjunctival staining in the limbal region after 4 h of lens wear was classified using the CCLRU Grading Scale. Comfort scoring was based on visual analog scales from 0 (very poor) to 100 (excellent).ResultsThe mean conjunctival imprint of all contact lens edges was 32.0 ± 8.1 μm before and 7.3 ± 6.5 μm after distortion correction of the OCT images. The distortion corrected conjunctival imprint with the 0.4 mm steeper lens (11.5 ± 6.2 μm) was statistically significantly greater compared to the optimally fitted lens (6.5 ± 5.9 μm) (One-way ANOVA followed Tukey-test; p = 0.017) and greater compared to the 0.4 mm flatter lens (3.9 ± 5.3 μm) (p < 0.001). There was no statistically significant difference between the optimally fitted lens and the 0.4 mm flatter lens (p = 0.209). The nasally measured imprint (11.4 ± 9.0 μm) was significantly greater than the temporally measured (3.3 ± 7.6 μm) (p < 0.001). There was no statistically significant correlation between the amount of conjunctival imprint and the graded conjunctival staining (p = 0.346) or the wearer’s comfort (p = 0.735).ConclusionsContact lens edges imaged by OCT exhibited displacement artefacts. The observed conjunctival imprints are a combination of real conjunctival compression and artefacts. A deeper imprint of the contact lens into the conjunctiva caused by a steeper base curve was not related to clinically significant staining or changes in comfort after 4 h of lens wear. The observed differences between nasal and temporal imprint are likely to be caused by variations of conjunctival thickness and the shape of the underlying sclera. 相似文献
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《Contact lens & anterior eye》2020,43(2):189-191
AimThis study aimed to investigate the effect of scleral lens (SL) use on conjunctival microbiota.MethodA total of 26 eyes of 26 patients using an SL and 25 eyes of 25 healthy controls were included in the study. The samples were obtained from the lower fornices of the eyes using sterile swabs. For the bacteriological examination, a bacterial culture was obtained by inoculating the samples on chocolate agar, blood agar, MacConkey agar, and fluid thioglycollate medium. After 24–48 h of incubation at 37 0C, the growth of different colonies of bacteria was identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (Bruker MALDI Biotyper).ResultsThe mean age of the study group was 41.6 ± 19.1 years (18–65); the mean age of the control group was 40 ± 6 (21–62) (p = 0.69). There were 10 male patients and 16 female patients in the study group and 9 male patients and 16 female patients in the control group (p = 0.86). The mean duration of SL use was 13.7 ± 13.4 months (1–42 months). No bacterial growth was observed in 17 (65.4 %) of the 26 eyes in the SL group and 5 (20 %) of the 25 eyes in the control group (p = 0.001). The most commonly observed microorganisms were Staphylococcus epidermidis (S.epidermidis) and Staphylococcus aureus (S.aureus) in both groups.ConclusionSL users were found to have a higher rate of culture negativity in comparison to the healthy controls, suggesting that SLs have a significant effect on conjunctival microbiota. 相似文献
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《Contact lens & anterior eye》2020,43(4):338-344
PurposeTo compare the sensitivity of two genotypes of P. aeruginosa to various disinfectant solutions and analyze the attached bacteria on worn cosmetic contact lenses (cosCLs).MethodsIn this prospective study, healthy volunteers wore etafilcon (brown), nelfilcon (gray), or hilafilcon (black) cosCLs and microbial adhesion analysis was performed. A rub-off test determined pigment dislodgement. Disinfectant sensitivity to Optifree Replenish (Alcon), Optifree Pure Moist (Alcon), Renu Fresh (Bausch & Lomb), and AoSept Plus (Ciba Vision) was tested at various disinfection times and compared between various genotypes and Type III secretion (T3S) system mutants.ResultsOf the 1152 cosCLs collected, 364 were culture positive (32%). The highest rate of culture-positive lens was hilafilcon (chi square, P = 0.0001). Hilafilcon also had a significantly greater number of isolates than etafilcon (P < 0.0001). Hilafilcon was the only lens to fail the rub-off test. Cytotoxic strains were significant more resistant to Renu Fresh than were invasive strains, even at 100% of recommended disinfection time (P = 0.0005). Of the tested disinfectants, Renu Fresh was significantly less effective in killing both genotypes of P. aeruginosa compared to AoSept Plus at all time points (25%, 50%, 75%, and 100% recommended disinfection time, P = 0.0001, 0.0001, 0.0005, and 0.0005, respectively). When the T3S system was dysfunctional, mutant strains were all susceptible to disinfectants (P = 0.0001 for both invasive and cytotoxic strains).ConclusionPseudomonas species is commonly found on cosCLs of asymptomatic individuals. Wearers of cosCLs that dislodge pigments may be predisposed to microbial contamination. Cytotoxic strains are more resistant to disinfectant solutions, especially to Renu Fresh. P. aeruginosa disinfectant resistance requires a functional T3S system. 相似文献
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《Contact lens & anterior eye》2020,43(6):602-608
PurposeTo estimate the prevalence of patient-reported midday fogging and to identify risk factors for midday fogging.MethodA multicenter, cross-sectional study was conducted with an electronic survey that was distributed to scleral lens practitioners. The survey asked them to describe their most recently examined established scleral lens patient. Respondents provided data about patient-reported midday fogging, patient demographic characteristics, indication for lens wear, lens-wearing schedule, lens design, and care products.ResultsOf the 248 survey respondents who indicated whether their patients had midday fogging, 64 (25.8 %) had patients who self-reported such issues. Midday fogging was not associated with demographic characteristics (age, sex, race/ethnicity), indications for scleral lens wear, mean lens diameter (P = .30), haptic design (P = .29), use of a daily cleaner (P = .12), disinfection/storage solution used (P = .71), or filling solution (P = .65). Patients who reported midday fogging more commonly reported redness or irritation associated with scleral lens wear compared with those who did not experience midday fogging (P = .03).ConclusionsPrevalence of midday fogging in this study was similar to previously reported rates. No specific lens design or care product was associated with patient-reported midday fogging. If inflammatory mediators are elevated in the postlens fluid reservoir of patients with midday fogging, as previously described, the redness or irritation associated with scleral lens wear suggests that ocular surface inflammation may be contributing to this phenomenon. 相似文献