Detection of mucus glycoconjugates in human conjunctiva by using the lectin-colloidal gold technique in TEM. II. A quantitative study in dry-eye patients

The mucus glycoconjugates produced by conjunctival goblet cells in dry-eye patients were studied by a specific cytochemical reaction in Transmission Electron Microscopy (TEM). Four lectins, proteins of vegetal origin which specifically bind glycosidic residues, (WGA, PNA, SBA and ConA) were used conjugated with colloidal gold as ultrastructural marker. We performed a quantitative analysis by counting the colloidal gold particles present on mucus granules. The results were compared with normal conditions. We found a decrease in sialic acid, N-acetyl-glucosamine, N-acetyl-galactosamine and galactose-N-acetyl-galactosamine and an increase in mannose. The different content of glycoconjugates in goblet cells may reflect in the change of physical and functional properties of mucus. We think these data may be useful in the search for a therapeutic mucomimetic drug.     

Detection of mucus glycoconjugates in human conjunctiva by using the lectin colloidal gold technique in TEM. I. A quantitative study in normal subjects

We applied a specific cytochemical reaction to characterize the glycoconjugates produced by goblet and non-goblet epithelial cells of normal human conjunctiva. For this purpose we utilized the lectins, proteins of vegetal origin, which are extremely sensitive in binding glycosidic residues. In particular, we used WGA, PNA, SBA and ConA conjugated with colloidal gold as ultrastructural marker for Transmission Electron Microscopy. This technique allowed us also to perform a quantitative analysis, by counting colloidal gold particles present on mucus granules. In this way we analyzed the content both of goblet and non-goblet epithelial cells. In the former, WGA, PNA, SBA and ConA receptors, here reported in decreasing density, were present. In the latter WGA was always positive, SBA and PNA sometimes were negative, ConA was always negative. We speculate the different contribution to mucus production by these two sources may be important in evaluating tear film stability alterations occurring in those diseases in which non-goblet epithelial cell vesicles increase.     

Number of type of inflammatory cells in conjunctiva of asymptomatic contact lens wearers.

Biopsy specimens were taken from the upper tarsal conjunctiva of eight asymptomatic contact lens wearers and quantitative histology was determined and compared to histology from 15 normals and 55 patients with contact lens-induced giant papillary conjunctivitis. No abnormalities were detected in the asymptomatic contact lens wearers. One or more of the three tissue characteristics of giant papillary conjunctivitis--(1) mast cells in the epithelium, (2) eosinophils in epithelium or substantia propria, and (3) basophils in epithelium or substantia propria--was found in all patients with this syndrome, but none was present in any of the eight asymptomatic lens wearers. Trauma occurring over months or even years does not induce histologic alteration in the upper tarsal conjunctiva; the surface changes seen previously by scanning electron microscopy in asymptomatic lens wearers are secondary to trauma, not early aspects of the giant papillary conjunctivitis syndrome.     

A multi-centre study of lapsed contact lens wearers

PURPOSE: Discontinuation from contact lens wear has been identified as a contributing factor in the lack of growth of contact lens use in Europe. The purpose of this study was to determine the proportion of lapsed contact lens wearers that can be refitted successfully with contact lenses and to evaluate the reasons for discontinuation from contact lens wear. METHODS: This was a multi-site clinical study involving 15 UK investigators and 236 lapsed contact lens wearers who had previously tried contact lenses and discontinued. The reasons for discontinuation were assessed by subjects, who were then refitted with contact lenses. Investigators subsequently evaluated factors associated with their initial discontinuation. Short-term success was defined as the successful completion of 1 month of contact lens wear with absence of complications that would prevent further wear. Subjects were interviewed by telephone 6 months after being refitted to determine whether they were still wearing contact lenses. Those who were not wearing lenses were questioned about the reasons for discontinuation and their likelihood of resuming lens wear. RESULTS: A majority of subjects (51%) cited discomfort as the principal reason for having previously given up contact lens wear. Problems with vision were the second most common reason (13%), either with reading (6%) or general vision (7%). The most common type of discomfort was dryness (40%). In almost all cases (97%), the investigator's assessment of the reasons for discontinuation agreed with the subject's own assessment but investigators also cited product-related and practitioner-related factors as contributing to previous failure. The short-term success rate for refitting lapsed wearers was found to be 77% (Cl: 70-82%). The highest short-term success rates were for 2-weekly/monthly soft spherical lenses (91%) and daily disposable lenses (89%). Lower success rates were found for soft toric (69%) and soft bifocal (53%) lenses. At the 6-month stage, 73% of those who continued in lenses after the 1-month visit were still wearing contact lenses and a further 18% indicated that they were either 'very likely' or 'likely' to resume lens wear. CONCLUSIONS: A high proportion of lapsed contact lens wearers can be successfully refitted with contact lenses. The prime reason for previous discontinuation from contact lenses is discomfort and, in particular, dryness-related discomfort. In many cases, previous contact lens failure is product or practitioner-related rather than because of patient-specific problems. Once refitted with contact lenses, lapsed wearers cite vision problems rather than discomfort as the most common reason for discontinuing. This finding suggests that recent advances in contact lens material, design, replacement frequencies and care systems have improved the prospects for avoiding lens-related discomfort and for continuing contact lens wear.     

Hydrogel lens dehydration and subjective comfort and dryness ratings in symptomatic and asymptomatic contact lens wearers.

PURPOSE: To determine whether lens dehydration correlates with discomfort, dryness, and noninvasive tear break-up time in symptomatic and asymptomatic contact lens wearers and whether dehydration of the two lens types varies. METHOD: Twenty hydrogel contact lens wearers with dryness-related symptoms and 20 asymptomatic wearers wore an Etafilcon A lens (Acuvue; Vistakon, Inc., Jacksonville, Florida) in one eye and an Omafilcon A lens (Proclear; Biocompatibles, Norfolk, Virginia) in the contralateral eye for 7 h in a randomized, double-masked study. Lens water content was measured before and after 7 h of lens wear and prelens noninvasive tear film break-up time (NIBUT) was measured immediately after insertion and after 5 h of lens wear. Subjective comfort and dryness were rated at 0, 1, 3, 5, and 7 h of lens wear. RESULTS: The symptomatic group had significantly reduced prelens NIBUT, decreased comfort, and increased dryness, but there was no difference between lenses for these variables. The Omafilcon A lenses dehydrated significantly less than the Etafilcon A lenses, but there was no significant difference in lens dehydration between two subject groups. CONCLUSION: No correlation was found between lens dehydration and subjective dryness and comfort. Symptomatic hydrogel contact lens wearers with decreased wearing time had measurably decreased comfort, increased dryness ratings, and reduced NIBUT.     

A retrospective study of myopia progression in adult contact lens wearers

PURPOSE: To study retrospectively the frequency of myopia progression and risk factors for progression in a sample of adult contact lens wearers. METHODS: From a database of 815 soft contact lens wearers, patients were identified whose age was between 20 and 40 years, who had at least -0.50 D spherical equivalent of myopia in both eyes, three or more refractions, and > or =5 years of follow-up. Only data from the right eye were used. Progression was defined as an increase of at least -1.00 D over 5 years. Subjects were also asked to complete a questionnaire regarding their ocular history, demographics, family history, and the amount of time spent performing different tasks at home and at work. RESULTS: Two hundred ninety-one subjects met the eligibility criteria with a mean baseline refractive error of -3.29 +/- 1.92 D and a mean age of 28.5 +/- 5.0 years. Of these, 21.3% progressed by at least -1.00 D over the 5-year period. The 5-year rate of progression decreased with increasing age (chi(2) = 12.44, P = 0.006). One hundred ninety-seven subjects (67.6%) completed and returned questionnaires. "Progressors" (N = 41) did not differ from "nonprogressors" (N = 156) in terms of hours per day spent reading and writing, computer use, education level, family history of myopia, age of onset of myopia, and contact lens wear. CONCLUSIONS: In this database of soft contact lens wearers, myopia progression was common for subjects in their twenties and less common for those in their thirties.     

Clinical grading of the upper palpebral conjunctiva of non-contact lens wearers.

PURPOSE: To categorize the appearance of the normal upper palpebral conjunctiva using a grading scale and to investigate interobserver agreement with a grading scale modified to include decimal increments. METHODS: Upper palpebral conjunctival appearance of 96 non-contact lens wearing subjects aged 18 to 75 years was assessed using a photographic grading scale that has a generic (zero to four) scale to score redness and roughness of the palpebral conjunctiva. RESULTS: Median redness and roughness was about 1.25 units. About 5% of subjects had redness or roughness >2.0 units. Interobserver agreement improved during the study. By the end of the study, the standard deviation of the discrepancy scores was 0.12 to 0.19 units. CONCLUSIONS: Upper palpebral conjunctival redness or roughness >2.0 units are unusual. The grading scale can be used successfully with decimal rather than integer scale increments. For experienced clinicians, a change in grade of > or =0.5 units may be significant.     

Presence of inflammatory mediators in the tears of contact lens wearers and non-contact lens wearers

The present studies have demonstrated the levels of N-methyl histamine in tears from normal physiological states, pathological states and contact lens wear Histamine was significantly increased in closed eye tears compared with both open and reflex tears. Tears from other ocular conditions had low levels of histamine except for environmental hypersensitivity, which contained significantly elevated levels compared to normal tear types. Interestingly tears from asymptomatic contact lens wearers had significant levels of histamine whereas tears from contact lens adverse events had lower levels, possibly reflecting a change in histamine metabolism.     

激光共焦显微镜观察长期配戴软性角膜接触镜者的角膜缘改变

目的探讨应用激光共焦显微镜观察长期配戴软性角膜接触镜者角膜缘改变的情况。方法2004年10至11月及2006年5至10月期间在北京大学第一医院眼科接受屈光手术术前检查者和常规体检者中选取22例有屈光不正并配戴软性角膜接触镜10年以上者（22只眼,年龄23～50岁）作为长期戴镜组;另选取38例有屈光不正但未配戴角膜接触镜者（38只眼,年龄18～52岁）作为未戴镜对照组。常规裂隙灯显微镜检查后,用激光共焦显微镜对受检眼上、下方角膜缘进行检查,各层角膜缘图像均被记录,观察组织结构和细胞形态,对细胞密度进行计数并分析。结果全部受检眼所获角膜缘各层图像均比较清晰。长期戴镜组角膜缘上皮细胞排列欠整齐,大小欠一致：22只眼中均有细胞间强反光点或强反光线出现,其中16只眼可见细胞间微囊形成。而未戴镜组角膜缘上皮细胞排列整齐,大小一致;38只眼中均未见细胞间强反光点或强反光线及微囊形成。长期戴镜组上方和下方角膜缘上皮下郎格罕细胞平均密度均分别高于未戴镜组（P〈0．05）。长期戴镜组22只眼的角膜缘基质中均可见圆形高反光点,未戴镜组38只眼中均未见此改变。长期戴镜组上方和下方角膜缘前基质细胞、后基质细胞平均密度及角膜缘基质层平均厚度均分别低于未戴镜组（P〈0．05）。结论长期配戴软性角膜接触镜可导致角膜缘上皮细胞间微囊形成、上皮下郎格罕细胞平均密度增高、基质内沉积物微粒出现及基质细胞密度减少等角膜缘系列改变。（中华腰科杂志,2007,43：514-518）     

Acanthamoeba keratitis. A growing problem in soft and hard contact lens wearers

Eleven contact lens-wearing patients presented with Acanthamoeba keratitis. Eight cases were culture- and/or stain-positive for Acanthamoeba and three were presumed to have Acanthamoeba keratitis based on history and clinical findings. Six wore daily wear soft contact lenses, two wore extended-wear soft contact lenses, one wore a polymethylmethacrylate hard contact lens, one wore a gas-permeable hard contact lens, and one wore a Saturn lens (combined hard and soft lens). Four patients used distilled water and salt tablet saline, three used tap water and salt tablet saline, two used tap water rinse, two used well water rinse or storage, and one used intravenous (IV) saline. It is apparent that all contact lens wearers are at some risk for Acanthamoeba keratitis developing if proper contact lens care is not maintained. Of great concern is the inability of most current chemical sterilization methods to kill the organism if the lens becomes contaminated. Heat disinfection will kill Acanthamoeba trophozoites and cysts but the lens must not be placed into contaminated solutions afterward. Prevention is very important because medical and surgical treatment failures are frequent. Eye care practitioners who fit contact lenses are advised to use heat disinfection for low-water content stock soft contact lenses, and to use hydrogen peroxide without a catalyst for a minimum of 6 hours for all other stock lens fitting sets, to specifically inquire about contact lens care habits used by their patients, and to discourage the use of homemade saline solutions.     

Giant papillary conjunctivitis in frequent replacement contact lens wearers: a retrospective study.

PURPOSE: We conducted a retrospective study of 47 patients who wore frequent replacement contact lenses on a daily-wear basis to determine the incidence of giant papillary conjunctivitis (GPC) and to assess the potential risk factors that may predispose frequent replacement contact lens wearers to develop GPC. METHODS: We reviewed the records of patients with no prior contact lens experience who were fit with frequent replacement contact lenses from September 1993 to February 1997. RESULTS: Forty-seven of 260 patients met the requirements for inclusion in the study. Ten (21.27%) patients had developed GPC. The incidence varied with the frequency of contact lens replacement. The contact lens replacement schedule ranged from 1 day to 12 weeks. In those patients replacing their contact lenses every 4 weeks or at a longer interval, the incidence of GPC was 36%, while for patients who replaced their lenses more frequently, the incidence was 4.5%. Coated contact lenses were also more common among patients who replaced their lenses at 4 weeks or longer (P = 0.23). A significantly greater number of patients in the GPC group incorporated enzymatic cleaning into their contact lens care system (P = .0004). A history of allergy was more prevalent in patients who developed GPC and was statistically significant (P = .012). There was no significant difference found between the groups for age, gender, average daily wearing time, FDA classification of contact lens material, time in contact lenses from fitting to diagnosis or last follow-up period, or the parameters and fitting characteristics of the contact lenses. CONCLUSION: The frequency at which patients replace their contact lenses appears to be an important variable in developing GPC. Although frequent replacement contact lenses do not eliminate GPC, patients on a 1-day to 3-week replacement cycle had a significantly lower risk of developing GPC than patients who replaced their lenses at longer intervals. Lens coating was present less often on contact lenses replaced daily and up to 3 weeks. For patients who are at high risk for GPC, replacing lenses at intervals ranging of one day to two weeks appears to offer a better strategy for avoiding GPC than incorporating enzymatic cleaning into their lens care system.     

Possible environmental sources of Acanthamoeba spp in contact lens wearers.

The water supply and dust samples from the home environment (bathrooms and kitchens) of 50 wearers of contact lenses (CLs) were cultured for the presence of free-living amoebae. CL cases, solutions, and water taps were cultured for bacteria, which amoebae require for growth. Acanthamoeba spp were isolated from water drawn from six bathroom cold water taps (tank supplied), five in the presence of limescale, and from one kitchen cold water tap (mains supplied). There was an association between the presence of limescale in water and direct culture for free-living amoebae, suggesting that scale provides a favourable microenvironment for amoebae. Acanthamoebae were also found in dust from around one washbasin. Nineteen of 50 CL cases, 12/122 CL care rinsing solutions, and 59/100 cold water taps yielded Gram negative bacteria which could be ingested by amoebae. It is concluded from this study that CLs should not be washed in first-drawn tank-fed cold water, especially if limescale is present, and that soft CLs should be rinsed in manufactured single-use, sterile solutions. Rigid CL and CL cases should only be washed with boiled tap water (preferably hot), or single-use sterile solutions, and stored dry to prevent multiplication of amoebae and Gram negative bacteria.     

Assessment of conjunctival hyperemia in contact lens wearers. Part I

A photographic reference scale representing six levels of conjunctival hyperemia has been developed for the assessment of responses to contact lenses. The scale has been found to be capable of detecting statistically significant differences in conjunctival hyperemia responses between samples of hard, soft, and noncontact lens wearers. For experienced observers, inter- and intraobserver reliability was found to be high and the conclusion is drawn that this type of scale is potentially useful in research and clinical applications.     

Detection of ocular mucus in normal human conjunctiva and conjunctiva from patients with cicatricial pemphigoid using lectin probes and histochemical techniques

Conjunctival biopsies from patients with cicatricial pemphigoid affecting the conjunctiva and patients undergoing cataract surgery (normal conjunctiva) were snap-frozen, cryostat sectioned and incubated with fluorescein-conjugated lectins; peanut agglutinin (PNA), Helix pomatia agglutinin (HPA), soybean agglutinin (SBA), wheat germ agglutinin (WGA) and succinylated wheat germ agglutinin (S-WGA). Controls consisted of preincubating the lectins with the appropriate blocking sugars before applying the lectins to the sections. PNA and HPA stained the mucus granules contained in the conjunctival goblet cells but did not stain mucus or glycocalyx at the ocular surface distal to the goblet cells. Native WGA and S-WGA had high affinities for conjunctival goblet cells and the apical epithelial cell layers. Native WGA stained mucus and glycocalyx at the ocular surface. This staining of the ocular surface by WGA was confirmed at the transmission electron microscopic level using WGA conjugated to ferritin. Cicatricial pemphigoid patients in this study had reduced numbers of goblet cells; however, those goblet cells which were observed in cicatricial pemphigoid conjunctiva stained positively with HPA, PNA, WGA, and SWGA as did goblet cells in normal conjunctiva.     

Assessment of conjunctival hyperemia in contact lens wearers. Part II

A photographic reference scale has been used to grade conjunctival hyperemia in contact lens wearers. A sample of hard lens wearers, included as a control, has been found to have significantly less conjunctival hyperemia (p less than 0.01) than either of two soft lens wearing groups (one using preserved storage solutions and the other using unpreserved storage solutions). Because both soft lens samples were found to have more hyperemia, it is concluded that factors other than storage solution preservative contribute to increase conjunctival hyperemia in soft lens wearers. However, the preserved storage soft lens wearers had significantly more hyperemia than the unpreserved storage solution group (p less than 0.01). The conclusion is that, apart from acute and subacute responses, there may be a relatively benign chronic response to soft lens storage solution that is associated with minimal symptoms.     

A survey of contact lens wearers. Part I: Design and demographics

A mail survey of several hundred hard and soft contact lens wearers was conducted, focusing upon demographic characteristics of wearers, factors involved with purchasing, wearing and caring for lenses, and the attitudes, perceptions, and anxieties which wearers have about lenses. The results are presented in two papers. This paper focuses upon survey design and the demographics of the respondents. A number of differences were found between hard and soft lens wearers and between the regular and the occasional and former wearers. For example, occasional and former wearers in general were less likely to have other lens wearers in their family and were more likely than regular wearers to report purchase of lenses to improve their appearance or their vision. Some implications are discussed.     

Temporal evolution of the corneal curvature in contact lens wearers

In the present work, we have measured the corneal radii in a group of 126 healthy subjects, studying the temporal evolution of these radii after adaptation to contact lenses of polyhydroxyethyl methacrylate with 55% hydration. We measured the horizontal and vertical radii before adaptation, as well as after 3, 6 and 9 months of wearing contact lenses. The decreases were not significant ( P < 0.05) in the corneal radii of these subjects; maximum decreases were reached the day after wearing contact lenses, with subsequent recuperation, such that at 9 months the decreases, though persisting, were minimal.