Purpose: Lectins play an important role in many biological processes. The aim of this work was to analyse mainly the expression of endogenic lectins, such as galectins and plant lectin, e.g. Dolichos biflorus agglutinin (DBA), and their glycoligands in the tear fluid, human corneal and conjunctival epithelium in physiological and disease conditions. Further, we studied the human natural antibody against Galα1,3Gal-R, which is mainly responsible for hyperacute rejection of xenografts transplants. We tried to investigate its localization in human corneal epithelium, lacrimal gland and tears. Material and Methods: Human tissue (lacrimal gland, tear fluid, conjunctiva, cornea, epidermis, keratinocyte and cultured corneal epithelium), as well as porcine tissue (cornea, liver and epidermis) were examined. Endogenous galectins (galectins-1, -3 and -7) were detected using immunohistochemistry methods. Binding sites for galectins, as well as binding sites for plant lectin Dolichos biflorus agglutinin, were localized by lectin histochemistry. Reverse lectin histochemistry was used for the study of binding reactivity of endogenous lectins using labelled (neo)glycoligands. Employing biotinylated natural human IgG anti -galactosides, as well as anti -galactosides, we detected reactive epitopes in human...

Human tear film is an accessible biospecimen rich with useful biological information. As tear protein biomarkers for both ocular and systemic diseases have been identified in tears, efforts are being made to create point-of-care tests useful for clinical diagnoses. However, there are significant obstacles to tear diagnostics, including inadequate sampling methods and biomarkers with insufficient sensitivity and specificity. Furthermore, tear film diagnostics are particularly challenging for dry eye disease (DED) patients, where low tear volume makes sampling more difficult and the multifactorial nature of DED makes identifying the exact pathological subtype very complex. As soft contact lenses (SCLs) are designed for optimal ocular surface interaction and concentrate proteins on the eye regardless of tear volume, we hypothesized that we could improve tear sampling methods for research and diagnostic purposes. We further hypothesized that we could identify new and existing and DED biomarkers using SCL tear film sampling. To begin, we demonstrate SCL sampling in vitro and then compare SCLs to other current tear sampling methods in vivo. Objectively, we observe that SCLs do not show signs of ocular surface irritation, regardless of previous SCL use. We also see that SCLs sample similar types and amounts of proteins relative to other methods. Subjective assessments of tear sampling methods are also made by subjects. Our results indicate that training and experience in tear sampling are key components which may significantly impact subject experience as well as the tear type collected. Next, we optimized our tear sampling method by comparing different SCLs materials in search of an ideal lens. Our data show that certain combinations of SCL materials and mass spectrometry (MS) sample preparation methods can lead to significant polymer contamination in MS. Furthermore, we observe individual protein binding specificity based on SCL chemistry. Our experiments reveal etafilcon A and verofilcon A lenses as the optimal SCL materials for tear film sampling. Finally, a pilot study in DED candidates using SCL sampling confirms the presence of previously reported biomarkers in DED subjects as well as identifies new biomarkers for future validation studies. We also correlate clinical metrics to biochemical findings and identify correlations between tear film homeostasis and pathologic phenotypes. Ultimately, these studies demonstrate SCL sampling is an advantageous alternative to current tear film sampling methods, useful for biomarker discovery, and potentially, clinical diagnostics.

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When a biomaterial is inserted into the body, the interaction of the surface with the surrounding biological environment is crucial. Given the importance of the surface, the ability to alter the surface properties to support a compatible environment is therefore desirable. Silicone hydrogel contact lenses (CL) allow for improved oxygen permeability through the incorporation of siloxane functional groups. These groups however are extremely surface active and upon rotation, can impart hydrophobicity to the lens surface, decreasing lens wettability and increasing protein and lipid deposition. Lens biofouling may be problematic and therefore surface modification of these materials to increase compatibility is exceedingly recognized for importance in both industry and research. The current work focuses on the creation of a novel anti-fouling polymer surface by the incorporation of 2-methacryoyloxyethyl phosphorylcholine (MPC), well known for its biomimetic and anti-fouling properties. A controlled polymerization method was used to generate a unique double-grafted architecture to explore the effect of increasing surface density of polyMPC chains on corresponding anti-fouling properties. The novel free polymer was synthesized by a 3-step atom transfer radical polymerization (ATRP). First, poly(2-hydroxyethyl methacrylate) (polyHEMA) was polymerized by ATRP, where the hydroxyl (OH) groups of the polymer then underwent an esterification to create macroinitiating sites. From these sites, a second ATRP of poly(MPC) varying in length occurred, yielding the double-grafted polymer poly(2(2-bromoisobutyryloxy-ethyl methacrylate)-graft-poly(2-methacryloyloxyethyl phosphorylcholine (pBIBEM-g-pMPC). The polymer was designed for resistance to protein adsorption through a possible synergistic effect between the surface induced hydration layer by surrounding PC groups coupled with steric repulsion of the densely grafted chains. To test its potential as a surface modifier, the polymer was grafted from model silicone hydrogel CL through a 4-step surface initiated ATRP (SI-ATRP) in a similar manner to the free polymer. First, the ATRP initiator was immobilized from the HEMA OH groups of the unmodified CL, generating Intermedate-1. A polyHEMA brush was grafted from the initiating sites yielding pHEMA-50, followed by the generation of a second initiator layer (Intermediate- 2). A sequential ATRP of poly(MPC) then generated the target pMPC-50/pMPC-100 surfaces. For the free pBIBEM-g-pMPC polymer analysis, 1H-NMR and GPC determined polymers formed with a predictable MW and low polydispersity (PDI). For surface grafting, using a sacrificial initiator, 1H-NMR and GPC indicated that the pHEMA-50 and pMPC-50/pMPC-100 polymers were well-controlled, with a MW close to the theoretical and a low PDI. For surface chemical composition, ATR-FTIR showed the presence of the ATRP initiator (Intermediate-1 and 2) by the appearance of a C-Br peak and disappearance of the OH peak. XPS confirmed the chemical composition of the 4-step synthesis by a change in the fraction of expected surface elements. Both the surface wettability and EWC of the materials increased upon pMPC modification, further improving upon increasing pMPC chain length. The contact angle was as low as 16.04 ± 2.37º for pMPC-50 surfaces and complete wetting for pMPC-100. Finally, the single protein adsorption using lysozyme and bovine serum albumin (BSA) showed significantly decreased protein levels for pMPC-50/100 lenses, as much as 83% (p 0.00036) for lysozyme and 73% (p 0.0076) for BSA, with no significant difference upon chain length variation. The aforementioned data demonstrates that the novel polymer has potential in providing an anti-fouling and extremely wettable surface, specifically regarding silicone hydrogel CL surfaces. / Thesis / Master of Applied Science (MASc)

Thesis (MPH.) -- University of Limpopo, 2021 / Dry eye disease (DED) is defined as a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is accompanied by increased osmolality of the tear film and inflammation of the ocular surface. DED is one of the most frequently established diagnoses in ophthalmology and represents a growing public health concern, with consequences that remain widely underestimated. There is variability of clinical manifestations and diagnostic criteria which leads to poor correlation between clinical signs and symptoms, therefore resulting in difficulties to assess prevalence of DED despite an improved understanding of pathogenic factors of acquired DED. However, its prevalence has been reported to range from 74% to 33% worldwide and the current study aimed to investigate the prevalence of DED and its determinants amongst people consulting at Focus Optometrists in Kwa-Mhlanga Township in Mpumalanga Province. Methodology: The current study was quantitative in nature and it followed a cross-sectional descriptive design to address the research question. The study population were people consulting at Focus Optometrists in Kwa-Mhlanga Township in Mpumalanga Province in which two standardized optometry diagnostic tests (Schimer test and the tear film break up time) were used for data collection coupled with a comprehensive case history which was taken for all participants. Data analysis was done using the STATA statistical software version 12 for Windows (STATA Corporation, College Station, Texas). Frequency tables were used to make comparisons between groups for continuous and categorical variables using student t-test, and chi-square test. P-value less than 0.05 at 95% confidence level were regarded as significant. Results: A total of 236 participants were recruited and the mean age of the participants was 39.7 in which majority of participants were females and there was a statistical significance difference in age groups of both males and females at p-value=0.011. Majority of the participants have reported to have experience of sensitivity to light vi and foreign body sensation sometimes. The poor vision and blurred vision have been reported by majority of participants sometimes and the prevalence of dry eye disease was found to be 80.9% and the risk of the dry eye disease in the current study was found significantly increasing with old age. Those who were older (35 years above) were 4.2 times more likely to develop dry eye disease at p-value <0.001 as compared to young participants. Female gender was found not to be protective of developing dry eye disease in the current and participants who were single, having secondary and education qualifications were more likely to develop dry eye disease. Participants with ocular conditions, systemic disease, surgery and those with high blood pressure were more likely to develop dry disease Conclusion: The prevalence of dry eye disease in the current study was found to be very high and therefore, patients coming to the clinic from the age of 40 with underlying systemic diseases should be screened for dry eyes. Dry eye disease can be a major contributor of refractive error in the visual systems and or can also be a sign or a symptom of hormonal or related ocular or systemic disease. More eye care awareness should be done at primary eye care level to detect the cause or to eliminate future associated symptoms.

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A relação trabalho e visão é tão remota que determinou a adaptação da espécie humana ao meio em que está inserida. Demonstrou-se que trabalhar em um ambiente confortável, sem doenças ocular, favorece o desempenho visual e aumenta a produtividade. Conhecer os efeitos do monitor de computador (VDT) sobre o sistema visual significa planejar melhor o ambiente de trabalho e a atividade laboral para se obter máximo conforto e produtividade. Este estudo teve como objetivo geral analisar as alterações do piscar, do filme lacrimal e da superfície ocular induzidas pelo uso de monitor de computador (VDT). Para sua realização efetivou-se um estudo transversal, descritivo, observacional, analítico, realizado na Volkswagen do Brasil, São José dos Pinhais (PR), tendo como amostra, a população de funcionários do setor administrativo que utiliza VDT, com idade acima de 18 anos, sem doenças da superfície ocular, sistema palpebral e lacrimal. O ambiente de trabalho foi caracterizado pela temperatura, grau de umidade, velocidade do ar e iluminamento. Preencheram os critérios de inclusão 108 funcionários (idade média 34,1±7,88 anos e tempo mínimo de utilização do VDT 6 horas/dia). Foram avaliados as sintomatologias, filmagem da face para mensuração do tempo entre piscadas na situação de conversação, exame do olho externo e biomicroscopia das pálpebras, conjuntiva e córnea, filmagem videoceratoscópica para determinar tempo de ruptura do filme lacrimal, avaliação da quantidade de lágrima do lago lacrimal pelo Zone-Quick Phenol Red Thread tear test, avaliação do epitélio corneano pelo teste da lissamina verde, filmagem da face dos sujeitos para mensuração do tempo entre piscadas em leitura de VDT. Ao final da jornada de trabalho, foram feitas a reavaliação do tempo de ruptura do filme lacrimal da quantidade de lágrima e a avaliação do epitélio corneano. Compararamse o tempo entre as piscadas em conversação e em uso de VDT e o tempo de ruptura do filme lacrimal, antes e ao final da jornada de trabalho. A comparação desses tempos classificou os sujeitos como expostos, com tempo médio de ruptura do filme lacrimal menor que o tempo médio entre piscadas e não expostos com tempo médio de ruptura do filme lacrimal maior que o tempo médio entre piscadas. Nas condições do estudo, em jornada de trabalho com tempo mínimo de 6 horas de uso de VDT, houve aumento da exposição da superfície ocular causada pelo aumento do tempo entre piscadas. O aumento da exposição da superfície ocular foi causado pela diminuição do tempo de ruptura do filme lacrimal constatado ao final da jornada de trabalho. O tempo entre piscadas na situação de leitura em VDT que foi significantemente maior que na situação de conversação. O tempo de ruptura do filme lacrimal, ao final da jornada de trabalho, foi significativamente menor que em seu início. A exposição ocular observada durante a jornada de trabalho com usuários de VDT, nas condições deste estudo, não causou alteração epitelial detectável ao teste da lissamina verde. Não houve alteração do volume lacrimal em olhos com exposição, antes da jornada de trabalho com VDT, nem houve alteração do volume lacrimal em olhos com exposição ocular, após a jornada de trabalho com VDT. / The relationship between work and vision is so remote that has determined the adaptation of human beings to the environment in which they are inserted. It has been demonstrated that working in a pleasant environment, without any ocular disease, has favored visual performance and increased productivity. Knowing the effects of video terminal display (VDT) on the visual system helps plan labor environments and labor activities more effectively so that optimal comfort and productivity are obtained. This transversal study, performed at Volkswagen do Brasil, São José dos Pinhais, PR, has the objective to investigate the influence of VDT labor activities on blinking, tear film and ocular surface, ocular exposure and amount of tear in the lacrimal lake. The population sample comprised VDT administrative department employees older than 18, without diseases on the ocular surface, tear film and blinking system. The evaluation of the working environment included measurements of temperature, humidity, air speed and lighting. One hundred and eight employees met the study criteria (mean age 34.1±7.88 and minimal VDT use time of 6 hours/day). Several evaluations were performed: the ocular surface symptomatology; the measurement of the blink time in conversation situations; the examination of the ocular surface and lacrimal film; a videokeratoscopy to establish the tear film break-up time; evaluation of the amount of tears of the lacrimal lake by means of the Zone-Quick Phenol Red Thread tear test; evaluation of the corneal epithelium by means of the lissamine green test; and determination of the blink time in VDT reading situations. At the end of the working period, the amount of tears and the corneal epithelium structure were re-evaluated. Comparisons between the blink time in conversation and VDT reading situations were performed before and at the end of the working day. The comparison data obtained classifies the subjects into two categories: exposed, with a tear film break-up time shorter than the mean time between blinks; and non-exposed, with tear film break-up time longer than the mean time between blinks. The findings obtained reveal that there was an increase in the ocular surface exposure caused by the increase in the time between blinks during the working period and increase of the ocular surface exposure caused by the decrease in the tear film break-up time determined at the end of the working day. The time between blinks at VDT reading situations was significantly longer than at conversation situations. The tear film break-up time at the end of the working day was significantly shorter than at the beginning. The ocular exposure during the VDT use has not caused epithelium alterations detectable at the lissamine green test. There were no alterations in the amount of tears in the eyes which underwent ocular exposure after VDT use situations.

The overarching theme of the thesis was to investigate the association between smart device use and computer vision syndrome. The initial study designed and developed the Open Field Tear film Analyser (OFTA) enabling a continuous, real-time assessment of the tear film and blink characteristics during smart device use. The monocular OFTA prototype was validated and showed good intra- and inter-observer repeatability relative to the Oculus Keratograph 5M and Bausch and Lomb one position keratometer. Subsequently, tear osmolarity following engagement with reading and gaming tasks on smart device and paper platforms was investigated. Discrete measures of osmolarity pre- and post-engagement with the tasks were obtained with the TearLab osmometer; osmolarity values differed between platforms when participants were engaged in a gaming task but no such difference was observed with the reading task. In addition, the influence of repeated measurements on tear osmolarity was also explored. To simulate the habitual binocular viewing conditions normally associated with smart device use, the binocular OFTA was developed. The device was used to assess the tear film and blink characteristics whilst engaging with reading and gaming tasks on smart device and paper platforms. The results revealed differences in blink characteristics and non-invasive tear break up time between the different platforms and tasks assessed. In addition, the thesis also reports on an investigation examining the real-time accommodative response to various targets displayed on smart devices using an open-field autorefractor with a Badal lens system adaptation. The results showed that accommodative latency, accommodative lag, mean velocity of accommodation, speed of disaccommodation and mean velocity of disaccommodation varied across the different platforms. Through the use of validated subjective questionnaires and smartphone apps, the relationship between duration of smartphone use and symptoms of dry eye were examined. The findings of this study demonstrated that longer duration of smartphone and personal computer use were associated with higher risk of dry eyes as indicated by subjective questionnaire outcomes.

Orientador: Cláudia Valéria Seullner Brandão / Resumo: O objetivo deste estudo foi comparar e avaliar a aplicação de célula tronco mesenquimal de tecido adiposo (CTM-TA) e plasma rico em plaquetas aquecido alogênico (PRP-AA) perilacrimal em cães com ceratoconjuntivite seca (CCS), bem como, se há diferença na resposta segundo o grau de gravidade da afecção. Foram analisados 20 cães com produção lacrimal <15mm/min e distribuídos aleatoriamente em dois grupos (n=10). O grupo 1 tratado com CTM-TA (5x106 e 3x106 células) (GCTM-TA) e com grupo 2 PRP-AA (0,7mL e 0,3mL) (GPRP-AA), ambos injetados perilacrimal nas glândulas lacrimal principal e da terceira pálpebra, respectivamente. Todos os olhos foram avaliados em quatro momentos (M0 M15, M30, M60 dias). As variáveis avaliadas foram: osmolaridade da lágrima; teste lacrimal de Schirmer (TLS); sensibilidade corneal; tempo de ruptura do filme lacrimal (TRFL); pressão intraocular; espessura corneal; e biopsia da conjuntiva bulbar, além das variáveis clínico-oftalmológicas. Houve melhora nos dois grupos a partir de M15 (p<0,05) na qualidade do filme lacrimal, avaliada por meio da osmolaridade e TRFL, sem diferença entre os grupos. A produção de lágrima aumentou, entretanto notou-se diferença significativa nos animais com CCS discreta no GPRP-AA a partir do M30, e nos cães com CCS grave no GCTM-TA a partir do M30 e no GPRP-AA a partir do M60. Verificou-se melhora dos sinais clínicos da inflamação em ambos os grupos. Aplicação única perilacrimal de CTM-TA e PRP aquecido alogênicos normaliza a ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of the study was to compare and evaluate the application of allogenic mesenchymal stem cell adipose tissue derived (MSCs-AD) and inativate platelet-rich plasma allogenic (PRP-IA), perilacrimal in dogs with keratoconjunctivitis sicca (KCS), and if there is difference in the response according to the degree of severity of the condition. Twenty dogs with lacrimal production <15mm/min randomly assigned to two groups were used. Group treated with MSCs-AD (5x106 and 3x106) (GMSCs-AD) and with PRP-IA (0.7ml and 0.3ml) (GPRP-IA), both intralacrimal in the main lacrimal glands and third eyelid, respectively. The eyes were evaluated in four moments after application (M0 M15, M30, M60). The variables evaluated were: tear osmolarity e; Schirmer's tear test (STT); sensitivity corneal; tear film break time (TBUT); intraocular pressure; corneal thickness; and biopsy of the bulbar conjunctiva, in addition to clinical-ophthalmologic variables. There was improvement in two groups at M15 (p <0.05) on tear film quality, assessed by osmolarity and TBUT, with there was no difference between groups. STT increased, however, statistical difference was only observed in animals with mild KCS in the GPRP-IA from the M30 and in the intense KCS at M30 in the G MSCs-AD and at M60 in the GPRP-IA. There was an improvement in the clinical signs of inflammation in both groups. The unique Intralacrimal application of MSCs-AD and PRP-IA normalizes tear film quality and improves clinical signs of inflamma... (Complete abstract click electronic access below) / Doutor