Essential fatty acids for dry eye:a review

Purpose Dry eye is a common complaint often encountered in optometric practice. However, it is a difficult condition to treat as clinical signs do not always correlate with patient symptoms. Essential fatty acids (EFA), particularly omega-3 EFA, may be effective in dealing with the underlying causes. Methods A literature review was carried out on the PubMed, ScienceDirect and Ovid databases. Searches included keywords such as ‘dry eye’, ‘essential fatty acids’ and ‘nutrition’ to find articles relating to the treatment of dry eye syndrome (DES) with omega-3 EFAs. Results Omega-3 and -6 EFAs need to be consumed together within a reasonable ratio to be effective. Currently, typical diets in developed countries lack omega-3 EFA and this results in an overexposure to omega-6. Omega-3 supplementation has an anti-inflammatory effect, inhibiting creation of omega-6 prostaglandin precursors. Omega-3 EFAs also demonstrate anti-inflammatory action in the lacrimal gland preventing apoptosis of the secretory epithelial cells. Supplementation clears meibomitis, allowing a thinner, more elastic lipid layer to protect the tear film and cornea. Conclusion Dietary supplementation of omega-3 EFA has already proven to be effective in coronary heart disease and arthritis. Safety is not a concern as it works synergistically with omega-6 in the body. Evidence suggests that supplementation with omega-3 EFA may be beneficial in the treatment and prevention of DES.

Evaluation of dry eye

Dry eye is a common yet complex condition. Intrinsic and extrinsic factors can cause dysfunction of the lids, lacrimal glands, meibomian glands, ocular surface cells, or neural network. These problems would ultimately be expressed at the tear film-ocular surface interface. The manifestations of these problems are experienced as symptoms such as grittiness, discomfort, burning sensation, hyperemia, and secondary epiphora in some cases. Accurate investigation of dry eye is crucial to correct management of the condition. Techniques can be classed according to their investigation of tear production, tear stability, and surface damage (including histological tests). The application, validity, reliability, compatibility, protocols, and indications for these are important. The use of a diagnostic algorithm may lead to more accurate diagnosis and management. The lack of correlation between signs and symptoms seems to favor tear film osmolarity, an objective biomarker, as the best current clue to correct diagnosis.

Immunoblotting and tear sampling techniques for the study of contact lens-induced variations in tear protein profiles

More information on the biochemical interactions taking place between the tear film and the contact lens is required to further our understanding of the causative mechanisms behind the symptoms of dryness and grittiness often experienced by contact lens wearers. These symptoms can often lead to an intolerance to contact lens wear.

The ageing ocular surface:challenges for biomaterials design and function

Changing demographics and in particular an increasingly ageing population, in combination with improved longevity, will have a major impact on changing the face of human diseases and likewise the demand for appropriate biomaterials. The ocular surface is a multifaceted system that combines to create a unique mucosal surface, which includes the cornea, conjunctiva, sclera and lids of the eye. Physical parameters such as the eyelids and eyelashes, combined with the numerous secretory glands that produce the complex tear film, act together to protect and maintain the cornea. Unfortunately an ageing tear film and lacrimal functional unit can lead to impairment of this magnificently orchestrated structure. No single mechanism or modification is responsible but, whatever the cause, the consequence is a reduction in tear stability. An uncompromised tear film is fundamental to a healthy ocular surface. In the face of progressively changing demographics and consequent requirements for medical intervention and medical device developments, it is important to understand what effects the ageing process has on these anterior ocular structures.

Manifestações oculares em mulheres com síndrome dos ovários policísticos: prevalência e associação com fatores de risco metabólicos e inflamatórios

Objetivos: Estimar a prevalência de alterações do filme lacrimal e da doença do olho seco (DOS), comparar as mudanças na pressão intraocular (PIO) e comparar as espessuras macular e da camada de fibras nervosas da retina (CFNR), entre mulheres com síndrome dos ovários policísticos (SOP) e mulheres saudáveis, estratificando-as em condições clínicas, metabólicas e inflamatórias. Metodologia: O estudo incluiu 45 mulheres com SOP e 47 mulheres saudáveis ovulatórias submetidas a avaliações clínico-ginecológicas e oftalmológicas, incluindo propedêuticas para a avaliação do filme lacrimal e medida da PIO, e medição da espessura macular, da CFNR e parâmetros do disco óptico usando tomografia de coerência óptica. Resultados: Tempo de ruptura do filme lacrimal (TRFL; p=0.001) e impregnação por fluoresceína (p=0.006) apresentaram diferenças estatisticamente significantes entre os grupos estudados. A prevalência de DOS foi de 44,4% nas portadoras de SOP. Houve redução estatisticamente significativa do TRFL na presença de SOP (p=0.001). Além disso, houve efeito estatisticamente significativo de intolerância à glicose e síndrome metabólica/inflamação na impregnação por fluoresceina (p=0.004; p=0.015, respectivamente). A PIO encontrou-se estatisticamente mais elevada no grupo SOP que no grupo controle (p=0.011). Houve um aumento na média do IPC (índice pressão-córnea) com a associação entre SOP e da síndrome metabólica (p = 0.005); A média da espessura da CNFR superior ao redor do nervo óptico foi estatisticamente mais espessa nas voluntárias com SOP que nas voluntárias saudáveis (p=0.036); Após estratificação pela presença de resistência insulínica, as médias dos subcampos das espessuras maculares “macular interno temporal, macular interno inferior, macular interno nasal e macular externo nasal, foram mais espessas no grupo SOP que no grupo controle (p<0.05); Houve associação significativa entre obesidade e resistência insulínica (p=0.037), e intolerância à glicose (p=0.001), com aumento médio do componente principal 1 (CP1), e, na presença de síndrome metabólica (p<0.0001), com aumento médio do componente principal 2 (CP2), respectivamente, em relação à espessura macular total. Na presença de obesidade e inflamação, houve redução no escore médio da CP2 (p=0.034), em relação à espessura da CFNR na mácula. xviii Conclusões: Há uma associação da SOP, suas alterações metabólicas e inflamatórias com alterações do filme lacrimal e com mudanças na PIO. A diminuição na espessura da CFNR macular e aumento da espessura total macular estão possivelmente associadas às alterações metabólicas, e, o aumento na espessura da CFNR ao redor do nervo óptico estão provavelmente associadas às alterações hormonais, inerentes à SOP.

Gravidade do olho seco em pacientes internados em unidade de terapia intensiva: análise de conceito e construção de definições

Dry eye syndrome is a multifactorial disease of the tear film, resulting from the instability of the lacrimal functional unit that produces volume change, up or tear distribution. In patients in intensive care the cause is enhanced due to various risk factors, such as mechanical ventilation, sedation, lagophthalmos, low temperatures, among others. The study's purpose is to build an assessment tool of Dry Eye Severity in patients in intensive care units based on the systematization of nursing care and their classification systems. The aim of this study is to build an assessment tool of Dry Eye Severity in hospitalized patients in Care Unit Intensiva.Trata is a methodological study conducted in three stages, namely: context analysis, concept analysis, construction of operational definitions and magnitudes of nursing outcome. For the first step we used the methodological framework for Hinds, Chaves and Cypress (1992). For the second step we used the model of Walker and Avant and an integrative review Whitemore seconds, Knalf (2005). This step enabled the identification of the concept of attributes, background and consequent ground and the construction of the settings for the result of nursing severity of dry eye. For the construction of settings and operational magnitudes, it was used Psicometria proposed by Pasquali (1999). As a result of context analysis, visualized from the reflection that the matter should be discussed and that nursing needs to pay attention to the problem of eye injury, so minimizing strategies are created this event with a high prevalence. With the integrative review were located from the crosses 19 853 titles, selected 215, and from the abstracts 96 articles were read in full. From reading 10 were excluded culminating in the sample of 86 articles that were used to analyze the concept and construction of settings. Selected articles were found in greater numbers in the Scopus database (55.82%), performed in the United States (39.53%), and published mainly in the last five years (48.82). Regarding the concept of analysis were identified as antecedents: age, lagophthalmos, environmental factors, medication use, systemic diseases, mechanical ventilation and ophthalmic surgery. As attributes: TBUT <10s, Schimer I test <5 mm in Schimer II test <10mm, reduced osmolarity. As consequential: the ocular surface damage, ocular discomfort, visual instability. The settings were built and added indicators such as: decreased blink mechanism and eyestrain.

Síndrome de Sjögren Primário

A Síndrome de Sjögren (SS) é uma das três patologias autoimunes mais frequentes na população mundial, ainda assim frequentemente infradiagnosticada. Esta síndrome é uma doença autoimune crónica que afeta as glândulas exócrinas, particularmente as glândulas salivares e lacrimais. A SS primária (SSp) afeta especificamente as glândulas exócrinas, enquanto que a SS secundária (SSs) aparece associada a outras patologias autoimunes sistémicas. A SS é caracterizada, histopatologicamente, por um infiltrado inflamatório linfocitário que interfere com a função glandular normal. Afeta 0,5% da população mundial, sendo claramente mais predominante em mulheres (9:1 versus homens), principalmente por volta dos 50 anos (após a menopausa), ainda que também possa aparecer depois da menarca (entre os 20 e os 30 anos). Considera se que a etiologia da SS é multifatorial. Fatores genéticos, ambientais, hormonais e virais estão implicados na sua etiopatogénese. É muito importante o papel dos Médicos Dentistas no diagnóstico da SSp, uma vez que na maior parte dos casos são eles quem detetam os primeiros sintomas, mais propriamente a boca seca. Diversos testes auxiliares são utilizados para o diagnóstico desta doença, tais como: o teste de Schimer, o teste de Rosa Bengala, a Sialometria, a Sialografia, a Biópsia das glândulas salivares, entre outros. A SSp, regra geral, tem um curso não doloroso, sendo a boca seca e a secura ocular as suas duas características clínicas mais salientes. A maior parte das manifestações orais que se apresentam nestes pacientes são resultado de hipofunção das glândulas salivares (da boca seca), tais como: a cárie dentária, a doença periodontal, as infeções fúngicas, entre outras. Esta doença também se pode associar a problemas a nível sistémico, que podem ser subdivididos em não viscerais (pele, artralgia, mialgia) e viscerais (pulmão, coração, rim, sistema gastrointestinal, sistema endócrino e sistema nervoso central e periférico). O tratamento é empírico, sintomático e direcionado a tratar as complicações da doença mais inicial, que consiste em limitar os danos da xerostomia e da queratoconjuntivite. A prevenção dos sintomas a nível oral e ocular é fundamental em pacientes com SSp, para assim terem maior qualidade de vida.

Tear Secretion Induced by Selective Stimulation of Corneal and Conjunctival Sensory Nerve Fibers

Purpose. To measure the increase in tear secretion evoked by selective stimulation of the different populations of sensory receptors of the cornea and conjunctiva by using moderate and intense mechanical, chemical, and cold stimuli. Methods. Six healthy subjects participated in the study. Tear secretion was measured in both eyes by the Schirmer’s test conducted under control conditions and after stimulation of the center of the cornea and the temporal conjunctiva with a gas esthesiometer. Mechanical stimulation consisted in three pulses of 3 seconds’ duration of warmed air (at 34°C on the eye surface) applied at moderate (170 mL/min) and high (260 mL/min) flow rates. Cold thermal stimulation was made with cooled air that produced a corneal temperature drop of −1°C or −4.5°C. Chemical (acidic) stimulation was performed with a jet of gas containing a mixture of 80% CO2 in air. Results. The basal volume of tear secretion increased significantly (P < 0.05, paired t-test) after stimulation of the cornea with high-flow mechanical stimuli (260 mL/min), intense cooling pulses (−4.5°C), and chemical stimulation (80% CO2). The same stimuli were ineffective when applied to the conjunctiva. Moderate mechanical (170 mL/min) and cold (−1°C) stimulation of the cornea or the conjunctiva did not change significantly the volume of tear secretion. Conclusions. Reflex tear secretion caused by corneal stimulation seems to be chiefly due to activation of corneal polymodal nociceptors, whereas selective excitation of corneal mechanonociceptors or cold receptors appears to be less effective in evoking an augmented lacrimal secretion. Conjunctival receptors stimulated at equivalent levels do not evoke an increased tear secretion.

Factores preditivos de linfoma no síndrome de Sjögren : a propósito de um caso clínico

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014