Ocular surface as mucosal immune site
Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald in Principles of Mucosal Immunology, 2020
Dry eye affects up to 34% of all people globally and is one of the most frequent ocular surface problems, whose primary manifestation is a dysfunction of the tear film, resulting in a gritty feeling, dryness, irritation, and inflammation of the ocular surface. Dry eye can stem from a number of causes: from neurogenic, due to dysfunction of parasympathetic nerves that control tear production, through autoimmune damage to the tear gland, to infections that can cause physical blockage of tear ducts or inhibition of tear production by inflammatory mediators. The classification of dry eye diseases, established in a 1995 National Eye Institute/Industry workshop, provides a compartmentalized classification system for these syndromes (Figure 24.4), but in practice, combined disorders are common, and it is not always possible to determine a single cause for the disease. As an example, chronic irritation of the ocular surface due to evaporative dry eye can lead to secondary autoimmunization to autologous tissue components of the ocular surface and lacrimal gland components, shifting from “simple” dry eye to Sjögren's syndrome. As a therapy, lipids have garnered more attention recently due to their ability to increase tear stability and modulate excessive inflammatory responses. Specifically, studies are investigating ways to increase natural production of lipids or more effectively deliver synthetic lipids to the ocular surface.
Medical Negligence in Otorhinolaryngology
John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie in Basic Sciences Endocrine Surgery Rhinology, 2018
Great care must be taken over the amount of skin that is excised. Lagophthalmos, incomplete upper eyelid closure, is a normal occurrence in the first 48 hours after surgery. It usually resolves spontaneously but a large lagophthalmos (greater than approximately 3 mm), or if it persists, indicates overexcision of upper eyelid skin. If left untreated, dry eye symptoms and corneal exposure occur. The best treatment is replacement of the excised skin, providing that this has been stored in a refrigerator at the time of the operation, as this provides the best match. Ectropion is often due to excessive removal of skin but may be due to other causes such as scar contracture or a lax lid margin. Taping of the lower lid, and if necessary a support stitch, for a few weeks may resolve the problem but permanent ectropion will require skin grafting that will leave additional scars.
Sjögren's Disease
Jason Liebowitz, Philip Seo, David Hellmann, Michael Zeide in Clinical Innovation in Rheumatology, 2023
The current diagnostic approach requires a multidisciplinary evaluation in most patients. The ophthalmologist seeks evidence of aqueous-deficient dry eye disease, with an assessment of the tear meniscus, tear debris, corneal filaments, ocular surface staining with vital dyes, and measurement of tear flow (generally with Schirmer test strips) and, occasionally, tear osmolarity. An oral medicine specialist or dentist measures salivary flow and examines the oral cavity for signs of salivary hypofunction, including root and incisal caries (relatively unique to salivary hypofunction) and chronic erythematous candidiasis (51). A minor salivary gland biopsy (MSGB) provides the most direct evidence for glandular involvement by SjD, with the finding of focal lymphocytic sialadenitis of sufficient severity to have one or more focal lymphocytic aggregates per 4 mm2 of glandular tissue (focus score ≥1). Finally, the rheumatologist evaluates for systemic manifestations, including serologic abnormalities, and the presence of other autoimmune diseases. Each element of the diagnostic evaluation must be interpreted in the context of the others. None has absolute specificity for the diagnosis.
Potential role of ocular surface microbiota in keratoconus etiopathogenesis
Published in Expert Review of Ophthalmology, 2021
Uğur Tunç, Yusuf Yıldırım, Ali Rıza Cenk Çelebi, Burçin Kepez Yıldız
Dry eye is a common condition in which a person lacks quality tears to lubricate and nourish the eye. It causes symptoms such as stinging, burning, and watering and can seriously decrease one’s quality of life. Currently, the etiopathogenesis of dry eye disease has not been fully elucidated. Interesting results have been obtained in this regard in an ocular microbiota study in patients with dry eye. Staphylococcus epidermidis has been shown to decrease in patients with dry eyes; in addition, Klebsiella oxytoca bacteria, which is not found in the normal population, has been detected in these patients [25]. The alteration in the dominant bacterial population can cause the inflammatory process to begin on the ocular surface. The demonstration of increased TLR activity in the corneal epithelium of dry eye patients in a study supports this idea [69,70].
Introduction to Machine Learning for Ophthalmologists
Published in Seminars in Ophthalmology, 2019
Alejandra Consejo, Tomasz Melcer, Jos J. Rozema
Dry eye disease, one of the most common eye conditions, occurs when either the eye does not produce enough tears or when the tears evaporate too quickly. Despite the high prevalence of the condition, diagnostic methods are usually slit lamp- or questionnaire-based, often leading to an inconclusive diagnosis. Machine Learning techniques have shown their potential to standardize dry eye diagnostics. Classification of 55 infrared Meibomian gland images by means of image processing and linear SVM achieved specificity of 96% and sensitivity of 98% when differentiating between dry eye and healthy eyes.110 Another approach used 105 slit-lamp images to evaluate the thickness of the tear film’s lipid layer by means of image processing and various classifiers, of which SVM was the most accurate (81.90%).111,112
The effect of sinomenine eye drops on experimental dry eye in mice
Published in Cutaneous and Ocular Toxicology, 2020
Hui Li, Feng Wei, Shiwei Li, Liang Yan, Peirong Lu
Dry eye disease is a frequently chronic and progressive condition of the tear fluid and ocular surface affecting 11–17% in the general population and rates of up to 29% in clinical optometry practices depending on the diagnostic criteria applied, the age of the population studied and geographic location1–4. The symptoms of dry eye syndrome include discomfort, burning or foreign body sensation, irritation, itchy or painful eyes, visual disturbance and, in some cases, even to blindness. Dry eye syndrome is caused by insufficient tear production or increased evaporation of the tears, hyperosmolarity, and inflammatory damage5. Recent studies have shown that dry eye syndrome is an inflammatory disease with many features in common with autoimmune disease5–7. Chronic inflammation stimulated by the activation of innate immune in the ocular surface, instability of the tear film, and the hyperosmolar tears plays a key role in the immuno-pathogenic mechanism of dry eye1–3,8. Whatever the initial aetiology of dry eye, once it has developed, inflammation becomes the key mechanism of ocular surface damage3,8.
Related Knowledge Centers
- Contact Lens
- Eye
- Meibomian Gland Dysfunction
- Vitamin A Deficiency
- Antihypertensive Drug
- Pregnancy
- Dryness
- Tears
- Sjögren Syndrome
- Antihistamine