Bacteriology of Ophthalmic Infections
K. Balamurugan, U. Prithika in Pocket Guide to Bacterial Infections, 2019
The infectious and inflammatory conditions of the lid margin, including the eyelash follicles and sebaceous and apocrine glands are generally described as blepharitis, the most encountered eye infection. It typically occurs bilaterally and exists as a recurrent chronic condition. Blepharitis is a multifactorial complex disease, which institutes several overlapping signs and symptoms (Jackson, 2008). Meibomian gland dysfunction, conjunctival redness, crusting, hyperkeratinization and redness of the eyelid, ocular itching, burning and irritation, dry or watery eyes, and photophobia are typical symptoms of blepharitis (McCulley and Shine, 2000; Favetta, 2015). Surplus colonization of lid-margin microbes, abnormal lid-margin secretion, or dysfunctional tear film will prompt the infection.
Vision Impairment and Its Management in Older Adults
K. Rao Poduri in Geriatric Rehabilitation, 2017
Disruption of the balance between proper tear production and tear drainage, can lead to dryness. Systemic and topical medication use is much higher in older adults and can cause deficient tear production. The CDC reported that greater than 76% of Americans 60 years or older used two or more prescription drugs and 37% used five or more between 2007 and 2008.21,22 Prescription drugs used more commonly by older adults including topical drops for glaucoma, antidepressants, diuretics, dopaminergic drugs for Parkinson’s disease, antimetabolites, frequently used in treating rheumatoid arthritis, as well as over-the-counter topical eye drops with preservatives, decongestants, antihistamines, and vitamins are linked with causing or exacerbating dry eye.23–25 Along with polypharmacy, the higher prevalence of autoimmune diseases (Sjogren’s syndrome and rheumatoid arthritis) and decreased corneal sensitivity contribute to decreased tear film, which in severe cases can have vision-threatening consequences. Lacrimal gland dysfunction from low levels of the androgens, including dehydroepiandrosterone sulfate (DHEAS), in some older men and more commonly in postmenopausal women leads to dry eye. Deficiency of estrogen, which stimulates meibomian glands, occurs in postmenopausal women and can contribute to dry eye.26–30
Eye Care
Akshaya Neil Arya in Preparing for International Health Experiences, 2017
Cultural and religious practices also come into play. A patient may present with classic symptoms of dry eye syndrome. The usual regimen of clinical tests may be less important than the observation on gross inspection of a significant application of home-made kohl (a dark composition of lead and admixture of other elements) on the lid margins. In addition to the mechanical blockage of the Meibomian gland orifices, this substance may have a significant negative impact on ocular health. The resolution of the issue must be undertaken with a very real sensitivity to the patient's cultural background and reasons for use of the kohl. Your local partners could tell you that its use ranges from cosmesis in adults to warding off ‘the evil eye’ in infants.
Impact of modulus of elasticity of silicone hydrogel contact lenses on meibomian glands morphology and function
Published in Clinical and Experimental Optometry, 2021
Asif Iqbal, Rinu Thomas, Rajeswari Mahadevan
The meibomian glands are specialised large sebaceous glands, located in the tarsal plate of eyelids, These glands secrete meibum which constitutes the oily (lipid) layer of the tear film and prevents excessive evaporation of the aqueous layer.1 Morphological and functional changes to these glands can result in meibomian gland dysfunction, which in turn alters lipid layer thickness and tear film stability.1 Meibomian gland dysfunction is one of the most common problems encountered in ophthalmic practice and is the leading cause of evaporative dry eye. It is characterised by a chronic and diffuse abnormality of the meibomian glands.2 Morphological and functional anomalies of meibomian glands are identified as potential markers for contact lens (CL) discomfort due to increase tear evaporation and altered tear lipid production.3
Homeostasis and Defense at the Surface of the Eye. The Conjunctival Microbiota
Published in Current Eye Research, 2021
Arnulfo Garza, Giancarlo Diaz, Marah Hamdan, Akaanksh Shetty, Bo-Young Hong, Jorge Cervantes
Meibomian glands are located on the rims of the eyes inside the tarsal plate and secrete meibum, the oily substance that prevents the evaporation of the eye’s tear film. Meibomian gland dysfunction (MGD) occurs when a chronic abnormality of the gland, characterized by terminal duct obstruction, or quantitative changes in the secretions are present. MGD can lead to evaporative dry eye and meibum abnormalities can increase the risk of ocular infections.43 Meibum composition could be influenced by the lipases and hydrolysis products secreted by bacteria, and could lead to decreased fluidity and increased viscosity, obstructing the ductal orifice and increasing bacterial growth. Bacterial abundance is, in fact, positively correlated with the severity of MGD.50 The phylum abundance of Firmicutes and Proteobacteria are significantly higher in patients with MGD compared to controls, while Actinobacteria is higher in the latter group.43 At the genus level, the abundance of Staphylococcus and Sphingomonas is significantly higher in MGD while Corynebacterium was significantly lower.43 There was a direct positive correlation between the degree of Meibomian gland loss and Staphylococcus abundance.43 The composition of these dysbiotic phenomena, and a direct correlation with the severity of MGD, could guide MGD treatment and operative management.
Evaluation of Meibomian Gland Loss and Ocular Surface Changes in Patients with Mild and Moderate-to-Severe Graves’ Ophthalmopathy
Published in Seminars in Ophthalmology, 2022
Büşra Yılmaz Tuğan, Berna Özkan
Meibomian glands located in tarsal plates of eyelids are modified, holocrine, sebaceous glands.10 Meibomian glands excrete lipid that forms the lipid layer of the tear film and reduces tear evaporation.11 Meibomian gland dysfunction (MGD) causes gland loss that leads to “evaporative dry eye disease” characterized by instability of the tear film lipid layer, increased evaporation of aqueous component, and increased osmolarity of the tear film.12,13 Recently, many factors have been reported to be responsible for MGD. Age-related changes like reduced acinar cell proliferation and atrophy of the gland are the major causes of MGD.14 Some of the other factors that have been reported are smoking, incomplete blinking, diabetes, and inflammatory diseases such as rosacea.15–19
Related Knowledge Centers
- Blepharitis
- Eye
- Eyelid
- Mass Spectrometry
- Meibomian Gland Dysfunction
- Lipid
- Sebaceous Gland
- Tarsus
- Tears
- Dry Eye Syndrome