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.
Dry-Eye Disease
Ching-Yu Cheng, Tien Yin Wong in Ophthalmic Epidemiology, 2022
Signs of meibomian gland dysfunction (MGD) are present in 30–35% of Caucasian individuals (Viso et al., 2009, 2012, 2014; Hashemi et al., 2014) and in 33–50% of Asian individuals (Tian et al., 2009; Han et al., 2011; Siak et al., 2012; Arita et al., 2019), rising to 51.8–60.8% in the over-65 age group (Lin et al., 2003; Han et al., 2011; Siak et al., 2012). In an Iranian population-based study, the prevalence of MGD was 26.3% in an adult population (Hashemi et al., 2017), rising to 71.2% in the over-60s age group (Hashemi et al., 2021). It is recognized, however, that up to two-thirds of the disease may be asymptomatic (Viso et al., 2012) and that age-related lid and gland changes underpin high rates of asymptomatic disease in older adults. A systematic review of interethnic disparities in the natural history of DED suggested that meibomian gland changes were apparent earlier in life in South-East Asian compared with Caucasian eyes (Wang and Craig, 2019). In comparison with studies exploring signs and symptoms of dry eye, several studies have suggested a higher prevalence of MGD in males (up to 2.5×) compared with females (Arita et al., 2019; Hashemi et al., 2021).
Ocular Infections
Thomas T. Yoshikawa, Shobita Rajagopalan in Antibiotic Therapy for Geriatric Patients, 2005
Chronic bacterial conjunctivitis is typically seen in conjunction with one of two conditions: chronic blepharitis and chronic dacryocystitis. Chronic bacterial conjunctivitis associated with blepharitis is generally caused by S. aureus and Moraxella lacunata and results in prominent lid margin erythema, scaling, and thickening in addition to purulent discharge, which is usually minimal, and conjunctival injection. Lid margin ulcerations may also develop during acute exacerbations. Because of the associated blepharitis, these patients will undoubtedly have some degree of meibomian gland dysfunction resulting in a compromised tear film. The tear film abnormality may intensify the ocular irritation these patients experience, as well as predispose them to corneal epithelial breakdown.
Clinical Accuracy of an Advanced Corneal Topographer with Tear-Film Analysis in Functional and Structural Evaluation of Dry Eye Disease
Published in Seminars in Ophthalmology, 2020
Jihei Sara Lee, Ikhyun Jun, Eung Kweon Kim, Kyoung Yul Seo, Tae-Im Kim
In 2017, the Tear Film and Ocular Surface Dry Eye Workshop has defined the dry eye disease (DED) as “a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by ocular symptoms.”1 As evident in the convoluted definition, the disease is complex and remains incompletely understood. So far, an increase in tear osmolarity and subsequent instability in the tear film have been touted as the key concept in the pathogenesis.2 The meibomian gland dysfunction has also gained significant attention as a major cause of tear deficiency and evaporative dry eyes.2–4 Until now, slit-lamp examinations as well as clinical tests like Schirmer tests were employed, and they have somewhat allowed the evaluation of the disease in various aspects. The imaging of meibomian glands has evolved from the transillumination on an everted eyelid by Tapie in 1977 to infrared photography and enabled easy visualization.5 However, demands for devices that combine multiple modalities to parallel expanding knowledge about the disease remain high. Numerous analytical tools for DED have emerged in response; yet no single diagnostic device has assumed the role of gold standard mode of diagnosis.
Therapeutic potential of castor oil in managing blepharitis, meibomian gland dysfunction and dry eye
Published in Clinical and Experimental Optometry, 2021
Emma C Sandford, Alex Muntz, Jennifer P Craig
The broad therapeutic potential of castor oil is highlighted by the spectrum of ocular surface conditions under investigation and the severity of disease included in these studies. Conditions range from mild dry eye disease, blepharitis, and contact lens discomfort, to more severe, refractory meibomian gland dysfunction. Administered as a topical eye drop, castor oil has demonstrated beneficial effects on the tear film lipid layer, including increased thickness and altered composition, with a longer residence time than that of a conventional eye drop.71 Topical castor oil use has been associated with improved subjective symptoms, tear lipid layer interferometry grades, tear evaporation, fluorescein and rose Bengal staining scores, tear film break‐up time and meibomian gland orifice obstruction.68–71,104 A recent trial on the periocular application of castor oil as a treatment for blepharitis reported clinical improvements in lid margin quality and eyelash appearance, as well as patient symptoms.103
Pathophysiology of Meibomian Glands – An Overview
Published in Ocular Immunology and Inflammation, 2021
Jana Dietrich, Fabian Garreis, Friedrich Paulsen
Pathologic changes of the meibomian gland causing meibomian gland dysfunction increases with age and can present symptomatically or asymptomatically.52,53 Meibomian gland dysfunction can be further classified into three subtypes (i) hypersecretory or meibomian seborrhea, (ii) hyposecretory or meibomian sicca and (iii) obstructive.54 Histopathologic changes in the meibomian gland are present as cystic dilation of the acini and/or ducts, atrophy of acini, basement membrane thickening, granulation and lipogranulomatous inflammation.55 It is likely that obstruction of the ducts and/or orifices is the major mechanism responsible for the observed histopathologic changes, as this will cause stasis of the meibum within the duct system. This will lead to dilation of the meibomian acini and ducts, which causes pressure-induced atrophy of the acinar epithelium as well as hyposecretion of the meibum onto the ocular surface.11
Related Knowledge Centers
- Meibomian Gland
- Blepharitis
- Chalazion
- Lipase
- Fatty Acid
- Thygeson'S Superficial Punctate Keratopathy
- Dry Eye Syndrome
- Demodex Brevis
- Warm Compress
- Lifitegrast