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====Anterior blepharitis====
====Anterior blepharitis====
Anterior blepharitis is often associated with [[staphylococcal infection]] and [[seborrhoeic dermatitis]]. The exact [[pathogenesis]] of anterior blepharitis is not fully understood.  
Anterior blepharitis is often associated with [[staphylococcal infection]] and [[seborrhoeic dermatitis]]. The exact [[pathogenesis]] of anterior blepharitis is not fully understood.  
It is thought that blepharitis is caused by bacterial colonization (''[[Staphylococcus aureus]]'' or ''[[Staphylococcus epidermidis]]'') in the eyelids. Following bacterial colonization, bacterial lipase changes [[meibomian gland]] secretions and increasing cholesterol concentration. These changes may result in an environment that effect the [[ocular|ocular surface]] and tear evaporation. It is  thought that bacterial toxins and enzymes may also cause [[inflammation]].
It is thought that blepharitis is caused by bacterial colonization (''[[Staphylococcus aureus]]'' or ''[[Staphylococcus epidermidis]]'') in the eyelids. Following bacterial colonization, bacterial lipase changes [[meibomian gland]] secretions and increasing cholesterol concentration. These changes may result in an environment that effect the [[ocular|ocular surface]] and tear evaporation. It is  thought that anterior blepharitis may also caused by [[allergic response]] to bacterial [[antigens]] (mostly [[staphylococcal antigens]]).<ref name="pmid24055901">{{cite journal| author=Bunya VY, Brainard DH, Daniel E, Massaro-Giordano M, Nyberg W, Windsor EA et al.| title=Assessment of signs of anterior blepharitis using standardized color photographs. | journal=Cornea | year= 2013 | volume= 32 | issue= 11 | pages= 1475-82 | pmid=24055901 | doi=10.1097/ICO.0b013e3182a02e0e | pmc=3947496 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24055901  }} </ref><ref name="pmid3957566">{{cite journal| author=Dougherty JM, McCulley JP| title=Bacterial lipases and chronic blepharitis. | journal=Invest Ophthalmol Vis Sci | year= 1986 | volume= 27 | issue= 4 | pages= 486-91 | pmid=3957566 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3957566  }} </ref>
Additionally, anterior blepharitis may also caused by [[allergic response]] to bacterial [[antigens]] (mostly [[staphylococcal antigens]]).<ref name="pmid24055901">{{cite journal| author=Bunya VY, Brainard DH, Daniel E, Massaro-Giordano M, Nyberg W, Windsor EA et al.| title=Assessment of signs of anterior blepharitis using standardized color photographs. | journal=Cornea | year= 2013 | volume= 32 | issue= 11 | pages= 1475-82 | pmid=24055901 | doi=10.1097/ICO.0b013e3182a02e0e | pmc=3947496 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=24055901  }} </ref><ref name="pmid3957566">{{cite journal| author=Dougherty JM, McCulley JP| title=Bacterial lipases and chronic blepharitis. | journal=Invest Ophthalmol Vis Sci | year= 1986 | volume= 27 | issue= 4 | pages= 486-91 | pmid=3957566 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3957566  }} </ref>
====Posterior blepharitis====
====Posterior blepharitis====
The exact pathogenesis of posterior blepharitis is not fully understood. It is thought that the abnormal meibomian gland secretions may result in posterior blepharitis.
The exact pathogenesis of posterior blepharitis is not fully understood. It is thought that the abnormal meibomian gland secretions may result in posterior blepharitis.
Posterior blepharitis is often associated with skin conditions, such as [[rosacea]] or [[seborrhoeic dermatitis]]. These conditions are associated with [[sebaceous glands]] abnormalities.
Posterior blepharitis is often associated with skin conditions, such as [[rosacea]] or [[seborrhoeic dermatitis]]. These conditions are associated with [[sebaceous glands]] abnormalities.
It is thought that the abnormal meibomian gland secretions may cause a direct toxic effect on the [[ocular|ocular surface]]. Additionally, abnormal meibomian gland secretions may result in an environment that affect bacterial growth.<ref name=Blepharitis-1> American Academy of Ophthalmology/ eyewiki (2014) http://eyewiki.aao.org/EyeWiki%3AGeneral_disclaimer| Accessed on July 14, 2016 </ref>
It is thought that the abnormal meibomian gland secretions may cause a direct toxic effect on the [[ocular|ocular surface]]. It may also result in an environment that affect bacterial growth.<ref name=Blepharitis-1> American Academy of Ophthalmology/ eyewiki (2014) http://eyewiki.aao.org/EyeWiki%3AGeneral_disclaimer| Accessed on July 14, 2016 </ref>


Additionally, it is though that anterior and posterior blepharitis may cause by ''Demodex folliculorum''.''Demodex folliculorum'' is an external [[parasite]] in [[hair follicles]], [[sebaceous glands]], and [[meibomian glands]]. ''Demodex folliculorum'' may infest the meibomian and sebaceous glands. The exact pathogenesis of blepharitis caused by this parasite is not fully understood. It is thought that over-proliferation of ''Demodex folliculorum'' may lead to lid-margin infection and ocular discomfort, such as [[itching]], [[irritation]], and foreign-body sensation.<ref name="pmid25371637">{{cite journal| author=Bhandari V, Reddy JK| title=Blepharitis: always remember demodex. | journal=Middle East Afr J Ophthalmol | year= 2014 | volume= 21 | issue= 4 | pages= 317-20 | pmid=25371637 | doi=10.4103/0974-9233.142268 | pmc=4219223 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25371637  }} </ref><ref name="pmid15774912">{{cite journal| author=Viswalingam M, Rauz S, Morlet N, Dart JK| title=Blepharokeratoconjunctivitis in children: diagnosis and treatment. | journal=Br J Ophthalmol | year= 2005 | volume= 89 | issue= 4 | pages= 400-3 | pmid=15774912 | doi=10.1136/bjo.2004.052134 | pmc=1772603 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15774912  }} </ref>
Additionally, it is though that anterior and posterior blepharitis may caused by ''Demodex folliculorum''.''Demodex folliculorum'' is an external [[parasite]] in [[hair follicles]], [[sebaceous glands]], and [[meibomian glands]]. ''Demodex folliculorum'' may infest the meibomian and sebaceous glands. Therefore over-proliferation of ''Demodex folliculorum'' may lead to lid-margin infection and ocular discomfort, such as [[itching]], [[irritation]], and foreign-body sensation.<ref name="pmid25371637">{{cite journal| author=Bhandari V, Reddy JK| title=Blepharitis: always remember demodex. | journal=Middle East Afr J Ophthalmol | year= 2014 | volume= 21 | issue= 4 | pages= 317-20 | pmid=25371637 | doi=10.4103/0974-9233.142268 | pmc=4219223 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25371637  }} </ref><ref name="pmid15774912">{{cite journal| author=Viswalingam M, Rauz S, Morlet N, Dart JK| title=Blepharokeratoconjunctivitis in children: diagnosis and treatment. | journal=Br J Ophthalmol | year= 2005 | volume= 89 | issue= 4 | pages= 400-3 | pmid=15774912 | doi=10.1136/bjo.2004.052134 | pmc=1772603 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15774912  }} </ref>


===Associated Conditions===
===Associated Conditions===

Revision as of 00:53, 25 July 2016

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sara Mehrsefat, M.D. [2]

Overview

The exact pathogenesis of blepharitis is not fully understood. It is thought that blepharitis is caused by either bacterial colonization in the eyelids, or meibomian gland dysfunction. Blepharitis may also caused by allergens and lice that affect the eyelashes.[1][2]

Pathophysiology

Pathogenesis

Anterior blepharitis

Anterior blepharitis is often associated with staphylococcal infection and seborrhoeic dermatitis. The exact pathogenesis of anterior blepharitis is not fully understood. It is thought that blepharitis is caused by bacterial colonization (Staphylococcus aureus or Staphylococcus epidermidis) in the eyelids. Following bacterial colonization, bacterial lipase changes meibomian gland secretions and increasing cholesterol concentration. These changes may result in an environment that effect the ocular surface and tear evaporation. It is thought that anterior blepharitis may also caused by allergic response to bacterial antigens (mostly staphylococcal antigens).[1][2]

Posterior blepharitis

The exact pathogenesis of posterior blepharitis is not fully understood. It is thought that the abnormal meibomian gland secretions may result in posterior blepharitis. Posterior blepharitis is often associated with skin conditions, such as rosacea or seborrhoeic dermatitis. These conditions are associated with sebaceous glands abnormalities. It is thought that the abnormal meibomian gland secretions may cause a direct toxic effect on the ocular surface. It may also result in an environment that affect bacterial growth.[3]

Additionally, it is though that anterior and posterior blepharitis may caused by Demodex folliculorum.Demodex folliculorum is an external parasite in hair follicles, sebaceous glands, and meibomian glands. Demodex folliculorum may infest the meibomian and sebaceous glands. Therefore over-proliferation of Demodex folliculorum may lead to lid-margin infection and ocular discomfort, such as itching, irritation, and foreign-body sensation.[4][5]

Associated Conditions

Blepharitis is associated with systemic diseases or skin diseases, such as:[6][7]

Blepharitis is associated with ocular diseases, such as:[6][7][8]

Gross Pathology

On gross pathology, lid margin swelling, misdirection of lashes, loss of lashes, oily or greasy deposits on lid margins, crusting of anterior lid margin, lid margin hyperaemia, and conjunctival hyperaemia are characteristic findings of blepharitis.[9]

Microscopic Pathology

On microscopic histopathological analysis, hyperkeratinization of the meibomian gland ductal epithelium, mononuclear cellular infiltrates, and spongiosis in eyelids are characteristic findings of seborrheic blepharitis.[10]

On microscopic histopathological analysis, non granulomatous inflammation with neutrophils, acanthosis, or parakeratosis are characteristic findings of staphylococcal blepharitis.[11]

On microscopic histopathological analysis, chronic inflammatory changes, epithelial hyperplasia, and follicular plugging are characteristic findings of chronic blepharitis.[12]

Images

The following are gross images associated with blepharitis.

  • Blepharitis [13]

    Blepharitis [13]

  • Infant with blepharitis [14]

    Infant with blepharitis [14]

  • Demodex folliculorum[12]

    Demodex folliculorum[12]

  • Toothpaste-like opaque meibum (meibomian gland dysfunction)[15]

    Toothpaste-like opaque meibum (meibomian gland dysfunction)[15]


References

  1. ↑ 1.0 1.1 Bunya VY, Brainard DH, Daniel E, Massaro-Giordano M, Nyberg W, Windsor EA; et al. (2013). "Assessment of signs of anterior blepharitis using standardized color photographs". Cornea. 32 (11): 1475–82. doi:10.1097/ICO.0b013e3182a02e0e. PMC 3947496. PMID 24055901.
  2. ↑ 2.0 2.1 Dougherty JM, McCulley JP (1986). "Bacterial lipases and chronic blepharitis". Invest Ophthalmol Vis Sci. 27 (4): 486–91. PMID 3957566.
  3. ↑ American Academy of Ophthalmology/ eyewiki (2014) http://eyewiki.aao.org/EyeWiki%3AGeneral_disclaimer%7C Accessed on July 14, 2016
  4. ↑ Bhandari V, Reddy JK (2014). "Blepharitis: always remember demodex". Middle East Afr J Ophthalmol. 21 (4): 317–20. doi:10.4103/0974-9233.142268. PMC 4219223. PMID 25371637.
  5. ↑ Viswalingam M, Rauz S, Morlet N, Dart JK (2005). "Blepharokeratoconjunctivitis in children: diagnosis and treatment". Br J Ophthalmol. 89 (4): 400–3. doi:10.1136/bjo.2004.052134. PMC 1772603. PMID 15774912.
  6. ↑ 6.0 6.1 McCulley JP, Dougherty JM (1985). "Blepharitis associated with acne rosacea and seborrheic dermatitis". Int Ophthalmol Clin. 25 (1): 159–72. PMID 3156100.
  7. ↑ 7.0 7.1 Nemet AY, Vinker S, Kaiserman I (2011). "Associated morbidity of blepharitis". Ophthalmology. 118 (6): 1062–8. doi:10.1016/j.ophtha.2010.10.015. PMID 21276617.
  8. ↑ Diseases Database (2016). http://www.diseasesdatabase.com/relationship.asp?glngUserChoice=1455&bytRel=2&blnBW=0&strBB=RL&blnClassSort=255 Accessed on July 15, 2016
  9. ↑ Benitez-Del-Castillo JM (2012). "How to promote and preserve eyelid health". Clin Ophthalmol. 6: 1689–98. doi:10.2147/OPTH.S33133. PMC 3484726. PMID 23118519.
  10. ↑ THYGESON P, VAUGHAN DG (1954). "Seborrheic blepharitis". Trans Am Ophthalmol Soc. 52: 173–88. PMC 1312591. PMID 13274422.
  11. ↑ Seal D, Ficker L, Ramakrishnan M, Wright P (1990). "Role of staphylococcal toxin production in blepharitis". Ophthalmology. 97 (12): 1684–8. PMID 2087299.
  12. ↑ 12.0 12.1 Wesolowska M, Knysz B, Reich A, Blazejewska D, Czarnecki M, Gladysz A; et al. (2014). "Prevalence of Demodex spp. in eyelash follicles in different populations". Arch Med Sci. 10 (2): 319–24. doi:10.5114/aoms.2014.42585. PMC 4042053. PMID 24904668.
  13. ↑ Wikipedia (2016) https://en.wikipedia.org/wiki/Blepharitis#/media/File:Infant_with_blepharitis_on_the_right_side.jpg%7C Accessed on July 12, 2016
  14. ↑ Wikipedia (2016) https://en.wikipedia.org/wiki/Blepharitis#/media/File:Infant_with_blepharitis_on_the_right_side.jpg%7C Accessed on July 12, 2016
  15. ↑ Tomlinson A, Bron AJ, Korb DR, Amano S, Paugh JR, Pearce EI; et al. (2011). "The international workshop on meibomian gland dysfunction: report of the diagnosis subcommittee". Invest Ophthalmol Vis Sci. 52 (4): 2006–49. doi:10.1167/iovs.10-6997f. PMC 3072162. PMID 21450918.

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