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Eyelash disorders
Updated: Dec 3, 2022
Summary
Conditions such as infection, inflammation, involutional changes, trauma or malignancy can result in eyelash dysfunction. Therefore, understanding of lid margin anatomy and the various eyelash disorders is essential for a robust clinical examination of the external eye.
Anatomy of the lid margin
From anterior to posterior:
Eyelashes
The grey line
The meibomian gland orifices
The mucocutaneous junction
Conjunctiva

Misdirected lashes
Trichiasis
Misdirection of the eyelashes toward the globe, from individual follicles. Often due to inflammation such as chronic blepharitis, but can also be secondary to trauma such as incision and curettage of a chalazion
Marginal entropion
There is not significant inversion of the eyelid, but the mucocutaneous junction advances anteriorally to the meibomian gland orifices, which results in the misdirection of the lashes
The posterior edge of the eyelid adjacent to the globe also loses its squared edges and becomes rounded
Typically involves numerous eyelashes
This condition may be perceived as a pathology of the lashes instead of its correct designation as eyelid malposition.
Distichiasis
Distichiasis is a congenital or acquired condition where eyelashes arise from the meibomian glands on the posterior lamella of the eyelid margin
Congenital: the germ cells destined to differentiate into a meibomian gland instead develop into a pilosebaceous unit. We see a second row of aberrant lashes emerging at, or slightly behind the meibomian gland orifices
Acquired: caused by metaplasia of the meibomian glands, into hair follicles. Important cause includes chemical injury, SJS, ocular cicatricial pemphigoid (all causes of intense conjunctival inflammation)
Management
Epilation with tweezers/forceps (recurrence is inevitable)
Electrolysis (requires local, can lead to scarring)
Laser ablation (lashes that are localised, as opposed to diffuse respond well to electrical ablation)
Tarsal facture for marginal ectropion
Cryotherapy (high rate of adverse effects!)

Eyelash ptosis
Downward angle of the eyelashes of the upper eyelid. Strongly associated with a condition known as floppy eyelid syndrome (a form of eyelid malposition).
💡 Eyelashes lack arrector pili muscles (the small muscles attached to most mammalian hair follicles which cause the hair to stand on end upon contraction). Eyelash position therefore depends upon support from surrounding structures. Therefore, anatomic changes to the upper eyelid are thought to be the cause of eyelash ptosis. In the case of floppy eyelid syndrome, Schlötzer-Schrehardt et al. has indicated that patients with this condition have less elastic fibre or elastin within the eyelid skin and tarsal plate compared to control subjects.
Trichomegaly
Eyelash trichomegaly is increased length (12 mm or more), curling, pigmentation or thickness of eyelashes.
Causes
Drug induced: topical prostaglandin analogues, phenytoin and ciclosporin
Other conditions: AIDS, porphyria, hypothyroidism
Congenital: Oliver–McFarlane syndrome, Cornelia de Lange syndrome
Madarosis
Madarosis is a clinical sign that refers to eyelash or eyebrow loss from any cause. This can be due to local causes (burns, radiotherapy, lid tumours), skin disorders, systemic disease (acquired syphilis, leprematous leprosy) or psychiatric (trichotillomania)

Poliosis
Localised whitening of hair (eyelashes and eyebrow). Important causes to learn for the Duke Elder Exam include:
Vitiligo
Tuberous sclerosis
Marfan syndrome
Waardenburg syndrome.

References
Salmon, John F., and Jack J. Kanski. Kanski’s Clinical Ophthalmology: A Systematic Approach. Ninth Edition, Elsevier, 2020.
Erdoğan, Mustafa, and Şeyda Karadeniz Uğurlu. ‘Marginal Entropion: A Frequently Overlooked Eyelid Malposition’. Turkish Journal of Ophthalmology, vol. 45, no. 5, Oct. 2015, pp. 203–07. PubMed Central, https://doi.org/10.4274/tjo.20591.
Scheie, H. G. & Albert, D. M. Distichiasis and trichiasis: origin and management. *Am. J. Ophthalmol.*61, 718–720 (1966)
Schlötzer-Schrehardt U, Stojkovic M, Hofmann-Rummelt C, Cursiefen C, Kruse FE, Holbach LM. The pathogenesis of floppy eyelid syndrome: involvement of matrix metalloproteinases in elastic fiber degradation Ophthalmology, 112 (4) (2005), pp. 694-704
Kaur, Sandeep, and Bharat Bhushan Mahajan. ‘Eyelash Trichomegaly’. Indian Journal of Dermatology, vol. 60, no. 4, 2015, pp. 378–80. PubMed Central, https://doi.org/10.4103/0019-5154.160484.
Sachdeva S, Prasher P. Madarosis: A dermatological marker. Indian J Dermatol Venereol Leprol. 2008;74(1):74–6
Rajak, Saul N., et al. ‘Trachomatous Trichiasis and Its Management in Endemic Countries’. Survey of Ophthalmology, vol. 57–341, no. 2, Mar. 2012, pp. 105–35. PubMed Central, https://doi.org/10.1016/j.survophthal.2011.08.002
Sung, Dongjin, et al. ‘Early Onset Sebaceous Carcinoma’. Diagnostic Pathology, vol. 6, no. 1, Sept. 2011, p. 81. BioMed Central, https://doi.org/10.1186/1746-1596-6-81
Lavezzo, Marcelo Mendes, et al. ‘Vogt-Koyanagi-Harada Disease: Review of a Rare Autoimmune Disease Targeting Antigens of Melanocytes’. Orphanet Journal of Rare Diseases, vol. 11, Mar. 2016, p. 29. PubMed Central, https://doi.org/10.1186/s13023-016-0412-4