Abnormalities of eyelashes of eye ?

Roots of the eyelashes lie against the anterior surface of the tarsal plate. The cilia pass between the most a part of the orbicularis oculi and its more superficial part, exiting the skin at the anterior lid margin and curving faraway from the world . 

it's particularly important to be conversant in the traditional anatomical appearance of the lid margin so as to be ready to identify the explanation for eyelash misdirection. From anterior to posterior,

• The grey line, by definition the border between the anterior and posterior (tarsal plate and conjunctiva) lamellae.

• The Meibomian gland orifices are located just anterior to the mucocutaneous junction. the sting of the tarsal plate is deep to the gland orifices; the glands themselves run vertically within the plate. • The mucocutaneous junction is where keratinized epithelium of the skin merges with conjunctival mucosa . • Conjunctiva lines the posterior margin of the lid.

 

Clinical features

 

Trauma to the corneal epithelium may cause punctate epithelial erosions, with ocular irritation often worsened by blinking.

Corneal ulceration and pannus formation may occur in severe cases. The clinical appearance varies with the cause.

 • Trichiasis refers to misdirection of growth from individual follicles, instead of a more extensive inversion of the lid or lid margin. 

The follicles are at anatomically normal sites. it's commonly thanks to inflammation like chronic blepharitis or herpes zoster ophthalmicus, but also can be caused by trauma, including surgery like incision and curettage of a chalazion. 

• Marginal entropion has increasingly been recognized as a really common explanation for eyelash misdirection, the mechanism of which is assumed to be subtle cicatricial posterior lamellar shortening that rotates a segment of the lid margin towards the attention . 

The mucocutaneous junction migrates anteriorly and therefore the posterior lid margin becomes rounded instead of physiologically square. Typically, numerous aligned lashes are involved. 

• Congenital distichiasis may be a rare condition that happens when a primary epithelial reproductive cell destined to differentiate into a Meibomian gland develops instead into an entire pilosebaceous unit.

 The condition is usually inherited in an autosomal dominant manner with high penetrance but variable expressivity. the bulk of patients also manifest primary lymphoedema of the legs (lymphoedema– distichiasis syndrome).

 A partial or complete second row of lashes is seen to emerge at or slightly behind the Meibomian gland orifices. The aberrant lashes tend to be thinner and shorter than normal cilia and are often directed posteriorly.

 they're usually well tolerated during infancy and should not become symptomatic until the age of about 5 years.

• Acquired distichiasis is caused by metaplasia of the Meibomian gland s into hair follicles such a variable number of lashes grow from meibomian gland openings.

The most important cause is intense conjunctival inflammation (e.g. chemical injury, Stevens–Johnson syndrome, ocular cicatricial pemphigoid). In contrast to congenital distichiasis, the cilia tend to be non-pigmented and stunted, and are usually symptomatic. • Entropion. In contrast to marginal entropion, profound inversion of a considerable width of the lid is quickly identified

Treatment

 

• Epilation with forceps is straightforward and effective but recurrence within a couple of weeks is actually invariable. 

It are often used as a temporizing measure or within the occasional patient who refuses or cannot tolerate surgery.

• Electrolysis or electrocautery (hyfrecation) are broadly similar electrosurgical techniques during which , under local anesthesia , a fine wire is passed down the follicle to ablate the lash.

 it's generally useful for a limited number of lashes; scarring can occur. Frequently multiple treatmentsare required to get a satisfactory result.

• Laser ablation is additionally useful for the treatment of limited aberrant eyelashes, and is performed employing a spot size of fifty μm, duration of 0.1–0.2 s and power of 800–1000 mW.

The base of the lash is targeted and shots are applied to make a crater that follows the axis of the follicle. Success is broadly like that achieved with electrosurgery.

• Surgery

 

○ Tarsal facture (transverse tarsotomy) is performed for marginal entropion. After placing a 4-0 traction suture, a horizontal incision is formed through the tarsal plate via the conjunctiva, a minimum of halfway down the plate, along the affected length of the lid and extended to 2–3 mm either side of the involved region. 

counting on the extent of lid involvement, either two or three double-armed absorbable sutures are skilled the upper fringe of the lower section of the tarsal plate to emerge just anterior to the lashes, leaving the lid margin very slightly everted. 

The sutures are left in situ following the surgery; occasionally short-term use of a bandage contact is required to stop corneal abrading. 

○ A full-thickness eyelid pentagon resection are often used for a focal group of aberrant lashes, typically after trauma, or for localized marginal entropion. 

○ lid splitting with follicle excision, and anterior lamellar rotation surgery.

 

• Cryotherapy

Cryotherapy applied externally to the skin just inferior to the bottom of the abnormal lashes or – especially in distichiasis – to the interior aspect of the anterior lamella of the lid following splitting of the margin at the grey line, are often used for varied lashes.

 A double freeze–thaw cycle at −20 °C is applied under local anesthesia (including adrenaline) with a plastic eye protector in place; suturing of the lid margin isn't usually necessary following limited splitting.

 the tactic is effective but carries a high rate of local adverse effects, and is a smaller amount commonly performed than previously.