Background
Distichiasis is a rare disorder defined as the abnormal growth of lashes from the orifices of the meibomian glands on the posterior lamella of the tarsal plate (see following image).
View Image | This picture demonstrates distichiasis of the lower lid. From Principles and Practice of Ophthalmology by Jakobiec. |
The term distichiasis is derived from "distrix," describing the splitting of the ends of hairs, originating from the Greek words dis (two) and thrix (hair).
Two types of distichiasis can be identified, acquired and congenital. In the acquired form, most cases involve the lower lids. Lashes can be fully formed or very fine, pigmented or nonpigmented, properly oriented or misdirected. The congenital form is often dominantly inherited with complete penetrance. It can be isolated or associated with ptosis, strabismus, congenital heart defect, or mandibulofacial dysostosis. This defect may be related to the epithelial germ cells failure to differentiate completely to meibomian glands, instead they become pilosebaceous units.
Pathophysiology
Distichiasis can affect the lower and upper lids (see following images). When these abnormal lashes come in contact with the cornea, they may cause severe irritation, epiphora, corneal abrasion, or even corneal ulcers.
View Image | This picture demonstrates distichiasis of the lower lid. From Principles and Practice of Ophthalmology by Jakobiec. |
View Image | This picture demonstrates distichiasis of the upper lid. From Ophthalmic Plastic Surgery: Prevention and Management of Complications by Dortzbach. |
Epidemiology
Frequency
United States
Distichiasis is a rare disorder.
Race
Distichiasis has been seen in all ethnic backgrounds.
Sex
This condition shows no sex discrimination.
Age
Distichiasis has been seen in all ages.
Prognosis
Fine lashes are usually well tolerated, but thicker eyelashes can threaten the integrity of the corneal epithelium.
History
Individuals with congenital distichiasis may have a family history. Distichiasis-lymphedema syndrome, an autosomal-dominant condition, results from mutations in FOXC2, a member of the forkhead/winged family of transcription factors. Other related findings may include congenital heart disease, webbing of the neck, and extradural spinal cysts.[1]
Individuals with acquired distichiasis may have a past history of chronic inflammation of the eyelids, including Stevens-Johnson syndrome, ocular cicatricial pemphigoid (OCP), trauma, chemical burns, and previous surgery.
Physical
Abnormal lashes from the meibomian gland orifices are noted on slit lamp examination.
The corneal epithelium should be evaluated at the slit lamp after instillation of fluorescein for any defects or abnormalities.
Causes
The congenital form of distichiasis is autosomal dominant with complete penetrance.[2, 3] The metaplasia of meibomian glands and abnormal growth of lashes from these glands, secondary to severe chemical burn, Stevens-Johnson syndrome, OCP, or chronic blepharoconjunctivitis, can cause acquired distichiasis.
Complications
In some cases, differentiation of acquired distichiasis from trichiasis may be difficult. In trichiasis, the lashes grow from the anterior lamella, not from the meibomian orifices (see following image). After lid reconstruction, this distinction may not be possible, especially if a skin graft was used.
View Image | This picture demonstrates distichiasis of the lower lid. From Principles and Practice of Ophthalmology by Jakobiec. |
Entropion may be confused with distichiasis. The lids must be held in their proper position to evaluate the lashes. Careful examination of the lid anatomy and the lid position prevents the misdiagnosis.
Epiblepharon is a condition that is mostly present in children. In this condition, the lashes are not truly misdirected, but pushed by the fold of pretarsal skin against the globe.
Lid scar, chronic blepharoconjunctivitis, and cicatricial conjunctivitis are other conditions that can be confused with distichiasis.
Complications of surgical interventions are hemorrhage, infection, wound dehiscence, lid margin deformities, entropion or ectropion, and regrowth.
Histologic Findings
Alkatan et al (2017) report that histopathologic findings of congenital distichiasis include perifollicular chronic inflammatory cell infiltration and abnormal pilosebaceous units within the posterior lamella of the eyelid.[4]
Medical Care
Lubricants and bandage contact lenses can be used temporarily to relieve symptoms. Definitive treatment is removal of the abnormal eyelashes. Mechanical epilation of lashes has been used, but the eyelashes regrow within 4-6 weeks.
Surgical Care
Multiple procedures have been described for treating distichiasis, to include the following: combination of lid splitting and cryotherapy, direct surgical excision by wedge resection, or tarsoconjunctival approach. Moosavi described a simple procedure that could be used to treat severe trichiasis.[5] In this procedure, the anterior lamella is removed, and the eyelid is allowed to heal by the laissez-faire technique.[5]
Complications of surgical interventions are hemorrhage, infection, wound dehiscence, lid margin deformities, entropion or ectropion, and regrowth. Adequate electrocautery, especially for marginal arcade vessel, can reduce the chance of hemorrhage.
Performing the procedure in a sterile environment should reduce the chance of infection, and the ability to close the defect can be reduced with a lateral superior or inferior cantholysis with or without Tenzel semicircular flap.
The permanent treatments of distichiasis include the following:
Electrolysis
This method is ideal for cases with few aberrant eyelashes. Topical with local anesthesia or general anesthesia may be used according to the age of the patient.
A fine 30-gauge electrode is used to deliver low current to each hair follicle. Visualization of the hair shaft is crucial.
Other recommended techniques involve use of the operating microscope, use of surgical loops, and use of the slit lamp.
If the treatment is adequate, the eyelashes should be easily wiped with a cotton swab or epilated with a forceps. Recurrent rate with this method is high.
Eyelid notching and focal madarosis can be seen with aggressive treatment.
Cryotherapy
This method results in a more permanent treatment of misdirected eyelashes. Since treatment is not very localized, the area of aberrant cilia should be at least slightly larger than the beveled-tipped cryoprobe.
Permanent destruction of follicles can be achieved with freezing the follicles to the temperature of –20°C. A thermocouple, if is available, should be used (see following image). The tip should be placed directly on the anterior tarsal surface for distichiasis.
View Image | This picture demonstrates the cryotherapy of the lower lid with distichiasis. From Ophthalmic Plastic Surgery: Prevention and Management of Complicati.... |
Protect the globe by placing a shield and lubricants. The lid also should be held away from the globe.
Nitrous oxide or carbon dioxide has been used as a cryogen. Effective cryosurgical treatment requires a double application of the probe and slow thaw. Complications of this procedure include depigmentation of the skin, eyelid notching, madarosis, severe postoperative pain, edema, symblepharon, necrosis, and regrowth. Cryotherapy, especially with the double freeze-thaw technique, may have a success rate of 95%.
Argon laser ablation
This procedure is not widely used, and it is only useful for few aberrant cilia.
The patient receives topical, local, or no anesthesia, and sits at the slit lamp that is equipped with an argon laser. The laser settings are as follows: power of 1000-1500 mW; spot size of 50-100 µm; and duration of 0.1-0.2 s.
The lid margin is rotated outward, and the laser is aimed at the hair shaft. A total of 12-30 shots are needed per lash.
The complications of this procedure are very similar to complications of electrolysis. Recurrence rate for electrolysis and argon laser ablation vary from 12-41%.
Diode laser
The 810 nm diode laser has been used to treat abnormal lashes. This laser has also been shown to be safe in the periorbital region. The pulse length used is approximately 50 ms, and the energy intensity is approximately 50 J/cm2.
For best results, 4-5 treatments are needed 4-6 weeks apart.
An efficacy study on diode laser treatment of trichiasis has been conducted, and, according to this study, diode laser treatment is an effective tool in treating trichiasis.[6]
Trephination
McCracken and Kikkawa described a new technique, in which they use a Sisler ophthalmic microtrephine 1.0 mm to cut the lash follicles.[7]
This technique seems to be safe and much faster than other surgical procedures for the treatment of trichiasis or distichiasis, with less complication and scarring.[7]
Consultations
Some comprehensive ophthalmologists are capable of taking care of simple cases of distichiasis. However, most patients with this disorder should be referred to an ophthalmic plastics and reconstructive surgeon.
Medication Summary
Ophthalmic lubricants without preservatives can be used in the eyes 3-4 times a day to protect the cornea in cases in which evidence of corneal epithelial damage is seen. Surgical intervention in these cases is eminent and the lubricants only help for a short period of time.
Author
Jitander Dudee, MD, MA(Cantab), FACS, FRCOphth, Ophthalmologist, Medical Vision Institute, PSC
Disclosure: Nothing to disclose.
Specialty Editors
Simon K Law, MD, PharmD, Clinical Professor of Health Sciences, Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, David Geffen School of Medicine
Disclosure: Nothing to disclose.
Chief Editor
Hampton Roy, Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Disclosure: Nothing to disclose.
Additional Contributors
Soheila Rostami, MD, FAACC, Director, Rostami Ophthalmic Plastic Consultants
Disclosure: Serve(d) as a speaker or a member of a speakers bureau for: Eclipse, Galderma, Mertz.
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