Video
- ■
5.1
Visit Expert Consult ( expertconsult.inkling.com ) for videos on topics discussed throughout the text.
Introduction
Trichiasis is said to exist when the eyelashes are misdirected against the eye . Trichiasis is often seen in practice. Patients complain of a foreign body sensation. Discharge or conjunctival injection is rarely present. Let’s preview what is discussed in this chapter.
The most common cause of trichiasis is a form of mild cicatricial entropion known as marginal entropion . Subtle cicatricial changes of the posterior lamella pull the eyelid margin inward, misdirecting the eyelashes. The concept that most instances of misdirected lashes result from mild posterior lamellar shortening is important.
Accidental trauma may tear the lid margin. Frequently the lacerations are not sharp, and the tissue is swollen at the time of repair. Poor healing or inadequate alignment may cause misdirection of the eyelashes. Surgical trauma , such as a wedge resection, can lead to misdirected lashes if the lid margin alignment is not exact.
Two congenital conditions cause the eyelashes to rub against the eye:
- ■
Epiblepharon
- ■
Distichiasis
Epiblepharon is an unusual condition in which an extra roll of eyelid skin pushes the eyelashes against the cornea. Epiblepharon is most commonly seen in Asian children. Distichiasis is a rare congenital condition in which an extra row of eyelashes arises from the meibomian gland orifices. Although both these conditions are unusual, it is worth the effort to learn about them.
An understanding of the anatomy of the lid margin is necessary to identify the specific cause of the trichiasis. This was discussed in Chapter 4 and is reviewed in this chapter. The history and physical examination identify the exact cause of the misdirected lashes and point to the appropriate treatment. Marginal entropion of the lower eyelid is usually treated with an incisional rotation of the posterior lamella. This procedure, the tarsal fracture operation , works well for redirecting the lower eyelashes. Individual or small numbers of misdirected lashes may be ablated using cryotherapy , hyfrecation (electrolysis) , or laser epilation . Larger segments of misdirected lashes are best excised using the pentagonal wedge resection followed by meticulous lid margin repair. The misdirected lashes of epiblepharon are reoriented by removing an ellipse of skin and muscle under the eyelashes. The extra row of eyelashes seen in distichiasis is removed by a lid-splitting operation with cryotherapy to destroy the abnormal lashes arising from within the posterior lamella but retain the normal eyelashes arising from within the anterior lamella ( Box 5.1 ).
- ■
Marginal entropion
- ■
Trauma
- ■
Epiblepharon
- ■
Distichiasis
The understanding of trichiasis has come a long way in the last 20 years. There has been a major shift away from destructive procedures , such as cryotherapy, toward reconstructive procedures that reorient the lashes or provide a continuous row of lashes on a newly reconstructed lid margin. Learning the concepts in this chapter is helpful in treating many patients. With the exception of the operations for epiblepharon and distichiasis, all the procedures discussed are useful on a routine basis.
Anatomic Considerations
The Normal Eyelid Margin
In Chapter 4 , we introduced the anatomy of the lid margin. You need to learn this anatomy well and pay close attention to anatomic details when evaluating a patient with misdirected lashes. The normal lid margin architecture is reviewed here before further discussion of trichiasis.
The lid margin is a thin, flat platform ending at right angles anteriorly and posteriorly ( Figure 5.1 ). The most posterior aspect of the normal lid margin is covered with conjunctiva. Anterior to this is the mucocutaneous junction . It is at this line that the mucosa of the palpebral conjunctiva stops and the keratinized skin of the eyelid margin begins. In Chapter 4 , I suggested that you look at several normal patients to see this junction. If you aren’t certain what this junction looks like, review it again when you examine one of your normal patients. If you can’t identify it, ask a colleague for help. It is important to be able to see these landmarks.
Just anterior to the mucocutaneous junction are the meibomian gland orifices extending out from the tarsal plate. Anterior to the meibomian gland orifices is the gray line (the most superficial extent of the orbicularis muscle, known as the muscle of Riolan). Anterior to the gray line is the anterior lamella, which includes the skin and muscle. The eyelashes arise anterior to the gray line, usually in one or two irregular rows in the lower lid and three or four irregular rows in the upper lid. Learn these anatomic landmarks during a slit lamp examination.
Anatomic Abnormalities Causing Misdirected Eyelashes
The causes of trichiasis are easy to understand on an anatomic basis:
- ■
Marginal entropion : Posterior lamellar shortening pulls the eyelashes posteriorly toward the eye ( Figure 5.2 ).
Figure 5.2
Marginal entropion. ( A and B ) Mild posterior lamellar shortening causes rounding of the lid margin and anterior migration of the mucocutaneous junction.
- ■
Traumatic misdirection of eyelashes : The position of eyelash follicles or surrounding tissues is physically altered, which causes the eyelashes to grow in an irregular manner, pointing in different directions and sometimes toward the eye ( Figure 5.3 ).
Figure 5.3
Traumatic misdirection of the eyelashes (aberrant eyelashes). ( A and B ) A laceration to the eyelid has created an irregular eyelid margin with eyelash loss. The soft tissue scarring causes a random orientation of the eyelashes.
- ■
Epiblepharon : A roll of extra skin pushes the normal eyelashes against the eye ( Figure 5.4 ).
Figure 5.4
Epiblepharon. ( A and B ) A redundant roll of skin pushes the eyelashes upward against the cornea in a parallel orientation.
- ■
Distichiasis : An incomplete row of eyelashes arises abnormally from the meibomian glands ( Figure 5.5 ).
Figure 5.5
Distichiasis. ( A ) An incomplete row of eyelashes arises from the meibomian gland orifices. ( B ) Close-up view showing eyelashes growing out of the meibomian gland orifices.
Many older textbooks define trichiasis as a condition in which the eyelashes are misdirected and the lid margin is in normal position . This definition stressed that the condition was an eyelash problem, not an abnormality of the eyelid. Eyelid malpositions such as involutional entropion and cicatricial entropion were not (and generally still are not) considered to be causes of trichiasis because the lid margin is obviously inverted ( Figure 5.6 ). Now that we have a greater appreciation of the lid margin architecture, we realize that many (probably most) cases of trichiasis are actually the result of subtle inversion of the lid margin, marginal entropion. From a semantic point of view, somewhere along the spectrum of severity, the trichiasis of marginal entropion becomes a cicatricial entropion. Figure 5.7 is an example of this. The definition of trichiasis is not as important as understanding the mechanics of the misdirected lashes. As you have seen, epiblepharon and distichiasis are usually included in the discussion of trichiasis because the lid margin is in a normal position. In this book, the terms misdirected eyelashes and trichiasis are used interchangeably.
- •
Review the anatomic landmarks of the eyelid margin. What are the four causes of misdirected eyelashes ( Boxes 5.1 and 5.2 )?
Box 5.2
Causes of Misdirected Lashes
- ■
Marginal entropion: Posterior lamellar shortening pulls the eyelashes posteriorly toward the eye.
- ■
Traumatic misdirection of eyelashes: The position of the eyelash follicles or surrounding tissues is physically altered, causing the eyelashes to grow in an irregular manner pointing in different directions, sometimes toward the eye.
- ■
Epiblepharon: A roll of extra skin pushes the normal eyelashes against the eye.
- ■
Distichiasis: An incomplete row of eyelashes arises abnormally from the meibomian glands.
- ■
You should understand the mechanics of each cause. Describe the changes in the anatomic landmarks of the lid margin for each cause.
- ■
Remember that the most common cause of trichiasis is marginal entropion.
- ■
History
Most adults with misdirected lashes complain of a foreign body sensation. Often, patients epilate the lashes themselves to eliminate the symptoms. Usually, patients can’t remember when the symptoms started or what caused the problem. Some patients may tell you that the problem started after trauma, an infection, or an operation.
With epiblepharon and distichiasis, the age of presentation varies, but is often not until age 4 or 5. Children usually don’t complain of irritation. More commonly, children rub the eye or have associated tearing and mild discharge. Photophobia suggests significant corneal irritation. I use the presence of symptoms of photophobia as a strong indication for treatment.
Physical Examination
The physical examination tells you the cause and extent of the trichiasis. Given this information, you can plan a treatment. The diagnosis is usually clear, but if the patient has recently had the lashes epilated, the cause or extent of the trichiasis may not be obvious. Ask the patient to return in about 2 weeks for a repeat examination. In the interim, the patient should not epilate any eyelashes. As the lashes grow back, they may be extremely irritating because they are short and stiff, so ask your patients to use lubricating ointment if necessary or to call you before doing any epilation. The problem can be determined when you see the abnormal lashes.
Marginal Entropion
I have told you that the most common cause of trichiasis is marginal entropion . Several lashes or a whole area of lashes is usually pointed against the cornea. Although the lashes are misdirected, they maintain their parallel orientation to one another. There is often corneal staining consistent with the eyelash position. Rarely, you see ulceration. The subtle inversion of the lid margin may go unnoticed without a careful examination of the lid margin anatomy. Start your examination on the most normal part of the lid margin and identify the normal landmarks. As you move toward the areas of trichiasis, the posterior lid margin loses its square edge and becomes rounded ( Figure 5.8A and B ). The rounding indicates that the lid margin is being pulled posteriorly. Go back to the normal part of the eyelid margin and look at the mucocutaneous junction. Follow this junction toward the involved lashes, noting the position of the junction related to the eyelashes. You see that the mucocutaneous junction has migrated anteriorly and is at or beyond the meibomian gland orifices. Anterior migration of the mucocutaneous junction indicates the diagnosis of marginal entropion (see Figure 5.8C to E ). As the lid margin moves into the tear lake, the normal relationship of the mucocutaneous junction to the meibomian glands changes. The conjunctiva migrates onto the wet part of the lid margin covered with tears. It may take some practice to see the mucocutaneous junction (use the position of the meibomian glands to help you if the mucocutaneous junction is normal). If you are having trouble with this concept, look at some more normal patients during a slit lamp examination.
Next look at the conjunctiva of the tarsal plate to see if there is any abnormality that would explain why the lid is being tugged inward. In most patients with marginal entropion, there is no obvious abnormality. Some inflammation consistent with blepharitis or meibomianitis may be present ( Figure 5.9 ). Occasionally, you see scar tissue where a chalazion has been excised. On occasion, you may see some obvious scar tissue without an identifiable cause ( Figure 5.10 ). Note the length of the involved lid margin so that you can plan the extent of the treatment required.
Traumatic Misdirection of the Eyelashes
If the lash problem occurs after trauma, there is usually an area of misdirected lashes associated with scarring of the lid margin. In these patients, the lashes are erratically positioned, pointing in different directions. In trauma patients, the misdirected lashes lose their parallel orientation to one another, a diagnostic feature differing from marginal entropion. Often there are lashes arising anteriorly from the skin away from the margin. Sometimes areas of lashes are missing (see Figure 5.3 ). During a slit lamp examination, you can imagine that the individual eyelash follicles have become disoriented, repositioned, or damaged as a result of the trauma. The irregular misdirection of these lashes appears different than that associated with marginal entropion in which the involved lashes are all misdirected in a similar manner, more or less parallel to one another (see Figure 5.3 ). The number of lashes and the length of the margin involved dictate the treatment. If the lid margin is discontinuous, surgical excision of the abnormal lashes and lid margin may improve the appearance and the trichiasis.
Epiblepharon
Epiblepharon is a relatively rare condition in which the eyelashes are pushed against the cornea by a roll of skin arising from the eyelid. The roll of skin is easy to see from the lateral view ( Figure 5.11 ; see also Figure 5.4 ). Epiblepharon most commonly involves the lower eyelid of Asian children. Often, half or more of the eyelid is involved. You may be surprised to see the number of lashes in contact with the eye. Sometimes 20 or more lashes are seen brushing across the cornea. Signs of corneal exposure are usually present but are less severe than you would predict by the number of lashes on the cornea. It has been said that children often outgrow this condition as adult facial features develop, but I don’t know if this is true. The treatment is an elliptical excision of the redundant skin and muscle.
Distichiasis
Distichiasis is a rare condition in which an extra row of lashes arises from the meibomian gland orifices (see Figure 5.5 ). When you first hear this word, you may think that it is dys-trichiasis. But don’t be confused. The word distichiasis is derived from the Greek words di and stichos , meaning “two rows.” As you probably recall, the meibomian glands are specialized sebaceous glands. Throughout the body, sebaceous glands are associated with hair follicles: the pilosebaceous apparatus. Presumably, in distichiasis, the meibomian glands have dedifferentiated, or retained, the associated hair. Often you see only a few lashes arising from the posterior lamella. In almost all patients, the row of lashes is incomplete. If the patient is symptomatic (photophobia is a good clue) and corneal exposure is present, treatment is recommended.
Treatment of Trichiasis
Goals of Treatment
The indications for treatment of any misdirected lash depend on the patient’s symptoms and the degree of corneal exposure present. Choose the appropriate treatment based on the cause of the misdirected lashes and the number of lashes involved. Epilation of lashes is a temporizing measure. In almost all patients, the lashes grow back within a month. As the lashes grow back, the irritation is often more severe when they are short and stiff. If you remove the lashes in anticipation of a more permanent procedure, try to perform it within 2 to 3 weeks.
In adults, the trichiasis is caused by either marginal entropion or trauma. Some patients have no history of trauma or physical findings suggesting the cause of the marginal entropion. Frequently, an unrecognized blepharitis is the cause. Regardless of the etiology, the principles of treatment discussed in this section can be applied to all patients even if the diagnosis does not fit neatly into one etiologic category.
The treatment of misdirected lashes has moved away from destructive procedures, such as cryotherapy, to more reconstructive procedures, which redirect or remove the abnormal lashes but at the same time preserve the normal lid margin and lashes. The goals of the treatment of misdirected lashes are to:
- ■
Reposition the misdirected lashes, if possible
- ■
Eliminate those lashes that cannot be repositioned
- ■
Create a continuous row of lashes on the lid margin
- ■
Reconstruct the lid margin if irregularities exist
The misdirected lashes seen in marginal entropion can be repositioned with the tarsal fracture operation.
Treatment of Marginal Entropion of the Lower Eyelid: The Tarsal Fracture Operation
The tarsal fracture operation returns the lid to a more normal position. Its use has dramatically changed my approach to the treatment of trichiasis and has almost eliminated cryotherapy from my practice. This operation has not found its way into the hands of most ophthalmologists. You should learn the tarsal fracture operation. A horizontal incision is made across the posterior surface of the tarsus. This incision allows the lid to bend or “fracture” anteriorly. Sutures are placed through the eyelid to hold the eyelid margin in an everted position.
The tarsal fracture operation includes:
- ■
Stabilizing the lid
- ■
Making a horizontal tarsal incision
- ■
Passing double-armed 6-0 Vicryl sutures
- ■
Tying the sutures to evert the margin
The steps of the tarsal fracture operation are:
- 1.
Prep the patient.
- A.
Instill topical anesthetic.
- B.
Inject local anesthetic with epinephrine under the skin and conjunctiva of the eyelid.
- A.
- 2.
Stabilize the lower eyelid.
- A.
Pass a 4-0 silk suture through the lid margin.
- B.
Evert the lid over a Jaeger lid speculum (shoehorn), a Desmarres retractor, or a wooden tongue blade.
- A.
- 3.
Make a horizontal tarsal incision.
- A.
Use a no. 15 blade to make a full-thickness horizontal incision through the tarsus about halfway down the tarsus. Extend the incision 2 to 3 mm medially and laterally beyond the area of entropion ( Figure 5.12A ). A Colorado needle works nicely for this also, but use a very light touch.
- A.
