Anatomy and Examination of the Eyelid
Eyelid closure (▶ Fig. 17.1, ▶ Fig. 17.2, ▶ Fig. 17.3) involves the orbicularis oculi muscle (innervated by branches of the facial nerve: cranial nerve [CN] VII).
Fig. 17.1 a, b (a) External appearance of the eyelid. (From Schuenke M, Schulte E, Schumacher U, Ross LM, Lamperti ED, Voll M. THIEME Atlas of Anatomy, Head and Neuroanatomy. Stuttgart, Germany: Thieme; 2007. Illustration by Markus Voll.) (b) Normal eyelids. In normal individuals, the upper lid covers the superior 1 to 2 mm of the iris, and the lower lid just reaches the inferior aspect of the iris.
Fig. 17.2 a, b (a, b) Anatomy of the eyelid showing the superficial (a) and deep (b) layers. (From Schuenke M, Schulte E, Schumacher U, Ross LM, Lamperti ED, Voll M. THIEME Atlas of Anatomy, Head and Neuroanatomy. Stuttgart, Germany: Thieme; 2007. Illustration by Karl Wesker.)
Fig. 17.3 a, b (a) Sagittal view through the eyelid. (From Schuenke M, Schulte E, Schumacher U, Ross LM, Lamperti ED, Voll M. THIEME Atlas of Anatomy, Head and Neuroanatomy. Stuttgart, Germany: Thieme; 2007. Illustration by Markus Voll.) (b) Sagittal view through the eyelid. (From Schuenke M, Schulte E, Schumacher U, Ross LM, Lamperti ED, Voll M. THIEME Atlas of Anatomy, Head and Neuroanatomy. Stuttgart, Germany: Thieme; 2007. Illustration by Karl Wesker.)
Eyelid opening involves the frontalis muscle (facial nerve), the levator palpebrae
(oculomotor nerve: CN III), the Müller muscle and inferior tarsal muscles (sympathetic innervation), and the aponeurosis of the levator muscle attached to the superior tarsal plate.
Eyelid position depends on the resting tone of the levator muscle, which varies with the patient’s state of arousal. Eyelid movements are coordinated with vertical eye movements: the eyelids move up and down with the eyes.
Examination of the eyelid includes evaluation of the position of the eyelids (looking for possible ptosis and retraction) and lid function, and inspection of the eyelid for any swelling or mass. It includes measurements of the palpebral fissure (9–12 mm), the margin reflex distance (4–5 mm), and the levator function, or the difference of position of the lid margin when the patient looks down, then up (> 12 mm) (▶ Fig. 17.4 and ▶ Fig. 17.5).
Fig. 17.4 Measurement of the palpebral fissure and margin reflex distance. The palpebral fissure is the distance between the upper and lower eyelid in vertical alignment with the center of the pupil (normal 9–12 mm). The margin (or marginal) reflex distance (normal 4–5 mm) can be measured for the upper and the lower eyelids:
— Marginal reflex distance-1 (MRD-1): distance between the center of the pupillary light reflex and the upper eyelid margin with the eye in primary gaze
— Marginal reflex distance-2 (MRD-2): distance between the center of the pupillary light reflex and the lower eyelid margin with the eye in primary gaze
Fig. 17.5 Measurement of levator function. The levator function is the distance the eyelid travels from downgaze to upgaze while the frontalis muscle is held inactive at the brow. A measurement of > 10 mm is considered excellent, whereas 0 to 5 mm is considered poor.
Palpation and inversion of the eyelids should be performed in all patients with ptosis.
When the eyelids are abnormal, the examiner should look for the presence of an orbital syndrome, diplopia with abnormal extraocular movements, and pupillary abnormalities, and should determine whether the findings are unilateral or bilateral.
17.2 Ptosis
Ptosis can be either congenital or acquired.
17.2.1 Congenital Ptosis
Congenital ptosis is present at birth or early childhood. It can be isolated or accompanied by an elevation deficit of the eye (elevator palsy). There is also incomplete lowering of the eyelid in downgaze, resulting in lid lag. The abnormal eyelid does not stretch well in downgaze (▶ Fig. 17.6) because there is congenital maldevelopment of the levator palpebrae or its tendon.
Fig. 17.6 Congenital right ptosis. Note that the right eyelid remains elevated when the patient looks down.
Causes of lid droop at birth include the following:
Congenital ptosis
Marcus Gunn jaw winking
Congenital fibrosis
Blepharophimosis syndrome (bilateral ptosis, telecanthus, epicanthus inversus)
Congenital (neonatal) myasthenia
Congenital third nerve palsy
Birth trauma (third nerve palsy, Horner syndrome)
Lid or orbital tumors (neurofibroma, hemangioma, dermoid)
Marcus Gunn jaw winking is a form of congenital ptosis associated with trigemino-oculomotor synkinesis (▶ Fig. 17.7)
Fig. 17.7 Left Marcus Gunn jaw-winking sign. Note the left ptosis, which improves with mouth opening.
Ptotic eyelid that retracts during contraction of the external pterygoid muscle (e.g., while sucking, opening the mouth, or moving the jaw)
Aberrant connection between the motor branches of the trigeminal nerve (CN V3) innervating the external pterygoid muscle and the fibers of the superior division of the oculomotor nerve (CN III) that innervate the levator superioris muscle of the upper eyelid (trigemino-oculomotor synkinesis)
17.2.2 Acquired Ptosis
Causes of acquired unilateral or bilateral ptosis include the following:
Mechanical ptosis
Aponeurotic defect (levator dehiscence)
Aging
Trauma, surgery (ocular with use of speculum, orbital)
Contact lens use
Dermatochalasis
Cicatricial
Eyelid or orbital tumor
Inflammation
Edema
Allergy
Chalazion
Blepharitis
Blepharochalasis
Myogenic ptosis
Chronic progressive external ophthalmoplegia (CPEO)
Myotonic dystrophy
Oculopharyngeal dystrophy
Chronic use of topical ocular steroid drops
Disorder of neuromuscular transmission
Myasthenia gravis
Botulism
Neurogenic ptosis
Horner syndrome (oculosympathetic paresis)
Third nerve palsy
Apraxia of lid opening
Mechanical Ptosis
Aponeurotic ptosis (▶ Fig. 17.8) is usually bilateral. The upper eyelid crease is high or indistinct, and levator function is relatively preserved.
Fig. 17.8 Aponeurotic defect from senile ptosis.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
