Clinical Pathways in Neuro-ophthalmology : An ... - E-Lib FK UWKS

422 Clinical Pathways in Neuro-Ophthalmology, second edition
What Are the Neurogenic Causes of Lid
Retraction and Lid Lag?
Neurogenic eyelid retraction and lid lag may be due to supranuclear, nuclear, or
infranuclear lesions affecting the LPS or conditions that produce hyperactivity of the
sympathetically innervated Müller’s muscle (Miller, 1985). Preterm infants may have a
benign transient conjugate downward gaze deviation with eyelid retraction thought to
be due to immature myelination of vertical eye movement control pathways (Kleinman,
1994; Miller, 1985). Approximately 80% of normal infants of 14 to 18 weeks of age may
demonstrate bilateral transient lid retraction (‘‘eye-popping reflex’’) when ambient light
levels are suddenly reduced. Both of these phenomena are usually benign and typically
require no evaluation if transient and in isolation (class IV, level C).
Dorsal mesencephalic supranuclear lesions may result in eyelid retraction, which is
noted when the eyes are in the primary position of gaze or on looking upward (Collier’s
sign or posterior fossa stare). Unlike the retraction from thyroid orbitopathy (see below),
with midbrain lid retraction there is typically no retraction in downgaze. Patients with
dorsal mesencephalic lesions often have associated vertical gaze palsies and other
dorsal midbrain findings. The etiologies of the dorsal midbrain syndrome and the
workup of these patients are discussed in Chapter 14. Spells of lid retraction lasting 20
to 30 seconds that may be seen with impending tentorial brain herniation may be due to
a dorsal mesencephalic mechanism (Miller, 1985).
Lesions of the medial and=or principal portion of the nuclear complex of the posterior
commissure (NPC) are involved in lid–eye coordination and provide inhibitory modulation
of levator motor neuronal activity (Schmidtke, 1992). Clinical and experimental
evidence suggests an inhibitory premotor network in the periaqueductal gray (the
supraoculomotor area or supra III) that is dorsal to the third cranial nerve nucleus and
projects from the NPC to the central caudal subnucleus (Galetta, 1993a,b, 1996;
Schmidtke, 1992). Lesions in the region of NPC may produce excessive innervation to
the lids with lid retraction in primary position. Bilateral eyelid retraction and eyelid lag
with minimal impairment of vertical gaze has been described with a circumscribed
unilateral lesion immediately rostral and dorsal to the red nucleus involving the lateral
periaqueductal gray area in the region of the NPC (Galetta, 1993a,b, 1996). Eyelid lag
without retraction has also been described in pretectal disease, implying that these lid
signs may have separate neural mechanisms (Galetta, 1996). Vertical gaze paralysis
without eyelid retraction may occur. In these cases the fibers and nucleus of the
posterior commissure are spared and the lesions involve the rostral interstitial nucleus
of the medial longitudinal fasciculus (MLF), the interstitial nucleus of Cajal, and the
periaqueductal gray area (Schmidtke, 1992). Ipsilateral ptosis and contralateral superior
eyelid retraction may be due to a nuclear oculomotor nerve syndrome (plus-minus lid
syndrome) (Galetta, 1993b; Gaymard, 1992; Vertrugno, 1997). The plus-minus syndrome
results from a unilateral lesion of the third nerve fascicle with extension rostrally and
dorsally to involve the nucleus of the posterior commissure or its connections. The plusminus
syndrome has been described with glioma, third nerve palsy, orbital myositis,
myasthenia gravis, congenital ptosis, and orbital trauma (Vertrugno, 1997). Also, a
patient has been described with a nuclear third nerve palsy, sparing the caudal central
nucleus and its efferent fibers, who had no ipsilateral ptosis but had contralateral lid
retraction (Gaymard, 2000). The contralateral eyelid retraction was thought to be due to
damage to fibers from the NPC, most probably in the region of the supraoculomotor
area, and it is inferred from this case that inhibitory connections between the NPC and