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Show Journal of Neuro- Ophthalmology 16( 2): 96- 98, 1996. > 1996 Lippincott- Raven Publishers, Philadelphia Eyelid Lag Without Eyelid Retraction in Pretectal Disease Steven L. Galetta, M. D., Eric C. Raps, M. D., Grant T. Liu, M. D., Naoyuki G. Saito, B. S., and Lanning B. Kline, M. D. We report a patient with pretectal eyelid lag without retraction. MRI showed high signal abnormality dorsal to the right red nucleus in a region thought responsible for premotor eyelid control. The dissociation of eyelid lag from eyelid retraction in this patient would suggest that these lid signs may have separate neural mechanisms or pathways. We propose that the lesion interrupts inhibitory connections between the vertical gaze center and the central caudal nucleus. Key Words: Lid lag- Lid retraction- Midbrain. Manuscript received January 12, 1995; accepted May 4, 1995. From the Departments of Neurology ( S. L. G., E. C. R., G. T. L., N. S.), University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, and Department of Ophthalmology ( L. B. K.), University of Alabama School of Medicine, Birmingham, Alabama, U. S. A. Address correspondence and reprint requests to Dr. Steven L. Galetta, Department of Neurology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, U. S. A. Pretectal eyelid retraction is usually not accompanied by eyelid lag ( 1,2). However, two patients were recently reported with both of these eyelid signs following circumscribed unilateral midbrain-thalamic infarction ( 3). Here we report a patient with a right upper midbrain lesion that produced eyelid lag without retraction. CASE REPORT A 25- year- old man was well until 7 years prior to evaluation when he developed acute vertigo and quadriparesis. Initial ocular motility examination showed a large right hypertropia and paralysis of vertical gaze. Catheter angiography demonstrated distal basilar occlusion. Over a several- week period, the patient recovered full motor function and resumed normal activities. However, slowing of vertical saccades persisted. Subsequent laboratory evaluation revealed a lupus anticoagulant, but IgM and IgG anti- phospholipid antibody levels were within normal limits. All serologic studies including thyroid function tests and serum potassium have been negative or normal. Examination revealed a blood pressure of 118/ 80. Mental status was normal. Visual acuity was 20/ 20 in both eyes. Visual fields were full to confrontation. Pupils were 4 mm and reacted slightly better to near stimuli than to light. Up- and downgaze were full but vertical saccades were slow. Pursuit movements were normal. In the primary position, lid retraction was not evident, but prominent eyelid lag was noted on downward gaze ( Fig. 1). Relaxation of the eyelids was nearly complete in prolonged downgaze, and the eyelid lag was not affected by manual compression of the frontalis muscle. The fundi were normal. The remainder of the cranial nerve examination was unremarkable. 96 EYELID LAG WITHOUT RETRACTION 97 FIG. 1. Normal eyelid position in primary gaze ( top) with obvious lid lag in downgaze ( middle). In prolonged downgaze, there is near complete relaxation of the lids ( bottom). Motor, sensory, coordination, and reflex examinations were also normal. Review of old photographs showed no prior lid retraction or change in lid fissure height after the infarction. Magnetic resonance imaging ( MRI) revealed high signal abnormality dorsal to the right red nucleus extending into the medial thalamus ( Fig. 2). No other abnormalities were observed. Magnetic resonance angiography of the posterior circulation was normal. The patient was placed on one tablet of aspirin twice a day. DISCUSSION Our patient had prominent eyelid lag in downgaze following a posterior midbrain thalamic infarction. Other abnormalities included slowing of vertical saccades and subtle pupillary light- near dissociation, both consistent with a pretectal localization. However, our patient's examination was remarkable for the absence of lid retraction in the primary position. Supranuclear lid lag without retraction is rare, but has been documented in extrapyramidal disorders such as progressive supranuclear palsy as well as other forms of parkinsonism ( 4). To our knowledge, eyelid lag without retraction has not been reported from a discrete midbrain lesion. Normally, eyelid relaxation occurs synchronously with downward eye movements ( 5). Pretectal lid retraction and lag indicate a disruption of the normal coordination that exists between the centers for vertical gaze and eyelid control. A recent review of clinical and experimental studies of lid retraction and lag concluded that lesions of the nucleus of the posterior commissure ( NPC) may be responsible for lid retraction of central origin ( 5). Presumably, the NPC or its connections have an inhibitory influence upon the central caudal nucleus. Thus, a lesion in the region of NPC may produce excessive innervation to the lids and, consequently, lid retraction in the primary position. Recently, two patients with pretectal eyelid retraction and lag were found on MRI to have a circumscribed unilateral lesion in the region of the NPC ( 3). The clinical and radiologic findings of these patients support the existence of a premotor neural network involved in the control of the lids. FIG. 2. T2 weighted magnetic resonance images showing high signal abnormality ( arrows) dorsal to right red nucleus ( top) and extending to medial thalamus ( bottom). / Neuro- Ophthalmol, Vol. 16, No. 2, 1996 98 S. L. GALETTA ET AL. FIG. 3. Proposed lesion producing isolated eyelid lag is shown interrupting connections between rostral interstitial nucleus of the medial longitudinal fasciculus ( riMLF) and central caudal nucleus ( CCN). The precise connections between riMLF and the nucleus of the posterior commissure ( NPC) remain ill- defined. The dissociation of eyelid lag from retraction observed in our patient and in some extrapyramidal disorders suggests that these lid signs may have separate neural mechanisms or pathways. In our patient, the normal lid position in straight- ahead gaze would imply that both the central caudal nucleus and the nucleus of the posterior commissure were relatively spared. Since discoordination of levator function only occurred on downgaze, we propose that our patient's resultant eyelid lag was caused by interrupted inhibitory projections from the riMLF to the central caudal nucleus ( Fig. 3). Although direct connections from the NPC to the levator motor neurons have not been reported, projections to the periaqueductal gray region known as the supraoculomotor area or supra III have been documented ( 5,6). Since supra III connects to dendritic projections of the levator motor neurons, the NPC may ultimately influence the central caudal nucleus by its projections through this intermediary region ( 5). However, the organization and effect of a lesion to this loosely defined region of supra III remains uncertain. Direct connections from the rostral interstitial nucleus of the medial longitudinal fasciculus ( riMLF) to the central caudal nucleus ( CCN) have also been observed ( 5). REFERENCES 1. Keane JR. The pretectal syndrome: 206 patients. Neurology 1990; 40: 684- 90. 2. Miller NR. Walsh and Hoyt's clinical neuro- ophthalmology, Vol 2. 4th ed. Baltimore: Williams and Wilkins, 1985: 945- 56. 3. Galetta SL, Gray LG, Raps EC, Schatz NJ. Pretectal eyelid retraction and lag. Ann Neurol 1993; 33: 554- 7. 4. Miller NR. Walsh and Hoyt's clinical neuro- ophthalmology, 4th ed. Vol 2. Baltimore: Williams and Wilkins, 1985: 948. 5. Schmidtke K, Buttner- Ennever JA. Nervous control of eyelid function. Brain 1992; 115: 227- 47. 6. Buttner JA, Buttner V. The reticular formation. In: Buttner- Ennever JA, ed. Neuroanatomy of the oculomotor system. New York: Elsevier, 1988: 162. / Neuro- Ophthalmol, Vol. 16, No. 2, 1996 |
