Overlooking: a Sign of Bilateral Central Scotomata in Children William V . Good Lucy S. Crain Richard D. Quint Thomas K . Koch
Children’s attempts to cope with visual impairment result in a wide range of behavioral adaptations, some of which are specific to the cause of the impairment (Good and Hoyt 1989). For example, eyepoking occurs solely in blinding bilateral congenital retinal disease (Jan el al. 1983); stereotypic head-turning represents an effort to dampen nystagmus, often caused by bilateral anterior afferent pathway disease in the visual system (Dell’Osso and Daroff 1975); and cortically visually impaired children stare at bright lights and prefer brightly colored objects in their environment (Jan el al. 1987). Some visually-impaired children consistently look above objects of interest. This phenomenon was termed ‘overlooking’ by Taylor et al. (1983), in their study of children with neuronal ceroid lipofuscinosis. These children presumably have late sparing of the inferior visual field, which would account for their instinct to search for an object by looking above it. In our experience, overlooking is not specific to neuronal ceroid lipofuscinosis or simple sparing of the inferior visual field: it is an important and specific sign of bilateral central scotomata in children.
Case reports PATIENT 1 A 15-year-old girl was examined for long-standing but stable visual impairment. Her family history, medical history and neurological examination were all normal. Best corrected visual acuity was 20/200 in each eye. There was no nystagmus. She read the Snellen chart by looking above it (Fig. 1). Color vision was poor. She could not co-operate with formal visual-field testing, but confrontational examination showed large, bilateral, central scotomata. O n every occasion that
required visual fixation, she preferred to use her superior retina (Fig. 2); eye movements were otherwise normal. Fundus examination showed optic atrophy with t e m p o r a l pallor a n d specific loss of papillomacular bundle fibers. Magnetic resonance imaging (MRI) of her central nervous system was normal, as was an electroretinogram (ERG).
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PATIENT 2 A three-year-old boy was referred for chronic upgaze to the Pediatric Ophthalmology Service of the University of California, San Francisco. He had been abused in infancy, but had suffered no apparent longterm neurological or developmental ill-effects. An MRI of his central nervous system was normal. Examination showed no nystagmus. Objects of interest in the examining room were viewed by looking above them (Fig. 3). I f the object was lowered, his eyes also dropped, always maintaining a fixation pattern in which the visual axis was aimed above the object of interest. Horizontal and vertical eyemovements were normal. Confrontational visual field examination demonstrated intact peripheral fields of vision. Fundus examination showed temporal atrophy of both optic nerves; the atrophy was symmetrical and affected papillomacular nerve fibers. PATIENT 3 A 14-year-old boy with progressive optic nerve atrophy of unknown etiology consistently looked above fixation targets. Family history, neurological history and neurological examinations were normal, as were neuro-imaging studies. His vision measured 5/200 in each eye. Retinal examination was normal, but the optic nerve showed bilateral atrophy. Visual field examination showed intact peripheral fields of vision, as best as could be determined. Central scotomata were demonstrable. Although he could not specify why, the patient stated that he could see things better if he looked up rather than down or sideways. PATIENT 4 A six-year-old girl with bilateral ocular colobomata was evaluated for vision loss. The CHARGE syndrome was present, and she had bilateral hearing deficit, external ear anomalies, choanal atresia, a mild heart defect and developmental delays. Nystagmus had been present since infancy: it was horizontal, not dissociated, and planar. She looked above objects of interest, but otherwise had normal eye-movements. Examination showed bilateral ocular colobomata affecting both maculae and inferonasal retina. Optic nerves were normal.
Discussion Looking above an object of visual interest occurs in children with bilateral central scotomata in an effort to adapt to poor central vision. The macula subserves the central visual field and visual acuity, i.e. the ability to see objects in fine detail. Axons from macular fibers form the papillomacular bundle, which forms the temporal aspect of the optic nerve. This
69
Fig. I. Overlooking: case I is looking at circle on stick in ,foreground. Note that gaze is directed above this visuul target
Fig. 2. Fundus pictures of patient I : right eye (left) and left eye (right). She is looking at fixation cue, which she lines up on retina superior to maculae. Normally this cue would line up on central, dimpled area
of macula.
Fig. 3. Patient 3 is following a command to look
70
at camera. Since he has bilateral, central scotornata, he adapts by looking above camera, using preserved superior retina for visual fixation.
series of patients demonstrates the oceurrence of so-called overlooking in papillomacular atrophy and ocular colobomata. In our experience, overlooking is not disease-specific: it is an adaptation to loss of central visual acuity, in which children preferentially fixate with the superior retina. Overlooking can be misinterpreted. It has some of the characteristics of tonic upgaze-a transient, supranuclear disturbance of eye movements in which the eyes deviate upward (Ahn et a/. 1989, Mets 1990). The children in our series were older than children with tonic upgaze and their overlooking persisted. None had trouble looking down, and when not visually fixating, the resting state of our patients’ eyes was approximately at the horizontal meridian. Overlooking can mimic down-gaze palsy, a rare disorder of supranuclear eyemovement control (Barontini et a / . 1983, Jacobs el al. 1984). The children in our series appeared to be unable to look down, but their eyes were aligned over the visual target. Testing of pursuit and saccadic eyemovements demonstrated no difficulty with up- or down-gaze. Transient tic disorder can affect the eyes (American Psychiatric Association 1987). Some children develop habits of forceful eyelid closure, eyelid pulling (Catalan0 et a/. 1990), or deliberate, rapid, multidirectional saccadic eye-movements. Repetitive looking up rarely occurs, but when it does the eye examination is normal. Upward eye-deviation can occur in petit ma1 epilepsy and postencephalitic Parkinson’s disease (Adams and Victor 1985), but none of our children had abnormalities on neurological examination to support such diagnoses. Bilateral sparing of the inferior visual field is a presumed cause of some cases of overlooking (Taylor et al. .1983). Inferior visual fields correspond with the superior retina. Overlooking uses the superior retina for fixation (see Fig. 2). Patient 4, with some loss of the inferior retina, demonstrated that overlooking may be more likely to occur with inferior retina/ superior visual field defects. In this instance, the preserved superior retina took over visual fixation. In our other cases, though, both superior and inferior
visual fields were preserved; therefore another explanation for overlooking is required for these children. Bilateral loss of macular vision is a prerequisite for overlooking. Preservation of any macular vision in one eye would not cause overlooking, since visual acuity is much better with macular than with extramacular function. This is the case for children, with asymmetric ocular colobomata, in which only one macula is significantly affected. Monocular or bilateral nystagmus may occur (Jan el al. 1986), but overlooking is absent. On the other hand, the finding of overlooking in a child with bilateral ocular colobomata clarifies that both maculae are involved and that central acuity is affected bilaterally. This is a particularly useful finding, since it is difficult to examine the degree of involvement of central vision in children with ocular colobomat a. Children with bilateral central scotomata could adapt by looking in any of four directions-why do they choose up? Looking down causes the upper eyelids to drop, which could restrict the superior visual fields. Looking left restricts the visual fields field to the left (the scotoma has moved left) and to the right (conjugate gaze is biased to the left); the reverse would be true for looking to the right. On the other hand, looking up raises the upper lids and expands all visual fields. The scotomata move up, but superior visual fields are relatively less important for visual function. Visual-field testing in normal young children fails to reveal a difference in sensitivity between the superior and inferior retina (Cummings et al. 1988), but threshold stimuli for testing children have been too large to define subtle differences. On the other hand, there is some evidence for increased sensitivity of the superior retina compared with the inferior retina. Jampolsky (1978) has noted that in individuals tested monocularly with equal and simultaneous light stimuli applied to the superior and inferior retina, the after-image from the superior retina lasts longer. The density of rod photoreceptors is higher in the superior compared with the inferior retina (Curcio el a/. 1990). Stereopsis testing
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also demonstrates a superior-inferior retina difference (Breitmeyer et a/. 1975). This up-down differential may also exist for spatial sensitivity testing. The backward tilt of the vertical horopter line is presumed to be secondary t o a differential in sensitivity between the superior and inferior retina (Nakayama et a/. 1977). (The vertical horopter is a n imaginary line in space created by corresponding retinal points above a n d below fixation.) In the young child, overlooking indicates bilateral dense central scotomata. We cannot explain why adults never use this same adaptation. Visual acuity of overlooking children is 20/200 or worse, but peripheral vision is preserved. The number of conditions that selectively destroy bilateral macular vision in children is small, therefore overlooking can be a helpful physical finding.
Understanding that overlooking is a n adaptation to vision loss is equally important. Families and referring physicians may be perplexed by this unusual but neurologically limited behavior, but its discovery should prompt a thorough ophthalmological examination. Accepted f o r publication 3lst June 1991. Acknowledgement This study was supported by the Northern California Society to Prevent Blindness. Authors’ Appointments *William V. Good, M.D., Assistant Professor of Ophthalmology, Department of Ophthalmology; Lucy S. Crain, M.D., Clinical Professor; Richard D. Quint, M.D., Associate Clinical Professor; Department of Pediatrics; Thomas K. Koch, M.D., Associate Professor; The Children’s Vision Impairment Program, University of California, San Francisco. *Correspondence to first author at Department of Ophthalmology, K-301, University of California School of Medicine, 10 Kirkham Street, San Francisco, CA 94143-0703.
SUMMARY Four children are reported who always looked above objects of visual interest (overlooking). All had bilateral central scotomata (loss of central visual field). Three had optic nerve disease selectively affecting the papillornacular fibers; the fourth had ocular colobornata affecting the rnaculae. Overlooking is an important sign of bilateral central scotomata in children: it is an adaptation to loss of central vision. RESUME Le regard au dessus: un signe de scotome central bilateral chez I’enfant L’article decrit quatre enfants regardant toujours au dessus des objets interessants sur le plan visuel (overlooking). Tous presentaient un scotome central bilateral (perte du champ visuel central). Trois d’entre eux presentaient une affection du nerf optique frappant selectivernent les fibres papillomaculaires; le quatrierne avait un coloborne oculaire affectant la macula. Le regard au dessus est un signe important de scotorne central bilateral chez I’enfant: il traduit une adaptation a la perte de vision. ZUSAMMENFASSUNG Overlooking (iiber einem Gegenstand fixieren): ein Zeichen f u r bilaterale zentrale Skotome bei Kindern Es wird uber vier Kinder berichtet, die immer iiber Gegenstande von visuellem Interesse hinwegsahen. Alle hatten bilaterale zentrale Skotome (Verlust des zentralen Sehfeldes). Drei hatten eine Sehnervenerkrankung, die selektiv die papillornakularen Fasern betraf; das vierte hatte Koloborne, die die Makula in Mitleidenschaft zogen. Overlooking ist ein wichtiges Zeichen fur bilaterale zentrale Skotome bei Kindern: es ist eine Anpassung beim Ausfall des zentralen Sehfeldes. RESUMEN Supramirada: signo de escotoma central bilateral en niiios Se refieren cuatro nifios que siempre rniraban 10s objectos de interes por encirna de ellos (suprarnirada). Todos tenian un escotorna central bilateral (peridada de la vision del campo visual central). Tres tenian una enterrnedad del nervio opitoc afectando selectivamente las fibras papilomaculare. El cuarto tenia un coloborna ocular afectando la rnacula. La suprarnirada es un signo irnportante de escotorna central bilateral en niilos; es una adaptacion a la perdida de la vision central.
72
References Adams, R. D., Victor, M. (Eds.) (1985) ‘Degenerative diseases of the nervous system.’ In Principles of Neurology. New York: McGraw-Hill. p. 876. Ahn, J . C., Hoyt, W. F., Hoyt, C. S. (1989) ‘Tonic upgaze in infancy: a report of three cases.’ Archives of Ophthalmology, 107, 57-58.
American Psychiatric Association (1987) Diagnostic and Siaiistical Manual of Mental DisordersDSM-III. Washington: A.P.A. p. 74. Barontini, F., Simonettia, C., Ferranini, F., Sita, D. (1983) ‘Persistent upward eye deviation: report of two cases.’ Neuro-ophthalmology, 3, 217-221.
Breitmeyer, T., Julesz, B., tiropfl, W. (1975) ‘Dynamic random-dot stereograms reveal updown anisotropy and left-right isotropy between cortical hemifields.’ Science, 187, 269-270. Catalano, R . A . , Trivisani, M. G., Simon, J . W. (1990) ‘Functional eyelid pulling in children.’ Americun Journal of Ophthalmology, 11 0, 300-302. Cummings, M . L., van Hof-van Duin, J., Mayer, D. L., Hansen, R . M . , Fulton, A. B. (1988) ‘Visual fields of young children.’ Behavioural Brain Research, 29, 7-16. Curcio, C. A , , Sloan, ti. R., Kalina, R . E., Hendrickson, A. E. (1990) ‘Human photoreceptor topography.’ Journal of Comparairve Neurology, 292. 497-523. Dell’Osso, L. F., Daroff, M. D. (1975) ‘Congenital nystagmus wave forms and foveation strategy.’ Docurnenia Ophihalomogicu, 39, 155-182. Good, W . V., Hoyt, C. S. (1989) ‘Behavioral correlates of poor vision in children.’ Iniernational Ophihalmology Clinics, 29, 57-60. Jacob5, L., Heffner, R . R . , Newman, N. (1984) ‘Selective paralysis of downward gaze caused by bilateral lesion of the periaqueductal gray commisure of the superior colliculi.’ Neurology, 34 (Suppl.), 95. (Absiraci.) Jampolsky, A . (1978) ‘Unequal visual inputs and
strabismus management: a comparison of human and animal strabismus.’ I n Helveston, E. M. (Ed.) Symposium on Strabismus, Transactions of [he New Orleans Academy of Ophihaltnolog-v. St. Louis: C . V . Mosby. p. 434. Jan, J . E., Freeman, R . D., McCormick, A . Q., Scott, E. P . , Robertson, W. D . , Newman, D. E. (1983) ‘Eye pressing by visually impaired children ,’ Developmental Medicine and Child Neurolog.v, 25, 75 5-762. - Farrell, ti., Wong, P . K., McCormick, A . Q . (1986) ‘Eye and head movements of visually impaired children.’ Developmenial Medicine and Child Neurology, 28, 285-293. - Grocnveld, M . , Sykanda, A . M., Hoyt, C. S. (1987) ‘Behavioural characteristics of children with permanent cortical visual impairment.’ Developmenial Medicine and Child Neurology, 29, 571-576. Mets, M. (1990) ‘Tonic upgaze in infancy.’ Archives of Ophihalmology, 108, 482-483. Nakayama, ti., Tyler, C. W., Appelman, J . (1977) ‘A new angle o n the vertical horopter.’ In vesti,putive Ophihalmology and Visual Sciences, 16, 82. Taylor, D., Lake, B. D., Stephens, R . (1983) ‘Neurolipidoses.’ I n Wybar, t i . , Taylor, D. (Eds.) Pediatric Ophihalmology, Curreni Aspecis. New York: Marcel Dekker. pp. 180-181.
Fami I i a I ParoxysmaI Rhabdomyolysi s Managemen- of Two Cases of the Non-exerti ona Type
attacks (Bowden et al. 1956, Korein et al. 1959, Favara et al. 1967, Savage el al. 1971). The pathogenesis is unknown, in contrast to our increasing understanding of rhabdomyolysis following exercise (McArdle 1951, Tarui et af. 1965, DiMauro and DiMauro 1973, Bank et al. 1975, DiMauro et al. 1981, Bresolin et at. 1987). We describe two affected families and suggest guidelines for management of the condition.
~
V. Ramesh D. Gardner-Medwin
Familial paroxysmal rhabdomyolysis is a rare but distinctive clinical entity which results in life-threatening episodes of muscular paralysis, myoglobinuria and renal failure. It occurs in young children, usually under the age of five; their siblings of either sex may be affected, suggesting an autosomal recessive mode of inheritance. The attacks have no relation to exercise. In susceptible children, intercurrent illnesses, commonly upper respiratory-tract infections, trigger the
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Case reports CASE 1 C.S. was a 33-month-old girl referred in 1981, three months after a single attack of rhabdomyolysis. At the time she had been suffering for two months from pertussis; her appetitie was poor and she had vomited for two days before the rhabdomyolysis occurred. During the attack she developed weakness of all four limbs, lost the ability to walk and passed reddish-brown urine over a period of 24 hours. O n admission to another hospital she was afebrile, hypotonic and drowsy, with moderate muscle weakness and reduced tendon reflexes. Neurological examination was otherwise normal. A convulsion o n the day of admission did not recur and her subsequent EEG was normal. There was heavy proteinuria, and urine microscopy showed red cells and occasional granular casts.
73
Children’s attempts to cope with visual impairment result in a wide range of behavioral adaptations, some of which are specific to the cause of the impairment (Good and Hoyt 1989). For example, eyepoking occurs solely in blinding bilateral congenital retinal disease (Jan el al. 1983); stereotypic head-turning represents an effort to dampen nystagmus, often caused by bilateral anterior afferent pathway disease in the visual system (Dell’Osso and Daroff 1975); and cortically visually impaired children stare at bright lights and prefer brightly colored objects in their environment (Jan el al. 1987). Some visually-impaired children consistently look above objects of interest. This phenomenon was termed ‘overlooking’ by Taylor et al. (1983), in their study of children with neuronal ceroid lipofuscinosis. These children presumably have late sparing of the inferior visual field, which would account for their instinct to search for an object by looking above it. In our experience, overlooking is not specific to neuronal ceroid lipofuscinosis or simple sparing of the inferior visual field: it is an important and specific sign of bilateral central scotomata in children.
Case reports PATIENT 1 A 15-year-old girl was examined for long-standing but stable visual impairment. Her family history, medical history and neurological examination were all normal. Best corrected visual acuity was 20/200 in each eye. There was no nystagmus. She read the Snellen chart by looking above it (Fig. 1). Color vision was poor. She could not co-operate with formal visual-field testing, but confrontational examination showed large, bilateral, central scotomata. O n every occasion that
required visual fixation, she preferred to use her superior retina (Fig. 2); eye movements were otherwise normal. Fundus examination showed optic atrophy with t e m p o r a l pallor a n d specific loss of papillomacular bundle fibers. Magnetic resonance imaging (MRI) of her central nervous system was normal, as was an electroretinogram (ERG).
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PATIENT 2 A three-year-old boy was referred for chronic upgaze to the Pediatric Ophthalmology Service of the University of California, San Francisco. He had been abused in infancy, but had suffered no apparent longterm neurological or developmental ill-effects. An MRI of his central nervous system was normal. Examination showed no nystagmus. Objects of interest in the examining room were viewed by looking above them (Fig. 3). I f the object was lowered, his eyes also dropped, always maintaining a fixation pattern in which the visual axis was aimed above the object of interest. Horizontal and vertical eyemovements were normal. Confrontational visual field examination demonstrated intact peripheral fields of vision. Fundus examination showed temporal atrophy of both optic nerves; the atrophy was symmetrical and affected papillomacular nerve fibers. PATIENT 3 A 14-year-old boy with progressive optic nerve atrophy of unknown etiology consistently looked above fixation targets. Family history, neurological history and neurological examinations were normal, as were neuro-imaging studies. His vision measured 5/200 in each eye. Retinal examination was normal, but the optic nerve showed bilateral atrophy. Visual field examination showed intact peripheral fields of vision, as best as could be determined. Central scotomata were demonstrable. Although he could not specify why, the patient stated that he could see things better if he looked up rather than down or sideways. PATIENT 4 A six-year-old girl with bilateral ocular colobomata was evaluated for vision loss. The CHARGE syndrome was present, and she had bilateral hearing deficit, external ear anomalies, choanal atresia, a mild heart defect and developmental delays. Nystagmus had been present since infancy: it was horizontal, not dissociated, and planar. She looked above objects of interest, but otherwise had normal eye-movements. Examination showed bilateral ocular colobomata affecting both maculae and inferonasal retina. Optic nerves were normal.
Discussion Looking above an object of visual interest occurs in children with bilateral central scotomata in an effort to adapt to poor central vision. The macula subserves the central visual field and visual acuity, i.e. the ability to see objects in fine detail. Axons from macular fibers form the papillomacular bundle, which forms the temporal aspect of the optic nerve. This
69
Fig. I. Overlooking: case I is looking at circle on stick in ,foreground. Note that gaze is directed above this visuul target
Fig. 2. Fundus pictures of patient I : right eye (left) and left eye (right). She is looking at fixation cue, which she lines up on retina superior to maculae. Normally this cue would line up on central, dimpled area
of macula.
Fig. 3. Patient 3 is following a command to look
70
at camera. Since he has bilateral, central scotornata, he adapts by looking above camera, using preserved superior retina for visual fixation.
series of patients demonstrates the oceurrence of so-called overlooking in papillomacular atrophy and ocular colobomata. In our experience, overlooking is not disease-specific: it is an adaptation to loss of central visual acuity, in which children preferentially fixate with the superior retina. Overlooking can be misinterpreted. It has some of the characteristics of tonic upgaze-a transient, supranuclear disturbance of eye movements in which the eyes deviate upward (Ahn et a/. 1989, Mets 1990). The children in our series were older than children with tonic upgaze and their overlooking persisted. None had trouble looking down, and when not visually fixating, the resting state of our patients’ eyes was approximately at the horizontal meridian. Overlooking can mimic down-gaze palsy, a rare disorder of supranuclear eyemovement control (Barontini et a / . 1983, Jacobs el al. 1984). The children in our series appeared to be unable to look down, but their eyes were aligned over the visual target. Testing of pursuit and saccadic eyemovements demonstrated no difficulty with up- or down-gaze. Transient tic disorder can affect the eyes (American Psychiatric Association 1987). Some children develop habits of forceful eyelid closure, eyelid pulling (Catalan0 et a/. 1990), or deliberate, rapid, multidirectional saccadic eye-movements. Repetitive looking up rarely occurs, but when it does the eye examination is normal. Upward eye-deviation can occur in petit ma1 epilepsy and postencephalitic Parkinson’s disease (Adams and Victor 1985), but none of our children had abnormalities on neurological examination to support such diagnoses. Bilateral sparing of the inferior visual field is a presumed cause of some cases of overlooking (Taylor et al. .1983). Inferior visual fields correspond with the superior retina. Overlooking uses the superior retina for fixation (see Fig. 2). Patient 4, with some loss of the inferior retina, demonstrated that overlooking may be more likely to occur with inferior retina/ superior visual field defects. In this instance, the preserved superior retina took over visual fixation. In our other cases, though, both superior and inferior
visual fields were preserved; therefore another explanation for overlooking is required for these children. Bilateral loss of macular vision is a prerequisite for overlooking. Preservation of any macular vision in one eye would not cause overlooking, since visual acuity is much better with macular than with extramacular function. This is the case for children, with asymmetric ocular colobomata, in which only one macula is significantly affected. Monocular or bilateral nystagmus may occur (Jan el al. 1986), but overlooking is absent. On the other hand, the finding of overlooking in a child with bilateral ocular colobomata clarifies that both maculae are involved and that central acuity is affected bilaterally. This is a particularly useful finding, since it is difficult to examine the degree of involvement of central vision in children with ocular colobomat a. Children with bilateral central scotomata could adapt by looking in any of four directions-why do they choose up? Looking down causes the upper eyelids to drop, which could restrict the superior visual fields. Looking left restricts the visual fields field to the left (the scotoma has moved left) and to the right (conjugate gaze is biased to the left); the reverse would be true for looking to the right. On the other hand, looking up raises the upper lids and expands all visual fields. The scotomata move up, but superior visual fields are relatively less important for visual function. Visual-field testing in normal young children fails to reveal a difference in sensitivity between the superior and inferior retina (Cummings et al. 1988), but threshold stimuli for testing children have been too large to define subtle differences. On the other hand, there is some evidence for increased sensitivity of the superior retina compared with the inferior retina. Jampolsky (1978) has noted that in individuals tested monocularly with equal and simultaneous light stimuli applied to the superior and inferior retina, the after-image from the superior retina lasts longer. The density of rod photoreceptors is higher in the superior compared with the inferior retina (Curcio el a/. 1990). Stereopsis testing
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also demonstrates a superior-inferior retina difference (Breitmeyer et a/. 1975). This up-down differential may also exist for spatial sensitivity testing. The backward tilt of the vertical horopter line is presumed to be secondary t o a differential in sensitivity between the superior and inferior retina (Nakayama et a/. 1977). (The vertical horopter is a n imaginary line in space created by corresponding retinal points above a n d below fixation.) In the young child, overlooking indicates bilateral dense central scotomata. We cannot explain why adults never use this same adaptation. Visual acuity of overlooking children is 20/200 or worse, but peripheral vision is preserved. The number of conditions that selectively destroy bilateral macular vision in children is small, therefore overlooking can be a helpful physical finding.
Understanding that overlooking is a n adaptation to vision loss is equally important. Families and referring physicians may be perplexed by this unusual but neurologically limited behavior, but its discovery should prompt a thorough ophthalmological examination. Accepted f o r publication 3lst June 1991. Acknowledgement This study was supported by the Northern California Society to Prevent Blindness. Authors’ Appointments *William V. Good, M.D., Assistant Professor of Ophthalmology, Department of Ophthalmology; Lucy S. Crain, M.D., Clinical Professor; Richard D. Quint, M.D., Associate Clinical Professor; Department of Pediatrics; Thomas K. Koch, M.D., Associate Professor; The Children’s Vision Impairment Program, University of California, San Francisco. *Correspondence to first author at Department of Ophthalmology, K-301, University of California School of Medicine, 10 Kirkham Street, San Francisco, CA 94143-0703.
SUMMARY Four children are reported who always looked above objects of visual interest (overlooking). All had bilateral central scotomata (loss of central visual field). Three had optic nerve disease selectively affecting the papillornacular fibers; the fourth had ocular colobornata affecting the rnaculae. Overlooking is an important sign of bilateral central scotomata in children: it is an adaptation to loss of central vision. RESUME Le regard au dessus: un signe de scotome central bilateral chez I’enfant L’article decrit quatre enfants regardant toujours au dessus des objets interessants sur le plan visuel (overlooking). Tous presentaient un scotome central bilateral (perte du champ visuel central). Trois d’entre eux presentaient une affection du nerf optique frappant selectivernent les fibres papillomaculaires; le quatrierne avait un coloborne oculaire affectant la macula. Le regard au dessus est un signe important de scotorne central bilateral chez I’enfant: il traduit une adaptation a la perte de vision. ZUSAMMENFASSUNG Overlooking (iiber einem Gegenstand fixieren): ein Zeichen f u r bilaterale zentrale Skotome bei Kindern Es wird uber vier Kinder berichtet, die immer iiber Gegenstande von visuellem Interesse hinwegsahen. Alle hatten bilaterale zentrale Skotome (Verlust des zentralen Sehfeldes). Drei hatten eine Sehnervenerkrankung, die selektiv die papillornakularen Fasern betraf; das vierte hatte Koloborne, die die Makula in Mitleidenschaft zogen. Overlooking ist ein wichtiges Zeichen fur bilaterale zentrale Skotome bei Kindern: es ist eine Anpassung beim Ausfall des zentralen Sehfeldes. RESUMEN Supramirada: signo de escotoma central bilateral en niiios Se refieren cuatro nifios que siempre rniraban 10s objectos de interes por encirna de ellos (suprarnirada). Todos tenian un escotorna central bilateral (peridada de la vision del campo visual central). Tres tenian una enterrnedad del nervio opitoc afectando selectivamente las fibras papilomaculare. El cuarto tenia un coloborna ocular afectando la rnacula. La suprarnirada es un signo irnportante de escotorna central bilateral en niilos; es una adaptacion a la perdida de la vision central.
72
References Adams, R. D., Victor, M. (Eds.) (1985) ‘Degenerative diseases of the nervous system.’ In Principles of Neurology. New York: McGraw-Hill. p. 876. Ahn, J . C., Hoyt, W. F., Hoyt, C. S. (1989) ‘Tonic upgaze in infancy: a report of three cases.’ Archives of Ophthalmology, 107, 57-58.
American Psychiatric Association (1987) Diagnostic and Siaiistical Manual of Mental DisordersDSM-III. Washington: A.P.A. p. 74. Barontini, F., Simonettia, C., Ferranini, F., Sita, D. (1983) ‘Persistent upward eye deviation: report of two cases.’ Neuro-ophthalmology, 3, 217-221.
Breitmeyer, T., Julesz, B., tiropfl, W. (1975) ‘Dynamic random-dot stereograms reveal updown anisotropy and left-right isotropy between cortical hemifields.’ Science, 187, 269-270. Catalano, R . A . , Trivisani, M. G., Simon, J . W. (1990) ‘Functional eyelid pulling in children.’ Americun Journal of Ophthalmology, 11 0, 300-302. Cummings, M . L., van Hof-van Duin, J., Mayer, D. L., Hansen, R . M . , Fulton, A. B. (1988) ‘Visual fields of young children.’ Behavioural Brain Research, 29, 7-16. Curcio, C. A , , Sloan, ti. R., Kalina, R . E., Hendrickson, A. E. (1990) ‘Human photoreceptor topography.’ Journal of Comparairve Neurology, 292. 497-523. Dell’Osso, L. F., Daroff, M. D. (1975) ‘Congenital nystagmus wave forms and foveation strategy.’ Docurnenia Ophihalomogicu, 39, 155-182. Good, W . V., Hoyt, C. S. (1989) ‘Behavioral correlates of poor vision in children.’ Iniernational Ophihalmology Clinics, 29, 57-60. Jacob5, L., Heffner, R . R . , Newman, N. (1984) ‘Selective paralysis of downward gaze caused by bilateral lesion of the periaqueductal gray commisure of the superior colliculi.’ Neurology, 34 (Suppl.), 95. (Absiraci.) Jampolsky, A . (1978) ‘Unequal visual inputs and
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Fami I i a I ParoxysmaI Rhabdomyolysi s Managemen- of Two Cases of the Non-exerti ona Type
attacks (Bowden et al. 1956, Korein et al. 1959, Favara et al. 1967, Savage el al. 1971). The pathogenesis is unknown, in contrast to our increasing understanding of rhabdomyolysis following exercise (McArdle 1951, Tarui et af. 1965, DiMauro and DiMauro 1973, Bank et al. 1975, DiMauro et al. 1981, Bresolin et at. 1987). We describe two affected families and suggest guidelines for management of the condition.
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V. Ramesh D. Gardner-Medwin
Familial paroxysmal rhabdomyolysis is a rare but distinctive clinical entity which results in life-threatening episodes of muscular paralysis, myoglobinuria and renal failure. It occurs in young children, usually under the age of five; their siblings of either sex may be affected, suggesting an autosomal recessive mode of inheritance. The attacks have no relation to exercise. In susceptible children, intercurrent illnesses, commonly upper respiratory-tract infections, trigger the
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Case reports CASE 1 C.S. was a 33-month-old girl referred in 1981, three months after a single attack of rhabdomyolysis. At the time she had been suffering for two months from pertussis; her appetitie was poor and she had vomited for two days before the rhabdomyolysis occurred. During the attack she developed weakness of all four limbs, lost the ability to walk and passed reddish-brown urine over a period of 24 hours. O n admission to another hospital she was afebrile, hypotonic and drowsy, with moderate muscle weakness and reduced tendon reflexes. Neurological examination was otherwise normal. A convulsion o n the day of admission did not recur and her subsequent EEG was normal. There was heavy proteinuria, and urine microscopy showed red cells and occasional granular casts.
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