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Eye-movement disorders in brain-stem and cerebellar stroke
294
Surv Ophthalmol
32(4) January-February
1988
CURRENTOPHTHALMOLOGY
to senescent changes of the retinal capillaries. (Author’s address: Dr. L. Wu, Eye Research Institute, Ophthalmic Center, Sun Yat-Sen, University of Medical Sciences, Guangzhou, China.)
Zhongshan
Comment This paper is similar to previous reports concerning FAZ characteristics. The authors confirmed the occasional findings of small capillaries running through the FAZ (Bird AC, Weale RA: Ex~ Eye Res 29:409-417, 1974). Th e d imensions of the FAZ are essentially the same as were found by Bresnick (Bresnick in diabetic and normal GH et al: Arch OphthalmolZ02: 1286-1293, 1984) in his study of FAZ characteristics subjects. However, unlike Bresnick and Bligard, (Bligard E et al: Invest Ophthalmol Vis Sci 22 (suppl):8, 1982) Wu et al, found a significant enlargement of the FAZ area in aged subjects. Laatikainen (Laatikainen L, Jouko L: Invest Ophthalmol Vis Sci 16: 1154-l 157, 1977) et al also found an increase in FAZ dimensions in the 40-50year age group. The authors’ speculation that increased FAZ area in their older patients is due to atrophic or occlusive changes appears premature. The variable conclusions reached in these studies may be attributed to sample size or differences in estimates of magnification used from retina to negative to print. Additionally, the increased size of the FAZ found by the authors in older patients may represent an apparent difference, rather than a real one, due to photographic limitations. That is, there may be a reduced concentration of fluorescein dye in elderly sclerotic perifoveal vessels as well as a hazy view related to media opacity. These changes would make accurate resolution of the FAZ more difficult. The authors stress the importance of fluorescein angiographic appreciation of FAZ dimensions prior to juxtafoveal laser treatment. This is an important point. When treating eyes with subretinal neovascularization or retinal vascular diseases associated with cystoid macular edema, we use the perifoveal capillary net as a landmark for “safe” treatment. However, laser treatment on the perifoveal capillary net of an eye with a large FAZ, is “safer,” or further from the foveola, than the same treatment in an eye with a small FAZ. FAZ dimension is valuable in assessing risk-benefit ratio in any type of juxta-foveolar laser treatment. “Safe” treatment should, therefore, be assessed in terms from the center of the foveola, not distance into the FAZ. In conclusion, though this paper breaks no new ground, it emphasizes the importance of variations in normal FAZ dimensions. These variations carry profound implications for juxtafoveal laser treatment. Agerelated changes in FAZ dimensions remain a matter of debate. H. RICHARD MCDONALD, M.D. SAN FRANCISCO. CALIFORNIA
Eye-Movement Disorders in Brain-Stem and Cerebellar Stroke, by J. Bogousslavsky 0. Meienberg. Arch New01 44:141-148, 1987
and
Disorders ofeye movements are common in vertebral basilar strokes because the brain stem and cerebellum contain a large number of structures belonging to the ocular motor system. Unique disorders combining supernuclear, nuclear and infranuclear syndromes may occur. Some eye movement abnormalities are useful localizing signs - for example, Gay’s palsies, rotatory nystagmus, and ipsilateral saccadic bias - but many others are of no localizing value. The use of techniques such as magnetic resonance imaging may provide new insights into the clinical pathographic correlations in patients with good recovery in the absence of pathologic verification. (Author’s address: Dr. Bogousslavsky, Department of Neurology, Centre Hospitalier, Universitaire Vaudois, 1011 Lausanne, Switzerland.)
Comment Description of the brainstem and cerebellar ocular motor apparatus, conceptualized in recent years as a biological control system, often includes diagrams and nomenclature confusing to the clinician. Major contributions in understanding eye movement disorders now involve quantitative recordings, that, although required for the understanding of nystagmus mechanisms, are unavailable to most practitioners. Fortunately,
CURRENT
OPHTHALMOLOGY
295
the common forms of nystagmus and other ocular oscillations may be recognized clinically without the need for eye movement recording. It is this clinical approach that Bogousslavsky and Meienberg employ in describing eye movement disorders following brainstem and cerebellar stroke. The authors review the blood supply of the mesencephalon, pons, cerebellum, and medulla and review the ocular motor abnormalities arising from strokes in each region. The paper is an extensive review of the clinical eye movement literature including 105 references. Given the complexity ofinterconnections among the structures of the posterior fossa, it is frequently difficult to give precise topographic localization to a particular eye movement disorder. The authors review the wellknown disturbances of vertical and horizontal gaze due to mesencephalic and pontine strokes, respectively. Often not appreciated are the variety of ocular motor disturbances caused by lesions within the medulla. Subjective complaints include vertical or oblique diplopia, oscillopsia, blurred vision, and tilt [either 90 degrees or 180 degrees] of the visual field. Objective findings include skew deviation, rotary or horizontalrotary nystagmus, downbeat nystagmus, upbeat nystagmus, palpebral nystagmus, ocular lateropulsion, and Horner’s syndrome. visualization of the brainstem and The advent of magnetic resonance imaging (MRI) h as revolutionized cerebellum. The authors point out that the impact of MRI may greatly expand “our knowledge ofclinicotopographic correlates in ocular movement disorders due to small vertebrobasilar strokes.“ MRI will provide a powerful new means of studying posterior fossa anatomy. Combined with recent advances in ocular motor neurophysiology, our understanding of pathways controlling eye movements may be on the verge of significant advancement. LANNIN(; &.rsr:, M.D. BIKXIINGH.ZXI,
AIAHAXLZ
Index to Advertisers Akorn. Inc. Bio-Rad Ophthalmics Burroughs Wellcome Carl Zeiss, Inc. Ciba Vision Corp. Lombart Instrument Mesco
Division Co.
2a lla cover 2, la 9a 8a, 12a 15a 13a
Mira, Inc. NoIR Medical Technologies Ophthalmic Reviews Site Microsurgical Summit Technology, Inc. Vistech Consultants, Inc.
4a, 5a 8a cover 3 cover 4 16a 7a
Surv Ophthalmol
32(4) January-February
1988
CURRENTOPHTHALMOLOGY
to senescent changes of the retinal capillaries. (Author’s address: Dr. L. Wu, Eye Research Institute, Ophthalmic Center, Sun Yat-Sen, University of Medical Sciences, Guangzhou, China.)
Zhongshan
Comment This paper is similar to previous reports concerning FAZ characteristics. The authors confirmed the occasional findings of small capillaries running through the FAZ (Bird AC, Weale RA: Ex~ Eye Res 29:409-417, 1974). Th e d imensions of the FAZ are essentially the same as were found by Bresnick (Bresnick in diabetic and normal GH et al: Arch OphthalmolZ02: 1286-1293, 1984) in his study of FAZ characteristics subjects. However, unlike Bresnick and Bligard, (Bligard E et al: Invest Ophthalmol Vis Sci 22 (suppl):8, 1982) Wu et al, found a significant enlargement of the FAZ area in aged subjects. Laatikainen (Laatikainen L, Jouko L: Invest Ophthalmol Vis Sci 16: 1154-l 157, 1977) et al also found an increase in FAZ dimensions in the 40-50year age group. The authors’ speculation that increased FAZ area in their older patients is due to atrophic or occlusive changes appears premature. The variable conclusions reached in these studies may be attributed to sample size or differences in estimates of magnification used from retina to negative to print. Additionally, the increased size of the FAZ found by the authors in older patients may represent an apparent difference, rather than a real one, due to photographic limitations. That is, there may be a reduced concentration of fluorescein dye in elderly sclerotic perifoveal vessels as well as a hazy view related to media opacity. These changes would make accurate resolution of the FAZ more difficult. The authors stress the importance of fluorescein angiographic appreciation of FAZ dimensions prior to juxtafoveal laser treatment. This is an important point. When treating eyes with subretinal neovascularization or retinal vascular diseases associated with cystoid macular edema, we use the perifoveal capillary net as a landmark for “safe” treatment. However, laser treatment on the perifoveal capillary net of an eye with a large FAZ, is “safer,” or further from the foveola, than the same treatment in an eye with a small FAZ. FAZ dimension is valuable in assessing risk-benefit ratio in any type of juxta-foveolar laser treatment. “Safe” treatment should, therefore, be assessed in terms from the center of the foveola, not distance into the FAZ. In conclusion, though this paper breaks no new ground, it emphasizes the importance of variations in normal FAZ dimensions. These variations carry profound implications for juxtafoveal laser treatment. Agerelated changes in FAZ dimensions remain a matter of debate. H. RICHARD MCDONALD, M.D. SAN FRANCISCO. CALIFORNIA
Eye-Movement Disorders in Brain-Stem and Cerebellar Stroke, by J. Bogousslavsky 0. Meienberg. Arch New01 44:141-148, 1987
and
Disorders ofeye movements are common in vertebral basilar strokes because the brain stem and cerebellum contain a large number of structures belonging to the ocular motor system. Unique disorders combining supernuclear, nuclear and infranuclear syndromes may occur. Some eye movement abnormalities are useful localizing signs - for example, Gay’s palsies, rotatory nystagmus, and ipsilateral saccadic bias - but many others are of no localizing value. The use of techniques such as magnetic resonance imaging may provide new insights into the clinical pathographic correlations in patients with good recovery in the absence of pathologic verification. (Author’s address: Dr. Bogousslavsky, Department of Neurology, Centre Hospitalier, Universitaire Vaudois, 1011 Lausanne, Switzerland.)
Comment Description of the brainstem and cerebellar ocular motor apparatus, conceptualized in recent years as a biological control system, often includes diagrams and nomenclature confusing to the clinician. Major contributions in understanding eye movement disorders now involve quantitative recordings, that, although required for the understanding of nystagmus mechanisms, are unavailable to most practitioners. Fortunately,
CURRENT
OPHTHALMOLOGY
295
the common forms of nystagmus and other ocular oscillations may be recognized clinically without the need for eye movement recording. It is this clinical approach that Bogousslavsky and Meienberg employ in describing eye movement disorders following brainstem and cerebellar stroke. The authors review the blood supply of the mesencephalon, pons, cerebellum, and medulla and review the ocular motor abnormalities arising from strokes in each region. The paper is an extensive review of the clinical eye movement literature including 105 references. Given the complexity ofinterconnections among the structures of the posterior fossa, it is frequently difficult to give precise topographic localization to a particular eye movement disorder. The authors review the wellknown disturbances of vertical and horizontal gaze due to mesencephalic and pontine strokes, respectively. Often not appreciated are the variety of ocular motor disturbances caused by lesions within the medulla. Subjective complaints include vertical or oblique diplopia, oscillopsia, blurred vision, and tilt [either 90 degrees or 180 degrees] of the visual field. Objective findings include skew deviation, rotary or horizontalrotary nystagmus, downbeat nystagmus, upbeat nystagmus, palpebral nystagmus, ocular lateropulsion, and Horner’s syndrome. visualization of the brainstem and The advent of magnetic resonance imaging (MRI) h as revolutionized cerebellum. The authors point out that the impact of MRI may greatly expand “our knowledge ofclinicotopographic correlates in ocular movement disorders due to small vertebrobasilar strokes.“ MRI will provide a powerful new means of studying posterior fossa anatomy. Combined with recent advances in ocular motor neurophysiology, our understanding of pathways controlling eye movements may be on the verge of significant advancement. LANNIN(; &.rsr:, M.D. BIKXIINGH.ZXI,
AIAHAXLZ
Index to Advertisers Akorn. Inc. Bio-Rad Ophthalmics Burroughs Wellcome Carl Zeiss, Inc. Ciba Vision Corp. Lombart Instrument Mesco
Division Co.
2a lla cover 2, la 9a 8a, 12a 15a 13a
Mira, Inc. NoIR Medical Technologies Ophthalmic Reviews Site Microsurgical Summit Technology, Inc. Vistech Consultants, Inc.
4a, 5a 8a cover 3 cover 4 16a 7a