| OCR Text |
Show Journal of Clinical Nellfo- ophthalmology 8( 1): 53- 59. 1988. Insight into the Recent European Literature A Review of Studies Concerning the Visual Pathways Avinoam B. Safran, M. D. ,~. 1988 Raven Press. Ltd .. New York The present review refers to articles published in the first half of 1987. For practical reasons, only some of these studies are reviewed in this article. They have been arranged into categories, sometimes arbitrarily. DISORDERS OF THE ANTERIOR VISUAL PATHWAYS Retinal Microvascular Alterations in Facioscapulohumeral Muscular Dystrophy Retinal microvascular alterations were found in 56 of 75 subjects with clinical or genetic evidence of facioscapulohumeral muscular dystrophy in a study by Fitzsimons et al. ( 1). Capillary alterations were mainly peripheral and included telangiectasis, closure, microaneurisms, and leakage revealed by retinal fluorescein angiography. They may be present early in life before there is overt evidence of muscle disease. Since visual loss if often preventable, fundus examination should be performed early in infants at risk. Evaluation of Retinal Vascular Abnormalities and Cells in Media Evaluation of retinal vascular abnormalities and Occurrence of cells in the media was performed in 50 patients with acute optic neuritis by Lightman et al. ( 2). After a mean follow- up of 3.5 years, multiple sclerosis had developed in 8 of 14 patients From the Department of Oto- neuro- ophthalmology, HopitaJ Cantonal Universitaire, Geneva, Switzerland. Address correspondence to Dr. A. B. Safran, Neuro- ophthalmology Unit, Department of Ophthalmology, Geneva UnIversity Hospital, CH- 1211 Geneva 4, Switzerland. 53 with vascular changes and/ or signs of inflammation, whereas it developed in only 5 of 32 without these signs. The authors discuss pathophysiologic implications resulting from the evidence that va. scular changes can occur in regions free of myelIn and oligodendrocytes. Intravenous Methylprednisolone A double- blind controlled trial of high- dose, pulsed intravenous ( i. v.) methylprednisolone ( a single daily dose of 500 mg or saline placeb?,. administered for 5 days) was carried out by MillIgan et al. ( 3) in 50 subjects with multiple sclerosis with either acute relapse or chronic progressive disease. One and 4 weeks after starting treatment, all patients clinically showed a highly significant beneficial effect of methylprednisolone; slight reddening of the face, transient ankle swelling, and a metallic taste in the mouth during infusion were mild side effects that were never as severe as with prolonged courses of intramuscular ACTH or oral corticosteroids. We believe, however, that at present, high dosage of pulsed methylprednisolone should be restricted to patients with severe relapses and in those patients with progressive forms in whom spasticity is a source of significant disability. . Interesting laboratory results were found III these patients. They were analyzed by Compston et al. ( 4). It was noted that although cerebrospinal tluid total cell count, IgG and C9 indices, and percentage of blood OK TS- positive cells showed closer to normal values following methylprednisolone treatment than after placebo treatment, differences were not statistically significant. At the beginning of the study, latency of visual evoked potentials was prolonged and the measurements were uninfluenced by methylprednisolone admin- RECENT EUROPEAN LITERATURE 55 Protein C Deficiency Can protein C deficiency cause amaurosis fugax? Protein C is a vitamin K- dependent plasma glycoprotein that inhibits coagulation and facilitates fibrinolysis. Deficiency in protein C may be inherited as an autosomal dominant trait; it is typically associated with venous thrombosis and pulmonary emboli. Smith and Ens ( 12) reported a 45year- old patient exhibiting protein C deficiency who complained of amaurosis fugax. The patient's medical history included only thrombophlebitis in the legs. Extensive clinical studies were normal except for protein C deficiency. Treated with coumadin, the patient was symptom- free during the following I- year period. Transient Uniocular Visual Loss Transient uniocular visual loss has been described upon deviation of the primary position in association with orbital tumors. Bradbury et a!. ( 13) were able to demonstrate that with abduction of an affected eye the fluorescein angiogram showed almost no perfusion of the optic nerve head, the surrounding choroid, or retinal arterioles, thus indicating that the visual loss \ vas due to a transient ischemia. Of particular interest was the loss of consensual reflex in the abducted position in one eye. The authors postulated that it was due to transient ischemia of the ciliary body. Empty Sella and Low- Tension Glaucoma Neetens and Smet ( 14) hypothesized that an empty sella could result in low- tension glaucoma, by means of the following mechanism: attrition of optic nerve axons by relative negative pressure, causing gliding ofaxons within the optic nerve, this phenomenon inducing excavation of the disc and defective oxygenation. Varia Some 15 articles devoted to various disorders of the optic nerve were assembled in the first issue of the new French journal " Ophtn/ lI1% gic, " issued by the French Society of Ophthalmology. Interested readers will find studies on topics related to optic nerve disorders, using fluorescein angiography, color vision evaluation by means of metameric equations, contrast sensitivity, or visual evoked potentials; traumatic section of the optic nerve; lupus erythematosus; Devic's disease; manioc in-toxication; meningioma radiotherapy; dysthyroid changes; radiologic appearance of calcification in optic nerve meningioma; or hypoplasia ( 15). DISORDERS OF PRIMARY POSTERIOR VISUAL PATHWAY Coenzyme Q lO Administration of high doses of coenzyme QlO ( 300 mg/ day) proved beneficial in a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes ( MELAS). The reported patient, a 17- year- old girl, presented with various clinical features, including generalized seizures and frequent episodes of cortical blindness lasting < 1 h. Lactate and the pyruvate levels were abnormally high in both serum and cerebrospinal fluid, and muscle biopsy showed typical " raggedred" fibers. In this patient, reported by Goda et a!. ( 16), coenzyme Q IO was effective in lowering serum lactate and pyruvate levels and decreasing attacks of blindness. Giant Arteritis and Posterior Cerebral Circulation Giant arteritis should be considered in the differential diagnosis of posterior circulation transient ischemic attacks because these episodes are uniquely responsive to corticosteroids. This was emphasized by Lipton et a!. ( 17), who reported the observation of such a disorder occasionally presenting with bilateral visual loss for several minutes and headaches. Prominent headaches and persistent elevated erythrocyte sedimentation rate suggested the diagnosis, which was eventually confirmed by temporal artery biopsy. Nonbenign Migraine The nonbenign aspects of migraine were studied by Kupersmith et a1. ( 18), based on their evaluation of 46 patients with complicated migraine. All their patients demonstrated transient or permanent visual dysfunction, most of which involved posterior visual pathways. Of 17 patients with cerebral infarcts, 16 showed visual field defects. The au thors believe isoprotenerol is effective when initiated with the onset of symptoms which suggest transient ischemic episode, esr""\ pcially those causing visual loss associated with migraine. Aspirin may prevent the deficit, particularly that I Clill NClIro- ol'htl", llIltll. Vol. S. No. 1, 1988 RECENT EUROPEAN LITERATURE 57 stimulation indicates that some features of the visual information displayed in the neglected hemifield are still perceived. Even when the subject was not sure that there would be stimulus in the left visual field, performance was excellent in interfield comparisons. A number of these observations are in accordance with the findings of studies reported above. Tactile Exploration of Space and Visual Neglect in Brain- Damaged Patients Tactile exploration of space and visual neglect in brain- damaged patients was investigated by Villardita ( 25) in a study involving 75 affected patients and 30 controls. The authors failed to establish any correspondence between visual and tactile neglect, and concluded that there was a modalityspecific nature of the syndrome. Recently, other authors reached similar conclusions. DIAGNOSTIC AND THERAPEUTICAL TECHNIQUES Evaluating Nerve Fiber Layer Variability in recommended techniques for evaluating nerve fiber layer by means of photography prompted Peli et al. ( 26) to compare the benefits of using one film, filter, or camera instead of another, in a masked fashion, using pairs of photographs taken from the same eye in the same manner. Twelve observers preferred photographs taken with a Canon CF- 60Z camera 69% of the time and those taken with a Zeiss FF- 111 17% of the time ( the difference was statistically significant, p < 0.01), 14 observers judged Panatomic- X film to be superior to Plus- X film 51% of the time and both films to be of the same quality 25% of the time ( p < 0.05), and 15 observers preferred standard SE- 40 filter 2: 1 over the green Spectrotech 540 filter. This difference was not statistically significant, but the blue filter gave better contrast for the nerve fibers in lightly pigmented fundi and the green filter resulted in less light scatter when ocular media opacities were present. Nerve Fiber Layer Loss in Outer Retinal Disease Nerve fiber layer loss can be demonstrated in diseases primarily involving the outer retinal layers, including the receptors, in a study by Newman et al. ( 27). Such a loss must presuppose transsynaptic degeneration, and was demonstrated in diseases like cone- rod dystrophies, Star-gardt's disease both with and without peripheral spots, vitelliform macular dystrophy, and Leber's congenital amaurosis. If this is not the result of transsynaptic degeneration, one might postulate changes in second- order neurons in the visual pathways, such as bipolar cells, amacrine cells, or ganglion cells. Image Analysis of Optic Nerve Head Computerized image analysis of the optic nerve head was performed by Walsh and Caprioli ( 28). The analyzer ( G. Rodenstock Instrumente GMBH, Munich, F. R. G.) has three functions: it evaluates optic cup size, nerve head color, and optic nerve topography. Reliability of the topographic parameters are consistent with practical clinical appraisal. The pallor maps, however, still have some variability from examination to examination; it is expected that with improvement in software, reproductibility and sensitivity of both topographic and pallor measurements will increase. Contrast Sensitivity Contrast sensitivity was assessed at nine locations within the central 100 of the visual field in cases of recovered optic neuritis showing varying degrees of residual deficit, in a study by Plant and Hess ( 29). The most common type of special loss encountered was associated with higher special frequency stimuli ( in 65 of the 82 patches examined); in 11 the loss was independent of special frequency, and in the remaining six the loss was maximal at intermediate frequency. No evidence was found that the central foveal projection is more likely to be affected following optic neuritis than projection of other eccentricities within the 100, as far as mechanisms subserving luminance vision are concerned at these spatial frequencies. Contrast sensitivity loss was studied in amblyopia and compared with that occurring in optic nerve disorders in a study by Volkers et al. ( 30). Two kinds of contrast sensitivity alterations were typical for amblyopia: ( a) discrepancy between high frequency cut- off (" grating acuity") and the Snellen acuity, and ( b) strong dependence of contrast sensitivity on the width of the stimulus. Decrease in high special frequency contrast sensitivity was atypical in optic nerve degeneration, a result which is in some contradiction to the Plant and Hess findings mentioned above; differences in methodology and subject selection may be the cause of this discrepancy. I Clill NClIro- ophtlta/ lIIol, Vol. 8, No. 1. 1988 RECENT EUROPEAN LITERATURE 59 1987; 75: 352- 355. [ Reprint requests to Sten Fredrikson, MD, Department of Neurology, Karolinska Institute, Huddinge University HospitaL S141 86 Huddinge, Stockholm, Sweden.] 9. Phadke JG. Survival pattern and cause of death in patients with multiple sclerosis: results from an epidemiological survey in north east Scotland. J Neurol Neurosurg Psychiatry 1987; 50: 523- 531. [ Reprint requests to X976 Dr. J. G. Phadke, Riyadh Military HospitaL PO Box 7897, Riyadh, 11159, Kingdom of Saudi Arabia.] 10. Thomas PK, Walker RWH, Rudge P, Morgan- Hugues JA, King RHM, Jacobs JM, Mills KR, Ormerod lEe Murray NMF, McDonald WI. Chronic demyelinating peripheral neuropathy associated with multifocal central nervous system demyelination. Brain 1987; 110: 53- 76. [ Reprint requests to Professor P. K. Thomas, Institute of Neurology, National HospitaL Queen Square, London WCl 3BG, UK) 11. Poole CJM, Russell RW, Harrison P, Savidge GF Amaurosis fugax under the age of 40 years. J Neurol Neurosurg PS1{ chiatYl{ 1987; 50: 81- 84. ( Reprint requests to Dr. C. J. M. Poole, Medical Unit, Westminster HospitaL 17 Page Street, London SWIP 2AP, U. K.] 12. Smith DB, Ens GE. Protein C deficiency: cause of amaurosis fugax? J Neurol Neurosurg Psychiatry 1987; 50: 361- 362. [ Reprint requests to Dr. Don B. Smith, 601 E Hampden Ave., Englewood, Colorado 80110, U. S. A. j 13. Bradbury PG, Levy IS, McDonald WI. Transient uniocular visual loss on deviation of the eye in association with intraorbital tumours. J Neur,, 1 Nellrosurg Psychiatry 1987; 50: 615- 619. [ Reprint requests to Dr. P Bradbury. National Hospital for Nervous Diseases, Queen Square, London WClN 3BG, U. K] 14. Neetens A, Smet H. Low tension glaucoma. A presenting sign of the empty sella syndrome. Nellro" l'hthalmolagy 1987; 7: 123- 131. [ Reprint requests to Professor A. Neetens, Eye Research Institute, University of Antwerp, UIA, Antwerp, Belgium.] 15. Optalmologie 1987; 1: 3- 89. 16. Goda S, Hamada T, Ishimoto S, Kobayashi T, Goto I, Kuroiwa Y. Clinical improvement after administration of coenzyme QJO in a patient with mitochondrial encephalomyopathy I NeuroI1987; 234: 62- 63. [ Reprint requests to S. Goda, Department of Neurology, Neurological Institute, Faculty of Medicine, Kyushi University 60,3- 1- 1 Maidashi, Higashi- ku, Fukuoka 812, Japan.] 17. Lipton RB, Rosenbaum 0, Mehler MF. Giant cell arteritis causes recurrent posterior circulation transient ischemic attacks which respond to corticosteroids. Ellr Neurol 1987; 27: 97- 100. [ Reprint requests to Dr. R. B. Lipton, Department of Neurology, Albert Einstein College of Medicine, Bronx, NY., U. S. A.) 18. Kupersmith Mj, Warren FA, Hass WK. The non- benign aspects of migraine. Neuroophthalmology 1987; 7: 1- 10. 19. Lauritzen M. Cortical spreading depression as a putative migraine mechanism. TINS 1987; 10: 8- 12. [ Reprint requests to M. Lauritzen, Department of Medical Physiology A, Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200DK Copenhagen N, Denmark. j 20. Bogousslavsky j, Miklossy J, Deruaz JP, AssaI G, Regli F. Lingual and fusiform gyri in visual processing: a clinicopathologic study of superior altitudinal hemianopia. I Neurol Neurosurg Psychiatry 1987; 50: 607- 614. [ Reprint requests to Dr. J. Bogousslavsky, Department of Neurology. CHUV, 1011 Lausanne, Switzerland.] 21. Weiskrantz L. Residual vision in a scotoma. A follow- up study of " form" discrimination. Brain 1987; 110: 77- 92. [ Reprint requests to Professor L. Weiskrantz, Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OXI 3UD, U. K.] 22. Bullier J, Kennedy H. Axonal bifurcation in the visual system. TINS 1987; 10: 205- 210. [ Reprint requests to J. Bul-lier and H. Kennedy, lNSERM, Unite 94, 16 avenue du Doyen Lepine, F- 69500 Bron, France.] 23. Ladavas E. Is the hemispatial deficit produced by right parietal lobe damage associated with retinal or gravitational coordinates? Brain 1987; 110: 167- 180. [ Reprint requests to Dr. E. Ladavas, Department of Psychology, University of Bologna Medical School, Viale Berti Pichat 5, Bologna, Italy.] 24. Karnath HO, Hartje W. Residual information processing in the neglected visual half- field. J Nellral 1987; 234: 180- 184. ( Reprint requests to Dr. W. Hartje, Department of Neurology, RWTH Aachen, Pauwelstrasse, 0- 5100 Aachen Federal Republic of Germany.) 25. Villardita C. Tactile exploration of space and visual neglect in brain- damaged patients. I Neuro/ 1987; 234: 292- 297. [ Reprint requests to Dr. C. Villardita Laboratorio de Neuropsicologia Clinica, Clinica Neurologica dell'Universita di Catania, Policlinico, Viale A. Doria 6, 1- 95, 100 Catania, Italy.) 26. Peli E, Hedges TR, Mcinnes T, Hamlin J, Schwartz B. Nerve fiber layer photography. A comparative study. Acta Ophthalmol 1987; 65: 71- 80. ( Reprint requests to Eli Peli, M. Sc., 0.0., Department of Ophthalmology, New England Medical Center, 171 Harrison Avenue, Box 450, Boston, MA 021ll, U. SA) 27. Newman NM, Stevens RA, Heckenlively JR. Nerve fiber layer loss in diseases of the outer retinal layer. Br J Ophthalmal 1987; 71: 21- 26. ( Reprint requests to N. M. Newman, Dept. OphthalmoL Pacific Presbyterian Med. Or., P. O Box 7999, San Francisco, CA 94120, U. S. A.] 28. Walsh T, Caprioli J. Computerized image analysis of the optic nerve head in neuro- ophthalmology. Neuroophthalmologll 1987; 7: 139- 146. [ Reprint requests to Th. Walsh, Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT, U. S. A.] 29. Plant GT, Hess RF. Regional threshold contrast sensitivity within the central visual field in optic neuritis. Brain 1987; 110: 489- 515. [ Reprint requests to Dr. Gordon T. Plant, National Hospital for Nervous Diseases, Queen Square, London WClN 3BG, U. K.] 30. Volkers ACW, Hagemans KH, Van der Wildt Gj, Schmitz PIM. Spatial contrast sensitivity and the diagnosis of amblyopia. Br I 0l'hthalma/ 1987; 71: 58- 65. [ Reprint requests to A. C. W. Volkers, Erasmus Universiteit Rotterdam, Postbus 1738, 3000 DR Rotterdam, The Netherlands.] 31. Regan 0, Maxner C. Orientation- selective visual loss in patients with Parkinson's disease. Bmin 1987; 110: 415- 432. [ Reprint requests to Dr. D. Regan, Department of Ophthalmology, University of Toronto, Toronto General Hospital, Toronto, Ontario M5G lL7, Canada.) 32. Wright CE, Drasdo N, Harding GFA. Pathology of the optic nerve and visual association areas. Brahl 1987; 110: 107- 120. [ Reprint requests to Dr. C. E. Wright, Clinical Neurophysiology Unit, Department oi Vision Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, U. K.] 33. Johnson LN, Yee RD, Hepler RS, Martin DA. Alteration of the visual evoked potential by macular holes: comparison with optic neuritis. Graefes Arch ( lill Exp Ol'htlwill/ ol 1987; 225: 123- 128. [ Reprint requests to R. D. Yee, Jules Stein Eye Institute, UCLA School of Medicine, 800 Westwood Plaza, Los Angeles, CA 90024, U. S. A.] 34. Holder GE. Significance of abnormal pattern electroretinography in anterior visual pathway dysfunction. Br I Opllflwill/ ol 1987; 71: 166- 171. [ Reprint requests to Dr. G. E. Holder, Regional Department of Clinical Neurophysiology, Brook General Hospital, Shooters Hill Road, London 5E18 4LW, U. K.] 35. Rushton D, Cox N. A new optical treatment for oscillopsia. f Nfl/ rol NeuroSlIrg Psychiatry 1987; 50: 411- 415. [ Reprint requests to Dr. D. N. Rushton, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, U. K.] - I Clill Nellro- ophthalmol. Vol. 8. No. 1. 1988 |
