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Show LITERATURE ABSTRACTS 53 Liesegang T, Lass J, Sutphin JE, Wilhelmus K, Jones DB, Chapman S, Segreti AC, King DH. Ophthalmology 1986;93:763-70 (June). [Reprint requests to L. Michael Cobo, M.D., Box 3802, Duke University Medical Center, Durham, NC 27710.] Seventy-one patients with herpes zoster ophthalmicus presenting within 7 days of the onset of skin lesions were randomized to receive either Acyclovir 600 mg five times a day for 10 days or a placebo. Although patients receiving the placebo seemed to start out with more corneal and anterior chamber disease than those receiving Acyclovir, while on therapy clearly fewer new manifestations of ocular disease occurred in treated versus nontreated patients. Pain was decreased in the treatment group during treatment, but Acyclovir did not affect the presence or severity of postherpetic neuralgia. Unfortunately for neuro-ophthalmologists, no patients had either optic neuritis or cranial neuropathies, and certainly a larger trial would be needed for statistical significance for these rare complications of herpes zoster ophthalmicus. One has the feeling from reading this and another current article [Watson PN, Evans RJ. Post-herpetic neuralgia. Arch Neural 1986;43:83640 (Aug)] on the subject that the best treatment for these patients probably is amitriptyline or prednisone and acyclovir (and perhaps J. Lawton Smith's secret weapon, Tagamet). LYIl A. Sedwick, M.D. Metamorphopsia and Permanent Cortical Blindness after a Posterior Fossa Tumor. Brau RH, Lameiro J, Llaguno AV, Rifkinson N. Neurosurgery 1986;19:263-6 (Aug). [Reprint requests to Richard H. Brau, M.D., Department of Neurosurgery, University of Puerto Rico School of Medicine, San Juan, Puerto Rico.] "Metamorphopsia" is generally considered to mean a perceived irregularity in appearance of objects. It usually indicates retinal disease and is caused by disruption of the normal photoreceptor architecture. In their article, the authors use the term metamorphopsia in a more general sense to describe an illusory distortion of objects of cortical origin. The authors quote a classic article by Macdonald Critchley, but unfortunately, in the reference list, an incorrect citation is supplied. (The correct citation should be: Critchley M. Metamorphopsia of central origin. Trans Ophthalmol Soc UK 1949;69:111-21.) Critchley described and gave clinical examples of a variety of cortical phenomena. Macropsia denotes a perceived enlargement of objects, whereas micropsia refers to a perceived diminution in their size. Achromatopsia designates a lack of color, and erythropsia signifies red monochrome vision. Teleopsia specifies a disturbance in vision where objects not only appear small, but at a distance, as if viewed through a concave lens. Palinopsia refers to visual perseveration, in which an object previously seen reappears. The article by Critchley is fascinating and I recommend it to those wishing to know more details than are covered here. Now that we have discussed cortical phenomena let us turn to the authors' case report. They describe a 57-year-old white woman who underwent a posterior fossa craniectomy for a large intraparencymatous cerebellar tumor. The pathological report identified the mass as an epidermoid tumor. The day after surgery, the patient felt dizzy and described seeing the ceiling light rotated 180°; intermittently, she would have the impression that people seemed shorter than they really were. On the third postoperative day, the ceiling lights in addition to being rotated, sometimes were seen to be far away. The patient saw her relatives and hospital personnel as being consistently shorter than they were and sometimes upside down. She also described a few instances in which only the upper half of a person was appreciated as upside down. On her fourth postoperative day, the patient stated she could not see at all. Her pupillary light reflexes were normal. On December 8, a repeat angiogram showed severe diffuse spasm on the basilar, posterior cerebral, right supraclinoid internal carotid, and anterior cerebral arteries. A follow-up computed tomographic scan demonstrated bilateral occipital low density lesions. The authors suggest posttumoral vasospasm as a possible etiological mechanism for the clinical picture. This case report illustrates multiple types of cortical visual alterations. Clearly the patient exhibited micropsia and teleopsia. Of particular interest is that the patient described the ceiling light to be rotated 180°. Perhaps this represents an example of tilting of the visual environment as described by Ropper. (Illusion of tilting of the visual environment. J Clill Neuro-OphthalnlOl 1983;3:147-51.) In this condition, patients perceive the visual fields as tilted through a variable arc, most frequently 90-180°. Ropper suggested that this illusion of tilting is due to disorders of the vestibular-otolithic apparatus or its central connections, most fre- I Clin Neuro-ophthallllol, Vol. 7, No. ], ]987 54 LITERATURE ABSTRACTS quently from vertebral-basilar ischemia. This would certainly be consistent with the pathology in the present case report. Walter M. Jay, M.D. Moyamoya Pattern of Vascular Occlusion after Radiotherapy for Glioma of the Optic Chiasm. Beyer RA, Paden P, Sobel OF, Flynn FG. Neurology 1986;36:1173-8 (Sept). [Reprint requests to Technical Publications Editor, Letterman Army Medical Center, Presidio of San Francisco, CA 94129-6700.] In the moyamoya pattern of vascular occlusion, there is an extensive basal cerebral rete mirabilea network of small anastomatic vessels at the base of the brain associated with occlusion of the terminal parts of both internal carotids. This vascular pattern was seen on arteriography in three children following intracranial irradiation for optic chiasm gliomas. All three patients had suffered massive strokes. Two of the three exhibited dramatic reduction in tumor size on computed tomography. There is controversy as to what is the appropriate therapy for chiasmal gliomas. Although radiation is commonly used in the treatment of chiasmal gliomas, its value is questioned by many. This article reviews three cases with severe complications of radiation therapy. Another recent article discusses two cases with similar complications. (Okuno T, Prensky A, Gado M. The moyamoya syndrome associated with irradiation of an optic glioma in children: report of two cases and a review of the literature. Pediatr Neurol 1985;1: 311-6.) In the present study, each of the three patients received more than 5,000 rads. Most authors recommend using fewer than 5,000 rads, especially in children under two. Proponents of radiation therapy could argue that the complications were not due to radiation therapy but to an excessive dosage. However, the two cases reported by Okuno et al. received fewer than 5,000 rads. Walter M. Jay, M.D. Near~EvokedNystagmus in Spasmus Nutans. Chrousos GA, Matsuo V, Ballen AE, Cogan DG. J Pediatr Ophthalmol Strabismus 1986; 23:141-3 (May/ June). [Reprint requests to Georgia A. Chrousos, M.D., Department of Ophthalmology, Georgetown University Medical Center, 3800 Reservoir Road N.W., Washington, D.C. 20007.] Spasmus nutans is characterized by nystagmus, head nodding, and an abnormal head position. The nystagmus is usually horizontal, of small amplitude, and of high frequency. It is often unilateral. When both eyes are involved, it tends to be asymmetric. The present article describes two cases of atypical spasmus nutans with nystagmus present only at near fixation. In the first case, nystagmus at near fixation could be blocked by covering either eye. In the second, covering either eye at near fixation alone did not dampen the nystagmus. However, the combination of occluding one eye and placing a + 3.00 spherical lens in front of the viewing eye eliminated the nystagmus. The authors concluded that in the first case, fusional convergence was necessary for development of nystagmus and in the second, accommodative convergence was. A clinical picture similar to spasmus nutans has been described in children with brain tumors, particularly of the anterior visual pathways. Some authors argue that all patients with spasmus nutans should be studied with computed tomography. It is not stated whether computed tomographic scanning was carried out on the authors' two patients. At any rate, both were followed over time. In the first, nystagmus disappeared, and in the second, episodes of nystagmus became less frequent. Walter M. Jay, M.D. A Severe Carotid-Cavernous Fistula Treated with a Balloon Catheter. Harbour RC, Luxenberg MN. Arch Ophthalmol 1986;104:1084-5 (July). [No reprint information given.] This "photo essay" depicts a 35-year-old man who had had a gunshot wound to the left side of his face 8 years previously. He had all the usual ophthalmic signs of a carotid-cavernous fistula and also quite remarkable, dilated, tortuous forehead veins. He was successfully treated with balloon occlusion. Lyn A. Sedwick, M.D. |