Cases reported "Vision Disorders"

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1/38. papilledema as a 'false' localizing sign.

    A 47-year-old woman with a 3 month's history of progressive visual loss in her right eye presented with right fundus normal but with marked papilledema on the left. magnetic resonance imaging (MRI) revealed a large right 'en plaque' meningioma which was successfully removed via a pterional craniotomy. The case outlines that unilateral papilledema offers little information concerning tumor localization, and may represent a 'false' localizing sign.
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2/38. A case of impaired auditory and visual speech prosody perception after right hemisphere damage.

    It is well established that vision plays a role in segmental speech perception, but the role of vision in prosodic speech perception is less clear. We report on the difficulties in prosodic speech perception encountered by KB after a right hemisphere stroke. In addition to musical deficits, KB was suspected of having impaired auditory prosody perception. As expected, KB was impaired on two prosody perception tasks in an auditory-only condition. We also examined whether the addition of visual prosody cues would facilitate his performance on these tasks. Unexpectedly, KB was also impaired on both tasks under visual-only and audio-visual conditions. Thus, there was no evidence that KB could integrate auditory and visual prosody information or that he could use visual cues to compensate for his deficit in the auditory domain. In contrast, KB was able to identify segmental speech information using visual cues and to use these visual cues to improve his performance when auditory segmental cues were impoverished. KB was also able to integrate audio-visual segmental information in the McGurk effect. Thus, KB's visual deficit was specific to prosodic speech perception and, to our knowledge, this is the first reported case of such a deficit.
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3/38. B-scan ultrasonography in the diagnosis of atypical retinoblastomas.

    Contact B- scan ultrasonography (Bronson-Turner unit) was performed on fourteen patients with retinoblastoma. In ten cases, the patient presented with leukocoria, and ultrasonography was helpful in confirming the clinical diagnosis. In four atypical cases contact B-scan ultrasonography was instrumental in making the diagnosis. The ultrasonographic pattern for retinoblastoma is characteristic but not pathognomic. There is a solid intraocular echo corresponding to the tumor and within it are numerous dense focal echoes which persist at lower sensitivities, suggesting calcification. Calcification was demonstrated ultrasonographically and confirmed histologically in all four of these atypical cases, but routine skull x-rays failed to demonstrate calcium in three of the four children. Contact B- scan ultrasonography is a safe and simple procedure which may provide valuable diagnostic information in children with suspected retinoblastoma.
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4/38. Abnormalities of scanning laser polarimetry associated with pituitary adenoma.

    PURPOSE: To report abnormalities of retinal nerve fiber layer (RNFL) thickness using scanning laser polarimetry in patients with pituitary adenoma. DESIGN: Observational case reports. methods: Two patients with pituitary adenoma who had bitemporal visual field abnormalities were examined using scanning laser polarimetry. RESULTS: In Case 1, destruction of the normal two-peak pattern in the RNFL thickness was seen nasally by scanning laser polarimetry; this RNFL pattern corresponded well to visual field abnormalities. In Case 2, abnormalities in the RNFL pattern corresponded well to visual field defects not only in the superotemporal fields but also in the inferotemporal fields where the visual field defects were mild. CONCLUSIONS: Measurement of RNFL thickness using scanning laser polarimetry provides useful information in the diagnosis of chiasmal lesions such as pituitary adenomas.
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5/38. levofloxacin-induced autoimmune hemolytic anemia.

    OBJECTIVE: To report a case of autoimmune hemolytic anemia (AIHA) secondary to levofloxacin. CASE SUMMARY: An 82-year-old white man was treated with levofloxacin 500 mg/d for cellulitis. Three days following completion of levofloxacin therapy, the patient presented to the emergency department with severe jaundice, dizziness, and loss of vision. He received packed red blood cells (PRBCs) and was discharged home. Two days later at the follow-up visit, he was diagnosed with AIHA secondary to levofloxacin. The patient was hospitalized and treated with a tapering dose of prednisone and additional PRBC infusion. He was discharged from the hospital in stable condition after 3 days. Repeated hematologic laboratory studies following discharge demonstrated that the hemolytic anemia had resolved. DISCUSSION: Hemolytic anemia due to levofloxacin is an extremely rare, but potentially fatal, adverse drug event. An objective causality assessment revealed that the adverse reaction was probable. To our knowledge, this is the first published case of levofloxacin-induced AIHA. However, there are published case reports of hemolytic anemia with other fluoroquinolones including ciprofloxacin (n = 12) and temafloxacin (n = 95). Temafloxacin was withdrawn from the market in 1992 due to this adverse effect. The mechanism by which levofloxacin triggers hemolytic anemia is unknown. We believe that an immune-mediated reaction is most likely. CONCLUSIONS: levofloxacin-induced AIHA is a rare but serious complication of therapy. Immediate discontinuation of the offending medication and treatment of the hemolytic anemia are essential. Until more information is available, levofloxacin should not be prescribed for patients with previous reactions to any fluoroquinolone.
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6/38. Clinical application of the multifocal visual evoked potential.

    BACKGROUND: Measures of visual function thresholds such as visual acuity and visual fields are generally dependent on subjective responses and assume maintenance of fixation, attention and motivation. In the young, elderly, cognitively impaired or malingering populations, such measures may be inaccurate or difficult to obtain. The Visual Evoked Response Imaging System (VERIS) has been claimed to give more objective topographic recordings of retinal and cortical function. This paper aims to explore the adequacy of this technique in four unusual, unrelated, clinically difficult cases. methods: Multifocal visual evoked potentials (mfVEPs) recorded on the VERIS System 3.01 are used to assess visual function in four cases with contradictory clinical findings or unreliable subjective responses. RESULTS: Patient 1 had sustained a head injury and had normal ocular and pupil examination but light perception in the right eye and 6/5 acuity in the left. Multifocal VEPs showed a marked depression of the right visual field with little macular response. Patient 2 had sustained a head injury, had a left field hemianopia, possible macular sparing and loss of much of the right field, reduced but variable visual acuities, good near vision and normal ocular fundi. Multifocal VEPs showed a severe depression in both visual fields (L more than R) with little macular response. Patient 3 had a left optic nerve meningioma and experienced great difficulty with visual field assessment. mfVEPs showed a bilateral depression in the superior field particularly the left field, with a larger deficit in the left eye. Patient 4 had unexplained visual acuity and peripheral field deficits. mfVEP results were inconclusive in this case. DISCUSSION: Where there is difficulty performing traditional techniques or conflicting clinical findings, mfVEPs may provide additional objective information to aid in the assessment of patients.
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7/38. Characteristics of patients with a favorable natural course of myopic choroidal neovascularization.

    OBJECTIVE: To identify the characteristics of patients with myopic choroidal neovascularization (CNV) who had a favorable visual prognosis without treatment. methods: We reviewed the medical records of 52 consecutive patients (57 eyes) with myopic CNV who were followed for at least 5 years after the onset of CNV. Clinical characteristics (patient age, CNV size and location, visual acuity at onset, chorioretinal atrophy development around CNV, and degree of myopia) were compared between patients whose visual acuity 5 years after CNV onset was better than 20/40 and those whose visual acuity was worse than 20/200. RESULTS: Among 57 eyes, eight eyes (14.0%; 8 patients) had a final visual acuity better than 20/40. On the other hand, 37 eyes (64.9%; 33 patients) had a final visual acuity worse than 20/200. Statistical analysis revealed that the patients with a good prognosis (final visual acuity better than 20/40) were significantly younger, had significantly smaller CNV, and significantly better initial visual acuity (Mann-Whitney U-test, p<0.05). Juxtafoveal CNV was more frequently observed in patients with a good prognosis than in those with a poor prognosis (Fisher's exact probability test, p<0.05). Only one patient (12.5%) in the good prognosis group developed a very limited area of chorioretinal atrophy around the regressed CNV, while 91.9% of the patients in the poor prognosis group developed chorioretinal atrophy. Refractive status and the axial length measurements did not differ between the two groups. CONCLUSIONS: Some young patients with myopic CNV retain favorable vision over the long term without active treatment. These information might be useful to predict the visual outcome of patients with myopic CNV.
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8/38. Combined three-dimensional anisotropy contrast imaging and magnetoencephalography guidance to preserve visual function in a patient with an occipital lobe tumor.

    OBJECTIVE: Three-dimensional anisotropy contrast (3-DAC) magnetic resonance imaging and magnetoencephalography (MEG) of visually evoked magnetic fields (VEFs) were used to accurately localize the optic radiation and primary visual cortex before surgery for an occipital tumor. PATIENT AND methods: A 26-year-old male presented with an occipital lobe tumor located intrinsically underneath the right calcarine fissure. 3-DAC imaging showed that the right optic radiation was located along the superior and lateral surfaces of the lesion. Mapping of the VEFs demonstrated that the primary visual cortex was located superior and lateral to the lesion. The lesion was totally resected via an infero-medial cortical incision using a frameless stereotactic system. Histopathology indicated a pilocytic astrocytoma. No visual deficit was found before or after surgery. CONCLUSION: Combined 3-DAC imaging and MEG can provide essential information about the optic radiation and primary visual cortex for planning the surgical treatment of occipital lobe tumors.
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9/38. Surgical procedures performed after refractive surgery.

    BACKGROUND: refractive surgical procedures have been performed for over one decade. The complications that cause visual disability are abnormalities in wound healing, residual ametropia, and/or severe irregular astigmatism. Many of these complications can be manifested clinically in terms of visually disabling problems (loss of best-corrected vision, glare, monocular diplopia, etc). Some of these complications require additional standard ophthalmic or refractive surgical procedures to restore vision. However, since these secondary procedures have been performed in only a few cases, we known little about their outcome. methods: We report the histopathologic analysis of 132 cases that have undergone a secondary surgical procedure following a primary keratorefractive procedure. We attempt to correlate the problems encountered with such secondary intervention with histopathologic information obtained from specimens that have been submitted to our pathology laboratory and that had undergone secondary surgical procedures. RESULTS: Many specimens displayed abnormalities in wound healing associated with visual difficulties such as loss of best corrected acuity, glare, and under- and overcorrection. A short time from the initial procedure to the time of secondary intervention was common. CONCLUSIONS: The combination of a secondary surgical or keratorefractive procedure can produce unpredictable refractive results. Judicious application of a refractive procedure and an appropriate time period before a second procedure is performed may reduce unexpected refractive complications.
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10/38. Differential impact of parvocellular and magnocellular pathways on visual impairment in apperceptive agnosia?

    The term "visual form agnosia" describes a disorder characterized by problems recognizing objects, poor copying,and distinguishing between simple geometric shapes despite normal intellectual abilities. Visual agnosia has been interpreted as a disorder of the magnocellular visual system, caused by an inability to separate figure from ground by sampling information from extended regions of space and to integrate it with fine-grain local information. However,this interpretation has hardly been tested with neuropsychological or functional brain imaging methods, mainly because the magnocellular and parvocellular structures are highly interconnected in the visual system.We studied a patient (AM) who had suffered a sudden heart arrest, causing hypoxic brain damage. He was/is severely agnosic, as apparent in both the Birmingham Object Recognition Battery and the Visual Object and Space Battery. First- and especially second-order motion perception was also impaired, but AM experienced no problems in grasping and navigating through space. The patient revealed a normal P100 in visual evoked potentials both with colored and fine-grained achromatic checkerboards. But the amplitude of the P100 was clearly decreased if a coarse achromatic checkerboard was presented.The physiological and neuropsychological findings indicate that AM experienced problems integrating information over extended regions of space and in detecting second-order motion. This may be interpreted as a disorder of the magnocellular system, with intact parvocellular system and therefore preserved ability to detect both local features and colors.
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