1/23. Bilateral angle closure glaucoma and visual loss precipitated by antidepressant and antianxiety agents in a patient with depression.A 71-year-old woman with depression had been treated with an antidepressant (maprotiline) and antianxiety agents (clotiazepam and alprazolam). She had previously complained of ocular pain and blurred vision. However, thorough ocular examination was not performed at those times. On examination, visual acuity was no light perception OD and hand motion OS. Intraocular pressures were 33 mm Hg OU. Moderately dilated pupils, atrophic irises, shallow anterior chambers and closed angles were seen in both eyes. Despite treatment, her visual acuity decreased to no light perception bilaterally. Psychiatrists and ophthalmologists should be aware that antidepressants and antianxiety agents can precipitate angle closure glaucoma in susceptible eyes.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
2/23. Can a motion-blind patient reach for moving objects?It has been claimed that the visual brain is organized in two separate processing streams for spatial vision: one for perception and one for action. To determine whether motion vision is also divided into vision for action and for perception we examined the interceptive behaviour of the motion-blind patient LM. The task for LM and three age-matched control subjects was to reach-and-grasp for an object that moved away. Three experiments were conducted to examine the effects on perfomance of target speed (Expt 1), observation time (Expt 2) and visual feedback (Expt 3). As LM is only able to reach for objects which move at 0.5 m/s or less, her performance is inferior to that of controls who can reach for objects moving at 1.0 m/s, but it is better than would be expected from her performance in psychophysical experiments on her motion vision. Kinematic analysis of LM's reaching movements showed that she adapted the speed of her moving hand to the speed of the target but only when full vision was available. In contrast to normal subjects, LM required long observation times and vision of her moving hand to produce successful reaching responses. Thus, the impairment of both perception and action in LM suggests that the motion area MT/V5 is located at an early stage of the extrastriate hierarchy and provides input to both the perception and the action processing streams.- - - - - - - - - - ranking = 8keywords = motion (Clic here for more details about this article) |
3/23. Unseen stimuli modulate conscious visual experience: evidence from inter-hemispheric summation.Emotional facial expression can be discriminated despite extensive lesions of striate cortex. Here we report differential performance with recognition of facial stimuli in the intact visual field depending on simultaneous presentation of congruent or incongruent stimuli in the blind field. Three experiments were based on inter-hemispheric summation. Redundant stimulation in the blind field led to shorter latencies for stimulus detection in the intact field. Recognition of the expression of a half-face expression in the intact field was faster when the other half of the face presented to the blind field had a congruent expression. Finally, responses to the expression of whole faces to the intact field were delayed for incongruent facial expressions presented in the blind field. These results indicate that the neuro-anatomical pathways (extra-striate cortical and sub-cortical) sustaining inter-hemispheric summation can operate in the absence of striate cortex.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
4/23. Bilateral optic disk edema and blindness as initial presentation of acute lymphocytic leukemia.PURPOSE: To report bilateral optic disk edema and blindness as the unusual initial presentation of acute lymphocytic leukemia (ALL) in an adult. methods: A 19-year-old man presented with a history of headaches, back pain, and 10 days of worsening vision that progressed to blindness. Ocular examination revealed light perception acuity in the right eye and no light perception in the left eye. Fundus examination revealed bilateral profound optic disk edema, tortuous vessels, and retinal hemorrhages. Acute lymphocytic leukemia was diagnosed with complete blood count and bone marrow biopsy. head computed tomography and magnetic resonance imaging, were normal. Lumbar puncture revealed normal opening pressure. Ocular ultrasonography showed bilateral optic nerve enlargement. DESIGN: Interventional case report and literature review. ESULTS: The presumptive diagnosis of leukemic infiltration of the optic nerves was made, and urgent radiotherapy, intrathecal methotrexate, and intravenous daunorubicin were instituted. visual acuity improved to hand motions in the right eye. CONCLUSIONS: Acute lymphocytic leukemia can rarely present in adults as visual changes due to leukemic optic nerve infiltration. radiation treatment should be considered as an urgent treatment modality for this rare condition.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
5/23. blindness after liver transplant.A 58-year-old woman developed a generalized seizure 12 days after undergoing liver transplantation and awakened with persistent hand motions vision binocularly. cyclosporine levels were normal and blood pressure was only mildly elevated. The ophthalmic and neurologic examinations were otherwise normal. brain MRI revealed bilateral parieto-occipital white matter signal abnormalities consistent with vasogenic edema. The cyclosporine was abruptly replaced with tacrolimus and the patient recovered normal vision within 48 hours. A subsequent brain MRI taken 30 days later showed that the patient had reverted to normal. This is an example of posterior leukoencephalopathy owing to cyclosporine toxicity. It points out that visual loss may be an isolated or most prominent clinical manifestation, cyclosporine and blood pressure levels may be normal, deficits are reversible if cyclosporine is promptly discontinued, and tacrolimus, a similar immunosuppressive agent, may be a safe substitute.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
6/23. Blindsight modulation of motion perception.Monkey data suggest that of all perceptual abilities, motion perception is the most likely to survive striate damage. The results of studies on motion blindsight in humans, though, are mixed. We used an indirect strategy to examine how responses to visible stimuli were modulated by blind-field stimuli. In a 26-year-old man with focal striate lesions, discrimination of visible optic flow was enhanced about 7% by blind-field flow, even though discrimination of optic flow in the blind field alone (the direct strategy) was at chance. Pursuit of an imagined target using peripheral cues showed reduced variance but not increased gain with blind-field cues. Preceding blind-field prompts shortened reaction times to visible targets by about 10 msec, but there was no attentional crowding of visible stimuli by blind-field distractors. A similar efficacy of indirect blind-field optic flow modulation was found in a second patient with residual vision after focal striate damage, but not in a third with more extensive medial occipito-temporal damage. We conclude that indirect modulatory strategies are more effective than direct forced-choice methods at revealing residual motion perception after focal striate lesions.- - - - - - - - - - ranking = 7keywords = motion (Clic here for more details about this article) |
7/23. aspergillosis presenting as an optic neuritis.A 59-year-old woman was referred to our clinic with sudden visual loss in her right eye after she was treated with 40 mg/day of oral prednisolone for 2 weeks under the diagnosis of idiopathic optic neuritis. At that time, computerized tomography (CT) of the brain showed no evidence of optic nerve or brain pathology. However, there was progressive diminution of right visual acuity associated with a limitation of adduction and abduction in the right eye. On magnetic resonance imaging and repeated CT, a malignant lesion was suggested, and was confirmed as an aspergillus fungus colony by histopathologic examination. Postoperatively, she was treated with intravenous administration of amphotericin B for 13 weeks. However, her condition continued to deteriorate. She developed ptosis and total ophthalmoplegia in the right eye and blindness in both eyes. After discharge, she was given itraconazole for 20 weeks. She has shown no recovery of visual acuity or extraocular motion during a two-year follow-up period. The clinical features of our case suggest that early diagnosis in a case of aspergilloma presenting with visual loss is difficult and that a high index of suspicion, repeated radiological examination and adequate biopsy may be required for diagnosis.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
8/23. visual perception in a blind subject with a chronic microelectronic retinal prosthesis.A retinal prosthesis was permanently implanted in the eye of a completely blind test subject. This report details the results from the first 10 weeks of testing with the implant subject. The implanted device included an extraocular case to hold electronics, an intraocular electrode array (platinum disks, 4 x 4 arrangement) designed to interface with the retina, and a cable to connect the electronics case to the electrode array. The subject was able to see perceptions of light (spots) on all 16 electrodes of the array. In addition, the subject was able to use a camera to detect the presence or absence of ambient light, to detect motion, and to recognize simple shapes.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
9/23. Perception of optical flow in cortical blindness: a case report.motion perception was studied in a subject with bilateral lesion of the visual cortex, involving severe damage to cortical areas V1 and V4, but with no apparent damage to visual associative areas situated in occipito-parietal and lateral occipito-temporal (presumably V5) zones. He was able to perceive optical flow motions simulating motion in depth in "blind" parts of his visual field, provided that the stimulus-onset was temporally dissociated from its motion. Moreover, he was able to discriminate between different velocities and directions of motion. The results suggest that perimetrically "blind" parts of the visual field in this patient have true capacities to process visual motion. They are discussed in reference to the subject's ability to move freely in his environment and in reference to the role of extrastriate visual pathways in visual motion processing.- - - - - - - - - - ranking = 6keywords = motion (Clic here for more details about this article) |
10/23. Stage IV hepatic encephalopathy associated with acute blindness after liver transplantation.A 5-yr-old boy who diagnosed acute liver failure and Stage IV hepatic encephalopathy underwent living related liver transplantation and awakened with persistent hand motions visual loss. serum tacrolimus, electrolytes, magnesium levels were normal as well as blood pressure. His neurologic and opthamologic examinations were otherwise normal. Visual evoked potential (VEP) was prolonged and brain magnetic resonance immaging (MRI) revealed bilateral parietooccipital white matter signal abnormalities with gliosis. During follow up his visual loss resolved spontoneously as well as the VEP and MRI abnormalities. In this case we aimed to point out hepatic encephalopathy might be a cause of postoperative visual loss and serial VEP analysis is an important diagnostic tool for monitoring visual function of liver graft recipients in the post-operative period.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
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