The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Moshe Lazar - One of the best experts on this subject based on the ideXlab platform.
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Dapiprazole for patients with night haloes after excimer keratectomy
Graefe's Archive for Clinical and Experimental Ophthalmology, 1996Co-Authors: Yair Alster, Anat Loewenstein, Tami Baumwald, Isaac Lipshits, Moshe LazarAbstract:• Background: Haloes causing difficulties during night driving are one of the common complications of photorefractive keratectomy (PRK). The presumed reason for this phenomenon is the different refraction of light through the treated and untreated areas of the cornea. Its magnitude is proportional to the ratio between the treated area and pupil size. At nighttime, when the pupil dilates, rays from treated and untreated areas of the cornea reach the retina at different foci and produce haloes. We investigated whether Dapiprazole, a miotic α-blocker drug, would be helpful in reducing night haloes in patients after PRK. • Methods: Twenty-four patients who complained of night haloes after PRK participated in our study. All were given Dapiprazole 0.5% before night driving. Change in pupil size was recorded, and all patients completed a questionnaire on changes in the severity of haloes after instillation of Dapiprazole. • Results: Improvement was described as very significant in five patients, moderate in ten and slight in seven. There was no improvement in two patients. The only side effect was slight irritation, which resolved within 1 h. • Conclusion: Our results demonstrate that Dapiprazole improves the subjective discomfort caused by night haloes in post-PRK patients.
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The additive miotic effects of Dapiprazole and pilocarpine
Graefes Archive for Clinical and Experimental Ophthalmology, 1995Co-Authors: Orna Geyer, Bruria Shalmon, Meira Neudorfer, Anat Loewenstein, Moshe LazarAbstract:• Background: Since Dapiprazole on alpha-adrenergic agent, produces miosis by paralyzing the dilator muscle, and pilocarpine, a parasympathetic drug, causes miosis by affecting the sphincter, we speculated that the two drugs might have additive effects. • Methods: The additive miotic actions of pilocarpine 2% and Dapiprazole 0.5% were evaluated by comparing the effects of two drugs given together and alone on the reversal of mydriasis induced by tropicamide (0.5%) and phenylephrine (10%) in one eye each of 60 healthy volunteers. • Results: Dapiprazole and pilocarpine together induced miosis significantly faster than each drug alone, showing additive effects. • Conclusion: Co-administration of Dapiprazole and pilocarpine at the end of the eye examination will induce fast pupillary constriction, which might be useful in preventing the development of an acute attack of angle-closure glaucoma in patients with anatomically narrow angles.
Misha Pless - One of the best experts on this subject based on the ideXlab platform.
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Pharmacological Isolation of Cognitive Components Influencing the Pupillary Light Reflex.
Journal of ophthalmology, 2015Co-Authors: Stuart R. Steinhauer, Ruth Condray, Misha PlessAbstract:Cognitive operations can be detected by reduction of the pupillary light response. Neurophysiological pathways mediating this reduction have not been distinguished. We utilized selective blockade of pupillary sphincter or dilator muscles to isolate parasympathetic or sympathetic activity during cognition, without modifying central processes. Pupil diameter was measured during the light reaction in 29 normal adults under three processing levels: No Task, during an easy task (Add 1), or a difficult task (Subtract 7). At three separate sessions, the pupil was treated with placebo, tropicamide (blocking the muscarinic sphincter receptor), or Dapiprazole (blocking the adrenergic dilator receptor). With placebo, pupil diameter increased with increasing task difficulty. The light reaction was reduced only in the Subtract 7 condition. Dapiprazole (which decreased overall diameter) showed similar task-related changes in diameter and light reflex as for placebo. Following tropicamide (which increased overall diameter), there was a further increase in diameter only in the difficult task. Findings suggest two separate inhibitory components at the parasympathetic oculomotor center. Changes in baseline diameter are likely related to reticular activation. Inhibition of the light reaction in the difficult task is likely associated with cortical afferents. Sustained sympathetic activity also was present during the difficult task.
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sympathetic and parasympathetic innervation of pupillary dilation during sustained processing
International Journal of Psychophysiology, 2004Co-Authors: Stuart R. Steinhauer, Ruth Condray, Greg J Siegle, Misha PlessAbstract:The contributions of separate sympathetic and parasympathetic pathways to pupillary dilation during a sustained processing task were studied through environmental and pharmacological manipulations. In Experiment 1, 22 healthy volunteers (11 female) performed a serial Subtract 7 task while pupil diameter was recorded both during moderate room light and in darkness. In a control for verbalization, subjects performed an easier Add 1 task. In all conditions, pupil diameter increased significantly during the response period as compared to a pre-verbalization baseline period. Pupillary dilation was increased for the difficult task, and further increase in dilation was associated with recording in light. This suggests a major differential contribution to task difficulty mediated through inhibition of the parasympathetic pathway. In Experiment 2, a subgroup of 12 volunteers (seven female) repeated all conditions at three additional sessions in which one eye was instilled with tropicamide (to block the parasympathetic sphincter muscle), Dapiprazole (to block the sympathetic dilator muscle) or placebo. All pharmacological conditions resulted in overall dilation during task performance. Differential performance similar to the placebo condition was seen only in the Dapiprazole condition, when parasympathetic activation was intact. The findings suggest that sustained performance during a difficult task is modulated by cortical inhibition of the parasympathetic pathway at the oculomotor nucleus. Moreover, modulation of both ambient light intensity and pharmacological blockade of the final pupillary musculature were observed to provide converging approaches for quantifying the activity of identifiable central autonomic pathways.
E Vesti - One of the best experts on this subject based on the ideXlab platform.
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Diagnosis and management of pigmentary glaucoma
Current Opinion in Ophthalmology, 1998Co-Authors: I Lehto, E VestiAbstract:Pigment dispersion syndrome and pigmentary glaucoma affect typically young, myopic persons. Iridozonular contact causes pigment dispersion and obstruction of the trabecular meshwork. Accumulation of pigment may result in transient elevation of intraocular pressure or irreparable damage to the meshwork accompanied by uncontrolled glaucoma. In the reviewed publications the transition from pigment dispersion syndrome to pigmentary glaucoma was found to be 20%. The main risk factors for the transition were ocular hypertension and myopia. Dapiprazole, an alpha-adrenergic blocking agent, was found to be effective in treating pigmentary glaucoma and in preventing pressure spikes after exercise. Dapiprazole causes miosis without affecting accommodation. Yttrium aluminum garnet laser iridotomy reduced the incidence of ocular hypertension in pigment dispersion syndrome, although the effect was less pronounced in persons older than 40 years of age. Lattice degeneration was found in 33.3% of the eyes with pigment dispersion syndrome.
Stuart R. Steinhauer - One of the best experts on this subject based on the ideXlab platform.
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Clinical Study Pharmacological Isolation of Cognitive Components Influencing the Pupillary Light
2016Co-Authors: Stuart R. Steinhauer, Ruth Condray, Misha L. PlessAbstract:License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Cognitive operations can be detected by reduction of the pupillary light response. Neurophysiological pathways mediating this reduction have not been distinguished. We utilized selective blockade of pupillary sphincter or dilator muscles to isolate parasympathetic or sympathetic activity during cognition, without modifying central processes. Pupil diameter was measured during the light reaction in 29 normal adults under three processing levels: No Task, during an easy task (Add 1), or a difficult task (Subtract 7). At three separate sessions, the pupil was treated with placebo, tropicamide (blocking the muscarinic sphincter receptor), or Dapiprazole (blocking the adrenergic dilator receptor). With placebo, pupil diameter increased with increasing task difficulty. The light reaction was reduced only in the Subtract 7 condition. Dapiprazole (which decreased overall diameter) showed similar task-related changes in diameter and light reflex as for placebo. Following tropicamide (which increased overall diameter), there was a further increase in diameter only in the difficult task. Findings suggest two separate inhibitory components at the parasympathetic oculomotor center. Changes in baseline diameter are likely related to reticular activation. Inhibition of the light reaction in the difficult task is likely associated with cortical afferents. Sustained sympathetic activity also was present during the difficult task. 1
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Pharmacological Isolation of Cognitive Components Influencing the Pupillary Light Reflex.
Journal of ophthalmology, 2015Co-Authors: Stuart R. Steinhauer, Ruth Condray, Misha PlessAbstract:Cognitive operations can be detected by reduction of the pupillary light response. Neurophysiological pathways mediating this reduction have not been distinguished. We utilized selective blockade of pupillary sphincter or dilator muscles to isolate parasympathetic or sympathetic activity during cognition, without modifying central processes. Pupil diameter was measured during the light reaction in 29 normal adults under three processing levels: No Task, during an easy task (Add 1), or a difficult task (Subtract 7). At three separate sessions, the pupil was treated with placebo, tropicamide (blocking the muscarinic sphincter receptor), or Dapiprazole (blocking the adrenergic dilator receptor). With placebo, pupil diameter increased with increasing task difficulty. The light reaction was reduced only in the Subtract 7 condition. Dapiprazole (which decreased overall diameter) showed similar task-related changes in diameter and light reflex as for placebo. Following tropicamide (which increased overall diameter), there was a further increase in diameter only in the difficult task. Findings suggest two separate inhibitory components at the parasympathetic oculomotor center. Changes in baseline diameter are likely related to reticular activation. Inhibition of the light reaction in the difficult task is likely associated with cortical afferents. Sustained sympathetic activity also was present during the difficult task.
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sympathetic and parasympathetic innervation of pupillary dilation during sustained processing
International Journal of Psychophysiology, 2004Co-Authors: Stuart R. Steinhauer, Ruth Condray, Greg J Siegle, Misha PlessAbstract:The contributions of separate sympathetic and parasympathetic pathways to pupillary dilation during a sustained processing task were studied through environmental and pharmacological manipulations. In Experiment 1, 22 healthy volunteers (11 female) performed a serial Subtract 7 task while pupil diameter was recorded both during moderate room light and in darkness. In a control for verbalization, subjects performed an easier Add 1 task. In all conditions, pupil diameter increased significantly during the response period as compared to a pre-verbalization baseline period. Pupillary dilation was increased for the difficult task, and further increase in dilation was associated with recording in light. This suggests a major differential contribution to task difficulty mediated through inhibition of the parasympathetic pathway. In Experiment 2, a subgroup of 12 volunteers (seven female) repeated all conditions at three additional sessions in which one eye was instilled with tropicamide (to block the parasympathetic sphincter muscle), Dapiprazole (to block the sympathetic dilator muscle) or placebo. All pharmacological conditions resulted in overall dilation during task performance. Differential performance similar to the placebo condition was seen only in the Dapiprazole condition, when parasympathetic activation was intact. The findings suggest that sustained performance during a difficult task is modulated by cortical inhibition of the parasympathetic pathway at the oculomotor nucleus. Moreover, modulation of both ambient light intensity and pharmacological blockade of the final pupillary musculature were observed to provide converging approaches for quantifying the activity of identifiable central autonomic pathways.
Wallace L M Alward - One of the best experts on this subject based on the ideXlab platform.
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Comparison of the miotic effects of Dapiprazole and dilute pilocarpine in patients with the pigment dispersion syndrome
J Glaucoma, 1995Co-Authors: William L Haynes, H. S. Thompson, A. Tim Johnson, Wallace L M AlwardAbstract:PURPOSE: Pharmacologically induced miosis can inhibit exercise-induced anterior chamber pigment dispersion in patients with the pigment dispersion syndrome. Long-term inhibition of pigment dispersion in these patients could delay or prevent the development of glaucoma. Unfortunately, most commercially available miotic medications are poorly tolerated by these patients due to their visual side effects. This study evaluates the miotic effects of two medications that cause minimal visual side effects in patients with the pigment dispersion syndrome. PATIENTS AND METHODS: Pupil diameter in darkness and amplitude of pupil constriction to light were measured before and 1 h after instillation of two drops of 0. 5 Dapiprazole in one eye and two drops of 1/6 pilocarpine in the fellow eye of 10 patients with the pigment dispersion syndrome. Gonioscopic photography of iris contour before and after medications was performed in two patients who had significant posterior iris bowing on baseline examination. RESULTS: Pupil diameter in darkness and amplitude of pupil constriction to light were significantly smaller in eyes treated with 1/6 pilocarpine. Posterior iris bowing was markedly reduced by 1/6 pilocarpine but not by 0. 5 Dapiprazole in the two patients with posterior iris bowing. CONCLUSION: Cholinergic agonists appear to be superior to alpha-adrenergic antagonists as candidate drugs for inhibiting pigment dispersion in patients with the pigment dispersion syndrome.
