Biomedical subjects
P Eustace
Publications and source records attributed to P Eustace.
Effect of anaesthesia on intraocular blood flow.
Pulsatile ocular blood flow, intraocular pressure, systemic blood pressure, and heart rate was measured in two groups of 15 patients. One received lignocaine 1.5 mg/kg intravenously prior to induction. There was a significant increase in intraocular pressure after suxamethonium, which was not associated with any rise in ocular blood flow. Both the IOP and ocular blood flow increased significantly after tracheal intubation. A rise in ocular blood flow reflects the stress response associated with intubation. Lignocaine failed to attenuate either response.
Intermittent downbeat nystagmus secondary to vermian arachnoid cyst with associated obstructive hydrocephalus.
A 27-year-old man presented with a history of dizziness and intermittent vertical oscillopsia after oblique extension of the head and neck, following a neck injury 2 years previously. He had no other symptoms of cerebellar or brainstem dysfunction. On examination, an intermittent downbeat nystagmus lasting about fifty seconds was elicited by head extension and rotation. Radiologic examination showed slight lateral instability of the odontoid on lateral rotation, and computed tomography brain scan with Iopamidol 300 (Niopam) contrast revealed a 5-cm vermian arachnoid cyst in the posterior fossa with obstructive hydrocephalus. Removal of the cyst cured the nystagmus.
Electroretinography, retinal ischaemia and carotid artery disease.
Reduction in the amplitude of oscillatory potential (OP) on the B wave of an electroretinogram (ERG) is a sensitive index of experimental retinal ischaemia and is being used clinically to evaluate the progression of diabetic retinopathy. This study assessed whether electroretinography could detect retinal ischaemia in a group of patients with normal fluorescein angiograms and carotid atherosclerosis. Two groups of patients were studied. Group A (n = 15) had carotid atherosclerosis on duplex ultrasonography while a matched control group B (n = 15) had normal vessels. All patients in Group A had flurorescein angiograms. ERGs were recorded bilaterally using a Ganzfeld stimulator and Medelec oscilloscope. The OP amplitudes were determined using the peak-nadir method. Of the 60 eyes examined, 18 had abnormal OPs and all of these occurred in Group A; ten associated with ipsilateral non-stenosing carotid lesions and eight with critical stenoses. Twelve had normal OPs in Group A, only one of which was associated with severe disease. The mean OP amplitudes were 292 mu and 198 mu in Group A and 172.89 mu and 115.6 mu in Group B (P less than 0.005 Wilcoxon Rank Sum Test). (Two readings reflect Medelec readings before and after computer adjustments.) This study demonstrates by electroretinography significant retinal ischaemia in the presence of normal fluorescein angiography in patients with proven carotid artery disease. Further evaluation is required to determine the relative importance of flow reduction and silent micro-embolisation in the genesis of this ischaemia particularly in relation to pre- and postoperative evaluation.
A 'family clinic' for information exchange in an oncology unit.
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Retinal ultrastructural findings in cone degeneration.
We studied an eye from a 73-year-old man with a sporadic type of retinal cone degeneration and choroidal melanoma. Histologic and ultrastructural studies of the nasal retina unaffected by the choroidal melanoma showed alterations at the outer retina predominantly involving the photoreceptors and retinal pigment epithelium. A wide spectrum of pathologic changes were observed, ranging from near normal retina showing only photoreceptor outer segment disease (distortion and kinking) to grossly pathologic regions where photoreceptor cell bodies were sparse and their outer segments absent. The retinal pigment epithelium in minimally affected regions of the retina showed an increased proportion of the melanin complement of the cell within complex granules. In severe disease, many cells showed only giant complex granules with no free melanin. Retinal pigment epithelial cell migration and relocation around blood vessels was also noted in severe disease.
Computerized tomographic scanning in ophthalmoplegic migraine.
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Yersinia-induced uveitis in Ireland.
A prospective study was undertaken on 54 patients with an apparently idiopathic first attack of acute anterior uveitis. Blood samples were assayed for antibodies to Yersinia enterocolitica and Yersinia pseudotuberculosis, and tested for HLA type. Thirteen patients were found to have serological evidence of recent yersinia infection, eight with Y. enterocolitica and five with Y. pseudotuberculosis. The clinical course of uveitis did not differ from that typically found in HLA-B27 positive patients. Five patients were observed to develop non-ocular inflammation at a variable interval. The means by which eye inflammation follows yersinia infection is discussed in the light of recent theories on pathogenesis of HLA-B27 associated diseases.
Fall in intraocular pressure during acute hypocalcemia in patients with insulin dependent diabetes.
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Ageing and alpha 1 adrenoceptors in the iris.
This study was undertaken to determine if the age related decrease in pupil size is attributable to altered sympathetic adrenoceptor responsiveness. Log dose response curves using the selective alpha 1 agonist phenylephrine and antagonist thymoxamine showed that there is no difference in alpha 1 adrenoceptor sensitivity in the elderly and the young. Therefore age related miosis is not caused by an alteration in alpha 1 receptors with age.
Management of intraocular pressure during cardiopulmonary bypass.
Intraocular pressure was measured in two groups of patients undergoing cardiopulmonary bypass surgery. A control group received mannitol at the start of bypass in accordance with standard practice; pressure was found to rise by 6.4 mmHg. In a second group of patients mannitol was administered 30 min prior to bypass; pressure elevation of 2.4 mmHg was found. These findings are discussed in relation to other clinical observations during bypass and to ocular morbidity complicating bypass surgery.
Intraocular pressure during cardiopulmonary bypass.
Intraocular pressure was measured in 24 patients undergoing elective cardiopulmonary bypass surgery. There was a rapid rise when the bypass circulation began, and this was maintained for about 30 minutes. A simultaneous drop in arterial perfusion pressure and packed cell volume occurred. We suggest that marked haemodilution is responsible for this effect, through increased ocular blood flow and low colloidal osmotic pressure. The possible aetiological significance in relation to ischaemic optic neuropathy complicating cardiopulmonary bypass is discussed.
Ischaemic optic neuropathy complicating cardiopulmonary bypass.
Bilateral anterior ischaemic optic neuropathy occurred in two patients undergoing cardiopulmonary bypass grafting. The causes may have been vasoconstriction of the posterior ciliary arteries by increased circulating angiotensin and diminished ciliary blood flow in the setting of systemic hypotension and elevated intraocular pressure.
A five-year survey of ocular shotgun injuries in Ireland.
Between November 1980 and September 1985 20 patients in Ireland sustained accidental ocular shotgun injuries severe enough to necessitate hospital admission. Eight patients had contusion injuries and 12 perforating injuries. Contusion damage was disproportionate to the size of the pellet. Through and through perforation of the globe occurred in eight patients; the remaining four patients in this group had retained intraocular pellets. Twelve patients sustained perforating eye injuries. Those that were treated by primary closure alone lost the sight in that eye. Those treated by vitreoretinal surgery recovered vision directly related to where the pellet had its exit from the eye. It was possible to contact 15 of the patients. All 15 were shooting pheasant. It was not possible to relate the distance of the patient from the gun to the severity of the ocular injury.
Paraneoplastic papilloedema in neuroblastoma.
We report a case of bilateral papilloedema in an adult male with neuroblastoma, in the absence of hypertension or detectable intracranial disease. This complication has not previously been described in the English-speaking literature. Possible mechanisms are discussed.
The retinotoxic effects of oncological agents.
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Intravenous lignocaine pretreatment to prevent intraocular pressure rise following suxamethonium and tracheal intubation.
Intravenous lignocaine (1.5 mg kg-1) was evaluated in patients undergoing intraocular surgery as a means of preventing the rise in intraocular pressure which accompanies tracheal intubation. In patients given either suxamethonium or pancuronium to facilitate tracheal intubation, lignocaine pretreatment conferred no benefit over placebo in preventing the intraocular hypertensive response.