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Biomedical subjects

N S Levy

Publications and source records attributed to N S Levy.

15 recordsLinked to original sources
PubMed1979

Non-diabetic retinal abnormalities in chronic pancreatitis.

To determine whether retinal abnormalities occur in patients with chronic pancreatitis, ophthalmoscopic and retinal-function evaluation was performed in 28 patients with chronic pancreatitis and 19 healthy subjects. The final threshold of dark adaptation was significantly increased 40 per cent (P less than 0.001) in patients with pancreatitis, whether or not they had steatorrhea. Patients with steatorrhea had a significant decrease of about 42 per cent (P less than 0.001) in the b-wave of the electroretinogram, a measure of both rod and cone function. Seven of the 28 patients complained of difficulty with hight vision; six of these seven had morphologic lesions on ophthalmoscopic examination, confirmed by fluorescein angiography. No correlation was found between any of the retinal abnormalities and the serum vitamin A or zinc levels or glucose tolerance. Non-diabetic retinal lesions and retinal-function abnormalities are common in patients with chronic pancreatitis, even in the absence of steatorrhea.

Adult↗
PubMed1978

Early diagnosis and evolution of dominant retinitis pigmentosa.

A 5-month-old girl with retinitis pigmentosa was the healthy offspring of a family with progressive autosomal dominant retinitis pigmentosa. Serial evaluation by both electroretinograph and ophthalmoscopy over a four-year period confirmed the diagnosis and indicated that as early as 5 months of age, electroretinographic abnormalities were present in the patient. These consisted of a reduction in the dark-adapted b-wave amplitude, prominent X-wave, and no suppression of the second b-wave response to paired light stimuli at 75 msec. Progressive reduction in the scotopic electroretinography amplitude has occurred over the ensuing four years, although light-adapted (cone) function still appears normal. Clinical evidence of retinitis pigmentosa became apparent only late in the patient's third year when fine peripheral pigment clumping and vessel attentuation could be seen.

Adolescent↗
PubMed1978

The monocularly elicited visual evoked response in chronic glaucoma.

The monocularly elicited transscleral visual evoked cortical response was measured in a group of patients with asymmetric visual field loss due to chronic open-angle glaucoma. It was established that the visual field loss in the 2 eyes was statistically different in the patients. In addition, the peak amplitude of the visual evoked response obtained from a common occipital cortical position was statistically different when the 2 eyes were separately stimulated. A good linear correlation was found between the amplitude of the monocular transscleral visual evoked response and the amount of visual field remaining on tangent screen perimetry. The best correlation was found when a red stimulus was used to elicit the VER. The monocularly elicited visual evoked response provides an objective measurement of visual field in chronic open-angle glaucoma. It has value in those patients who have asymmetric disease and who are unable to provide reliable subjective responses. It may be useful in such patients to follow progression of the glaucomatous process.

Adult↗
PubMed1977

Intraocular pressures in children with glaucoma during halothane anesthesia.

Thirty measurements of intraocular pressure (IOP) were performed on 10 children either with congenital or secondary glaucoma, before and after halothane anesthesia. In 7 normal eyes, IOP decreased a mean of 3 mm Hg, while in 23 glaucomatous eyes, mean IOP decreased from 43 to 34 mm Hg. In 5 of the 23 glaucomatous eyes, IOP decreased below 25 mm Hg and in only one patient below 21 mm Hg. Our findings indicate that an abnormally elevated IOP during halothane anesthesia suggests a glaucomatous process. A normal IOP during halothane does not absolutely preclude the absence of glaucoma. Intraocular pressure greater than 21 mm Hg during halothane anesthesia should be viewed with suspicion when coupled with other clinical observations of pathologic significance. Awake, sedated IOP measurements appeared to provide a reliable index of glaucoma in the population studied.

Anesthesia, Inhalation↗
PubMed1977

The effect of systemic hypotension during cardiopulmonary bypass on intraocular pressure and visual function in humans.

The effect of controlled systemic hypotension on intraocular pressure (IOP) and visual function was measured in a group of 12 patients undergoing extracorporeal perfusion during cardiovascular surgery. When venous pressure was controlled, intraocular pressure was noted to fall following a fall in the systemic blood pressure. There was a return of IOP toward normal levels with recovery of the systemic blood pressure. Systemic hypotension of 25 to 100 mm Hg for up to 201 minutes in the presence of hemodilution and hypothermia was not associated with any functional or morphologic change in ocular function.

Adult↗
PubMed1976

Strabismus in children with cerebral palsy.

A group of 238 patients with cerebral palsy were identified of whom 108 could be studied through their charts. Only 20 of these patients had strabismus. Of this group, 10 received no surgical therapy. In these patients followed up to a period of four years, no evidence of significant change in the strabismic deviation was found. Patients who were treated by medical and optical means alone did not show evidence of improvement. Surgical therapy was effective in providing a cosmetically acceptable result. Surgery was performed between two and one-half and 13 years of age in eight patients, with an average age of surgery of 6.5 years. The results which we obtained are comparable to those obtained by others at an earlier age. It does not appear that the age of surgery affects the ultimate cosmetic nor functional outcome in children with cerebral palsy.

Age Factors↗
PubMed1976

Juvenile glaucoma in the Rubinstein-Taybi syndrome.

A 10-year-old retarded child was seen by an ophthalmologist because of strabismus. Examination of the optic nerve heads revealed cupping consistant with glaucoma and initiated a referral. The appearance of this girl, with flat-broad based thumbs and toes, small head, low set ears, high arched brows, antimongoloid slant to the eyes, high arched palate, associated with mental retardation, and strabismus suggested the Rubinstein-Tabyi Syndrome. Gonioscopy revealed a high iris insertion, while tonometry indicated mildly elevated pressures in the right eye. Examination of the optic nerve heads showed large glaucomatous type cups, more so on the right with compromise of the temporal rim. Trabeculectomy was effective in controlling the intraocular pressure in the right eye. The association of juvenile glaucoma with the Rubinstein-Taybi Syndrome requires that ophthalmic referral to assess glaucoma be an essential part of the evaluation.

Abnormalities, Multiple↗
PubMed1976

The effect of interruption of the short posterior ciliary arteries on slow axoplasmic transport and histology within the optic nerve of the rhesus monkey.

Tritiated leucine was injected into the vitreous of rhesus monkey eyes to make it available for protein synthesis by the ganglion cells. The short posterior ciliary arteries were cut three hours later or several weeks prior to the leucine injection. A reduction of labeled protein within the retrolaminar optic nerve was seen in all eyes so treated. Autoradiography revealed a diffuse reduction of axoplasmic transport into these optic nerve heads. There was consistent evidence of focal obstruction of labeled protein at the interface between the lamina scleralis and retrolaminar optic nerve. Vacuoles appeared in the most severely affected areas. These histologic changes were followed by gliosis in the areas of ischemic damage. Glaucomatous cupping of the optic nerve head was not seen within six weeks following the induced ischemia.

Animals↗
PubMed1975

Intraocular pressures in children during isoflurane and halothane anesthesia.

The effects of isoflurane and halothane on intraocular pressure (IOP) were studied in 28 children. Measurements were made during spontaneous ventilation and at a various levels of reduced PaCO2 achieved by controlled ventilation. Control IOP values were determined prior to anesthesia following premedication with chloral hydrate, pentobarbital, pentobarbital with meperidine. At roughly equivalent levels of anesthesia, mean IOP values during spontaneous ventilation ranged frm 16.3 to 17.6 torr for each anesthetic. These values were significantly less (P less than 0.01) than control values only in those patients receiving chloral hydrate who did not cooperate. In contrast, no significant change in IOP was found in more sedated and cooperative patients who received pentobarbital and meperidine. Moderate hypocarbia and hypercarbia over a range of PaCO2 greater than 42 torr had little influence on IOP. We conclude that IOP's during isoflurane and halothane anesthesia do not differ significantly from IOP in the sedated, cooperative, healthy pediatric patient.

Adolescent↗
PubMed1975

Slow axonal protein transport and visual function following retinal and optic nerve ischemia.

Retinal ganglion cell protein synthesis and slow axonal protein flow have been measured in eight optic nerves from four macacus rhesus monkeys after producing ganglion cell ischemia. Comparison of the slow axonal protein flowing into the two optic nerves of the same control animal reveals a variability of up to 27 per cent. Following central retinal artery ligation, infarction of the retinal ganglion cells was reflected by a 97 per cent reduction in the radioactively labeled protein within the optic nerve. This profound reduction in labeled protein within the nerve confirmed that only ganglion cell dependent intra-axonal protein flow was being measured. Ischemia to the ganglion cell axons, with preservation of blood flow to the cell soma, was obtained in two optic nerves from different animals by severing all the posterior ciliary vessels entering about the optic nerve. Six weeks later, only a modest histologic loss of axons was present in these optic nerves. However, a profound reduction (up to 97 per cent) in labeled optic nerve protein was found at four days following intravitreal leucine injection. This is the time when the optic nerve slow axonal protein flow is dominated by the foveomacular ganglion cells. The reduction in slow axonal protein flow corresponds histologically to a preferential retrograde degeneration of the foveomacular ganglion cells, suggesting increased sensitivity of the smaller foveal axons to the induced ischemia. Electrophysiologic measurements support this conduction.

Animals↗
PubMedDate not supplied

Ketamine and intraocular pressure in children.

The effect of ketamine on intraocular pressure (IOP) was studied in 10 children. Control IOP values were determined prior to induction of anesthesia, following premedication with atropine alone or in combination with pentobarbital and meperidine. After the IM injection of 8 mg/kg of ketamine, the IOP was determined at 5, 10, 15, and 20 minutes. Mean (+/- SD) IOP values before and after ketamine were 22.2 +/- 4.8 and 16.7 +/- 3.3 torr (p less than 0.001), respectively. The authors believe that the reduction in IOP was not due to ketamine, per se, but rather to lack of patient relaxation and cooperation during control measurements. At the end of 20 minutes, a second dose of ketamine, this time 1 mg/kg IV, was given and measurements were repeated at the same intervals. In 5 patients, the effects on IOP of d-tubocurarine, endotracheal intubation, and N2O inhalation also was evaluated. A significant increase (6.7 torr) in IOP was observed only after endotracheal intubation. The authors conclude that ketamine does not raise IOP in the healthy pediatric patient and, therefore, can be used for ophthalmic procedures requiring sedation or anesthesia.

Anesthesia, Inhalation↗
PubMedDate not supplied

Infantile glaucoma associated with contralateral esotropia.

A 20-month-old white male was first seen with an esotropia at four months of age by his pediatrician. The esotropia had been present by history since early in life. After pediatric evaluation, which demonstrated delayed motor development, he was referred for ophthalmic consultation. A comprehensive ophthalmic evaluation established the diagnoses of infantile glaucoma and myopia of the preferred eye, and esotropia and amblyopia of the emmetropic eye. The infantile glaucoma was surgically treated and amblyopia reversed following patching of the glaucomatous eye. Orthophoria was achieved. Esotropia may be the presenting manifestation of unilateral infantile glaucoma of the contralateral eye. Comprehensive appraisal should include pediatric, neurologic, and ophthalmic evaluation.

Amblyopia↗