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Biomedical subjects

A Loewenstein

Publications and source records attributed to A Loewenstein.

At least 91 records · Page 5Linked to original sources
PubMed1992

[Acute systemic side-effects of topical timolol for glaucoma].

Topically-administered ophthalmic medication may reach clinically significant serum concentrations, as evidenced by the variety of systemic side effects reported. These drugs may interact with other drugs administered orally and intravenously, increasing the frequency and severity of their side-effects. We report 4 patients examined in the emergency room because of various systemic manifestations, in whom the symptoms could be attributed either to antiglaucomatous eye drops, or to interaction between these eye drops and systemic medication. Considering the high incidence of glaucoma (0.5-2%), physicians should be aware of the systemic side-effects of antiglaucomatous eye drops and of possible interaction between such treatment and systemic medications.

Aged↗
PubMed1992

Dosing problems in the use of topical ophthalmic drops.

The effect of two drops of the same drug, one instilled immediately after the other, was compared to the effect of a single drop in 100 healthy volunteers. The drugs investigated were tropicamide, 0.125%, and phenylephrine, 2.5%. The mydriatic effect of two drops was 30%-35% stronger than the effect achieved by a single drop.

Adult↗
PubMed1992

Interferon-related cortical blindness.

The term cortical blindness indicates loss of sight due to bilateral lesions in the occipital lobes. It is a rare but severe side effect produced by chemotherapeutic agents. Cortical blindness was diagnosed in a 75-year-old man who had been treated with alpha-interferon for metastatic renal-cell carcinoma. The absence of focal neurological signs and of abnormal findings as determined by two repeated computed tomography (CT) scans of the brain, which excluded structural damage to the occipital lobes, suggest that metabolic or toxic reactions may have caused the cortical blindness diagnosed in our patient. The temporal relationship between the treatment with alpha-interferon and the development of cortical blindness indicates that this substance may have been the causative agent for this phenomenon.

Aged↗
PubMed1992

Cortical blindness--a catastrophic side effect of vincristine.

The term 'cortical blindness' indicates loss of sight due to bilateral lesions of the occipital lobes. It is a rare, but severe, side effect of chemotherapeutic agents. Cortical blindness was diagnosed in a 67 year old woman with leiomyosarcoma of the large bowel, treated by vincristine-containing chemotherapy. Cortical blindness without focal neurological signs and with two repeated normal brain computed tomography scans, in which there was no structural damage to the occipital lobes, suggests a metabolic or toxic reaction as a cause in our patients. The temporal relationship between vincristine treatment and cortical blindness implicates vincristine as the possible causative agent for this catastrophic phenomenon.

Acute Disease↗
PubMed1992

Spontaneous resolution of proliferative vitreoretinopathy.

A case of proliferative vitreoretinopathy that spontaneously regressed, leading to reattachment of the retina, is presented. The importance of such a spontaneous resolution in terms of understanding the pathogenesis, and planning a treatment, is discussed.

Adult↗
PubMed1992

Tono-Pen tonometry in normal and in post-keratoplasty eyes.

Oculab Tono-Pen tonometry was compared with Goldmann applanation tonometry in 82 eyes of 82 patients with normal corneas and in 54 eyes of 54 patients who had undergone penetrating keratoplasty and whose corneas did not preclude the use of Goldmann tonometer. We found that the intraocular pressure (IOP) in 48% of the eyes with normal corneas and in 57% after keratoplasty has different measurements with Goldmann and Tono-Pen pressures of 3 mm Hg or more. Despite the correlation between the Goldmann tonometer and the Tono-Pen in the group of eyes with normal corneas (r = 0.83) as well as in the group of eyes after keratoplasty (r = 0.79) the Tono-Pen tended to significantly overestimate the Goldmann tonometer reading (p < 0.0001). The mean difference between the two instruments was highest across the lower IOP range (< 9 mm Hg) in the group of eyes after keratoplasty. Because the mean absolute values of the paired differences between Goldmann and Tono-Pen measurements varied significantly across all IOP intervals it was not possible to establish a correction factor which could be used when comparing the two measurements. Based on this study the Tono-Pen consistently overestimated the actual IOP in an unpredictable manner. Where possible Goldmann measurements of the IOP are still to be preferred.

Humans↗
PubMed1992

Trilateral retinoblastoma.

Retinoblastoma is the most common intraocular malignancy of childhood. Trilateral retinoblastoma is a syndrome characterized by bilateral ocular retinoblastoma in conjunction with an intracranial neuroblastic neoplasm in the pineal body, or in supraseller or parasellar location. We report the case of a three year old girl with trilateral retinoblastoma and review the literature on this subject.

Brain Neoplasms↗
PubMed1991

[Procurement of corneas for transplantation].

We prospectively studied all deaths in this hospital from July 1, 1989 through December 31, 1989 for possible eye donations. During this period 539 patients died, of whom, 219 were suitable candidates for donation, and 61 donations were obtained (11.3%). In the course of the study the procurement rate increased progressively as a result of a higher level of effort and awareness by the medical staff.

Cornea↗
PubMed1991

Intentional retention of Descemet's membrane during keratoplasty.

Detachment of the host's Descemet membrane inadvertently occurred while removing the decompensated graft in a patient undergoing rekeratoplasty. The membrane was purposefully left intact and the new graft sutured on top of it. In this way, opening of the anterior chamber was avoided and the operation completed as an 'extraocular' procedure. The graft and the membrane have remained clear during 3 years of follow-up.

Adult↗
PubMed1991

Prevention of the rise in intraocular pressure following neodymium-YAG posterior capsulotomy using topical clonidine.

We studied the ability of topical clonidine, an alpha-agonist, to suppress the acute rise in intraocular pressure (IOP) following neodymium-YAG posterior capsulotomy (YPC). In a randomized controlled trial 63 eyes were pretreated with one drop of either 0.25% clonidine or saline 1 h before performing YPC and immediately following the procedure. The greatest IOP rise in the saline treated eyes occurred in the second hour after YPC, when the mean (+/- SD) IOP rose from a baseline pressure of 12.7 +/- 3.2 to 18.7 +/- 10.7 mmHg. In clonidine treated eyes, the IOP fell from a mean of 11.9 +/- 3.4 to 9 +/- 3.3 mmHg 2 h postoperatively. In the saline treated group 9 eyes (27%) developed an IOP rise greater than 10 mmHg. Clonidine proved to be highly effective in preventing the rise in IOP following YPC.

Administration, Topical↗
PubMed1991

Intraocular lens in a fighter aircraft pilot.

A pseudophakic pilot of the Israeli air force flying an F-15 (Eagle) aircraft was followed up for three years. He experienced about 100 flying hours, 5% of the time under high g stress. The intraocular lens did not dislocate and no complications were observed. It seems that flying high performance fighter aircraft is not contraindicated in pseudophakic pilots.

Adult↗
PubMed1991

The effects of Depo-Medrol preservative on the rabbit visual system.

Periocular injections of corticosteroids play an important role in the management of various ophthalmologic diseases. The Depo-Medrol vehicle, injected into the vitreous, was shown to be toxic to the lens and to the retina when applied at double strength. The authors examined the effects of Depo-Medrol and one of the components of its vehicle, myristyl-gamma-picolinium chloride (MGP), on the functional integrity of the rabbit visual system. Visual function was assessed objectively from the electroretinogram (ERG) and the visual evoked potential (VEP). The experimental drugs were injected into the vitreous humor of one eye while saline was injected into the fellow eye for control. Depo-Medrol did not produce any measurable effects on the ERG or the VEP. When MGP solutions were injected in concentrations at least twice as large as that in the Depo-Medrol, significant reductions in the light- and dark-adapted ERG responses were seen. The effects of the drug on the ERG responses was seen as early as 3 days postinjection and developed to its maximal level within 1-2 weeks. No ERG recovery was seen over a period of more than 2 months. The VEP, elicited by applying light stimuli to the experimental eye, was characterized by low amplitude and delayed implicit time compared with the response obtained from the control eye.

Animals↗