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At least 19 recordsLinked to original sources
PubMedDate not supplied

Systemic response to mydriatic eyedrops in neonates: mydriatics in neonates.

During routine dilation of 48 newborns, systemic responses and pupil dilation were monitored. Both 10 percent aqueous and viscous phenylephrine caused blanching around the eyes and produced considerable rise in blood pressure. Dilatation average 4.7 mm. In a double blind study, a 2.5 percent solution caused no skin blanching and no change in pressure or heart rate. Average dilation was 4.5 mm. No blood pressure changes were observed with either one percent cyclopentolate or one percent tropicamide. Average dilatations were 5.0 mm and 5.3 mm respectively. The above agents, used individually for a total dosage of three drops in each eye did not provide adequate dilation for a thorough funduscopic examination. Our protocol at United Hospitals Medical Center is a safe combination of drugs and provides excellent dilatation averaging greater th an 7 mm. No skin blanching or change in heart rate was observed.

Birth Weight↗
PubMed1992

[Effects of pre-instilled mydriatics on the intraocular concentration and anti-inflammatory action of topical 0.1% pranoprofen (2)--Study on multiple dosing].

We studied the effects of multiple dosing and pre-instilled mydriatics (0.5% tropicamide and 0.5% phenylephrine) on the intraocular concentration and anti-inflammatory action of topical 0.1% pranoprofen (PPF) in rabbit eyes. PPF was applied in a single or multiple doses: 1 to 4 times consecutively at 5-minute intervals with or without pre-instilled mydriatics. PPF concentrations in the aqueous humor increased dose-dependently. The PPF concentrations also increased dose-dependently, and reached the maximal concentration by instillation 3 times in the presence of pre-instilled mydriatics, and the concentrations were 3.4 to 5.8 times higher than those without mydriatics. The PPF concentrations in the cornea, secondary aqueous, and iris-ciliary body increased in a dose-dependent manner, and the concentrations were higher in the presence of mydriatics. PPF reduced the protein rise in the secondary aqueous and miotic responses which were seen after paracentesis. The percent inhibitions ranged from 75 to 83, but the inhibitory actions were not enhanced by increases of intraocular PPF concentrations. These data indicate that the potent anti-inflammatory actions of PPF were obtainable by a single instillation, but it might be useful to instill the drug 3 times consecutively to ensure higher intraocular drug concentrations in combination with pre-instilled mydriatics.

Administration, Topical↗
PubMed1992

[Effects of pre-instilled mydriatics on the intraocular concentration and anti-inflammatory action of topical 0.1% pranoprofen (3)--study on permeability factor].

The authors studied a mechanism of an increase in intraocular concentration of topical 0.1% pranoprofen (PPF) induced by pre-instilled mydriatics (0.5% tropicamide and 0.5% phenylephrine) in rabbit eyes. Ingredient solutions of mydriatics were instilled 60 minutes prior to instillation of PPF. The PPF concentrations in the cornea, aqueous humor and iris-ciliary body did not increase with pre-instilled benzalkonium chloride, chlorobutanol and tropicamide. The PPF concentrations were increased by pre-instilled phenylephrine (PHE), and the concentrations were 2 to 3 times higher than those without mydriatics. The PHE concentration in the aqueous humor was increased about 3 times in the presence of PPF. The octanol/water partition coefficient of PPF was increased in the presence of PHE. These data indicate that the increase of intraocular PPF concentration by the pre-instilled mydriatics was caused by PHE, and the enhancement of transcorneal permeability to PPF may have resulted from the formation of ion-pair complexes between PPF, an anionic drug, and PHE, a cationic drug.

Animals↗
PubMed1976

An explanation for the long duration of mydriatic effect of atropine in eye.

The mydriatic effect of topically applied 3H-atropine (2%) was compared in the pigmented rabbits (black fur and dark brown irides) and nonpigmented (albino) atropinesterase-negative rabbits. The duration, t1/2, of the mydriatic effect in the nonpigmented and pigmented rabbit was 43.5 and greater than 96 hours, respectively. At hour 96, the tissue 3H-atropine in the pigmented iris was greater than that in the nonpigmented iris by the factor of eight. The longer duration of mydriatic effect in the pigmented iris is explained by the slow release of the bound drug from the pigment onto the muscarinic receptors.

Administration, Topical↗
PubMedDate not supplied

A mydriatic eye-drop combination without systemic effects for premature infants: a prospective double-blind study.

Eye drops used for diagnostic mydriasis may produce systemic side effects in preterm infants. Studies on the pupil dilating and systemic effect of various mydriatic agents yielded conflicting results. We conducted a prospective randomized double-blind study on the systemic effect of two mydriatic eye-drop combinations. Thirty-nine preterm infants were randomly assigned to two groups. An eye-drop combination of 2.5% phenylephrine and 0.5% tropicamide (group D) was compared with the combination of 0.5% cyclopentolate and 0.5% tropicamide (group F). Either eye-drop combination was followed by 0.5% tropicamide given 20 minutes later. Heart rate (HR) and the systolic, mean, and diastolic blood pressure (BP) were recorded before and after eye-drop instillation and after ophthalmoscopy. A control session with NaCl eye drops was added for each infant. A significant increase of BP and HR peak values was observed within 7 to 10 minutes after the cyclopentolate/tropicamide combination only. On the other hand, the mydriatic effect of the phenylephrine/tropicamide combination was significantly superior to that of the cyclopentolate/tropicamide combination. We recommend the combination of 2.5% phenylephrine and 0.5% tropicamide to achieve a sufficient diagnostic mydriasis without systemic side effects in preterm infants.

Blood Pressure↗
PubMedDate not supplied

Modification of a Kowa RC-2 fundus camera for self-photography without the use of mydriatics.

Research on retinal circulation during space flight required the development of a simple technique to provide self monitoring of blood vessel changes in the fundus without the use of mydriatics. A Kowa RC-2 fundus camera was modified for self-photography by the use of a bite plate for positioning and cross hairs for focusing the subject's retina relative to the film plane. Dilation of the pupils without the use of mydriatics was accomplished by dark adaption of the subject. Pictures were obtained without pupil constriction by the use of a high speed strobe light. This method also has applications for clinical medicine.

Fluorescein Angiography↗
PubMed1977

Mydriatic angle-closure glaucoma--mechanism, evaluation and reversal.

Ocular mydriatics are diagnostic agents that generally facilitate a preferable ophthalmoscopic examination. However, the optometrist should be aware of certain iatrogenic side effects including the precipitation of an acute angle-closure. The purpose of this paper is to summarize the mechanism of mydriatic angle-closure glaucoma. In addition, a shallow anterior chamber is a fundamental ocular variable which should be evaluated before inducing mydriasis and/or cycloplegia. The technical procedures for the oblique illumination shadow test and the van Herick slit lamp test are presented, both of which provide an accurate estimation of the anterior chamber angle. The risk of precipitating an attack after reasonable circumspection by such evaluations approaches zero. However, should an attack occur, the procedures to rapidly lower the intraocular pressure and open the chamber angle are discussed.

Anterior Chamber↗
PubMed1979

Mydriatic effect of anticholinergic drugs used during reversal of nondepolarizing muscle relaxants.

Large doses of anticholinergic drugs (atropine, glycopyrrolate) produced mydriasis in a group of adults with no eye abnormalities except strabismus, though the usual intramuscular and intravenous doses of these drugs do not have this tendency. Such large doses are often given intravenously during general anesthesia to prevent the side effects of neostigmine methylsulfate, which is used to reverse the effect of nondepolarizing muscle relaxants. Neostigmine methylsulfate (Prostigmin) reduced the mydriatic effect when given intravenously in conjunction with atropine or glycopyrrolate. Mydriasis was more likely to occur in lightly pigmented eyes than in eyes with dark irides. Pilocarpine eyedrops instilled at the beginning of anesthesia caused miosis that persisted after the large intravenous doses of atropine or glycopyrrolate were given. To prevent an attack of acute angle-closure glaucoma in any patient who is to receive large doses of anticholinergic drugs during general anesthesia, miotic drug therapy should be continued before, during, and after anesthesia at the same frequency as when awake.

Adolescent↗
PubMed1976

Factors determining the potency of mydriatic drugs in man.

1 The mydriasis resulting from topical application of five atropine-like drugs was measured photographically in man. Drug potency was obtained from log dose-response curves. 2 The in vitro potency of eight cholinoceptor blocking drugs, including those studied in man, was obtained by measuring their affinity constants for binding to the receptors of an isolated preparation of the rabbit sphincter pupillae. Values agreed closely with those obtained for the muscarinic receptors of guinea-pig ileum. 3 In vitro and in vivo potency was compared to obtain a quantitative measure of the relative ease with which drugs gain access to the receptors after topical application. 4 The large differences that occur in the intensity and duration of the mydriatic response to atropine-like drugs is primarily the result of differences in their ability to blcok the receptors. Only with tropicamide does its relatively high accessibility affect its potency in man.

Administration, Topical↗
PubMed1975

[Prescription of mydriatics in the treatment of dosed-angle glaucoma].

The indication for the use of mydriatics in the treatment of dosed-angle glaucoma are discussed. The value of their use consists in the elimination of pupillary block and in an antiphlogistic action. This claimed that these effects prevent the formation of posterior and peripheral anterior synechiae and thus prevent the condition from becoming chronic.

Aged↗
PubMed1976

Effects of mydriatics and a miotic on ocular discomfort and pupil responses.

Mydriatics produced two different effects on the discomfort threshold following administration of the drugs depending upon whether the mydriasis was produced by paralysis of the sphincter muscle or by activation of the dilator. When the sphincter was paralyzed by tropicamide, the discomfort threshold was elevated during the period of time that the pupillary light reflex was significantly reduced to the flashing stimulus. Initially, phenylephrine-induced mydriasis had no effect on the discomfort threshold, but as the pupil responses returned to normal the threshold rapidly increased and then gradually returned to a pre-drug level. The return of the threshold back to normal seemed to parallel the decline of action of phenylphrine on the dilator muscle. Significant impairment of the light reflex by pilocarpine-produced miosis was also related to an increase of the discomfort threshold.

Humans↗
PubMed1979

Potentiation of the mydriatic effect of norepinephrine in the rabbit after monoamine oxidase inhibition.

Dose-response curves of pupillary dilation after topical administration of norepinephrine or methoxamine have been determined in rabbits after chronic inhibition of ocular monoamine oxidase by treatment with pargyline or pheniprazine. Eyes treated with either monoamine oxidase inhibitor showed an enhanced responsiveness to the mydriatic effect of norepinephrine given either topically or intravenously. Increments in pupil size of the treated and control eyes in response to methoxamine applied topically, on the other hand, were the same. These results suggest that monoamine oxidase may play a role in the iris as one factor influencing the concentration of norepinephrine at the receptors.

Animals↗
PubMed1977

The mydriatic effect of tropicamide on light and dark irides.

Tropicamide 0.5% was topically applied to the eyes of thirteen subjects to study its effectiveness as a mydriatic. A comparison was made between the subjects with light colored irides and those with dark brown irides, and also between those who had worn contact lenses previous to dilation and those who had not. Results indicate that a minimum pupil size of 6 mm was achieved within 25 minutes after instillation and this dilation was independent of iris pigmentation. Typically, IOP was reduced during dilation with tropicamide.

Adult↗
PubMed1992

The follow-up of patients screened for glaucoma with non-mydriatic fundus photography.

In order to evaluate the value of photographic screening in predicting progressive glaucomatous damage, we re-examined 26 subjects 5 years after the initial screening. Of the 26 patients 16 had typical glaucomatous optic disc and visual field abnormalities (n = 7), retinal nerve layer damage (n = 6), or other risk factors of glaucoma (n = 3). In 10 of 26 patients suspected of having glaucoma, no abnormalities were initially confirmed. Of the 16 eyes with initially abnormal findings, 10 (63%) showed progressive changes during the 5-year follow-up period. The 10 initially suspected cases have remained healthy throughout the follow-up, giving a false positive rate of 5.5%. The results of this study indicate that it is possible to identify correctly patients with progressive glaucomatous changes with a non-mydriatic fundus camera.

Female↗
PubMed1975

Mydriatic effects using low concentrations of phenylephrine hydrochloride.

The dose response relationship of different concentrations of phenylephrine with and without prior application of topical anesthetic was measured to determine the minimum concentration which produced maximum mydriasis. As little as 0.125% phenylephrine caused mydriasis in some subjects and maximum mydriasis was achieved with 2%. Concentrations greater than 2% produced very little additional mydriasis. A therapeutically effective dose could be as low as 1% with prior installation of a topical anesthetic.

Administration, Topical↗