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At least 919 records · Page 51Linked to original sources
PubMed2003

The effect of topical administration of atropine sulfate on the normal equine pupil: influence of age, breed and gender.

OBJECTIVES: The purpose of this study was to determine the influence of age, breed and gender on vertical pupil diameter (VPD) following a single dose of 1% atropine sulfate ophthalmic solution in the normal equine eye. ANIMALS STUDIED: Thirty-two horses of various ages, breeds and genders were included. The horses had no history or clinical signs of ophthalmic disease. All horses studied had darkly pigmented irides. PROCEDURES: Two milligrams of 1% atropine sulfate ophthalmic solution was topically administered as a single dose in the right eye of each horse on Day 0. The VPD (mm) was measured in both eyes using digital calipers prior to treatment and every 24 h after administration for 2 weeks (Days 1-14). Duration of effect on VPD was then calculated for treated and untreated eyes. Data were also analyzed for effect of age, breed and gender on mean VPD, maximum VPD and time to maximum VPD. RESULTS: The VPD in the treated eye was significantly elevated compared to baseline measurements and compared to the untreated eye at all time points. Arabians had a greater mean VPD at Day 0 and on several days following treatment. Females had greater mean VPD compared to males on 5 out of 15 days. CONCLUSIONS: Duration of mydriasis after administration of 1% atropine sulfate ophthalmic solution in the normal equine eye is greater than 14 days. Horses of the Arabian breed and female horses may be more sensitive to effects of cholinergic blockade in the eye.

Administration, Topical↗
PubMed1997

The influence of drop size of cyclopentolate, phenylephrine and tropicamide on pupil dilatation and systemic side effects in infants.

In this prospective study, microdrops (mean drop volume 5.6 microl) and commercially available standard drops (mean drop volume 35.4 microl) of cyclopentolate, phenylephrine and tropicamide's clinical efficacy and systemic side effects were compared. Sixty-one infants requiring diagnostic pupil dilatation were studied for pupillary diameter, systemic blood pressure, heart rate and skin flushing changes related to the instillation of mydriatic drops. Both microdrops and standard drops of the drugs produced significant increase in pupillary diameter compared with the baseline (p<0.01). In cyclopentolate and phenylephrine groups, there was no significant pupillary diameter changes between microdrops and standard drops (p>0.05). Mean blood pressure increased significantly in infants given standard drops. There was no significant change in the group that was given microdrops. In our opinion, reduced volume of mydriatics can prevent possible side effects.

Administration, Topical↗
PubMed2006

A non-invasive method for studying an index of pupil diameter and visual performance in the rhesus monkey.

BACKGROUND: A non-invasive model has been developed to estimate gaze direction and relative pupil diameter, in minimally restrained rhesus monkeys, to investigate the effects of low doses of ocularly administered cholinergic compounds on visual performance. METHODS: Animals were trained to co-operate with a novel device, which enabled eye movements to be recorded using modified human eye-tracking equipment, and to perform a task which determined visual threshold contrast. Responses were made by gaze transfer under twilight conditions. 4% w/v pilocarpine nitrate was studied to demonstrate the suitability of the model. RESULTS: Pilocarpine induced marked miosis for >3 h which was accompanied by a decrement in task performance. CONCLUSIONS: The method obviates the need for invasive surgery and, as the position of point of gaze can be approximately defined, the approach may have utility in other areas of research involving non-human primates.

Animals↗
PubMed1978

An increased effect of pilocarpine on the pupil by application of the drug in oil.

In healthy volunteers pilocarpine in an oily solution had a greater degree and duration of effect on the pupil than the same amount of drug given in aqueous solution. Blue- and brown-eyed subjects had similar degrees of miosis, but the time taken to reach peak effects was longer with the latter. It can be concluded that eye drops made with an oily solvent may provide an improvement in the treatment of glaucoma with pilocarpine.

Adolescent↗
PubMed1979

Acute aphakic pupil block glaucoma: an alternative surgical approach.

In a series of 7 cases of acute aphakic pupil block glaucoma a surgical approach designed to break adhesions between the iris and the anterior hyaloid face was uniformly successful. Reasons for the success of the method are discussed and comparisons made with other surgical approaches.

Acute Disease↗
PubMed1991

Pupil cycle time and early autonomic involvement in ocular leprosy.

Ocular complications of leprosy patients often develop insidiously and with few if any symptoms. This study involves measurement of the pupil cycle time (PCT) to evaluate the autonomic nerve system of the iris to determine the presence of subclinical intraocular involvement. The study included 19 lepromatous (LL), 19 borderline lepromatous (BL), and five borderline tuberculoid (BT) leprosy patients and involved 25 healthy volunteers, 10 patients with pulmonary tuberculosis and eight with Duhring disease. The PCT was measured in these groups. In all leprosy groups included in the study the PCT was higher than in the control groups. Moreover, the PCT of the leprosy patients without any intraocular involvement was higher than in the controls. These results show that in the ophthalmic examination of leprosy patients without any symptoms the fact that autonomic nerve system of the eye is affected by the leprosy can often be determined by measuring the PCT.

Adolescent↗
PubMed1990

Light and target distance interact to control pupil size.

Light and target distance stimuli were presented to normal human subjects, and their pupillary responses were measured. A homeomorphic computer model of the pupillary control system is presented in which the form of interaction of controller signals due to light and target distance was investigated. The error remaining when model parameters were optimized to fit experimental pupil size (area or diameter) was smaller for the linear interaction hypothesis than for either power law or logical law interaction. A generalized second-order nonlinear model with six parameters (vs. 3 for each of the other models) yielded somewhat lower residual error. With the use of a modified Akaike information criterion, the value (in an information theoretic sense) of the improved fit afforded by the three additional parameters in the generalized nonlinear model was shown to be small, and thus the generalized second-order nonlinear model was rejected in favor of the simpler and more parsimonious linear model.

Humans↗
PubMed2006

Morphine-induced reduction of intraocular pressure and pupil diameter: role of nitric oxide.

The present study was performed to evaluate the role of nitric oxide in the intraocular pressure (IOP) lowering effect and in the miotic action of morphine. The IOP was measured in conscious, normal, dark-adapted New Zealand white rabbits using a calibrated pneumatonometer. Experiments were conducted, in which rabbits' eyes were treated with morphine topically and unilaterally, while the fellow eyes received vehicle. IOP and pupil diameter (PD) measurements were taken 0.5 and 0 h before morphine administration and 0.5, 1, 2, 3, 4, and 5 h thereafter. The effects of a nonselective opioid receptor antagonist (naloxone), a nitric oxide synthase inhibitor (Nomega-nitro-L-arginine methyl ester; L-NAME), and a sulfhydryl reagent (reduced L-glutathione; GSH) on morphine-mediated changes in IOP and PD were also determined. Morphine (10, 33, and 100 microg) produced concentration-dependent decreases in IOP and reduced PD in both treated and untreated eyes of New Zealand white rabbits. IOP-lowering effect of morphine (100 microg) and reduction in PD were both significantly inhibited by pretreatment with naloxone (100 microg), L-NAME (0.5%), or GSH (100 microg). The results from this study indicate that morphine-induced ocular hypotension and reduction in PD are opioid-receptor-mediated responses that are associated with the release of nitric oxide. Because the mu3 opioid receptor subtype has a nitric-oxide-releasing activity and is sensitive to inactivation by GSH, it is concluded that morphine-induced ocular hypotension and miosis are mediated, in part, by activation of mu3 opioid receptors.

Animals↗
PubMed1977

Argyll-Robertson-like pupils in the neural type of Charcot-Marie-Tooth disease.

The authors report of Argyll-Robertson-like pupils in three patients presenting the neural type of Charcot-Marie-Tooth (CMT) disease with peroneal muscular atrophy. Up to now the light-near dissociation had been reported in the hypertrophic variety of CMT disease. Stress is laid upon the fact that the presence of the light-near dissociation in patients with CMT disease does not help in clinically differentiating the neural from the hypertrophic type of this disease.

Charcot-Marie-Tooth Disease↗
PubMed1987

Dilatation of pupils in a 'top of the basilar' stroke. Case report.

A case is presented of a 'top of the basilar' stroke followed by a well circumscribed midbrain lesion mainly involving the parenchyma around both third nerve nuclear complexes. Prominent clinical features were: third nerve paralysis including huge pupils unresponsive to light, transient unconsciousness, and slight cerebellar dyscoordination.

Adult↗
PubMed1989

Interaction between nalbuphine and alfentanil on intraocular pressure and pupil size of conscious rabbits.

The ocular hypertension caused by the mu agonist alfentanil (10 micrograms/kg, i.v.) in spontaneously breathing rabbits was reversed to ocular hypotension by pretreatment with the kappa agonist-mu antagonist, nalbuphine (0.6 mg/kg, i.v.). This is probably due to nalbuphine's mu antagonistic action which prevents the respiratory-depressant effect of alfentanil that elevates the blood pCO2 with a drop in blood pH. It is known that hypoxia and hypercarbia lead to uveal vasodilation and increase in aqueous production which cause elevation of intraocular pressure. Both alfentanil and nalbuphine have miotic effects when used individually. However, no further reduction in the pupil size was noted by their combined use. These results indicate that using nalbuphine and alfentanil together may be considered a safe combination for eye surgery because it preserves the analgesic effect of either drug while prevents the undesirable respiratory-center depression and the ocular hypertension observed with alfentanil alone.

Alfentanil↗
PubMed1981

[Direction-changing spontaneous nystagmus with simultaneous change in pupil diameter and eyelid interspace. Oculopupillomotor syndrome in blindness due to dysgenesis mesodermalis iridis et corneae Rieger].

Case report on a 47-year-old man who got blind during the last 10 years because of dysgenesis mesodermalis iridis et corneae Rieger. The patient showed an oculopupillomotor syndrome consisting of direction-changing spontaneous nystagmus and simultaneous changes of pupil diameter and eyelid interspace. The specific modification of direction, form, frequency, and amplitude of nystagmus under central influences such as emotional excitement, change of gaze, eye closure, head tilt, and other vestibular stimuli was registered electronystagmographically and is described in this paper. The unique oculomotor disturbance is compared pathogenetically with periodic oculomotor phenomena such as periodic alternating nystagmus, other types of direction-changing nystagmus, and uninhibited oculomotoricity of the blind. Loss of cerebellar inhibition mechanisms in the central pathogenesis of this syndrome is discussed hypothetically.

Adult↗
PubMed1985

Pupil increment thresholds are influenced by color opponent mechanisms.

Pupillomotor and sensory spectral sensitivity curves of light-adapted eyes were compared. Experimental conditions were designed to favor (despite the threshold criterion) opponent processing of signals: long (500-ms) stimuli of large diameter (60 degrees) were presented centrally on an intense (16 cd/m2) white background. Narrow spacing of monochromatic stimuli permitted the recording of peaks and troughs in the increment spectral sensitivity curve which neither coincided with the characteristics of receptor pigment absorption spectra nor with the V-lambda curve. They are considered as showing influences of opponency mechanisms. Pupillomotor spectral sensitivity paralleled the sensory one, exhibiting the influence of opponency mechanisms on the pupil. Using more physiological conditions, human photopic spectral sensitivity was revealed as a three-peaked function, in sensory as well as in pupillomotor terms.

Adaptation, Ocular↗
PubMed2000

Fixed, dilated pupils in the ICU: another recoverable cause.

A 41-year-old woman presented unconscious with fixed dilated pupils following a massive overdose of carbamazepine and an unknown quantity of venlafaxine prescribed for the management of bipolar affective disorder. Her course in the intensive care unit was marked by a number of complications related to the overdose including prolonged coma, seizures and cardiac arrest. The patient eventually recovered to leave hospital.

Adult↗