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PubMed1981

Guanethidine - adrenaline eye drops in glaucoma simplex. Pupil behaviour and response of intraocular pressure.

In the study reported here, the relation between the dilatation of the pupil and the course of intraocular pressure (IOP) is examined in open angle glaucoma patients and in glaucoma suspects after topical administration of the combination of guanethidine 3% and adrenaline 0.5% in one eye drop (GA). By treating one eye with GA and leaving the fellow eye untreated on the same day, there was a symmetrical response of IOP, independent of the mydriasis in the treated eyes. It leads to the conclusion that the mydriatic response has no influence on the course of IOP. The physiological explantation for the symmetrical course of IOP in both treated and untreated fellow eyes seems to be a mediation by the bloodstream of GA to the eye which was left untreated.

Drug Combinations↗

PubMed1991

Effects of ultraviolet radiation and visible light on hamster pupil.

Light does not cause a miotic response in mammals after a topical application of atropine. However, such common sense is based on the pupillary response to visible light. We found ultraviolet (UV) caused slight but evident miosis, even when the patient did not perceive visible light. In order to understand this mechanism further, we conducted in vitro experiments using hamsters. The in vitro hamster iris contracted even when the retina was withdrawn in an incubation solution. The contraction of the hamster pupil caused by visible light was inhibited by procaine, quinacrine, and by the withdrawal of divalent cations, but not by indomethacin, AA861, FPL55712 or autonomic blocking agents. UV-induced miosis was very delayed, continuing after cessation of UV stimuli. Nordihydroguaiaretic acid did not inhibit the miosis induced by UV and/or visible light. The UV-induced miosis was not significantly affected by allopurinol or verapamil, suggesting mechanisms other than neuronal mediation and oxidative stress. This study shows that the isolated hamster iris can react to UV and visible rays. UV-induced miosis is different from the miosis caused by light reflex. To our knowledge, UV-induced miosis has not yet been reported.

Animals↗

PubMed1983

Neurohypophyseal peptides and the eye: use of synthetic analogs in analyzing effects on the pupil.

Effects of neurohypophyseal (NHP) and synthetic analogs on the pupil of the rabbit were explored. This was prompted by the recent emergence of synthetic analogs with selective agonist and antagonist properties. The miotic effect of the NHP was examined in an isolated iris preparation. Minimum concentrations of arginine-vasopressin (AVP) needed to cause threshold pupillary constriction were approximately 10(-10) M. The miotic potency of several NHP analogs correlated best with their pressor activity. In addition, the synthetic NHP pressor antagonist d(CH2)5 Tyr(Me)AVP specifically antagonized the miotic effect, confirming that a pressorlike receptor mediates this pharmacologic action of the NHP. We also employed the technique of in vivo intravitreal administration of pharmacologic doses of the NHP in the rabbit. Once again, potent miotic activity was demonstrated. The relative miotic potency of the NHP in vivo provided further support to the relationship between the NHP "pressor" receptor and pupillary constriction. We believe that the use of a variety of NHP natural and synthetic analogs may also prove helpful in investigating potential physiological effects of the NHP on other intraocular smooth muscle.

Animals↗

PubMed1975

The influence of topically applied bethanidine on intraocular pressure and pupil in the rabbit.

Bethanidine sulphate was administered topically to the eyes of conscious rabbits using a 0.5%, 1%, 2% and 5% solution of the drug. The intraocular pressures and pupil sizes were measured in the right treated and left control eyes at 0,1,2,3, 6 and 24 hrs. With all concentrations a pressure decrease with a maximum between 3 and 6 hrs after topical treatment occured. The 5% solution of bethanidine sulphate showed a delayed effect which was submaximal when compared to the 2% bethanidine solution. Using the 1% and 2% solution a ppressure decrease probably due to systemic action of the drug happened in the untreated control eyes. In all experiments the pressure responses had disappeared after 24 hrs in the treated and untreated eyes respectively. By means of the experimental conditions in this study no significant pupillary reactions were found after bethanidine application. The tension effect of 0.5% adrenaline borate remained essentially unchanged when repeated with additional 1% topical bethanidine. Some aspects of sympatholytic drug action on the intraocular pressure in the rabbit are discussed.

Animals↗

PubMed1996

Pseudoexfoliation syndrome with poorly dilating pupil: a light and electron microscopic study of the sphincter area.

BACKGROUND: The study was carried out to examine histological changes in the iris sphincter muscle and surrounding tissue in eyes with pseudoexfoliation syndrome (PXS). METHODS: Seventeen patients with PXS, 14 of them having capsular glaucoma, were enrolled into the study. Iris biopsies were obtained during extracapsular cataract extractions (ECCE) requiring sphincterotomies. Thirteen biopsy specimens underwent histological examination by light microscopy, and four were examined with the electron microscope. Three iris biopsies from cadaver eyes and one obtained during ECCE from a patient with a miotic pupil (no PXS) served as control specimens on light microscopy. Electron microscopic controls included three iris specimens from cadavers. RESULTS: In the light microscopic examination, blood vessel walls were stained with Congo Red in seven of the 13 PXS specimens. In three of these seven specimens the stromal tissue was extensively fibrotized, and in two specimens fibrosis was moderate. Distinct stromal fibrosis was also observed in one and moderate fibrosis in two PXS specimens negative for amyloid. The control specimens were not positive for Congo Red, but stromal tissue was moderately fibrotized in one specimen. Light microscopy did not reveal differences in muscle tissue between PXS and control specimens. Electron microscopically, however, the muscle tissue was fibrotic or disorganized in three PXS specimens and in one control specimen. Fibrils, similar to the fibrillar component of pseudoexfoliation material described in previous studies, were found in intimate association with the capillary basal lamina in all of the PXS specimens showing muscular fibrosis. CONCLUSIONS: These findings support the theory that PXS is associated with amyloid, and in some PXS eyes miosis is connected with degenerative changes both in the stromal tissue and in the muscular layer of the iris.

Adult↗

PubMed1991

Intravenous buprenorphine reduces pupil size and the light reflex in humans.

The pupillary effects of intravenous buprenorphine were studied in eight nondependent male subjects who reported previous opiate use. Buprenorphine (0.3, 0.6, and 1.2 mg) decreased pupil size, the amplitude of the light reflex, and the velocities of constriction and dilation. Significant pupillary effects occurred within 15 min of the injection and persisted for 24 hr. At 48 hr most measures returned to baseline levels. Generally the magnitude of the effect was not dose related although recovery occurred sooner after the lower dose. The time course of the pupillary effects of buprenorphine exceeds duration of its analgesic and subjective effects. Previous studies have reported that pupillary measures are especially sensitive to the acute effects of full opiate agonists. The results of the present study indicate that buprenorphine, a partial opiate agonist, causes profound and persistent effects on pupillary size and dynamic measures.

Adult↗

PubMedDate not supplied

Unequal pupils. A flow chart for sorting out the anisocorias.

When anisocoria is present, the ophthalmologist knows that something is wrong. However, location of the lesion and diagnosis of the problem can be difficult. A step-by-step flow chart for diagnosis of unequal pupils is presented, with explantation of various signs and descriptions of appropriate diagnostic tests.

Adie Syndrome↗

PubMed1985

Cone mosaic observed directly through natural pupil of live vertebrate.

Using a simple ophthalmoscopic technique, the cone mosaic of a live garter snake was clearly visible when viewed directly through its natural pupil, providing the first definitive cone map in a vertebrate eye. The optical MTF was also measured in natural conditions by projecting gratings in the snakes' field of view. Marrying these two results gives, unequivocally, the interrelation of optical image quality and the photoreceptor mosaic.

Animals↗

PubMed1986

On the gekko pupil and Scheiner's disc.

The four pinhole apertures of the constricted gekko pupil are an adaptation for decreasing the depth of field of the eye, while decreasing the total light flux to the retina. This may be useful for distance estimation at high light levels.

Animals↗

PubMed1988

2-Deoxyglucose uptake in the rat visual system following pupil dilation with atropine.

The 2-deoxyglucose (2-DG) technique was used to assess rat visual system metabolic activity after topical eye application of atropine sulfate. After one pupil had been dilated with atropine, the alert and freely moving rats were surrounded by a montage of horizontal and vertical, black and white, square wave gratings of varying spatial frequencies during the 45 min 2-DG uptake period. Autoradiographic analysis of interhemispheric differences in 2-DG uptake revealed that metabolic activity was less in all primary visual structures lying contralateral to, and primarily fed by, the treated eye. The depression was most evident in the dorsal lateral geniculate nucleus, the lateral posterior nucleus and the superior colliculus. These findings urge caution in the use of atropine in studies of rat visual system metabolic activity.

Animals↗

PubMed1993

An improved mathematical description of the foveal visual point spread function with parameters for age, pupil size and pigmentation.

An analytical description of the point spread function (PSF) for human foveal vision, together with its closed form two-dimensional Fourier transform, the modulation transfer function (MTF), is proposed. It also possesses an analytical line spread function (LSF) counterpart. It fits to both PSF and MTF experimental data and holds over the full angular and spatial frequency domain. Variation in the PSF and MTF descriptions with pupil size, age and iris/skin pigmentation are accounted for by analytical expressions in the parameters.

Adult↗

PubMed2006

Customizable neuroinformatics database system: XooNIps and its application to the pupil platform.

The developing field of neuroinformatics includes technologies for the collection and sharing of neuro-related digital resources. These resources will be of increasing value for understanding the brain. Developing a database system to integrate these disparate resources is necessary to make full use of these resources. This study proposes a base database system termed XooNIps that utilizes the content management system called XOOPS. XooNIps is designed for developing databases in different research fields through customization of the option menu. In a XooNIps-based database, digital resources are stored according to their respective categories, e.g., research articles, experimental data, mathematical models, stimulations, each associated with their related metadata. Several types of user authorization are supported for secure operations. In addition to the directory and keyword searches within a certain database, XooNIps searches simultaneously across other XooNIps-based databases on the Internet. Reviewing systems for user registration and for data submission are incorporated to impose quality control. Furthermore, XOOPS modules containing news, forums schedules, blogs and other information can be combined to enhance XooNIps functionality. These features provide better scalability, extensibility, and customizability to the general neuroinformatics community. The application of this system to data, models, and other information related to human pupils is described here.

Computational Biology↗

PubMed2004

Effect of accommodation and pupil size on the movement of a posterior chamber lens in the phakic eye.

PURPOSE: Although a posterior chamber phakic intraocular lens provides effective refractive correction of high myopia and hyperopia, mechanical contact between the implantable contact lens (ICL) and the crystalline lens and inadequate aqueous circulation in the prelenticular space could cause subcapsular opacification. To assess whether and to what extent such mechanical contact occurs, changes in the distance between the STAAR Collamer ICL and the crystalline lens under various conditions were investigated. DESIGN: Open pilot study. PARTICIPANTS: Thirteen eyes of 11 myopic and 2 hyperopic patients with a mean age of 38 years (range, 19-53 years) were examined at least 6 months after ICL implantation. METHODS: A noninvasive, high-resolution biometry technique, partial coherence interferometry, was used to measure distance changes between the ICL and the crystalline lens during subjective accommodation, after instillation of pilocarpine, and under changing light conditions. MAIN OUTCOME MEASURES: Mean distance changes from the posterior corneal surface to the ICL, from the posterior corneal surface to the anterior surface of the crystalline lens, and the distance between the ICL and the crystalline lens. RESULTS: In the nonaccommodated state, the mean distance between the ICL and the crystalline lens was 457 microm (range, 123-924 microm). During subjective accommodation, a significant (P<0.01) decrease and, after topical application of pilocarpine, a nonsignificant (P=0.35) decrease of anterior chamber depth was accompanied by a nonsignificant (P = 0.71) reduction of the ICL-crystalline lens distance. Under photopic conditions, a significant mean reduction (P<0.01) of the ICL-crystalline lens distance of -28 microm (range, -16 to -188 microm) was observed. CONCLUSIONS: Partial coherence interferometry biometry enabled noninvasive high-precision investigation of ICL dynamics. No significant changes between the ICL and the crystalline lens were detected during subjective accommodation and after application of pilocarpine. However, under photopic conditions, with constriction of the pupil, the distance between the ICL and the crystalline lens was significantly reduced. This mechanism might cause inadequate aqueous circulation in the prelenticular space and might be one of the causes of subcapsular opacification in some of the eyes after ICL implantation.

Accommodation, Ocular↗

PubMed2005

[Segmental anhidrosis associated with Adie's pupil: an incomplete case of Ross syndrome].

We present the case of a 43-year-old woman who presented with a localized area of anhidrosis on the upper left trunk and ipsilateral upper limb. It was associated with Adie's tonic pupil and an area of compensatory hyperhidrosis on the contralateral side. After 9 years of follow up, the alterations have remained stable. These alterations of the autonomous nervous system correspond to an incompletely expressed Ross syndrome.

Adult↗

PubMed1995

Influence of the time interval between instillation of two drops of cyclopentolate 1% on refraction and dilation of the pupil in children.

PURPOSE: Because the usual length of time to instill two drops of cyclopentolate 1% (five to ten minutes) is time-consuming and inconvenient to clinical staff as well as to the child and the child's parents, we investigated the influence of the time interval between the instillation of the two drops on refraction and mydriasis in children. METHODS: We conducted a crossover study on 48 children at the Tel-Aviv Medical Center. Gender, iris color, ethnic origin, and age were recorded. Two cyclopentolate 1% eyedrops were instilled at a one- or five-minute time interval. Retinoscopy was performed and the mydriatic effect was recorded. One week later, the procedure was repeated, this time with a different time interval. RESULTS: The time interval between the instillation of the two drops had no significant influence on retinoscopy results (P = .65 and P = .50 for right and left eyes, respectively) or on pupil dilation (P = .377 and P = .113 for right and left eyes, respectively). CONCLUSIONS: Instilling two drops of cyclopentolate 1% one minute apart is as effective as instilling them five minutes apart.

Child↗

PubMed1983

Tadpole-shaped pupils caused by segmental spasm of the iris dilator muscle.

Segmental spasms of the iris dilator muscle produce intermittent pupillary distortion. A study of 26 case histories (six previously reported and 19 reported for the first time) showed that the episodes are brief (lasting less than five minutes in 23 of 26 patients, less than two minutes in 18 patients, and less than one minute in eight patients) but can occur several times a day. The patients ranged in age from 24 to 48 years (the age of one patient was not known); five were men and 21 were women. Eleven patients had Horner's syndrome, four had Adie's tonic pupil, and eight had definite or probable migraine (another three had possible migraine). The episodes eventually stopped, leaving no serious sequelae. Focal application of phenylephrine produced a similar distortion in a normal human eye.

Adult↗

PubMed1994

Pupilloplasty for small pupil phacoemulsification.

In the pupilloplasty technique, the surgeon creates multiple partial sphincterotomies and stretches the sphincterotomies to enlarge any inadequately dilated pupil so that phacoemulsification can be safely performed. The technique recovers excellent physiologic function and cosmesis postoperatively.

Cataract Extraction↗

PubMed1990

Noncicatricial oval deformation of the pupil induced by sulcus-fixated one-piece posterior chamber lenses.

A retrospective analysis of 40 cases of sulcus-fixated one-piece poly(methyl methacrylate) posterior chamber lenses revealed ten cases (25%) that demonstrated oval deformation of the pupil, similar to the condition associated with anterior chamber lenses. This complication was not noted until several weeks after surgery, appears to be progressive, and might be the cause of glare symptoms. Possible mechanisms of the pupillary deformation include mechanical stretching of the iris by oversized lenses and fibroproliferation on the posterior iris surface. Prevention rests upon firm capsular bag fixation aided by capsulorhexis and reduction of the overall lens loop diameter.

Humans↗