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At least 433 records · Page 24Linked to original sources
PubMed2000

Pupil perimetry using M-sequence stimulation technique.

PURPOSE: M-sequence stimulation technique allows mapping of the retinal function by multifocal electroretinographic (ERG) recordings. However, the information provided about visual field is limited to retinal function. Optic nerve diseases and diseases of the higher visual pathways usually show normal multifocal ERGs. Using pupillary responses instead of the electrical retinal responses might enhance the diagnostic possibilities of this system. The problems of local ERG recordings are very similar to those encountered in pupil perimetry: Local stimuli have to be dim to avoid or at least reduce stray-light responses. Dim stimuli, close to the absolute threshold, elicit only subtle pupillomotor responses. Therefore, techniques that are able to detect small focal responses are promising. METHODS: Pupillography was done by means of an infrared video camera and real time image processing (50 Hz) using a custom-designed videoboard in a personal computer (486). Recording conditions: The stimulus was presented on a monitor (75 Hz) in 26 cm distance from the patient's eyes. It contained 37 hexagons in a 25 degrees visual field. Each element changed between black (1.6 cd/m2) and white (160 cd/m2) after a binary M-sequence independently from other elements. Four thousand ninety six different stimulus pictures of 120-msec duration were shown during a single pupillogram recording. Thirty-seven local pupillograms were calculated in a cross-correlation of stimulus sequence and the pupil diameter. RESULTS: The pupillomotor fields in normals showed a shape and sensitivity distribution as known from conventional pupil perimetry techniques. Artificial paracentral scotomas (5 degrees) created by masking different locations could be demonstrated convincingly. Even in patients with optic nerve lesions it was possible to demonstrate visual field defects. CONCLUSIONS: Pupil perimetry using the M-sequence technique is a promising method of objective perimetry that may find its entrance into clinical application.

Adult↗
PubMed1999

Effects of defocus and pupil size on human contrast sensitivity.

Defocus lowers the contrast sensitivity function (CSF), producing a complex function with local dips and peaks. Previously, we were able to predict the shape of the CSF with large pupils from measured transverse aberrations with hypermetropic defocus but not with myopic defocus (Atchison et al., 1998c, J. Opt. Soc. Am. A. 15, 2536). As there is no reason that myopic defocus should be more difficult to predict than hypermetropic defocus, we modified the procedure to try to improve CSF predictions with myopic defocus. Also, we extended the study to consider a range of pupil sizes. CSFs were measured for three subjects at three defocus levels (in-focus, -2D and +2D) and three pupil sizes (2 mm, 4 mm and 6 mm). Using a diffraction optics model, transverse aberration measures and in-focus CSF measures, we predicted the defocused CSFs. The predicted defocused CSFs were lower than the in-focus CSF as expected, and had complex shapes that varied with defocus and pupil size and between subjects. While a few predictions were poor, generally, the overall magnitude and shape of the defocused CSFs were well predicted and similarly so for myopic and hypermetropic defocus. Some further improvements in technique are indicated.

Accommodation, Ocular↗
PubMed1992

[A case of early syphilis presenting general paresis-like symptoms and bilateral tonic pupils].

A 40-year-old man was admitted after 8 months of speech disturbance and locomotive ataxia. He had no seizures, lightning pains, paresthesia, visual loss, bladder disturbance or rectal incontinence. He had never been neurologically or psychiatrically ill and had no history of syphilis. When the patient was admitted, his general physical examination including blood pressure and dermatologic examination was normal. His consciousness was alert. He was found to have a deterioration of mental status such as inability to concentrate, failing memory, amnesia and circumstantiality. His pupils were anisocoric and Achilles jerks were absent. No rigidity of the neck muscles, paralysis and sensory disturbance were recognized. Romberg's sign was absent. The right pupil was 7.0 mm and the left was 6.0 mm in room illumination. The pupils were nonreactive to bright light and both did not constricted to near stimuli. 0.125% pilocarpine eyedrops produced bilateral pupillary constriction. The results indicated bilateral tonic pupils. Laboratory data revealed white cell count of 12,600/mm3 and normal erythrocyte sedimentation rate of 8 mm/hr. Cerebrospinal fluid (CSF) examination revealed the following: opening pressure, 140 mm of water; cell counts, 76/mm2 (mononuclear cells); total protein, 116 mg/dl; glucose, 57 mg/dl. A serum venereal disease research laboratories (VDRL) test was positive in a 1:32 titer confirmed by positive treponema pallidum hemagglutination (TPHA) test in a 1:40,960 titer and positive fluorescent treponemal antibody-absorption (FTA-ABS) test. Serum TPHA-IgM was positive in a 1:320 titer but TPHA-IgG was negative. CSF examination revealed positive TPHA test (titer of 1:2,560) and positive FTA-ABS test.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Corneal permeability in patients with tonic pupil. A reevaluation of its cholinergic supersensitivity.

Cholinergic supersensitivity of the iris sphincter helps to make the diagnosis of "tonic pupil." Because uncertain responses sometimes occur with mecholyl 2.5%, dilute solutions of pilocarpine are often used. There has always been some question as to whether individual variation in corneal permeability was one of the factors contributing to the variability in pupillary constriction to topical cholinergics in these patients. In this study, the degree of intraocular penetration of topical fluorescein was compared with the degree of pilocarpine-induced miosis in six tonic pupils and in seven age-matched normal controls. A noncontact fluorophotometer and a computerized videopupillogram were used. The patients showed a significant cholinergic supersensitivity in their affected tonic pupils and had normal intraocular penetration of fluorescein through the cornea in both eyes. It is concluded that the cholinergic supersensitivity of the iris in tonic pupils is not the result of increased corneal permeability but instead results from an increased sensitivity of the cholinergic receptors in iris sphincter muscles.

Adult↗
PubMed1990

[Mammalian pupil constriction to light in the presence of atropine in hamster. Part I. Hamster and visual rays].

Mammalian pupils constrict in reaction to lights. Miosis occurs via afferent and efferent nerves. Therefore, once the pupil is pretreated with atropine, miosis no longer occurs, even when the retina is intact. We found that hamster pupil constricts in reaction to light in the presence of atropine. We examined the relationship with pupillary size, light intensity, wavelength and intervals of darkness. Pupillary constriction was found when the retina was withdrawn, and the miosis was not affected by autonomic blocking agents, capsaicin pretreatment and tetrodotoxin, a nerve blocking agent. Hamster pupil reacts to lights (visible rays-ultraviolet) in the presence of atropine and in the absence of retinal function.

Animals↗
PubMed1989

[The threshold of pupil-blocking force].

The purpose of this study was to quantitate the dynamic changes which take place in the anterior eye segment during the prone position test. The pupil-blocking force was measured before and after the prone position test (PTT) by a method of image analysis using a computer. The changes in the magnitude of pupillary block were evaluated. The mechanics of this provocation seems to be both pupillary block and direct lens block angle-closure. Pupil-blocking force standardizes the assessment of the eyes with relative pupil-block. The present results provide valuable information in the analysis of the mechanism of primary angle-closure glaucoma and also contribute to the determination of a real value for the threshold of the pupil-blocking force (approximately 0.1 or greater), followed by a clinically significant elevation of intraocular pressure.

Biomechanical Phenomena↗
PubMed1988

Factors affecting the normal perimetric profile derived by automated static threshold LED perimetry. I. Pupil size.

The relationship between pupil size and perimetric sensitivity was investigated in a group of clinically normal emmetropic subjects using the Dicon AP3000 computer-assisted perimeter at bowl luminances of 10 asb and 45 asb. Pupil size was modified with the miotic thymoxamine 0.5% and the mydriatic phenylephrine 10%; saline was used as the control. Perimetric sensitivity increased with an increase in pupil size. The effect was greatest for peripheral locations for both bowl luminances. The fluctuations in perimetric sensitivity increased with peripheral angle and with decrease in pupil size for both bowl luminances.

Adult↗
PubMed1987

Pupil response as an objective measure of visual acuity.

Pupillary responses to brief presentations of sinusoidal grating patterns were measured. The results show that the amplitude of the pupillary responses varies systematically with grating spatial frequency. Gratings of spatial frequencies in the range 1-5 c deg-1 elicited the maximum percentage change in pupil area, with higher and lower spatial frequency gratings producing smaller responses. The bandpass nature of the pupil response function was compared to contrast sensitivity functions obtained under the same viewing conditions. The effects of defocus and eccentric fixation on both contrast sensitivity and pupil response functions were qualitatively similar. Grating acuities calculated from contrast sensitivity data correlated well with similar data extracted from pupil response functions. The results suggest that automated pupillometry can provide an attractive means for objective measurement of visual acuity.

Fixation, Ocular↗
PubMed1986

Effects of 0.1% cyclopentolate or 10% phenylephrine on pupil diameter and accommodation.

The mydriatic and cycloplegic effects of either one drop of 0.1% cyclopentolate or two drops of 10% phenylephrine were studied over a period of up to 6 hours after drug instillation, using 5 subjects aged between 25 and 43 years. The extent of mydriasis was determined from the horizontal diameter of the pupil. Dynamic accommodation responses were monitored with an infra-red, continuously recording optometer. Static measurements of the accommodation response/stimulus curve were made with a laser optometer. With either drug, dilation of the pupil occurred more rapidly than recovery of normal pupil diameter. Both drugs caused alterations in the dynamic and static accommodation responses. Response times were generally slowed, and the slope of the accommodation response/stimulus curve and the amplitude of accommodation were reduced. The time course of these changes was broadly similar to that of the pupil dilation. Cyclopentolate hydrochloride was more efficient as a mydriatic but exercised a greater unwanted cycloplegic effect.

Accommodation, Ocular↗
PubMed1985

Oculomotor areas involved in the parasympathetic control of accommodation and pupil size in the marmoset (Callithrix jacchus).

The motoneurons of the oculomotor complex responsible for controlling accommodation and pupil size of the marmoset were identified by injecting horseradish peroxidase (HRP) into the ciliary ganglion. The anatomical organization of accommodation and pupil constrictor motoneurons was determined using electrical stimulation techniques. HRP-labelled cells were found through the whole length of the Edinger-Westphal nucleus (EW) and also just ventral to this nucleus in caudal sections. A projection from the antero-median nucleus to the ciliary ganglion could not be demonstrated. Electrical stimulation data showed that currents of less than 1 microampere applied inside the EW evoked accommodation responses. Pupil constriction responses, on the other hand, were evoked with weak currents at sites ventral to those in the EW generating accommodation at caudal and central levels. It was concluded that the EW was responsible for accommodation and areas containing HRP-labelled cells ventral to the caudal part of the EW were responsible for pupil constriction.

Accommodation, Ocular↗
PubMed1979

The influence of 1,3,7-trimethyl-xanthine (caffeine) on the pain-caused dilation of pupil.

The pupil dilation in man caused by pain was investigated. The pain stimulus was induced electrically. The size of the pupil was measured according to the "flying spot scanning method". The accuracy of measurement was increased by computer-assisted addition of repeated responses as well as by elimination of the, usually not considered constriction due to light compensation over Maxwellian view. The pure psycho-sensory dilation shows no initial contraction. The central stimulant 1,3,7-trimethyl-xanthine (caffeine) does not influence the course and adaption of the pupil reaction by a pain stimulus over the threshold. The pupil reaction correlates with the subjective feeling of pain. This suggests that caffeine does not influence the feeling of pain.

Adult↗
PubMed1978

A small pupil binocular indirect ophthalmoscope.

A description of a lightweight small pupil binocular indirect ophthalmoscope is presented. This instrument can be used with well dilated pupils and clear media as any stereoscopic indirect ophthalmoscope. However, the instrument can be simply and easily adjusted for usage in patients with small pupils or opacities of the media. The optical and mechanical principles employed are presented. The technique of utilization for small pupil viewing is outlined.

Dilatation↗
PubMed1978

The refraction of the eye in the relation to spherical aberration and pupil size.

Available theoretical and experimental data on the dependence of the subjective refraction of the eye on spherical aberration and pupil size are reviewed and additional experimental results are presented. Under photopic conditions, refraction varies little (similar to 0.3 DS) with pupil diameter, even when substantial amounts of spherical aberration are present (similar to 1.0 DS). It is argued that this result may be attributed to the insensitivity of optimal focus to spherical aberration at the spatial frequencies involved in photopic refraction, to the Stiles-Crawford effect and to the influence of aberrations other than primary spherical aberration in the outer zones of the pupil. The signficance of these findings is indicated in relation to possible discrepancies between the results of objective and subjective refractions when large pupils are in use.

Humans↗
PubMed1995

[Small pupil and phacoemulsification].

Miotics pupils are compatible with phacoemulsification. Several techniques have been proposed to enlarge the pupil. We present a multiple sphincterotomies technique which enlarges the pupil to a size compatible with phacoemulsification, and retains postoperatively the circular shape of the pupil as well as its functional role.

Humans↗
PubMed1994

Apparent pupil displacement in videokeratography.

With videokeratography, the apparent position of the entrance pupil of some eyes is displaced by up to 0.5 mm from the center of the target ring image or the corneal map. This displacement occurs because of the alignment system and is not affected significantly by the corneal central radius of curvature, peripheral asphericity, or other shape parameters. It is determined primarily by angle lambda between the line of sight and the pupillary axis and is reduced when the real pupil is decentered nasally. The displacement of the entrance pupil position occurs in all commercial videokeratographs and is responsible for the difference in the apparent position of the entrance pupil when observed directly by the examiner's eye, in refractive surgery, and when measured by videokeratography. This difference also demonstrates that the line of sight should represent the primary reference axis for videokeratography and photorefractive surgery rather than the vertex normal or the visual axis.

Cornea↗
PubMed1993

Tonic pupil in lymphomatoid granulomatosis.

Tonic pupil is due to a lesion of orbital parasympathetic neurons in the ciliary ganglion or short ciliary nerves (1). Precise etiology of the condition remains obscure. In the case described here, development of "tonic pupil" was followed by systemic features typical of lymphomatoid granulomatosis, and diagnosis was confirmed by histology of the skin rash. This case underlines the heterogeneity of the causes of tonic pupil. Vascular occlusion can be a possible mechanism in the pathogenesis of tonic pupil.

Adult↗
PubMed1996

Effects of topical administration of 0.5% apraclonidine on intraocular pressure, pupil size, and heart rate in clinically normal cats.

OBJECTIVE: To evaluate the effect of a topical alpha 2-agonist, 0.5% apraclonidine, on intraocular pressure (IOP), pupil size, and heart rate in clinically normal cats. DESIGN: Randomized masked saline-controlled case study. ANIMALS: Nine clinically normal conditioned adult cats of either sex. PROCEDURE: Normal diurnal variation in IOP, pupil size, and resting heart rate was determined from 7 AM to 7 PM (day 1). On day 2, the same measurements were made after the topical application of 30 microliters of 0.5% apraclonidine to 1 randomly chosen eye of each cat. The contralateral eye received saline solution. RESULTS: Apraclonidine lowered IOP a mean of 4.8 mm of Hg (24.0%) when compared with IOP in the fellow saline-treated eye 6 hours after treatment. Unilateral administration of the drug also may have reduced IOP in both eyes. Pupil size was reduced a mean 46% in only the apraclonidine-treated eye, and miosis persisted for up to 24 hours. Heart rate was significantly lower (11.8%) at 3 hours, and 8 of 9 cats vomited after topical administration of the drug. Mild blanching of the conjunctiva occurred in all apraclonidine-treated eyes. CONCLUSIONS: Apraclonidine reduced IOP, pupil size, and resting heart rate in clinically normal cats, but also induced undesirable systemic side-effects. In contrast to dogs where the drug induced mydriasis, apraclonidine caused miosis in cats. CLINICAL RELEVANCE: The current commercially available formulation of topical 0.5% apraclonidine is too toxic for clinical use in cats. Reformulation, or identification of a less toxic congener, may result in a clinically useful antiglaucoma preparation for cats.

Administration, Topical↗
PubMed2000

Evaluation of a teaching package designed to improve teachers' recognition of depressed pupils-a pilot study.

This pilot study evaluated the impact of a teaching package for school staff on their ability to recognize depressed pupils within a year group in their school. Sixteen teachers were tested before and after training on their ability to identify depressed pupils in that year. The pupils were screened using a 2-stage procedure to determine caseness for Major Depressive Disorder (MDD). After training, teachers felt more confidant about their ability to recognize depressed pupils but this was not able to be statistically verified because of small teachers numbers. This suggests a promising way forward in recognizing depression in the community.

Adolescent↗