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At least 703 records · Page 39Linked to original sources
PubMed1987

Optical management of posterior chamber lens tilt.

A pseudophakic patient reported blurred vision and diplopia one year after the surgery. We suspected that the origin of both these problems was subluxation of the intraocular lens. His blurred vision was eliminated by a cylindrical spectacle lens at an oblique axis. Monocular diplopia could only be eliminated occasionally. The displacement of the IOL is shown photographically in this report.

Adult↗
PubMed1992

Pupil perimetry.

The pupillomotor and visual sensitivity were compared at the same 76 points across the 30 degrees field. The timing and amplitude of pupillary contractions to focal light stimuli were recorded using a computerized infrared pupillometer linked to a Humphrey automated perimeter. Pupil perimetry and standard threshold perimetry showed matching defects in the visual field of patients with ischemic and compressive optic neuropathy, but not in patients with primary open-angle glaucoma. Patients with isolated occipital strokes showed matching homonymous visual and pupillary fields, suggesting a suprageniculate influence upon the pupillary light reflex. Pupil perimetry is a useful objective form of perimetry and can be used to compare the effect of disease on the visual and pupillary pathways.

Humans↗
PubMed1998

Pupil noise is a discriminator between narcoleptics and controls.

The pupil light reflex has a long history of being able to indicate states of mental arousal, ranging from sleepiness to concentrated cognitive effort. Such mental states have usually been inferred from pupil diameter or pupil area movements relative to some reference; sleepiness, for example, is characterized by a smaller than average pupil while mental effort brings on a slightly larger pupil. But all pupil movements and associated states of arousal are accompanied by a persistent random pupil diameter motion which has previously been attributed to neurological noise, the noise apparently arising in the neurological controller of the pupil reflex control system. Our experiments and signal processing methods show that the amplitude of this pupil noise is an indicator of the sleeping disorder narcolepsy. Narcoleptics are found to have diminished pupil noise amplitudes relative to control subjects. Pupil noise is estimated by statistical procedures which yield unbiased noise measures in the form of six-dimensional Gaussian vectors. Each subject is associated with a Gaussian vector which is optimally projected onto a scalar axis so as to maximize the mean square distance between the narcoleptic and control samples. The Kullback-Leibler discrimination function is estimated and then evaluated for each projection as a means of discriminating narcoleptics from controls. The projected noise measures correctly classify 18 out of 20 subjects. The projected values also form the basis for supporting or rejecting a hypothesis of narcoleptic or control class membership. Parametric and nonparametric hypothesis tests suggest that, with probabilities close to one, narcoleptics and controls are distinguishable classes. To emphasize the importance of pupil noise as a diagnostic tool we present evidence from the neurophysiology literature indicating that Alzheimer's disease and narcolepsy have some of the same brainstem nuclei implicated. Further, Alzheimer patients and narcoleptics share some of the same disturbed sleep patterns.

Adult↗
PubMed2005

Pupil campimetry in patients with visual field loss.

Pupil campimetry is an objective test of the visual field. In pupil campimetry, the pupil light response elicited by focal light stimuli at different locations within the visual field is measured. Pupil campimetry was performed in patients with visual field loss because of different pathologies. The match between reduced pupil response and visual field loss was assessed. The pupil field of 23 patients was recorded by infrared video-pupillography with light stimuli generated on a computer screen. A visual field was obtained on the same day with the Tuebingen Automated Perimeter. Both fields were compared by subjective judgement. Six of nine patients with large, two of five patients with incomplete, and three of six patients with minor field loss showed matching defects in their pupil and their visual fields. In functional loss of visual field sensitivity, no pupil field defect was seen (three patients). In most patients, the loss of visual field sensitivity could be revealed objectively by pupil campimetry.

Adolescent↗
PubMedDate not supplied

Thalamic hemorrhage. A study of 23 patients with diagnosis by computed tomography.

A series of 23 patients with thalamic hemorrhage with computed tomography confirmation is reported. Nine of these died, all had hematomas larger than 3.3 cm. The value of the syndrome of downward and convergent ocular deviation is stressed, and its possible mechanisms are analyzed. The characteristics and mechanisms of the pupillary abnormalities are reported, as well as the speech abnormalities observed in patients with lesions of the dominant hemisphere. Prognostic conclusions are drawn.

Adult↗
PubMed1985

Pupillary and vascular effects of calcium antagonists in migraine.

In migraine patients the effect of calcium antagonists (flunarizine, verapamil and nifedipine) on both venous and pupillary neuromuscular functions, as well as on blood pressure have been evaluated. A single oral dose of flunarizine (10 mg) and verapamil infusion (50 micrograms/ml/min) increased venous compliance. Verapamil also counteracted dose-dependent dopamine induced venoconstriction. Nifedipine (10 mg orally) reduced mean arterial pressure in upright position in migraineurs but not in controls. In addition, chronic treatment with flunarizine (10 mg for 2 weeks) induced a transient miotic effect and a reduction of tyramine induced mydriasis. These findings demonstrated that calcium antagonists affect vascular and extravascular structures. It is postulated that, in migraine, calcium entry blockers may prevent exaggerated responses to catecholaminergic stimulation.

Blood Pressure↗
PubMed1987

Tolerance to visual defocus.

Low-resolution optical systems are more tolerant to defocus than are high-resolution systems. We wished to determine whether this principle applies to human vision. We used psychophysical methods to measure the effects of defocus in normal eyes under low-resolution conditions. Modulation transfer of sine-wave gratings was measured as a function of dioptric defocus at low and medium spatial frequencies. We defined the depth of focus at a given spatial frequency to be the dioptric range for which the modulation transfer exceeds 50% of its peak value. For dilated pupils, depth of focus increased from about 2.5 diopters (D) at 3.5 cycles/deg to about 17 D at 0.25 cycles/deg. From our results we predicted that tasks requiring only low spatial frequencies will be more tolerant to defocus than tasks requiring higher spatial frequencies. This prediction was confirmed in a letter-recognition experiment. The increasing tolerance to defocus at low spatial frequencies also implies that individuals with low acuity will be more tolerant to defocus than people with normal vision. We confirmed this prediction by measuring tolerance to defocus in 30 low-vision eyes.

Humans↗
PubMed1995

The Nambour study of ocular disease. I. Design, study population and methodology.

In association with a study of actinic skin disease, we undertook a comprehensive survey of ocular disease in a population sample of the town of Nambour, Queensland, Australia. Particular emphasis was placed on those diseases with a putative relationship to exposure to solar radiation. In addition to collecting prevalence data, a randomized controlled trial was commenced to determine, among other things, if daily ingestion of 30 mg of beta-carotene supplements reduces the incidence or progression of ocular diseases possibly related to solar radiation exposure. The study design, population and methodology of the study are described in detail as a background to the future reporting of the results. The study should provide unique epidemiological information about eye disease in an Australian community setting due to the representative nature of the subjects and the comprehensive examination performed.

Adult↗