Midbrain corectopia.

Intermittent corectopia was recently observed in a patient with bilateral, rostral midbrain infarction. Results from neuropathologic examination disclosed isolated but intact Edinger-Westphal nuclei. An explanation of midbrain corectopia centered on segmental innervation of the pupil by the Edinger-Westphal nucleus. In the presence of a paralyzed dilator muscle, select, central inhibition of sphincter tone resulted in an oval and eccentric pupil.

A horseradish peroxidase study of the innervation of the internal structures of the eye. Evidence for a direct pathway.

The sources of innervation of the internal structures of the eye in monkey and rabbit were investigated by injecting horseradish peroxidase (HRP) intraocularly and monitoring its retrograde transport. HRP-labeled cells were found in the ciliary ganglia and in the midbrain throughout the dorsoventral extent of the midline of the oculomotor complex. The results suggest that a direct pathway exists from the midbrain, and it is argued that this pathway is for the control of accomodation. Either this pathway is direct, with no synapse interposed, or the postsynaptic neurons are near or in the intrinsic musculature. A third but not so likely possibility is that retrograde transsynaptic transport of HRP occurred across electrotonic synapses in the ciliary ganglion. These findings may challenge the commoly held view that the entire pathway for the control of the intrinsic musculature synapses in the ciliary ganglion. On the other hand, it may be that this direct path is a sensory system much like the mesencephalic nucleus of the trigeminal nerve.

Sympathetic pupillary tone in old age.

In an attempt to determine whether autonomic neural factors might be involved in senile miosis, we tested pupillary responses to agents acting on the ocular sympathetic system in old subjects and compared them to responses in young adults. Our results suggest that sympathetic tone is decreased in the elderly. The dilator pupillae muscle does not lose its sensitivity to norepinephrine with age.

Projections of the postero-medial lateral suprasylvian area (PMLS) to cortical area 20 in cats with special reference to pupillary constriction: a physiological and anatomical study.

Projections of the pupillo-constrictor area in the postero-medial lateral suprasylvian area (PMLS) to that in cortical area 20 was studied using electrophysiological and anatomical methods. Cats were injected with wheatgerm agglutinin-conjugated horseradish peroxidase in the latter area, which was located by intracortical stimulation. Retrogradely labeled cells were found in the PMLS pupillo-constrictor area. It was concluded that the pupillo-constrictor area in the PMLS has direct projections to that in area 20.

Pupillographic analysis of morphine action in the rabbit: role to the autonomic nervous system.

Pupillary response of albino rabbits were recorded using an infrared video pupillometer. The transient response to an i.v. injection of morphine (1-12 mg/kg) consists of three phases. Phase 1 is a brief mydriasis of 20 s duration. Phase 2 is a miosis that reaches a maximum within 2-4 min and is the only dose-related endpoint observed. Time-averaged pupil size is not decreased by morphine in a dose-related manner when measured 5 min after injection. Phase 3 is large amplitude fluctuation that reaches peak amplitude within 20 min and may last for several hours. Thus, dynamic pupillography reveals that the terms "miosis' and "mydriasis' may be insufficient to fully describe opiate-induced pupillary effects. All three phases are blocked by naloxone (0.1 mg/kg i.v.) and by topical pretreatment with scopolamine. These results are consistent with the theory that morphine alters pupil size by interaction with opiate receptors that are involved in the control of parasympathetic output to the iris.

Cholinergic supersensitivity of the iris sphincter in Adie's tonic pupil.

In patients with unilateral Adie's syndrome, we compared the relative supersensitivity of the tonic pupil to methacholine hydrochloride (Mecholyl 2.5%) and pilocarpine 0.125%. We tested a large series of patients and photographed the pupils before and 30 minutes after the eyedrops. In a group of 36 patients, Mecholyl was positive in 64% of the tests; and in a group of 20 patients, pilocarpine 0.125% was positive in 80% of the tests. Eight patients who failed to show supersensitivity with Mecholyl were tested with pilocarpine and five of the eight were shown to be supersensitive. We concluded that pilocarpine, in this concentration is not only an adequate substitute for Mecholyl 2.5%, but is a more sensitive testing substance in unilateral cases, simply because it has a slightly stronger miotic action.

Opposite pupillary size effects in the cat and dog after microinjections of morphine, normorphine and clonidine in the Edinger-Westphal nucleus.

The Edinger-Westphal complex (EW) was explored as a possible site of action for the effects of morphine and clonidine to produce mydriasis in the cat and miosis in the dog. Morphine, normorphine and clonidine, dissolved in 0.5 microliter 0.9% NaCl, were injected via chronic indwelling cannulae into or near the EW of the restrained cat and dog. In the cat, all 3 drugs produced a dose-dependent mydriasis. Clonidine (3-30 nmol) was 1.7 times more potent than normorphine (3-30 nmol) and 9.6 times more potent than morphine (10-60 nmol). Normorphine was 5.5 times more potent than morphine. Significant miosis resulted from single doses of morphine (17.5 nmol), normorphine (15.5 nmol) and clonidine (19 nmol) injected in the EW of the dog. Injections sites closest to the EW yielded the greatest changes in pupillary diameter. Naloxone antagonized the pupillary effects of normorphine in the cat and dog but had no effect on clonidine mydriasis in one cat. It was concluded that the EW region is an important site of action for the effects of morphine and clonidine on pupil diameter in both species. However, the neurocircuitry and neurochemistry of the EW probably differ between the cat and dog.

Anisocoria with orbital floor fractures: worry and wait.

We present a new complication: transient pupillary dilatation in an eye that sustained a posterior orbital floor blow-out fracture. By reviewing the neural pathways involved with pupillary motor function, we surmise the causes of this complication to include trauma to the ciliary ganglion, short ciliary nerves, or the parasympathetic motor root. This type of injury has only recently been reported in the ophthalmologic literature, and has not, prior to this report, been included in the otolaryngologic literature.

Vegetative imbalance in migraine. A dynamic TV pupillometric evaluation.

In this study we investigated the variations of pupillary diameter obtained in different experimental conditions (dark/light adaptation, light reflex, sural nerve stimulation) in a group of migraine patients with unilateral location of pain in almost all the attacks and in healthy controls by means of a TV pupillometric device. The data obtained seems to document the existence in migraine of unbalanced vegetative function ascribable either to a strong sympathetic activity or to a parasympathetic deficiency. Moreover, an involvement of central integrative pathways regulating pupil functioning cannot be excluded.

Electronic pupillometry in healthy controls. Response to sympathicomimetics.

The ocular sympathetic function was examined in 79 healthy volunteers (37 males and 42 females) by electronic pupillography. Pupillary diameters were first estimated under standard light conditions prior to drug application, these diameters being termed "basal values". Then, the pupils were stimulated pharmacologically by instillation of various sympathicomimetic drugs: tyramine tests were carried out in 42 individuals (24 females; 18 males), hydroxyamphetamine tests in 38 (22 females and 16 males), and phenylephrine tests in 43 individuals (23 females and 20 males). Generally, only a minor variation in the frequency of asymmetries was observed between sexes as well as between the various age groups, both when calculating the increase in pupillary diameter in millimeters, in per cent, and as the anisocoria index. In agreement with previous investigations, pupil size was found to diminish with age. The use of an age-matched control material is mandatory when comparing pupillographic recordings in patients in various categories, in the ordinary condition, as well as after topical drug administration.

Respiratory fluctuations of the human pupil.

We simultaneously recorded respiration and pupil size in six normal subjects with an age range of 23-40 years (mean = 30.1), to study the relationship between the respiratory rhythm and changes in pupil size. In all subjects, respiratory fluctuations of the pupil (inspiratory mydriasis and expiratory miosis) were observed during normal spontaneous respirations. The amplitude of these pupillary changes was closely proportional to the tidal volume.

The pupil cycle time in familial dysautonomia. Further evidence for denervation hypersensitivity.

The pupil cycle time (PCT) was prolonged in 11 subjects with familial dysautonomia. In the younger age group (10-19 years), mean PCT was 872 +/- 88 msec as compared to 15 normal age matched controls (728 +/- 88). In the 3 oldest patients (30-39 years) mean PCT was 980 +/- 133 msec as compared to 13 age matched normals (748 +/- 56). It is proposed that prolongation of PCT in familial dysautonomia may be due to functional denervation of the iris or that it is a result of a structural abnormality of its musculature and/or its neuromuscular junctions.