Objective Verification of Physiologic Changes during Accommodation under Binocular, Monocular, and Pinhole Conditions

BACKGROUND

To objectively investigate accommodative response to various refractive stimuli in subjects with normal accommodation.

METHODS

This prospective, non-randomized clinical trial included 64 eyes of 32 subjects with a mean spherical equivalent -1.4 diopters (D). We evaluated changes in accommodative power, pupil diameter, astigmatic value, and axis when visual stimuli were applied to binocular, monocular (dominant eye, non-dominant eye, ipsilateral, and contralateral), and pinhole conditions. Visual stimuli were given at 0.25 D (4 m), 2 D (50 cm), 3 D (33 cm), and 4 D (25 cm) and accommodative response was evaluated using open view binocular autorefractor/keratometer.

RESULTS

The accommodative response to binocular stimulus was 90.9% of the actual refractive stimulus, while that of the monocular stimulus was 84.6%. The binocular stimulus induced a smaller pupil diameter than did the monocular stimulus. There was no difference in accommodative response between the dominant eye and non-dominant eye or between ipsilateral and contralateral stimuli. As the refractive stimuli became stronger, the absolute astigmatic value increased and the direction of the astigmatism axis became more horizontal. Pinhole glasses required 10%-15% less accommodative power compared with the monocular condition.

CONCLUSION

Binocular stimuli enable more precise and effective accommodation than do monocular stimuli. Accommodative response is composed of 90% true accommodation and 10% pseudo-accommodation, and the refractive stimulus in one eye affects the contralateral eye to the same extent. This should be taken into account when developing guidelines for wearing smart glasses while driving, as visual stimulation is applied to only one eye, but far distance attention is constantly needed.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03557346.

A Rare Cause of Acute Anisocoria in a Child: The Angel's Trumpet Plant

Anisocoria is a significant finding in several ocular and potentially life-threatening neurological disorders. The angel's trumpet (Datura suaveolens), widely used as a garden plant, is a natural alkaloid with anticholinergic effects containing high levels of scopolamine. The authors present a pediatric case of acute anisocoria secondary to contact with the angel's trumpet plant. This case report emphasizes the importance of considering herbal mydriatics in patients with acute, isolated, unilateral mydriasis. It is also important to raise public awareness about the potential risks of the angel's trumpet plant, particularly in areas close to schools and playgrounds. [J Pediatr Ophthalmol Strabismus. 2018;55:e33-e35.].

Stereopsis Simulating Small-Aperture Corneal Inlay and Monovision Conditions

PURPOSE

To analyze stereoscopic vision under a broad range of experimental conditions simulating small-aperture corneal inlay and monovision conditions.

METHODS

A total of 10 patients participated in the study. The anisocoria generated by corneal inlays was simulated by using a small-aperture contact lens fitted on the non-dominant eye. Visual acuity, contrast sensitivity function, visual discrimination capacity (halo perception), and stereoacuity tests were performed under natural conditions or when the non-dominant eye wore the small-aperture contact lens under two conditions: induced anisocoria and induced anisocoria combined with monovision (using two add-powers: +0.75 and +1.25 diopters [D]). Stereoscopic vision and binocular summation were analyzed under those experimental conditions and for far, intermediate, and near vision.

RESULTS

The results showed a deterioration in stereoacuity with respect to natural conditions, being significant mainly for near and intermediate distances. Results with other visual functions showed a deterioration of the binocular summation and therefore of visual performance, although not in a generalized way for all distances. Binocular visual acuity under the conditions that used the small-aperture contact lens was comparable to that of the natural eye.

CONCLUSIONS

The deterioration of stereopsis and other binocular functions found in this study may be acceptable for patients who had this surgical technique because it is similar to the deterioration found in other surgical procedures of emmetropization. [J Refract Surg. 2018;34(7):482-488.].

The Degree of Anisocoria in Pediatric Patients With Horner Syndrome When Compared to Children Without Disease

PURPOSE

To study the magnitude of anisocoria in pediatric patients using the plusoptiX A08 (plusoptiX GmbH, Nuremberg, Germany) photoscreener as compared to a literature review of pediatric patients with known Horner syndrome to determine if anisocoria alone should raise suspicion for the diagnosis.

METHODS

The medical records of 592 consecutive patients, neonates to 9 years old, were collected and analyzed. All patients had complete ophthalmic examinations that included photoscreening with the plusoptiX A08. Data included age, pupil sizes, and anisocoria. A complete literature search of documented pupillary size in pediatric patients with the diagnosis of Horner syndrome was performed. This was then compared to the normative pediatric pupil data from the study.

RESULTS

Of the 592 children without Horner syndrome, 372 had an anisocoria of 0.1 to 0.5 mm (62.84%), 167 had an anisocoria of 0.6 to 1.2 mm (28.16%), and 21 had an anisocoria of 1.3 mm or greater (3.70%). There was no correlation between increasing age and severity of anisocoria (P = .55). For pediatric patients with a diagnosis of Horner syndrome, the average level of anisocoria was 1.37 mm in room light and 2 mm in darkness. In room light, three children had anisocoria of 0.1 to 0.5 mm (9.4%), 14 had anisocoria of 0.6 to 1.2 mm (43.8%), and 15 had anisocoria of 1.3 mm or greater (46.9%). In darkness, the level of anisocoria increased in 19 patients, causing the first category, 0.1 to 0.5 mm, to include 1 patient (3.1%), the second group to include 5 patients (15.6%), and the last group to include 26 patients (81.3%). Other associated signs/symptoms included ptosis (100%), heterochromia (28.1%), anhidrosis (9.4%), straight hair on affected/curly on unaffected side (9.4%), and neck mass (6.3%). In 37.5% of cases, imaging results were negative and no specific etiology was determined.

CONCLUSIONS

In a study of 592 children without Horner syndrome, the average pupillary size increased with age, but the degree of anisocoria remained stable with increasing age. Over half of the children studied had anisocoria up to 0.5 mm (62.84%), but rarely had anisocoria greater than 1.3 mm (3.70%). In children with a diagnosis of Horner syndrome, the majority had anisocoria greater than 1.3 mm, with the discrepancy in pupil size becoming more apparent in low levels of light intensity. Anisocoria greater than 1.3 mm is unlikely to be physiologic in a child; therefore, he or she should be carefully evaluated for other localizing signs, such as ptosis, anhidrosis, and neck mass. [J Pediatr Ophthalmol Strabismus. 2016;53(3):186-189.].

Oral Implant-Prostheses: New Teeth for a Brighter Brain

Several studies have demonstrated that chewing can be regarded as a preventive measure for cognitive impairment, whereas masticatory deficiency, associated with soft-diet feeding, is a risk factor for the development of dementia. At present the link between orofacial sensorimotor activity and cognitive functions is unknown. In subjects with unilateral molar loss we have shown asymmetries in both pupil size and masticatory muscles electromyographic (EMG) activity during clenching: the molar less side was characterized by a lower EMG activity and a smaller pupil. Since implant-prostheses, greatly reduced both the asymmetry in EMG activity and in pupil's size, trigeminal unbalance, leading to unbalance in the activity of the Locus Coeruleus (LC), may be responsible for the pupil's asymmetry. According to the findings obtained in animal models, we propose that the different activity of the right and left LC may induce an asymmetry in brain activity, thus leading to cognitive impairment. According to this hypothesis, prostheses improved the performance in a complex sensorimotor task and increased the mydriasis associated with haptic tasks. In conclusion, the present study indicates that the implant-prosthesis therapy, which reduces the unbalance of trigeminal proprioceptive afferents and the asymmetry in pupil's size, may improve arousal, boosting performance in a complex sensorimotor task.

Sensorimotor trigeminal unbalance modulates pupil size

We studied whether patients affected by Temporo-Mandibular Disorder (TMD), showing asymmetric electromyographic (EMG) activity of masticatory muscles also display asymmetries in pupil size. In 30 pain free TMD patients a highly significant, positive correlation was found between left-right differences in EMG and pupil size. The asymmetry in pupil size was induced by the asymmetric sensorimotor signals arising from the orofacial region, since pupils became of about the same size following orthotic correction, which greatly reduced the EMG asymmetry. Moreover, bite wearing bilaterally increased the mydriasis induced by performing haptic tasks. Finally, unbalancing the occlusion by a precontact increased the diameter of the ipsilateral pupil and abolished the mydriasis induced by haptic tasks. In conclusion, trigeminal sensorimotor signals may exert a tonic control on autonomic structures regulating pupil size at rest and during sensorimotor tasks. Since task-associated mydriasis is correlated with task performance and is strictly proportional to the phasic release of noradrenaline at cerebral cortical level, the present findings may suggest an impact of unbalanced trigeminal activity on brain processing not directly related to the orofacial region.

Bilateral tonic pupils: Holmes Adie syndrome or generalised neuropathy?

AIM

To compare the pupil signs in patients with bilateral pupillotonia caused by Holmes-Adie syndrome or generalised peripheral neuropathy.

METHODS

Infrared video pupillographic techniques were used to measure a number of pupil variables in patients with Holmes-Adie syndrome, generalised neuropathy (various aetiologies) and healthy age-matched control subjects.

RESULTS

Regardless of aetiology, the patients generally had pupil signs typical of pupillotonia (small dark diameters, large light diameters, tonic near responses, attenuated light responses with light-near dissociation, and sector palsy). However, significant differences were found in the prevalence and magnitude of several pupil variables in the two patient groups. In particular, sector palsy and anisocoria exceeding 1 mm (in the light) were seen much more commonly in Holmes-Adie patients than patients with generalised neuropathy. The presence of both these pupil signs can be used to distinguish between these diagnoses with a sensitivity of 58% and a specificity of 90%.

CONCLUSIONS

The tonic pupils of patients with Holmes-Adie syndrome are significantly different to those found in patients with generalised neuropathy; recognition of these differences may allow distinction between these diagnoses.

The dilated pupil: an update

The dilated pupil can present a significant challenge to the clinician. Although in most cases a complete history and physical examination is sufficient to make an accurate diagnosis, selected patients will require further investigation, including pharmacologic testing and neuroimaging. This review outlines the physiology, clinical features, and diagnostic approach to the most important causes of the dilated pupil. Particular attention is given to recent publications on this topic.

Horner’s syndrome, Pseudo-Horner’s syndrome, and simple anisocoria

This discussion reviews the common causes of Horner's syndrome, with emphasis on case reports from the past several years. Much of the recent literature concerns the use of apraclonidine as a diagnostic test for Horner's syndrome, possibly as an alternative for the current gold standard of cocaine eye drops. This new literature is discussed in the context of the current standards for clinical diagnosis.

Primary germinoma arising from the midbrain

A 29-year-old man presented with diplopia, dysarthria, anisocoria, oculomotor nerve paralysis, abducens nerve paralysis, right facial palsy, and spastic hemiparetic gait. Magnetic resonance imaging (MRI) showed a homogenously enhanced mass in the midbrain. MRI-guided stereotactic biopsy was performed, and the histologic diagnosis was pure germinoma. The tumor disappeared after chemotherapy and radiotherapy. Germinoma should be included in the differential diagnosis of midbrain lesions in young adults. MRI-guided stereotactic biopsy provided a helpful diagnostic clue in a patient with a midbrain lesion.

When cluster headache was called histaminic cephalalgia (Horton's headache)

The Author revives his experiences and reminiscences in the frontline research and everyday clinical practice dealing with what was then called "histaminic cephalalgia" (Horton's headache). In this context, the Author, one of the historical representatives of the School of Florence, reports an outline of the contribution of this pioneering period in order to promote research ideas concerning possible brain involvement in cluster headache (CH) pathogenesis, which is currently accepted worldwide. The recent history of CH has registered remarkable progress in revealing the mystery of this pathology and it is likely that, in the near future, through the development of better education and new treatments, the overall suffering of patients will be further minimised.

Concomitant Ectatic Posterior Communicating Artery and Tentorial Meningioma as a Source of Oculomotor Palsy: Case Report

OBJECTIVE AND IMPORTANCE:

Although non-aneurysmal vascular compression of the oculomotor nerve is rare, it should be considered in the evaluation of unilateral oculomotor palsy.

CLINICAL PRESENTATION:

A 36-year-old non-diabetic man presented with two months of intermittent retro-orbital headache and third nerve paresis caused by compression of the oculomotor nerve between an ectatic, atherosclerotic posterior communicating artery (PComA) and a small tentorial meningioma. At operation, the subarachnoid portion of the nerve, prevented from migrating posteriorly and laterally by the meningioma, was grooved by the apex of the artery's loop.

INTERVENTION:

Microvascular decompression (MVD) of the artery loop from the nerve and resection of the meningioma were performed. Postoperatively, the patient's retro-orbital headache and oculomotor paresis, with the exception of mild anisocoria, resolved. Tumor infiltrating the posterior tentorium and lateral cavernous sinus was treated by Cyberknife radiosurgery five months later. One year after surgery, the patient had improvement in his headaches, full extra-ocular movements, and minimal residual anisocoria.

CONCLUSION:

Only one other report describes MVD of the third nerve from PComA compression. A review is presented of MVD carried out for similar cases of non-aneurysmal vascular compression of the oculomotor nerve. By analogy from cases in which an aneurysm is the compressing vascular structure, prompt surgical treatment is advocated. Complete evaluation of an isolated third nerve palsy should include MRI sequences designed to detect vascular compression of cranial nerves.

Pharmacological testing of anisocoria

Anisocoria, or a difference in pupil size, is a common condition. Its aetiology ranges from benign to life-threatening conditions. The clinical evaluation of anisocoria is discussed, emphasising the pharmacological aids (e.g., cocaine 10% eye drops, hydroxyamphetamine eye drops, pilocarpine 0.1% eye drops, pilocarpine 1% eye drops, apraclonidine) used in differentiating the different causes of anisocoria (e.g., physiological anisocoria, Horner syndrome, Adie pupil, pharmacological anisocoria, third nerve palsy).

The pupillary light reflex in migraine

The literature suggests that there may be pupil size and response abnormalities in migraine headache sufferers. We used an infra-red pupillometer to measure dynamic pupil responses to light in 20 migraine sufferers (during non-headache periods) and 16 non-migraine age and gender matched controls. There was a significant increase in the absolute inter-ocular difference of the latency of the pupil light response in the migraine group compared with the controls (0.062 s vs 0.025 s, p = 0.014). There was also a significant correlation between anisocoria and lateralisation of headache such that migraine sufferers with a habitual head pain side have more anisocoria (r = 0.59, p < 0.01), but this was not related to headache laterality. The pupil changes were not correlated with the interval since the last migraine headache, the severity of migraine headache or the number of migraine headaches per annum. We conclude that subtle sympathetic and parasympathetic pupil abnormalities persist in the inter-ictal phase of migraine.

Diagnostik des Horner-Syndroms mit Hilfe des Dilatationsdefizites der Pupille

BACKGROUND

In the first seconds after switching off the lights, Horner pupils often show a dilation lag. This dilation lag is diagnostic for Horner syndrome. We investigated whether the visibility of the dilation lag can be improved by increasing the amplitude of pupil dilation.

PATIENTS AND METHODS

In four patients with pharmacologically confirmed Horner syndrome pupil sizes were registered bilaterally simultaneously with an infrared camera. Dilation lag was induced by switching off the light while the patient was fixating at distance or by turning off the light and changing fixation from near to far at the same time. An increase of anisocoria of 0.5 mm or more within the first 4 seconds was interpreted as dilation lag.

RESULTS

Dilation lags were seen in one patient with both methods, in two patients only with the second method, and in one patient with neither method.

CONCLUSIONS

Dilation lag visibility can be improved by asking the patient to change fixation from near to far at the moment when the lights are switched off.

False negative hydroxyamphetamine test in horner syndrome caused by acute internal carotid artery dissection

A patient with Horner syndrome from internal carotid artery dissection initially had a false negative hydroxyamphetamine test. Two months later, the ophthalmic signs had disappeared but the hydroxyamphetamine test was positive. This case illustrates that hydroxyamphetamine testing may be falsely negative in acute Horner syndrome because norepinephrine stores in oculosympathetic postganglionic terminals have not yet been depleted. However, the hydroxyamphetamine test may be positive even after the ophthalmic signs of Horner syndrome have disappeared.

Accidental mydriasis from exposure to Angel's trumpet (Datura suaveolens)

PURPOSE

To report clinical findings after accidental instillation into the eye of sap from Angel's trumpet (Datura suaveolens).

METHODS

We report findings on seven patients who developed sudden onset of unilateral mydriasis. At least three of them also had ipsilateral cycloplegia and one developed transient tachycardia.

RESULTS

The symptoms evolved after ocular exposure to sap from Angel's trumpet, a plant containing natural alkaloids with parasympatholytic properties. Six patients were initially unaware of the cause of their symptoms. In these cases, patient history revealed recent contact with Angel's trumpet.

CONCLUSION

Accidental ocular instillation of sap from Angel's trumpet should be noted as a cause of sudden onset of mydriasis in otherwise unaffected patients and also of general symptoms like tachycardia.

Naso-temporal asymmetry and contraction anisocoria in the pupillomotor system

BACKGROUND

Differences between the pupillomotor sensitivity of nasal and temporal retinal hemifields may contribute to the relative afferent pupillary defect (RAPD) seen in optic tract or pretectal lesions. To understand the architecture of the pupillary pathway, it is necessary to know the size and the prevalence of such naso-temporal differences and also of contraction anisocoria (unequal direct and consensual pupillary responses) in normal individuals. The results of previous studies have been only partially consistent.

METHODS

We registered the direct and consensual pupillary light reactions in both central retinal hemifields of 42 healthy subjects by means of IR video pupillography. Stimuli were generated under mesopic conditions on a computer screen as half-circles with 4.6 cd/m2 and 10 deg radius. Stimulus duration was 200 ms with a stimulation interval of 4 s.

RESULTS

The nasal retina was significantly more sensitive than the temporal retina, and the direct pupillary reactions were significantly larger than the consensual reactions. For the nasal retina, direct pupillary reactions exceeded the consensual reactions, whereas there was nearly no difference between direct and consensual reactions for the temporal retina.

CONCLUSION

RAPD in optic tract damage or pretectal lesions cannot be explained by the only slightly more sensitive nasal retina. Considerably more input would be needed from the contralateral than from the ipsilateral retina into the optic tract. The nearly equal direct and consensual pupil reactions when stimulating the temporal retina suggest an input of temporal retina to both sides of the pretectum. Such a crossing of temporal fibres may take place in the chiasm.

An anisocoria produces a small relative afferent pupillary defect in the eye with the smaller pupil

OBJECTIVES

To determine whether an anisocoria can produce a relative afferent pupillary defect of clinical importance.

MATERIAL AND METHODS

Anisocoria and relative afferent pupillary defect were measured with infrared videography in three clinical experiments: 1) every few minutes in eight normal subjects who remained in darkness as one pupil was dilating from mydriatic drops; 2) every 2 hours, for 8 hours in six normal subjects who remained in room light after one pupil was dilated with mydriatic drops; and 3) before and after dilation of one pupil in 24 patients with known afferent defects from optic nerve disease and who remained in room light.

RESULTS

In the presence of an anisocoria, the relative afferent pupillary defect was almost always in the eye with the smaller pupil. The results of the three experiments were: 1) In darkness, the induced pupillary defect was found to be related to the ratio of the areas of the two pupils (R = 0.942), and 0.14 log unit of pupillary defect was produced in the eye with the smaller pupil for every millimeter of anisocoria. 2) In room light, the induced pupillary defect was in the eye with the smaller pupil but was less than in Experiment 1 and persisted throughout the 8 hours. This was presumably because the eye with the larger pupil had become more light adapted in the clinic light than the eye with the smaller pupil. 3) In room light, inducing an anisocoria in patients with preexisting afferent pupillary defect tended to shift the pupillary defect toward the eye with the smaller pupil (R = 0.68).

CONCLUSIONS

Clinically, approximately 0.1 log unit of relative afferent pupillary defect is produced in the eye with the smaller pupil for every millimeter of anisocoria. Therefore, the anisocoria must be larger than 2 mm in diameter difference to induce a clinically significant relative afferent pupillary defect.

Pupil involvement in patients with diabetes-associated oculomotor nerve palsy

OBJECTIVE

To derive a reliable estimate of the frequency of pupil involvement in patients with diabetes-associated oculomotor nerve palsy.

PATIENTS AND METHODS

In this prospective study, standardized enrollment criteria were employed to identify 26 consecutive patients with diabetes-associated oculomotor nerve palsy who were evaluated in a referral-based, outpatient neuro-ophthalmology practice. A pupil ruler accurate to within 0.5 mm was used to measure pupil diameters using a standardized procedure. The degree of anisocoria, if present, was recorded at each office visit until the ophthalmoplegia had resolved. Descriptive statistics were used to identify the frequency and characteristics of pupil involvement.

RESULTS

Internal ophthalmoplegia occurred in 10 (38%) of 26 patients. The size of the anisocoria was 1 mm or less in most patients. None of the patients had a fully dilated unreactive pupil.

CONCLUSIONS

Pupil involvement in patients with diabetes-associated oculomotor nerve palsy occurs more often than has been previously recognized, although the degree of anisocoria in any 1 patient is usually only 1 mm or less. Some characteristics of the internal ophthalmoplegia may help to distinguish diabetic ophthalmoplegia from injury of the oculomotor nerve caused by aneurysmal compression.

Anisocoria--a pupillary sign of hippocampal lesions: an experimental study in the cat by using neurotoxins

Pupillary inequality developed after unilateral lesions of the hippocampal formation (HF) of the cat. Lesions were made by an injection of a small amount of colchicine, ibotenic acid or kainic acid. In all anisoric cats, the pupil on the side of the lesions was invariably smaller than its partner. Evident pupillary inequality developed in the cats with dorsal HF lesions. Although there was a considerable variation in the extent and the location of lesions among these cats, the involvement of the giganto-pyramidal CA 3-2 appeared very responsible for the development of the pupillary sign. However, an evidently anisoric cat hat a lesion affecting only the prosubiculum and the subiculum in the posterior part of the dorsal HF. Despite a large involvement of CA 3-2 with or without coincident injuries to CA1, the prosubiculum and the subiculum, only slight pupillary inequality developed following ventral HF lesions. Evident anisocoria in the cats with large dorsal HF lesions disappeared after bilateral cervical sympathectomy, implying that the asymmetry of sympathetic nervous activity might be critically involved in the development of the pupillary sign. The hippocampo-spinal pathway relayed by the lateral septal nucleus and, then, by the lateral hypothalamic area to terminate in the intermedio-lateral cell column of the spinal cord was considered to be most concerned with anisocoria caused by HF lesions.

Effect of light on the prevalence of simple anisocoria

PURPOSE

Because simple anisocoria is believed to decrease in bright light, the authors determined the prevalence of simple anisocoria under different lighting conditions.

METHODS

The authors measured the pupil size of 104 healthy subjects with infrared videography at four clinically accessible light levels: darkness; darkness with a hand-held light shining from below; room light; and room light with the hand light shining from below.

RESULTS

Of the 104 subjects, 40 (38%) were men and 64 (62%) were women. The ages ranged from 12 to 71 years (mean, 36.3 +/- 12.5 years). The mean decrease in pupillary diameter from darkness to the brightest condition was 1.89 mm. Based on the traditional definition of a pupillary diameter difference of 0.4 mm or greater, the prevalence of simple anisocoria decreased from 18% in darkness to 8% in room light with the hand-held light shining from below. The prevalence of anisocoria varied considerably when other definitions were used. Repeated measures analysis of variance showed that pupillary area difference decreased with brighter conditions (P = 0.026). However, the ratio of the pupillary areas did not change with brighter conditions (P = 0.666).

CONCLUSIONS

The prevalence of simple anisocoria decreases with brighter conditions based on pupillary diameter difference. However, this decrease is not apparent when anisocoria is expressed as pupillary area ratio. Those clinicians who measure pupils will find that simple anisocoria decreases in bright light. However, with gross observation where perception of an anisocoria may be related more to the ratio of the pupillary areas, simple anisocoria may not seem to change much with brighter conditions.

Migraine aura without headache and ictal fast EEG activity in an 11-year-old boy

A case of an 11-year-old boy with recurrent migraine auras without headache is reported. Aura was preceded by an anisocoria and was characterized, besides other brain-stem signs, by confusional state. Ictal EEG recordings showed fast activity. Recognition of this finding may prevent an inappropriate diagnosis of drug ingestion. However, whether non-reactive beta activity is typical for basilar migraine remains to be determined.

The Pulfrich effect in optometric practice

The Pulfrich effect can occur spontaneously, giving severe symptoms of changed visual perception in a variety of conditions in which an interocular latency difference has occurred. The symptoms principally involve misjudgements on the location of objects, especially when driving. Interocular latency differences can inadvertently be created in patients in practice and this study has investigated the Pulfrich effect in anisocoria, uniocular mydriasis, and with uniocular tint (X-chrom lens). In all cases a Pulfrich effect was consistently evident and compared to the size of the effect provoked by neutral density filters. The results show that with anisocoria, uniocular mydriasis and the X-chrom lens, the provoked Pulfrich effect is similar to that found reported previously in cases of trauma. These cases had severe visual symptoms so that care should be exercised in practice, where procedures likely to provoke the Pulfrich effect are contemplated. Specifically, patients who have received uniocular mydriasis in practice should be cautioned about the possible visual effects and advised not to drive until the effect of the mydriatic has finished and equal pupil sizes have been restored.

[Photo- and videographic determination of the dilatation deficit in differential diagnosis of Horner syndrome]

Physiological anisocoria, a very frequent condition among normal subjects, must be differentiated from Horner's syndrome. Aside from a history including evaluation of older photographs, pharmacological pupil testing with cocaine eye drops has been the "gold standard". Measurement of dilation lag, occurring in Horner's syndrome, is much less common and normal values are missing. Therefore, we evaluated various photographic parameters for testing for the best parameter to discriminate Horner's syndrome (22 patients) from physiological anisocoria (16 patients). Additionally, we tested whether a commercially available camcorder is sufficient to record pupillary dilatation lag. An anisocoria of 0.6 mm or more 4s after switching off the illumination discriminates physiological anisocoria from Horner's syndrome with a sensitivity of 82% and a specificity of 69%. A dilatation speed of 1.1 mm/4 s shows the same ability to differentiate in anisocoria and does not provide any better results. Because of the good correlation between post-cocaine anisocoria and anisocoria after 4 s in darkness, photographic or videographic measurements of the pupillary dilatation lag may complete or in some cases even replace cocaine testing.

A prospective evaluation of cholinergic supersensitivity of the iris sphincter in patients with oculomotor nerve palsies

To evaluate the frequency and clinical correlates of preganglionic cholinergic supersensitivity of the iris sphincter, I prospectively tested 31 consecutive outpatients with oculomotor nerve palsies by comparing their pupil diameters in darkness before and 30 minutes after topical application of pilocarpine 0.1%. Supersensitive pupil responses were observed in the involved eye in five of 11 patients with compressive palsies, four of five patients with traumatic palsies, in the two patients with congenital palsies, and in none of the patients with ischemic palsies. Supersensitivity was statistically significantly associated with pupil involvement but not with aberrant regeneration of the extraocular muscles or pupil. The degree of supersensitivity was directly correlated with the amount of baseline anisocoria. These results establish that cholinergic supersensitivity of the pupil occurs frequently with nonischemic oculomotor nerve palsies and may be related to the degree of preganglionic injury to the pupillomotor fibers.

The simultaneous interocular brightness sense test. A test of optic nerve function

OBJECTIVE

To describe and establish control data from controls for a simultaneous interocular brightness sense test in which the apparent brightness of two independently viewed light patches was compared.

DESIGN

Dichoptic viewing was achieved by dissociation of right and left eyes using a septum and cross-polarization. Brightness matches were obtained by using adjustments to the illumination of the left retina while the illumination of the right retina was kept constant. OBSERVERS: Ninety-one control observers (age range, 20 to 91 years) participated in the study to provide normal brightness-matching data.

RESULTS

Effects from ocular dominance, age, and long- and short-term adaptation were negligible, but the test was sensitive to anisocoria. Just noticeable differences in dichoptic brightness matching were proportional to retinal illuminance; this finding was consistent with the Weber-Fechner law.

CONCLUSION

The test is quick and simple to complete and appears to offer considerable scope for the assessment of visual function when differences in the functional integrity of the optic nerves of the right and left eyes are suspected.

The localizing value of asymmetry in pupillary size in severe head injury: relation to lesion type and location

Reliable Assessment of the probability that a head injury patient harbors a surgical intracranial lesion is critical to both triage and treatment. The authors analyzed data from 608 patients with severe head injuries (Glasgow Coma Scale score, < or = 8) in the Traumatic Coma Data Bank to assess the reliability of pupillary asymmetry in predicting the presence and location of an intracranial mass lesion. Of 210 patients with pupillary asymmetry of > or = 1 mm, 63 (30%) had intracranial mass lesions, 52 (25%) of which were extra-axial in location, 38 (73%) of these located ipsilateral to the larger pupil. Of 51 patients with asymmetry of > or = 3 mm, 22 (43%) had intracranial mass lesions, 18 (35%) of which were extra-axial in location, 14 (64%) of these located ipsilateral to the larger pupil. For both asymmetry categories, strong interactions were found with age and mechanism of injury, the highest incidence of extra-axial lesions occurring in older patients injured other than as occupants of motor vehicles. The authors developed regression equations that provide a graphic means to predict the presence of an intracranial hematoma using data on pupillary asymmetry, age, and mechanism of injury. This predictive model, interpreted in a hospital- and patient-specific fashion, should be of significant use in directing triage, activating diagnostic and therapeutic resources, and evaluating the utility of exploratory trephination.

Sinus arrhythmia and pupil size in Chiari I malformation: evidence of autonomic dysfunction

In a prospective study on latent autonomic dysfunction in the Chiari type I malformation, 15 patients were examined for degree of sinus arrhythmia in the supine and the sitting positions with a deep breathing test, and for pupil size and function with electronic pupillometry after sympathicomimetic eyedrop stimulation. The 5 patients with brainstem signs had a marked disturbance of sinus arrhythmia, which was more pronounced in the supine than in the sitting position. The clinical signs suggested a dysfunction of the reflex centers in the medulla rather than of the lower cranial nerves. The patients also tended to have more anisocoria than healthy controls, but no clear-cut pattern existed as to pupil dysfunction. Of the 4 patients with syringomyelia, however, the two with the most extensive cord cavitations had a Horner-like pupil reaction ipsilaterally to a marked hand wasting, indicating a sympathetic lesion at the T1 level of the cord.

Influence of pupil size, anisocoria, and ambient light on pilocarpine miosis. Implications for supersensitivity testing

BACKGROUND

This study determines how pupil size, anisocoria, and ambient light influence miotic responses to dilute pilocarpine. The aim is to establish whether mechanical properties of the iris affect miotic behavior using a cholinergic agonist and, if so, to define a more specific clinical definition of supersensitivity testing for suspected tonic pupil disorders.

METHODS

The right pupil of 42 normal subjects was first dilated with phenylephrine to create an experimental anisocoria. Then, pilocarpine 0.1% was placed in both eyes. Net constriction of the larger right pupil was determined by subtracting the amount of pilocarpine-induced constriction of the control left pupil from the amount of pilocarpine-induced constriction of the experimental right pupil. Pupil diameters were measured in room light and darkness.

RESULTS

In only a few subjects, the larger right pupil became smaller than the left pupil after pilocarpine administration. Net constriction of the right pupil was greater when determined in room light than in darkness. The amount of net constriction of the right pupil showed good correlation with the degree of baseline anisocoria when evaluated in room light, but not so in darkness.

CONCLUSION

Pupil size, degree of anisocoria, and light conditions influence the amount of pilocarpine-induced change in anisocoria. If a patient's larger pupil becomes the smaller pupil in darkness after dilute pilocarpine is applied to both eyes, then it is likely that such a response occurred independent of mechanical properties of the iris, and likely represents a supersensitive response. Ophthalmology.

Cervical sympathetic deficit in unilateral migraine headache

Pupil diameter was measured during the headache-free interval in 38 migraine sufferers selected from the general community. In each case, at least 70 percent of attacks recurred on the same side. Anisocoria was greater than in 40 control subjects, but miosis was not consistently greater on the usual side of headache. Average pupil diameter was similar in migraine sufferers and controls. In patients with pupillary dilation lag on the usual side of headache, miosis persisted after 4% cocaine eyedrops. These findings suggest that cervical sympathetic outflow was lower on the usual side of headache in a subgroup of migraine sufferers. Pupillary dilatation to tyramine eyedrops was greater in control subjects than in migraine sufferers, consistent with decreased function of post-ganglionic cervical sympathetic fibres. Pupillary dilatation to 1% phenylephrine eyedrops did not differ consistently between the headache and headache-free sides, and was similar in migraine sufferers and controls. Thus, adrenergic supersensitivity of the pupils was not evident in this community sample of migraine sufferers. Vasodilatation or swelling of the arterial wall in the carotid canal could cause minor cervical sympathetic deficit in patients with frequent or severe attacks of migraine. Loss of sympathetic vascular tone could increase vasodilatation and pain during attacks.

The clinical significance of Tournay's pupillary phenomenon

The act of lateral gaze in some normal individuals causes the pupil of the adducting eye to be smaller than that of the abducting eye. This phenomenon was described by Tournay more than 70 years ago, but it has generally been considered to have no clinical significance. We discuss two situations, episodic anisocoria and aberrant regeneration of the third nerve, in which Tournay's phenomenon should be considered by the clinician. We also describe familial occurrence of this interesting pupillary variant.

Pupillary response to topical naloxone in cluster headache

Eye drops of naloxone were applied and pupillary diameters recorded at standard time intervals in 18 healthy controls and in 20 patients with episodic cluster headache during pain free intervals by means of a pupillometer. In the basal condition, the mean symptomatic side pupil in the cluster headache group was significantly smaller than the pupil of controls. Patients in the cluster period had a significantly smaller symptomatic-side pupil when compared to patients outside the bout. After naloxone, the pupils on the symptomatic as well as on the non-symptomatic side were significantly smaller than those in controls when expressed in mm. The difference between patients and controls persisted, and was, grossly speaking, of a not widely varying magnitude during the drug test. This study thus does not render any definite evidence for a role of opioids in the mechanism underlying the miosis of cluster headache.

Anisocoria in the pigmentary dispersion syndrome

We studied four patients with anisocoria and the pigmentary dispersion syndrome. In all patients, the larger pupil was on the side of the greater iris transillumination. The amount of anisocoria was between 0.5 and 1.5 mm and was the same in both the light and dark. There was no blepharoptosis, and all pupils dilated normally with cocaine. All of the patients were young men with myopia, and one patient had increased intraocular pressure.

The pupil response to E-10-hydroxynortriptyline in rabbits with ocular sympathetic paresis

E-10-hydroxynortriptyline, a metabolite of nortriptyline with half the norepinephrine re-uptake blocking potency of the parent drug, but only 5% of its anticholinergic effect, was as effective as cocaine in demonstrating ocular sympathetic paresis. In five rabbits with unilateral superior cervical ganglionectomies, bilateral 5% cocaine HCl or E-10-hydroxynortriptyline maleate eye drops increased (P less than 0.001) the mean +/- SE anisocoria at 1 h by 1.84 +/- 0.03 mm or 2.16 +/- 0.33 mm, respectively. A single drop of E-10-hydroxynortriptyline did not alter corneal thickness or endothelial cell count.

The abnormal pupil in Cheyne-Stokes respiration. Case report

Cheyne-Stokes respiration commonly induces a rhythmic pupillary dilatation during hyperpnea and constriction during apnea. Failure of a pupil to dilate during hyperventilation indicates underlying sympathetic nerve paralysis. This report deals with an instance in which one pupil failed to constrict during apnea due to oculomotor nerve compression. The periodic respirations and anisocoria disappeared following surgical evacuation of a large ipsilateral subdural hematoma.