Aims : To derive a reliable estimate of the frequency of pupillary involvement and to study the patterns and course of anisocoria in conjunction with ophthalmoplegia in diabetes-associated oculomotor nerve palsy. Materials and Methods: In this prospective analytical study, standardized enrolment criteria were employed to identify 35 consecutive patients with diabetes-associated oculomotor nerve palsy who were subjected to a comprehensive ocular examination. Standardized methods were used to evaluate pupil size, shape, and reflexes. The degree of anisocoria, if present and the degree of ophthalmoplegia was recorded at each visit. Results: Pupillary involvement was found to be present in 25.7% of the total number of subjects with diabetic oculomotor nerve palsy. The measure of anisocoria was < 2 mm, and pupil was variably reactive at least to some extent in all cases with pupillary involvement. Majority of patients in both the pupil-involved and pupil-spared group showed a regressive pattern of ophthalmoplegia. Ophthalmoplegia reversed much earlier and more significantly when compared to anisocoria. Conclusions: Pupillary involvement in diabetes-associated oculomotor nerve palsy occurs in about 1/4 th of all cases. Certain characteristics of the pupil help us to differentiate an ischemic insult from an aneurysmal injury to the 3 rd nerve. Ophthalmoplegia resolves much earlier than anisocoria in diabetic oculomotor nerve palsies.
Use of electrogastrography in preclinical studies of cholinergic and anticholinergic agents in experimental pigs
- Physiological research / Academia Scientiarum Bohemoslovaca
- Published over 5 years ago
Electrogastrography (EGG) is a non-invasive method for the assessment of gastric myoelectrical activity. Porcine EGG is comparable with human one. The purpose of this study was to evaluate the effect of atropine and neostigmine on the EGG in experimental pigs. Adult female pigs were administrated atropine (1.5 mg i.m., n=6) and neostigmine (0.5 mg i.m., n=6) after the baseline EGG, followed by a 90-minute trial recording (MMS, Enschede, the Netherlands). Running spectral analysis was used for the evaluation. The results were expressed as dominant frequency of slow waves and EGG power (areas of amplitudes). Neostigmine increased continuously the dominant frequency and decreased significantly the EGG power. Atropine did not change the dominant frequency significantly. However, atropine increased significantly the EGG power (areas of amplitudes) from basal values to the maximum at the 10 - 20-minute interval. After that period, the areas of amplitudes decreased significantly to the lowest values at the 60 - 90-minute interval. In conclusion, cholinergic and anticholinergic agents affect differently EGG in experimental pigs. This paper is scheduled for Physiological Research, Vol. 64, Supplement 5 (2015).
The pupillary light reflex is a critical component of the neurologic examination, yet whether it is present, depressed, or absent is unknown in patients with significant opioid toxicity. Although opioids produce miosis by activating the pupillary sphincter muscle, these agents may induce significant hypercarbia and hypoxia, causing pupillary constriction to be overcome via sympathetic activation. The presence of either “pinpoint pupils” or sympathetically mediated pupillary dilation might prevent light reflex assessment. This study was designed to determine whether the light reflex remains quantifiable during opioid-induced hypercarbia and hypoxia.
Ophthalmoplegic migraine is a rare disorder characterized by childhood-onset ophthalmoplegia and migraine headaches. The third cranial nerve is commonly involved, while involvement of the sixth and fourth cranial nerves is uncommon. We present the case study of a 15-year-old female teenager whose condition was diagnosed with ophthalmoplegic migraine when she was 9 years old and since then has experienced multiple and recurrent attacks. Since the diagnosis, she has exhibited a persistent right-eye mydriasis, despite resolution of migrainous episodes. Pupillary involvement in ophthalmoplegic migraine is the rule in children, with total recovery in the majority of cases. We will discuss some aspects related to the eventual association between this entity and other comorbidities, such as Adie tonic pupil, emphasizing the fact that the underlying mechanisms of this residual mydriasis are not fully understood.
Abstract Introduction: Anticholinergic and sympathomimetic ophthalmic solutions are used for mydriasis. These solutions have well-documented systemic side effects despite their topical administration. However, no studies have been conducted regarding the effect of mydriatic drops on cognitive function. The purpose of this study is to determine the effect, if any, of mydriatic drops on cognitive function, including memory, concentration, and orientation. Methods: Participants were randomized into two groups using the technique of permuted block randomization, and randomization was stratified by gender, age, and education. Participants in Group 1 completed the Montreal Cognitive Assessment (MoCA) test with undilated pupils, while participants in Group 2 completed the MoCA test with dilated pupils. Administration time of the MoCA test was approximately 10 minutes, and each participant could receive a maximum of 30 points, with a score of 26 or greater being considered normal cognitive function. Dilation was achieved in both eyes with a combination of tropicamide 0.5% and phenylephrine 2.5%. Results: There was no statistical difference between the MoCA scores of Group 1 and Group 2 (p = 0.65). In addition, MoCA scores were not statistically different between the glaucoma and non-glaucoma subpopulations within each group. MoCA test scores were shown to correlate with education (p = 0.004), age (p = 0.0003), and race (p = 0.03). Patients with confirmed or suspected glaucoma whom eyes dilated required 10.8 minutes to complete the MoCA test, while patients with no confirmed or suspected glaucoma whom eyes dilated required 8.5 minutes to complete the test (p = 0.02). Discussion: Age, race, and education were found to be the most important factors affecting cognitive function in this study. There was no significant difference in the MoCA test scores of participants with confirmed or suspected glaucoma and participants without glaucoma. There was also no significant difference in the MoCA scores of dilated participants and non-dilated participants as a whole. However, dilation significantly increased the amount of time required to complete the MoCA test among the glaucoma and suspected-glaucoma population. The results of this study suggest that physicians should spend more time with dilated glaucoma patients while explaining medical conditions and treatment instructions in order to ensure that patients have adequate time to comprehend instructions for glaucoma management.
Purpose: To estimate and compare change in iris cross-sectional area (IA) after physiologic and pharmacologic mydriasis in subjects with different dominant mechanisms for primary angle closure. Methods: Anterior segment optical coherence tomography (ASOCT) measurements in light, dark and following pharmacologic dilation were obtained on primary angle closure suspects (PACS), primary angle closure (PAC) and primary angle closure glaucoma (PACG) examined during the 5-year follow-up of the Handan Eye Study. Subjects were categorized into three subgroups according to their dominant angle closure (AC) mechanisms: pupillary block (PB), plateau iris configuration (PIC) and thick peripheral iris roll (TPIR). IA and other biometric parameters measured using the Zhongshan Angle Assessment Program in the right eyes of all subjects were analyzed. Results: A total of 364 right eyes of subjects with PACS (333), PAC/PACG (31) were included in the analysis. Significant differences in the change of IAs (p = 0.030), IA loss per mm pupil diameter (PD) increase (p = 0.001) in light versus pharmacologic dilation and IA loss per mm PD increase (p = 0.011) from dark versus pharmacologic dilation were observed between the three groups. The smallest decrease occurred in the PB group. Conclusions: There are significant differences in IA and IA loss per mm of pupil change following physiologic or pharmacologic mydriasis in Chinese subjects with dissimilar dominant mechanisms for AC. Dynamic iris change may play a more important role in angle closure where PB is the dominant mechanism.
Isoflurane-Associated Mydriasis Mimicking Blown Pupils in a Patient Treated in a Neurointensive Care Unit
- Journal of neurological surgery. Part A, Central European neurosurgery
- Published over 4 years ago
We report a misinterpretation of bilateral mydriasis as blown pupils related to elevated intracranial pressure (ICP) under volatile sedation with isoflurane (Anesthetic Conserving Device [AnaConDa], Hudson RCI, Uppland Vasby, Sweden) in a 59-year-old patient with a severe traumatic brain injury with frontal contusion. The patient showed bilateral mydriasis and a missing light reflex 8 hours after changing sedation from intravenous treatment with midazolam and esketamine to volatile administration of isoflurane. Because cranial computed tomography ruled out signs of cerebral herniation, we assumed the bilateral mydriasis was caused by isoflurane and reduced the isoflurane supply. Upon this reduction the mydriasis regressed, suggesting the observed mydriasis was related to an overdose of isoflurane. Intensivists should be aware of the reported phenomenon to avoid unnecessary diagnostic investigations that might harm the patient. We recommend careful control of the isoflurane dose when fixed and dilated pupils appear in patients without other signs of elevated ICP.
If a mental image is a rerepresentation of a perception, then properties such as luminance or brightness should also be conjured up in the image. We monitored pupil diameters with an infrared eye tracker while participants first saw and then generated mental images of shapes that varied in luminance or complexity, while looking at an empty gray background. Participants also imagined familiar scenarios (e.g., a “sunny sky” or a “dark room”) while looking at the same neutral screen. In all experiments, participants' eye pupils dilated or constricted, respectively, in response to dark and bright imagined objects and scenarios. Shape complexity increased mental effort and pupillary sizes independently of shapes' luminance. Because the participants were unable to voluntarily constrict their eyes' pupils, the observed pupillary adjustments to imaginary light present a strong case for accounts of mental imagery as a process based on brain states similar to those that arise during perception.
This study evaluated whether music-induced aesthetic “chill” responses, which typically correspond to peak emotional experiences, can be objectively monitored by degree of pupillary dilation. Participants listened to self-chosen songs versus control songs chosen by other participants. The experiment included an active condition where participants made key presses to indicate when experiencing chills and a passive condition (without key presses). Chills were reported more frequently for self-selected songs than control songs. Pupil diameter was concurrently measured by an eye-tracker while participants listened to each of the songs. Pupil size was larger within specific time-windows around the chill events, as monitored by key responses, than in comparison to pupil size observed during ‘passive’ song listening. In addition, there was a clear relationship between pupil diameter within the chills-related time-windows during both active and passive conditions, thus ruling out the possibility that chills-related pupil dilations were an artifact of making a manual response. These findings strongly suggest that music chills can be visible in the moment-to-moment changes in the size of pupillary responses and that a neuromodulatory role of the central norepinephrine system is thereby implicated in this phenomenon.
Eyedroppers deliver medication volumes exceeding conjunctival absorptive capacity, causing spillage and risking ocular/systemic complications. We evaluated piezoelectric microdosing. Results/methodology: Subjects (n = 102) received precision microdroplet delivery of phenylephrine (2.5%) and tropicamide (1.0%): 1 × 1.5 μl, 1 × 6 μl or 2 × 3 μl of each (randomized 1:1:1), into one eye. Contralateral eyes received eyedropper doses of both drugs. Outcomes were pupil dilation (0-60 min) and patient satisfaction. Six-microliter microdosing achieved comparable, and 2 × 3 μl met/exceeded dilation speed and magnitude versus eyedropper. Separately, participants preferred piezoelectric saline self-delivery to eyedroppers, reporting better head-positioning comfort, reduced tearing/overflow and increased likelihood of adhering to ocular medication regimens.