Mydriasis

Synchrony has been used to describe simple beat entrainment as well as correlated mental processes between people, leading some to question whether the term conflates distinct phenomena. Here we ask whether simple synchrony (beat entrainment) predicts more complex attentional synchrony, consistent with a common mechanism. While eye-tracked, participants listened to regularly spaced tones and indicated changes in volume. Across multiple sessions, we found a reliable individual difference: some people entrained their attention more than others, as reflected in beat-matched pupil dilations that predicted performance. In a second study, eye-tracked participants completed the beat task and then listened to a storyteller, who had been previously recorded while eye-tracked. An individual's tendency to entrain to a beat predicted how strongly their pupils synchronized with those of the storyteller, a corollary of shared attention. The tendency to synchronize is a stable individual difference that predicts attentional synchrony across contexts and complexity.

BackgroundDuring cataract surgery, maintaining an adequate degree of mydriasis throughout the entire operation is critical to allow for visualisation of the capsulorhexis and the crystalline lens. Good anaesthesia is also essential for safe intraocular surgery. Mydrane® is a new injectable intracameral solution containing two mydriatics (tropicamide 0.02% and phenylephrine 0.31%) and one anaesthetic (lidocaine 1%) that was developed as an alternative to the conventional topical pre-operative mydriatics used in cataract surgery. This study aimed to estimate the budget impact across a one year time frame using Mydrane® instead of topical dilating eye drops, for a UK hospital performing 3,000 cataract operations a year.MethodsA budget impact model (BIM) was developed to compare the economic outcomes associated with the use of Mydrane® versus topical drops (tropicamide 0.5% and phenylephrine 10%) in patients undergoing cataract surgery in a UK hospital. The outcomes of interest included costs and resource use (e.g. clinician time, mydriasis failures, operating room time, number of patients per vial of therapy etc.) associated with management of mydriasis in patients undergoing cataract surgery. All model inputs considered the UK hospital perspective without social or geographical variables. Deterministic sensitivity analyses were also performed to assess the model uncertainty.ResultsIntroduction of Mydrane® is associated with a cost saving of £6,251 over 3,000 cataract surgeries in one year. The acquisition costs of the Mydrane® (£18,000 by year vs. £3,330 for eye drops) were balanced by substantial reductions in mainly nurses' costs and time, plus a smaller contribution from savings in surgeons' costs (£20,511) and lower costs associated with auxiliary dilation (£410 due to avoidance of additional dilation methods). Results of the sensitivity analyses confirmed the robustness of the model to the variation of inputs. Except for the duration of one session of eye drop instillation and the cost of Mydrane®, Mydrane® achieved an incremental cost gain compared to tropicamide/phenylephrine eye drops.ConclusionsDespite a higher acquisition cost of Mydrane®, the budget impact of Mydrane® on hospital budgets is neutral. Mydrane® offers a promising alternative to traditional regimes using eye drops, allowing for a better patient flow and optimisation of the surgery schedule with neutral budget impact.

Purpose(1) To use finite element (FE) modelling to estimate local iris stresses (i.e. internal forces) as a result of mechanical pupil expansion; and to (2) compare such stresses as generated from several commercially available expanders (Iris hooks, APX dilator and Malyugin ring) to determine which design and deployment method are most likely to cause iris damage.MethodsWe used a biofidelic 3-part iris FE model that consisted of the stroma, sphincter and dilator muscles. Our FE model simulated expansion of the pupil from 3 mm to a maximum of 6 mm using the aforementioned pupil expanders, with uniform circular expansion used for baseline comparison. FE-derived stresses, resultant forces and area of final pupil opening were compared across devices for analysis.ResultsOur FE models demonstrated that the APX dilator generated the highest stresses on the sphincter muscles, (max: 6.446 MPa; average: 5.112 MPa), followed by the iris hooks (max: 5.680 MPa; average: 5.219 MPa), and the Malyugin ring (max: 2.144 MPa; average: 1.575 MPa). Uniform expansion generated the lowest stresses (max: 0.435MPa; average: 0.377 MPa). For pupil expansion, the APX dilator required the highest force (41.22 mN), followed by iris hooks (40.82 mN) and the Malyugin ring (18.56 mN).ConclusionOur study predicted that current pupil expanders exert significantly higher amount of stresses and forces than required during pupil expansion. Our work may serve as a guide for the development and design of next-generation pupil expanders.

ObjectiveThe recent examination of a woman who presented a migraine attack with visual aura and unilateral mydriasis, followed, a few days later, by an episode of Takotsubo Syndrome, prompted us to review the existing literature correlating migraine and TS as well as the most recent studies regarding the association between Takotsubo Syndrome and neurological dysfunction. Our aim is to define the role of dysautonomia and the contribution of the Autonomic Nervous System in the pathogenesis of both diseases, also, to define the functional role of the hypothalamus in the both the determination of headache attacks and the onset of clinical manifestations in other organs and tissues.BackgroundMigraine with aura and Takotsubo Syndrome (TS) share emotional, psychological and physical triggering factors which are implicated in the pathogenetic process. The autonomic nervous system plays a crucial, though antipodal, role in both pathologies. Indeed, migraine clinical manifestations imply the activation of the parasympathetic system whereas a massive catecholamine release following sympathetic nervous system activation is pivotal in triggering the Takotsubo Syndrome.MethodsReview of anatomy, physiology and neural regulation in both physiological and stress responses. Examination of the functional connections of the hypothalamus.Results and discussionThe coexistence of psycho-emotional stressors, endocrine/hormonal factors and a possible genetic predisposition might explain the pathophysiological overlap between these two distinct clinical manifestations. The hypothalamus is functionally connected with all the pain-related brain regions and pathways and can be responsible for the clinical manifestations in both the nervous system and the cardiovascular apparatus. Migraine is the most frequent chronic, early onset condition associated with TS.