Pattern of reading eye movements during monovision contact lens wear in presbyopes

Monovision can be used as a method to correct presbyopia with contact lenses (CL) but its effect on reading behavior is still poorly understood. In this study eye movements (EM) were recorded in fifteen presbyopic participants, naïve to monovision, whilst they read arrays of words, non-words, and text passages to assess whether monovision affected their reading. Three conditions were compared, using daily disposable CLs: baseline (near correction in both eyes), conventional monovision (distance correction in the dominant eye, near correction in the non-dominant eye), and crossed monovision (the reversal of conventional monovision). Behavioral measures (reading speed and accuracy) and EM parameters (single fixation duration, number of fixations, dwell time per item, percentage of regressions, and percentage of skipped items) were analyzed. When reading passages, no differences in behavioral and EM measures were seen in any comparison of the three conditions. The number of fixations and dwell time significantly increased for both monovision and crossed monovision with respect to baseline only with word and non-word arrays. It appears that monovision did not appreciably alter visual processing when reading meaningful texts but some limited stress of the EM pattern was observed only with arrays of unrelated or meaningless items under monovision, which require the reader to have more in-depth controlled visual processing

Comparison of the effects of salbutamol and adrenaline on airway smooth muscle contractility in vitro and on bronchial reactivity in vivo.

BACKGROUND--The effect of adrenergic agonists in asthma depends on their net effect on microvascular leakage, mucosal oedema, vascular clearance of spasmogens, inhibition of cholinergic neurotransmission, and airway smooth muscle contractility. It has been postulated that adrenaline, by virtue of its alpha effects on the vasculature and cholinergic neurotransmission, may have additional useful properties in asthma compared with selective beta agonists such as salbutamol. METHODS--The airway effects of adrenaline (a non-selective adrenoreceptor agonist) were compared with the selective beta 2 agonist salbutamol. Their airway smooth muscle relaxant potencies and effect on histamine contraction in human bronchi in vitro were compared with their effects on airway calibre and histamine reactivity in asthmatic subjects in vivo. For the in vitro studies changes in tension were measured in response to these agents in thoracotomy specimens of human airways. In vivo the effects of adrenaline and salbutamol on airway calibre and histamine reactivity were measured in eight subjects with mild to moderate asthma in a randomised crossover study. RESULTS--Salbutamol and adrenaline had approximately equivalent airway smooth muscle relaxant potencies in vitro and bronchodilator potency in vivo. However, their effects on histamine induced contraction in vitro were significantly different from their effects on histamine reactivity in vivo. Salbutamol was less potent in vitro producing a mean (SE) 2.4 (0.15) doubling dose increase in the histamine EC20 and adrenaline a 5.2 (0.18) doubling dose increase (mean difference between salbutamol and adrenaline 2.8 doubling doses; 95% CI 1.1 to 4.5). Salbutamol had no effect on the maximal response to histamine whereas adrenaline reduced it by 54%. In contrast, salbutamol was more potent in vivo producing a mean (SE) increase in PD20 histamine of 1.84 (0.5) doubling doses whereas adrenaline was without effect increasing PD20 by only 0.06 (0.47) doubling doses (mean difference between adrenaline and salbutamol 1.78, 95% CI 0.26 to 3.29 doubling doses). CONCLUSIONS--These findings suggest that the alpha adrenergic airway effects of non-selective adrenoreceptor agonists such as adrenaline offer no additional protection against histamine-induced broncho-constriction in vivo than beta 2 selective drugs such as salbutamol, despite adrenaline providing greater protection against histamine-induced contraction in vitro. The differences between the effects of these agents in vitro and in vivo may be related to their opposing vascular effects in vivo

Light disturbance analysis in the controlled randomized clinical trial MiSight assessment study Spain (MASS)

Purpose: To evaluate the perception of light disturbances (LD) in children wearing Dual Focus (DF) MiSight (R) contact lenses (CLs) for myopia control compared with children wearing single vision spectacles (SV).Methods: This was a randomized, controlled clinical trial involving subjects aged 8-12 with myopia of -0.75 to -4.00D and astigmatism 0.05). However, monocular BFCIrreg. as well as monocular and binocular BFCIrreg.SD showed a significant decrease at 24 month visit compared with 12 month visit.Conclusions: DF lenses increase the monocular light disturbance perception compared with a single vision spectacle correction. However, this effect decreased over the follow-up time and presented a significant binocular attenuation effect.This study has been funded in part by projects PTDC/SAU-BEB/098392/2008 and PTDC/SAU-BEB/098391/2008, which in turn have been funded by the Portuguese Fundação para a Ciência e Tecnologia through the European Social Fund and by FEDER through the COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project UID/FIS/04650/2013. JMG-M has proprietary interests in the experimental device used to measure light disturbance.CooperVision S.L. Spain also provided financial support. CooperVision S.L. provided the study contact lenses and the funding to carry out the clinical trial. The sponsor had no role in designing or conducting this research