Vision, Volume 1, Issue 2 (June 2017) – 7 articles

A number of social cognition studies posit that humans spontaneously compute the viewpoint of other individuals. This is based on experiments showing that responses are shorter when a human agent, located in a visual display, can see the stimuli relevant to the observer’s task. Similarly, responses are slower when the agent cannot see the task-relevant stimuli. We tested the spontaneous perspective taking theory by incorporating it within two classic visual cognition paradigms (i.e., the flanker effect and the Simon effect), as well as reassessing its role in the gaze cueing effect. Results showed that these phenomena (e.g., the Simon effect) are not modulated according to whether a gazing agent can see the critical stimuli or not. We also examined the claim that previous results attributed to spontaneous perspective taking are due to the gazing agent’s ability to shift attention laterally. Results found no evidence of this. Overall, these data challenge both the spontaneous perspective taking theory, as well as the attentional shift hypothesis. Full article

The Spatial-Numerical Association of Response Codes (SNARC) suggests the existence of an association between number magnitude and response position, with faster left-key responses to small numbers and faster right-key responses to large numbers. The attentional SNARC effect (Att-SNARC) suggests that perceiving numbers can also affect the allocation of spatial attention, causing a leftward (vs. rightward) target detection advantage after perceiving small (vs. large) numbers. Considering previous findings that revealed similar spatial association effects for both numbers and musical note values (i.e., the relative duration of notes), the aim of this study is to investigate whether presenting note values instead of numbers causes a spatial shift of attention in musicians. The results show an advantage in detecting a leftward (vs. rightward) target after perceiving small (vs. large) musical note values. The fact that musical note values cause a spatial shift of attention strongly suggests that musicians process numbers and note values in a similar manner. Full article

Importance: Trabeculectomy is very effective in lowering intraocular pressure for the treatment of glaucoma, but it carries with it possible complications and failure. The ExPress shunt (Alcon Laboratories, Fort Worth, TX, USA) is an adjunctive device that can be used at the time of trabeculectomy to create an external fistuliztion. An alternative established and highly efficacious technique is the implantation of a glaucoma drainage device for sustained intraocular pressure (IOP) lowering. Specifically, evidence has established the Baerveldt 101-350 glaucoma implant (BGI) to have the best sustained IOP lowering in long-term follow-up amongst the many options for glaucoma drainage devices. Objective: To compare outcomes in eyes that underwent Baerveldt 101-350 glaucoma implant (BGI) and trabeculectomy with ExPress shunt (Trab) in primary open angle glaucoma without any prior incisional glaucoma surgery. Design, Setting, and Participants: This was a retrospective study of outcomes in patients identified by CPT codes as having undergone glaucoma implantation or trabeculectomy (with ExPress shunt) for the treatment of Primary Open Angle Glaucoma between 2012 and 2015 at a single institution by 2 fellowship trained glaucoma surgeons. A total of 57 eyes that underwent Baerveldt 101-350 glaucoma implant and 38 eyes that underwent trabeculectomy cases with ExPress™ shunt were included in the study. All patients were diagnosed with primary open angle glaucoma. Cases were included into the study if the patient underwent BGI or trabeculectomy with ExPress shunt without any prior incisional glaucoma surgery. Main Outcomes and Measures: Main outcomes included IOP, medications, visual acuity (VA), and secondary glaucoma surgery, if any. Results: Survival rate at 12 months was 85% in the BGI group and 80% in trabeculectomy with ExPress Shunt. A statistically significant difference was not found in the survival distributions between surgery groups using the log–rank test. A total of 12 trabeculectomy and 9 BGI cases failed by our definition of success. These cases were included in the analysis of IOP, number of glaucoma medications, and VA. The mean IOP was reduced from 20.6 ± 5.6 mmHg to 12.4 ± 3.2 mmHg and from 20.7 ± 5.5 mmHg to 11.3 ± 4.8 mmHg at one year post-operation in the BGI group and the trabeculectomy with ExPress shunt group, respectively. On average, the BGI group showed an IOP reduction of 7.7 ± 6.1 mmHg, while trabeculectomy with ExPress shunt experienced a decrease of 7.9 ± 5.2 mmHg at one year post-operation. Medications were reduced from 3.5 ± 0.8 to 2.6 ± 1.3 at one year in the BGI group and from 3.7 ± 0.5 to 0.6 ± 1.8 in the trabeculectomy with ExPress shunt group. At one year post-operation, the BGI group had an average of 0.9 ± 1.1 medication reduction, while trabeculectomy with ExPress shunt cases had a reduction of 3.2 ± 1.3 medications. VA was compared in logMar. At baseline, the average for BGI logMar was 0.5 ± 0.7 and the average for trabeculectomy was 0.2 ± 0.3. At one year post-operation, the BGI group’s VA was 0.4 ± 0.4 while the trabeculectomy with ExPress shunt group’s VA was 0.1 ± 0.1. Conclusions and Relevance: The Baerveldt 101-350 glaucoma implant and trabeculectomy (with ExPress™ shunt) may have similar rates of success in the surgical treatment of primary open angle glaucoma in eyes that are naïve to prior incisional glaucoma surgery, with a higher dependence on topical medications post-operation in patients undergoing Baerveldt glaucoma implantation. Full article

The P2X7 receptor is expressed in both anterior and posterior segments of the eyeball. In the ocular surface, the P2X7 receptor is activated in case of external aggressions: preservatives and surfactants induce the activation of P2X7 receptors, leading to either apoptosis, inflammation, or cell proliferation. In the retina, the key endogenous actors of age-related macular degeneration, diabetic retinopathy, and glaucoma act through P2X7 receptors’ activation and/or upregulation of P2X7 receptors’ expression. Different therapeutic strategies aimed at the P2X7 receptor exist. P2X7 receptor antagonists, such as divalent cations and Brilliant Blue G (BBG) could be used to target either the ocular surface or the retina, as long as polyunsaturated fatty acids may exert their effects through the disruption of plasma membrane lipid rafts or saffron that reduces the response evoked by P2X7 receptor stimulation. Treatments against P2X7 receptor activation are proposed by using either eye drops or food supplements. Full article

Focusing attention on a limited space within the environment allows us to concentrate our resources selectively on that location while ignoring the rest of the space. In this study we investigated how the deployment of the focal attention in foveal vision can be affected by task and stimuli specificity. In particular, we measured the cue-size effect in four experiments: shape detection (Experiment 1), shape discrimination (Experiment 2), letter detection (Experiment 3), and letter discrimination (Experiment 4). Our results highlight that, although the focal component can be elicited by different tasks (i.e., detection or discrimination) and by using different types of stimuli (i.e., shapes or letters), those effects interact with each other. Specifically, the effect of focal attention is more noticeable when letter stimuli are used in the case of a detection task, while no difference between letters and geometrical shapes is observed in the discrimination task. Furthermore, the analysis of the cue-size effect across the four experiments confirmed that the deployment of focal attention in foveal vision is mainly reflexive. Full article

A tremendous amount of research has been devoted to understanding how attention can be committed to space or time. Until recently, relatively little research has examined how attention to these two domains combine. The present study addressed this issue. We examined how implicitly manipulating whether participants used a cue to orient attention in time impacts reflexive or volitional shifts in spatial attention. Specifically, participants made speeded manual responses to the detection of a peripherally presented target that appeared either 100, 500, or 1000 ms after the onset of a central cue. Cues were either spatially non-predictive arrows (p = 0.50) or spatially-predictive (p = 0.80) letter cues. Whereas arrow cues can reflexively orient spatial attention even when non-predictive of a target’s spatial location, letters only orient spatial attention when they reliably predict a target location, i.e., the shift is volitional. Further, in one task, a target was presented on every trial, thereby encouraging participants to use the temporal information conveyed by the cue to prepare for the appearance of the target. In another task, 25% of trials contained no target, implicitly discouraging participants from using the cue to direct attention in time. Results indicate that when temporal information is reliable and therefore volitionally processed, then spatial cuing effects emerge regardless of whether attention is oriented reflexively or volitionally. However, when temporal information is unreliable, spatial cuing effects only emerge when spatial cue information is reliable, i.e., when spatial attention is volitionally shifted. Reflexive cues do not elicit spatial orienting when their temporal utility is reduced. These results converge on the notion that reflexive shifts of spatial attention are sensitive to implicit changes in a non-spatial domain, whereas explicit volitional shifts in spatial attention are not. Full article

The P2X7 receptor (P2X7R) is a membrane receptor for the extracellular adenosine triphosphate (ATP). It functions as a ligand-gated non-selective cation channel and can mediate formation of a large non-selective membrane pore. Activation of the P2X7R induces multiple downstream events, including oxidative stress, inflammatory responses and cell death. Although the P2X7R has been identified in the retinal pigment epithelium (RPE) and different layers of retina, its biological and pathological functions as well as its downstream signaling pathways in the RPE and retina are not yet fully understood. Better understanding of the function of P2X7R in the RPE and retina under normal and disease states might lead to novel therapeutic targets in retinal diseases, including age-related macular degeneration (AMD). This brief review will mainly focus on recent findings on in vitro and in vivo evidence for the role of the P2X7R in the RPE and AMD. Full article