Going back to "basics": Harlow's learning set task with wolves and dogs.

To survive and reproduce, animals need to behave adaptively by adjusting their behavior to their environment, with learning facilitating some of these processes. Dogs have become a go-to model species in comparative cognition studies, making our understanding of their learning skills paramount at multiple levels, not only with regards to basic research on their cognitive skills and the effects of domestication, but also with applied purposes such as training. In order to tackle these issues, we tested similarly raised wolves and dogs in a serial learning task inspired by Harlow's "learning set." In Phase 1, different pairs of objects were presented to the animals, one of which was baited while the other was not. Both species' performance gradually improved with each new set of objects, showing that they "learnt to learn," but no differences were found between the species in their learning speed. In Phase 2, once subjects had learned the association between one of the objects and the food reward, the contingencies were reversed and the previously unrewarded object of the same pair was now rewarded. Dogs' performance in this task seemed to be better than wolves', albeit only when considering just the first session of each reversal, suggesting that the dogs might be more flexible than wolves. Further research (possibly with the aid of refined methods such as computer-based tasks) would help ascertain whether these differences between wolves and dogs are persistent across different learning tasks.

GoFish: A low-cost, open-source platform for closed-loop behavioural experiments on fish.

Fish are the most species-rich vertebrate group, displaying vast ecological, anatomical and behavioural diversity, and therefore are of major interest for the study of behaviour and its evolution. However, with respect to other vertebrates, fish are relatively underrepresented in psychological and cognitive research. A greater availability of easily accessible, flexible, open-source experimental platforms that facilitate the automation of task control and data acquisition may help to reduce this bias and improve the scalability and refinement of behavioural experiments in a range of different fish species. Here we present GoFish, a fully automated platform for behavioural experiments in aquatic species. GoFish includes real-time video tracking of subjects, presentation of stimuli in a computer screen, an automatic feeder device, and closed-loop control of task contingencies and data acquisition. The design and software components of the platform are freely available, while the hardware is open-source and relatively inexpensive. The control software, Bonsai, is designed to facilitate rapid development of task workflows and is supported by a growing community of users. As an illustration and test of its use, we present the results of two experiments on discrimination learning, reversal, and choice in goldfish (Carassius auratus). GoFish facilitates the automation of high-throughput protocols and the acquisition of rich behavioural data. Our platform has the potential to become a widely used tool that facilitates complex behavioural experiments in aquatic species.

Two-Step Iridocorneal Endothelial Syndrome Management: Endocapsular Intraocular Lens and Artificial Iris Followed by Descemet's Stripping Automated Endothelial Keratoplasty.

A 54-year-old female presented with complaints of glare and progressive visual loss OS with a corrected distance visual acuity (CDVA) OS of 20/100. The patient had grade 1 corneal edema with a "beaten bronze" appearance on specularly reflected light, pseudopolycoria, and a nuclear sclerotic cataract. The diagnosis of nuclear cataract and progressive iris atrophy iridocorneal endothelial (ICE) syndrome was made, and the patient underwent uneventful phacoemulsification with capsular bag placement of an AcrySof SA60AT intraocular lens combined with pseudopolycoria repair using an endocapsular Model A REPER artificial iris. Six months later, the patient was submitted to a Descemet's stripping automated endothelial keratoplasty (DSAEK) procedure, and 6 months after that the CDVA was 20/32 with no corneal edema and normal intraocular pressure. This two-step surgical approach, combining phacoemulsification and endocapsular foldable iris prosthesis placement followed by DSAEK, may be considered a promising option to successfully treat progressive iris atrophy ICE syndrome patients.

Barriers and motivations for blood donation: an integrative review.

INTRODUCTION: It has been estimated that the proportion of blood donors in Brazil is below 2.0 %, lower than that recommended by the World Health Organization, which is between 3 % and 5 % of the population. OBJECTIVE: The aim of this study was to analyze the factors that can influence blood donation. METHOD: This is an integrative review, whose bibliographic search was carried out through the Virtual Health Library, considering scientific articles indexed in the Latin American and Caribbean Literature in the Health Sciences database. RESULTS: This process was performed in July 2022 with term "blood donors" and 901 publications were identified, without delimitation of the study period or any other aspects. After applying the inclusion and exclusion criteria, 40 articles were fully reviewed. The studies were categorized according to the main content discussed in "characteristics and perspectives of donors", "perspective of health professionals and services" and "loyalty strategies: marketing and communication in health". Access to coherent information about the donation process was the motivational aspect evidenced in the three categories of analysis, that is, indispensable from the perspective of users, health professionals who work in blood therapy services and for marketing and communication in health. It is through the knowledge of the procedure that uncertainties and fear are decreased and loyal donors are increased. CONCLUSION: Altruism was the most frequent driving feeling in the consulted literature, whereas the lack of time and fear were the routine obstacles. The campaigns were identified as communication and health education actions relevant to attracting and retaining the donor, as well as applications and social networks.

Using temperature to analyze the neural basis of a time-based decision.

The basal ganglia are thought to contribute to decision-making and motor control. These functions are critically dependent on timing information, which can be extracted from the evolving state of neural populations in their main input structure, the striatum. However, it is debated whether striatal activity underlies latent, dynamic decision processes or kinematics of overt movement. Here, we measured the impact of temperature on striatal population activity and the behavior of rats, and compared the observed effects with neural activity and behavior collected in multiple versions of a temporal categorization task. Cooling caused dilation, and warming contraction, of both neural activity and patterns of judgment in time, mimicking endogenous decision-related variability in striatal activity. However, temperature did not similarly affect movement kinematics. These data provide compelling evidence that the timecourse of evolving striatal activity dictates the speed of a latent process that is used to guide choices, but not continuous motor control. More broadly, they establish temporal scaling of population activity as a likely neural basis for variability in timing behavior.

Intrastromal corneal ring segments: effect of depth of implantation in visual, refractive, and topographic outcomes in patients with keratoconus.

PURPOSE: To evaluate visual, refractive, and topographic outcomes of intracorneal ring segment implantation in relation to the achieved segment depth, using the manual technique. SETTING: Ophthalmology Department, Hospital de Braga, Braga, Portugal. DESIGN: Retrospective cohort study. METHODS: We obtained 104 eyes of 93 patients with keratoconus submitted to Ferrara intracorneal ring segment (ICRS) implantation, using a manual technique. Subjects were divided into 3 groups according to the achieved depth of implantation: 40% to 70% (Group 1), 70% to 80% (Group 2), and 80% to 100% (Group 3). Visual, refractive, and topographic variables were evaluated at baseline and 6 months. Topographic measurement was performed using Pentacam. Thibos-Horner and Alpins methods were used to analyze the vectorial change of refractive and topographic astigmatism, respectively. RESULTS: We found a significant improvement of uncorrected distance visual acuity and corrected distance visual acuity in all groups at 6 months ( P < .005); no differences were observed regarding safety and efficacy indexes in the 3 groups ( P > .05). Manifest cylinder and spherical equivalent significantly reduced in all groups ( P < .05). Topographic evaluation showed a significant improvement of all parameters in the 3 groups ( P < .05). A shallower (Group 1) or deeper (Group 3) implantation was associated with topographic cylinder overcorrection, a higher magnitude of error, and a higher mean centroid postoperative corneal astigmatism. CONCLUSIONS: ICRS implantation with the manual technique showed to be equally effective in visual and refractive outcomes despite the depth of implantation; however, shallower or deeper implants were associated with topographic overcorrection and a higher mean centroid postoperative astigmatism, which explain the lower topographic predictability associated with manual surgery for ICRS implantation.

Comparison of outcomes between cross-linking plus topoguided excimer laser ablation and intrastromal corneal ring segments for keratoconus.

OBJECTIVE: To compare cross-linking (CXL) plus topography-guided photorefractive keratectomy (t-PRK) and intrastromal corneal ring segments (ICRS) in keratoconus patients, at 12 months of follow-up. METHODS: This was a longitudinal, retrospective multi-center study. We included a referred sample of 154 eyes from 149 patients with grade I-III Amsler-Krümeich keratoconus with insufficient corrected-distance visual acuity (CDVA). In group 1 (CXL plus t-PRK, 87 eyes), another possible indication for surgery was evidence of progression. Group 2 (ICRS, 67 eyes) included only eyes with paracentral keratoconus (thinnest point at the inferotemporal quadrant) with coincident axes, and evidence of stabilization was required. A subgroup analysis was performed regarding the disease topographic phenotype. At 12 months postoperatively, visual, refractive, and topographic outcomes were evaluated. RESULTS: Comparison of the outcomes between CXL plus t-PRK (group 1) and ICRS (group 2) showed similar improvements in CDVA (in group 1, CDVA improved 0.18 logMAR, and in group 2 0.12 logMAR, P = .18) and K2 (-2,45 [6.46] D in group 1 and -2.13 [1.67] D in group 2, P = .34) The improvement in cylinder power was greater in group 2 (-2.37 [2.07] D in group 2 versus -1.18 [2.63] D in group 1, P = .003); group 1 had a higher decrease in Kmax (- 3.26 [3.64] versus-1.74 [2.67], P = .001). CONCLUSIONS: Both CXL plus t-PRK and ICRS were equally effective in improving CDVA and topographic parameters in a similar group of keratoconus patients at 12 months.

Testing cognitive models of decision-making: selected studies with starlings.

The behavioural sciences are home to controversies that have survived for centuries, notably about the relation between observable behaviour and theoretical constructs addressing out-of-sight processes in the agents' brains. There is no shared definition for cognition, but the very existence of a thriving journal called Animal Cognition proves that such controversies are still live and help to (a) promote research on the complexity of processes leading to action, and (b) nudge scholars to restrict their cognitive models to those that can be falsified experimentally. Here, we illustrate some of these issues in a limited arena, focusing on the construction and expression of subjective value and choice. Using mainly work from our own laboratory, we show that valuation of alternatives is sensitive to options' properties, to subject's state, and to background alternatives. These factors exert their influence at the time the subject learns about individual options, rather than at choice time. We also show that valuation can be experimentally dissociated from the cognitive representation of options' metrics and argue that experimental animals process options independently at the time of choice, without elaborated comparisons along different dimensions. The findings we report are not consistent with the hypothesis that preference is constructed at the time of choice, a prevalent view in human decision-making research. We argue that animal cognition, viewed as a research program at the crossroads of different behavioural sciences rather than as a debate about properties of mental life, is inspiring and solid, and a progressive and progressing paradigm.

Paradoxical choice and the reinforcing value of information.

Signals that reduce uncertainty can be valuable because well-informed decision-makers can better align their preferences to opportunities. However, some birds and mammals display an appetite for informative signals that cannot be used to increase returns. We explore the role that reward-predictive stimuli have in fostering such preferences, aiming at distinguishing between two putative underlying mechanisms. The 'information hypothesis' proposes that reducing uncertainty is reinforcing per se, somewhat consistently with the concept of curiosity: a motivation to know in the absence of tractable extrinsic benefits. In contrast, the 'conditioned reinforcement hypothesis', an associative account, proposes asymmetries in secondarily acquired reinforcement: post-choice stimuli announcing forthcoming rewards (S+) reinforce responses more than stimuli signalling no rewards (S-) inhibit responses. In three treatments, rats faced two equally profitable options delivering food probabilistically after a fixed delay. In the informative option (Info), food or no food was signalled immediately after choice, whereas in the non-informative option (NoInfo) outcomes were uncertain until the delay lapsed. Subjects preferred Info when (1) both outcomes were explicitly signalled by salient auditory cues, (2) only forthcoming food delivery was explicitly signalled, and (3) only the absence of forthcoming reward was explicitly signalled. Acquisition was slower in (3), when food was not explicitly signalled, showing that signals for positive outcomes have a greater influence on the development of preference than signals for negative ones. Our results are consistent with an elaborated conditioned reinforcement account, and with the conjecture that both uncertainty reduction and conditioned reinforcement jointly act to generate preference.

Efficacy and safety after posterior chamber Implantable Collamer Lens implantation according to preoperative anterior chamber depth: Short-term comparative study.

PURPOSE: To compare visual, refractive, and safety outcomes of posterior chamber Implantable Collamer Lens (ICL) implantation for the correction of myopia according to the preoperative anterior chamber depth (ACD). METHODS: Retrospective, comparative study, patients submitted to implantation of myopic posterior-chamber phakic Implantable Collamer Lens (ICL), model V4C/V5, minimum follow-up of 12 months; two groups were created: Group 1 (ACD 2.80 to 2.99 mm) and Group 2 (ACD equal to or greater than 3.00 mm). The parameters evaluated were uncorrected and corrected visual acuity, subjective refraction, efficacy and safety index, predictability, endothelial cell density, central vault, anterior chamber angle and postoperative complications. A total of 558 eyes from 298 patients were evaluated: 111 eyes (19.9%) in group 1 and 447 eyes (80.1%) in group 2. RESULTS: At 12 months, the efficacy index was similar in both groups (p = 0.264); the safety index was higher in group 1 (p = 0.031); the mean central Vault was significantly lower in group 1 (212.8 vs 410.6 µm; p < 0.001). Respectively, 93 (83.8%) and 366 (84.1%) eyes were within ±0.50 D of targeted refraction. Anterior chamber angle significantly decreased during follow-up in both groups (p < 0.001; p < 0.001). Intraocular pressure did not change significantly (p = 0.310 and p = 0.446, respectively). There were no significant differences in endothelial cell density loss (p = 0.278) or in the rate of complications observed (p = 0.733). CONCLUSIONS: ICL implantation is an effective and safe procedure in eyes with shallow anterior chambers, with visual and refractive results and complication rates identical to those obtained in deeper anterior chambers.

Bilirubin oxidase as a single enzymatic oxygen scavenger for the development of reductase-based biosensors in the open air and its application on a nitrite biosensor.

The commercialization of amperometric or voltammetric biosensors that operate at potentials lower than -0.2 V vs SHE has been hindered by the need for anoxic working conditions due to the interference of molecular oxygen, whose electrochemical reduction can potentially mask other redox processes and generate reactive oxygen species (ROS). A deoxygenation step must be thus integrated into the analytical process. To this end, several (bio)chemical oxygen scavenging systems have been proposed, such as the bi-enzyme system, glucose oxidase/catalase. Still, a few issues persist owing to enzyme impurities and the formation of oxygen reactive species. Here in, we propose a new mono-enzymatic oxygen scavenging system composed of a multicopper oxidase as a single biocatalytic oxygen reducer. As a model, we used bilirubin oxidase (BOD), which catalyzes the direct reduction of oxygen to water in the presence of an electron donor substrate, without releasing hydrogen peroxide. Both the direct electron transfer and mediated electrochemical approach using different co-substrates were screened for the ability to promote the enzymatic reduction of oxygen. An optimal combination of BOD with sodium ascorbate proved to be quick (5 min) and effective. It was subsequently employed, as a proof-of-concept, in a voltammetric biosensor based on a multiheme cytochrome c nitrite reductase, which performs the reduction of nitrite to ammonia at potentials below -0.3 V vs SHE. The nitrite biosensor performed well under ambient air, with no need for a second enzyme to account for the build-up of oxygen reactive intermediaries.

Efficacy and Safety After Toric Posterior Chamber Implantable Collamer Lens and Toric Iris-Fixated Foldable Phakic Intraocular Lens for Myopic Astigmatism.

PURPOSE: To compare visual, refractive, and safety outcomes of toric posterior chamber Implantable Collamer Lens (T-ICL) (STAAR Surgical) and toric iris-fixated foldable phakic intraocular lens (IOL) (T-Artiflex; Ophtec BV) implantation for the correction of myopic astigmatism. METHODS: This retrospective cohort study included 312 eyes of 312 patients who had phakic IOL implantation for myopic astigmatism. Two groups were defined: 205 eyes that underwent T-ICL implantation and 107 eyes that underwent T-Artiflex implantation. Safety, efficacy, and predictability outcomes were evaluated preoperatively and at 12 months postoperatively. Refractive and corneal astigmatic vector analysis were performed using the Alpins method. RESULTS: One year postoperatively, uncorrected distance visual acuity was 0.05 ± 0.18 (T-ICL) and 0.10 ± 0.16 (T-Artiflex) logMAR, with efficacy indexes of 1.16 ± 0.27 and 1.05 ± 0.31, respectively (P < .001). Safety indexes were 1.28 ± 0.30 and 1.21 ± 0.31, respectively (P = .04). Spherical equivalent was within ±0.50 diopters (D) of emmetropia in 165 (80.5%) and 88 (82.2%) eyes, respectively. Refractive astigmatic analysis showed an index of success of 0.28 ± 0.33 (T-ICL) and 0.31 ± 0.26 (T-Artiflex) (P = .07). Surgically induced corneal astigmatism was 0.48 ± 0.74 and 0.81 ± 0.61 D, respectively (P < .001). Mean endothelial loss was 1.11% and 2.05%, respectively (P = .42). Six (2.9%) eyes in the T-ICL group and 1 (0.9%) eye in the T-Artiflex group had phakic IOL repositioning due to significant misalignment. No vision-threatening complications occurred. CONCLUSIONS: Both the T-ICL and T-Artiflex groups showed high visual and refractive efficacy with a good safety profile for the correction of myopic astigmatism. T-ICL implantation demonstrated significantly better efficacy and safety indexes after 12 months. Vector analysis showed similar refractive astigmatic correction in both groups, but T-Artiflex implantation revealed higher surgically induced corneal astigmatism. [J Refract Surg. 2022;38(6):339-347.].

Visual and refractive outcomes following secondary intraocular lens implantation.

PURPOSE: To analyze the visual and refractive results after secondary IOL implantation using different surgical techniques - iris-claw aphakic IOL through a corneal incision or scleral tunnel, and 3-piece IOL into the ciliary sulcus. PATIENTS AND METHODS: Retrospective study including patients that were submitted to secondary IOL implantation from January 2017 to December 2019 at the Department of Ophthalmology of Hospital de Braga, Portugal. We collected demographic data (age, surgical indication, comorbidities, surgical technique, IOL implanted, and intra and postoperative complications) and visual and refractive data [preoperative and 3-month, 6-month, and 12-month postoperative corrected-distance visual acuity (CDVA), spherical equivalent (SE), manifest cylinder, and intraocular pressure]. RESULTS: 128 eyes from 123 patients were included. The most frequent surgical indications were IOL subluxation/luxation (62.5%) and intraoperative posterior capsular rupture (23.4%). CDVA improved from 1.26 ± 0.51 to 0.47 ± 0.49 logMar (p < .001). CDVA was significantly better in the 3-piece into the ciliary sulcus IOL group than both other groups. The final SE was -0.68 ± 0.94 diopters. The mean manifest refractive cylinder remained stable until the 6th month after the surgery (p = .454) and improved in the last 6 months of follow-up (p = .015). In the postoperative period, the cylinder was higher in the corneal incision iris-claw aphakic IOL group and lower in the 3-piece IOL into the ciliary sulcus group (p < 0,05). The corneal incision iris-claw aphakic IOL group presented the most postoperative complications. CONCLUSION: All techniques showed satisfying results. The 3-piece IOL into the ciliary sulcus group showed the best visual and refractive performance, followed by the scleral tunnel iris-claw IOL group and the corneal incision iris-claw IOL group.

Intraocular Lens Position and Anterior Chamber Parameters Evaluation After Nd:YAG Laser Posterior Capsulotomy for Posterior Capsular Opacification Using Anterior Segment Swept-Source Optical Coherence Tomography.

PURPOSE: To evaluate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy on intraocular lens (IOL) position and anterior segment parameters with a new swept-source anterior segment optical coherence tomography (AS-OCT) device (Anterion®, Heidelberg Engineering GmbH). PATIENTS AND METHODS: A total of 50 eyes from 50 consecutive patients were included. All patients had visually significant posterior capsular opacification (PCO) after uneventful phacoemulsification surgery with manual capsulorhexis and single-piece C-loop acrylic IOL implantation (AcrySof® SA60AT) and were treated with Nd:YAG laser. Anterior segment images were captured with Anterion® in non-dilated conditions before and one month after the procedure. In the "Metrics App", we collected data of the anterior chamber angle (ACA) 3 and 9 o'clock, the anterior chamber depth (ACD), the anterior chamber volume (ACV), and the central corneal thickness (CCT). We also collected demographic and clinical data [age, gender, months from surgery to Nd: YAG capsulotomy, pre- and post-capsulotomy corrected distance visual acuity (CDVA) and spherical equivalent, and axial length]. RESULTS: We did not find a statistically significant difference in ACD after the Nd:YAG capsulotomy (3.96 ± 0.55 vs 3.97 ± 0.55 mm, p = 0.10). In 28 patients, we noted a backward movement of the IOL; in the remaining 22, the IOL moved forward or did not change at all. We did not observe significant changes in ACA at the 3 and 9 o'clock reference points, ACV, or CCT. There was an improvement in CDVA after the procedure (0.37 ± 0.21 vs 0.12 ± 0.27 logMAR, p = 0.015), without statistically significant differences in SE (-0.15 ± 0.84 vs -0.25 ± 0,93, p = 0.42). Axial length was not correlated with ACD variations after the procedure (p = 0.67). CONCLUSION: Our results show that Nd:YAG laser capsulotomy does not change the axial position of a single-piece C-loop acrylic IOL inside the capsular bag, as well as other anterior chamber parameters.

Imprinting on time-structured acoustic stimuli in ducklings.

Filial imprinting is a dedicated learning process that lacks explicit reinforcement. The phenomenon itself is narrowly heritably canalized, but its content, the representation of the parental object, reflects the circumstances of the newborn. Imprinting has recently been shown to be even more subtle and complex than previously envisaged, since ducklings and chicks are now known to select and represent for later generalization abstract conceptual properties of the objects they perceive as neonates, including movement pattern, heterogeneity and inter-component relationships of same or different. Here, we investigate day-old Mallard (Anas platyrhynchos) ducklings' bias towards imprinting on acoustic stimuli made from mallards' vocalizations as opposed to white noise, whether they imprint on the temporal structure of brief acoustic stimuli of either kind, and whether they generalize timing information across the two sounds. Our data are consistent with a strong innate preference for natural sounds, but do not reliably establish sensitivity to temporal relations. This fits with the view that imprinting includes the establishment of representations of both primary percepts and selective abstract properties of their early perceptual input, meshing together genetically transmitted prior pre-dispositions with active selection and processing of the perceptual input.

Microelectrode Sensor for Real-Time Measurements of Nitrite in the Living Brain, in the Presence of Ascorbate.

The impaired blood flow to the brain causes a decrease in the supply of oxygen that can result in cerebral ischemia; if the blood flow is not restored quickly, neuronal injury or death will occur. Under hypoxic conditions, the production of nitric oxide (●NO), via the classical L-arginine-●NO synthase pathway, is reduced, which can compromise ●NO-dependent vasodilation. However, the alternative nitrite (NO2-) reduction to ●NO, under neuronal hypoxia and ischemia conditions, has been viewed as an in vivo storage pool of ●NO, complementing its enzymatic synthesis. Brain research is thus demanding suitable tools to probe nitrite's temporal and spatial dynamics in vivo. In this work, we propose a new method for the real-time measurement of nitrite concentration in the brain extracellular space, using fast-scan cyclic voltammetry (FSCV) and carbon microfiber electrodes as sensing probes. In this way, nitrite was detected anodically and in vitro, in the 5-500 µM range, in the presence of increasing physiological concentrations of ascorbate (100-500 µM). These sensors were then tested for real-time and in vivo recordings in the anesthetized rat hippocampus; using fast electrochemical techniques, local and reproducible transients of nitrite oxidation signals were observed, upon pressure ejection of an exogenous nitrite solution into the brain tissue. Nitrite microsensors are thus a valuable tool for investigating the role of this inorganic anion in brain redox signaling.

Interfacing the enzyme multiheme cytochrome c nitrite reductase with pencil lead electrodes: Towards a disposable biosensor for cyanide surveillance in the environment.

The present study reports a novel voltammetric biosensor for cyanide based on its inhibitory effect on cytochrome c nitrite reductase (ccNiR). Interestingly, the earlier development of a point-of-care test for nitrite based on the direct electrochemistry of ccNiR has shown that the cyanide inhibition depends on the type of carbon material employed as transducer (Monteiro et al., 2019). In this work, commercial graphite pencil leads were employed in the construction of both working and pseudo-reference electrodes, with ccNiR being simply drop casted onto the former. In this way, we produced a functional and fully integrated voltammetric biosensor for nitrite quantification that also allows to observe a decrease in the catalytic current due to cyanide addition. Under turnover conditions, the biosensor showed a linear response with the logarithm of cyanide concentration in the 5-76 µM (cyclic voltammetry) and 1-40 µM (square-wave voltammetry) ranges, with a sensitivity of 20-25% ln [cyanide µM]-1 and a detection limit of 0.86-4.4 µM. The application of the pencil lead as a putative pseudo-reference was very promising, since the potentials profile matched those observed with a true reference electrode (Ag/AgCl). Overall, the direct electron transfer between ccNiR and a pencil lead electrode was demonstrated for the first time, with cyanide-induced inhibition being easily monitored, paving the way for the employment of these low-cost bioelectrodes as cyanide probes for on-site surveillance of aquatic environments.

Visual and Tomographic Outcomes of a 300° Arc-length ICRS Implantation in Moderate to Advanced Central Keratoconus.

PURPOSE: To assess the outcomes of implanting a new 300° arc-length intrastromal corneal ring segment (ICRS) in moderate to advanced central hyperprolate keratoconus. METHODS: Forty-two eyes with moderate to advanced central hyperprolate keratoconus were evaluated before and after implanting an inferior 300° ICRS (AJL Ophthalmic). The clinical measurements taken included manifest refraction, uncorrected (UDVA) and corrected (CDVA) distance visual acuity (logMAR scale), and corneal tomographic analysis (Sirius; Costruzioni Strumenti Oftalmici). Changes in the anterior and posterior corneal surfaces and the root mean square (RMS) for coma-like aberrations for a pupil size of 4.5 mm were evaluated. All examinations were performed before surgery and 6 months after surgery. RESULTS: The mean UDVA improved from 1.12 ± 0.48 logMAR preoperatively to 0.73 ± 0.37 logMAR postoperatively (P < .0001). The mean CDVA changed from 0.33 ± 0.20 to 0.20 ± 0.11 logMAR (P < .0001). Postoperatively, the CDVA improved by two or more lines in 45.2% of the eyes and increased by one line in 19.04%, and none of the patients lost lines of CDVA. All of the anterior and posterior corneal tomographic parameters analyzed were significantly improved after surgery, except posterior flat keratometry, which remained unchanged. In 80.95% of the eyes, the postoperative mean keratometry was 50.00 diopters or less. The 6-month RMS for coma-like aberrations also declined significantly from 1.57 ± 0.68 to 1.06 ± 0.42 µm after surgery (P < .0001). CONCLUSIONS: These results suggest that implanting a 300° arc-length ICRS is a safe and effective procedure for treating patients with moderate to advanced central hyperprolate keratoconus and clear cornea. [J Refract Surg. 2021;37(4):249-255.].

Posterior chamber collamer phakic intraocular lens implantation: Comparison of efficacy and safety for low and moderate-to-high myopia.

PURPOSE: To compare visual, refractive and safety outcomes of central-hole posterior chamber collamer phakic intraocular lens implantation for low and moderate-to-high myopia. SUBJECTS/METHODS: This retrospective cohort study included 338 eyes submitted to posterior chamber collamer phakic intraocular lens implantation that completed a 12-month postoperative follow-up. Two groups were defined depending on preoperative spherical equivalent: group 1 comprised 106 eyes with manifest spherical equivalent of -6.00 D or less; group 2 comprised 232 eyes with manifest spherical equivalent higher than -6.00 D. Effectiveness, predictability, stability and safety outcomes were compared preoperatively and at 1, 6 and 12 months postoperatively. RESULTS: At 1-year postoperative, uncorrected and corrected visual acuities were 0.02 ± 0.17 and -0.01 ± 0.12 logMAR (group 1) and 0.04 ± 0.20 and 0.01 ± 0.16 logMAR (group 2), with an efficacy index of 1.05 ± 0.17 and 1.17 ± 0.28. Respectively, 92 (86.8%) and 199 (85.8%) eyes were within ±0.50 D of targeted refraction, and postoperative manifest refraction changes were -0.07 ± 0.25 D and -0.07 ± 0.35 D. Intraocular pressure did not change significantly. The mean rate of endothelial cell loss was 1.12% and 1.10%, respectively. One case of anterior subcapsular cataract (group 2) was observed. ICL exchange occurred in one case (group 1) and three cases (group 2). No vision-threatening complications were reported. CONCLUSION: The posterior chamber collamer phakic intraocular lens implantation demonstrated high visual and refractive efficacy with an excellent safety profile for the correction of both low and moderate-to-high myopia, revealing equivalent 1-year outcomes regardless of the degree of preoperative myopia.

Long-term efficacy and safety results after iris-fixated foldable phakic intraocular lens for myopia and astigmatism: 6-year follow-up.

PURPOSE: To evaluate the long-term efficacy and safety of iris-fixated foldable phakic intraocular lenses (pIOLs) for the management of myopia and astigmatism after 6-year follow-up. SETTING: Ophthalmology Department, Hospital Braga, Portugal. DESIGN: Retrospective cohort study. METHODS: Patients included underwent iris-fixated foldable Artiflex pIOL implantation between January 2010 and December 2013. Follow-up evaluations were performed 6 months postoperatively and every 12 months until 72 months. Preoperative and follow-up data on uncorrected and corrected distance visual acuity (CDVA), manifest refraction, endothelial cell density (ECD), and anterior chamber depth (ACD) were analyzed. RESULTS: A total of 177 eyes of 98 patients with a mean age of 32.33 ± 7.13 years were analyzed. There was a statistically significant improvement in CDVA from 0.09 ± 0.02 logMAR preoperatively to 0.04 ± 0.02 logMAR (P < .0001) at 6 years postoperatively. The spherical equivalent demonstrated a statistically significant improvement from -9.50 ± 2.93 diopters (D) to -0.41 ± 0.45 D at 6 years. At 72 months, the efficacy and safety indexes were 0.94 and 1.15, respectively. A mean loss of 31.77 cells/mm2 (1.19%) was observed each year until the sixth year. The overall mean ECD loss after correction for the physiological loss was 3.02% after 6 years. No correlations were observed between the mean ECD loss and the preoperative ACD. CONCLUSIONS: The Artiflex pIOL was a safe, effective, and a stable option to correct myopia. A mean ECD loss of 3.02% was observed over 6 years. No pIOL was explanted due to corneal decompensation.