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Purpose: To study the relationship between the amplitude of accommodation (AA) measured by the Royal Air Force (RAF) rule and near addition (NA) prescribed in presbyopic patients to assess how far practice is different from theoretical recommendations.Methods: Patients, aged 40 to 60 years with best corrected vision of 6/6 N5 were included in this cross sectional observational study. AA was measured using the RAF rule. Refined with near Duochrome chart, the NA was given with the chart at 40 cm. Accommodative reserve was calculated from the measured AA, NA required and the calculated additional accommodation expended by the patient for reading. The percentage of reserve was calculated with and without the correction for depth-of-field.Results: A total of 130 patients were studied. In the patients above 50 years of age, the negative correlation of AA with age was -0.298 (P = 0.065) and AA and NA was -0.365 (P = 0.002) was weak. Among the patients aged between 40 and 50 years, the negative correlation of AA with Age and NA were strong; -0.853 (P < 0.0001) and -0.823 (P < 0.0001) respectively. When prescribing glasses, 62.01% (CI 58.78 to 65.23) and 90.93% (CI 62.50 to 119.37) of the AA was found to be kept in reserve for patients below and above 50 years of age respectively.Conclusion: Accommodative reserve kept in our study patients when prescribing NA was two to three times the theoretical recommendation. High percentage of accommodation kept in reserve suggest that the measured AA is not activated normally and require higher NA and one should not rely on patient's ability to generate accommodative power especially in patients over 50 years. [ABSTRACT FROM AUTHOR]

Many patients with concussion experience visual symptoms following injury that lead to a diagnosis of convergence insufficiency, accommodative insufficiency, or saccadic dysfunction. However, these diagnostic categories are based on aggregates of clinical tests developed from a non-concussed population and therefore may not accurately describe visual deficits in the concussed population. Thus, we sought to understand individual metrics of visual dysfunction in chronically symptomatic post-concussion patients. This retrospective cross-sectional study included patients examined at the multidisciplinary concussion clinic (MDCC) at Boston Children's Hospital over four years. Patients aged 5-21 years who had a complete assessment of eye alignment, vergence, accommodation, and visual tracking, and had visual acuity better than or equal to 20/30 in each eye were included. Patients with history of amblyopia, strabismus, or ocular pathology were excluded. Chart review yielded 116 patients who met inclusion criteria (median age 15 years, 64% female). The majority of patients (52%) experienced a single concussion and most were sports-related (50%). Clinical data show vergence, accommodation, or visual tracking deficits in 95% of patients. A receded near point of convergence (NPC, 70/116) and reduced accommodative amplitude (63/116) were the most common deficits. Both NPC and accommodative amplitude were significantly correlated with one another (r = -0.5) and with measures of visual tracking (r = -0.34). Patients with chronic post-concussion symptoms show deficits in individual metrics of vergence, accommodation and visual tracking. The high incidence of these deficits, specifically NPC and accommodative amplitude, highlights the need for a detailed sensorimotor evaluation to guide personalized treatment following concussion. [ABSTRACT FROM AUTHOR]

Aim of the study: To compare the accuracy of intraocular lens power calculation formulas and examine the correlation of this accuracy with the axial length for eyes larger than 25.00 mm Material and methods:. The data of myopic patients who underwent uneventful phacoemulsification between October 2015 and June 2019 were reviewed. The intraocular lens power for each patient was calculated using 6 formulas (Holladay1, SRK/T, Hoffer Q, Holladay 2, Haigis and Barrett Universal II) before cataract surgery. Postoperative refraction was measured and refractive prediction error was calculated 3 months after phacoemulsification. The correlation between axial length and absolute error was evaluated. Results: Seventy patients (81 eyeballs with ocular axial length between 25.01 mm and 28.57 mm) were studied. The Barrett Universal II formula achieved the lowest level of mean absolute error of 0.08 ±0.08 D (p < 0.001). Significant correlations for the Holladay 1 (r = 0.478, p < 0.001), the Barrett Universal II (r = 0.312, p = 0.005) and for the Hoffer Q (r = 0.293, p = 0.008) formula were observed. Conclusions: 1. The Barrett Universal II formula obtained the lowest absolute error and is recommended for intraocular lens power calculation for eyeballs with axial length exceeding 25.0 mm. 2. The correlation between axial length and absolute error is a factor which should be considered when calculating intraocular lens power, especially for eyeballs with an extremely large axial length. [ABSTRACT FROM AUTHOR]

Introduction. Simultaneous Bilateral Cataract Surgery (SBCS) is still a relatively controversial procedure. The main objection is the risk of bilateral endophthalmitis or bilateral refractive error. However, SBCS has also some advantages (faster visual rehabilitation, lower risk of nosocomial infection, and lower cost). Performing surgery on both eyes in one session has one additional advantage which has not yet been described in the literature (according to the information available to authors). It allows surgeons to distinguish the effect of minor differences in the surgical protocol on the subjective perception of the procedure more accurately, which is a more suitable method than comparing two independent groups of patients. Purpose. To compare the effect of minor changes in the surgical protocol during SBCS on intraindividual subjective perception of surgery (pain, pressure, glare, and perception of the duration of the surgery). Methods. During the surgery of the right and left eyes of one patient, we randomly changed one surgical parameter (use of intracameral anesthesia, light intensity of the operating microscope, type of eyelid speculum, creation of the posterior circular capsulorhexis, and communication with the patient during surgery). Patients immediately after both surgeries subjectively evaluated the perception of pain (on the scale 0–10), pressure, and glare (on the scale 0–5) and estimated the duration of the surgery, separately for each eye. Each change was evaluated in a group of 50 patients. Results. In the control group with no parameters changed, we noted no difference in subjective perception of the first and second surgery. In subgroups, where we changed the protocol, we detected only minor differences in subjective perception of pain, pressure, glare, and duration of the surgery. Only one statistically significant difference in subjective pain perception was in the subgroup where we used eye intracameral anesthesia (0.34 eyes with intracameral anesthesia, 0.44 eyes with only topical anesthesia). We did not note any statistically significant differences in the perception of the time of surgery. Conclusion. SBCS can be used to optimize the parameters of cataract surgery. In our study, we noted a positive effect of intracameral anesthesia on subjective perception of surgery. [ABSTRACT FROM AUTHOR]

Purpose: To assess pre and post vergence and accommodation parameters after monitored reading on a smartphone device.Methods: This prospective comparative study was performed in a tertiary eye care center for a duration of 6 months (December 2017 - May 2018). A total of 47 healthy emmetropic subjects of age group ranging from 18-30 years were recruited for the study. Participants underwent an initial visual screening protocol, followed by accommodation and vergence parameters assessment. The subjects were given reading text of optotype N6 at 40cm working distance for 30 minutes in a smart phone device. Pre and post measurements were documented.Results: Among 47 subjects there were 17 male and 30 females with mean age group of 21.2+2.06 years. There was a statistically significant worsening of accommodative components (negative & positive relative accommodation, lag of accommodation). In vergence parameters, a statistically significant deterioration of negative (12.8 + 1.65 to 12.38 + 1.93 PD) and positive fusional vergence (15.48 + 1.53 to 16.08 +1.61 PD) was observed. The mean vergence facility also showed a statistically significant change in pre and post task measurements (13.51 + 1.64 to 10.71 + 1.91 cpm (cycles per minute)).Conclusion: The current study investigated that perusing text with a smart phone for 30 minutes shows significant effect on accommodative and vergence components for near task, with greater impact on vergence parameters. Drawn out exposure to digital screens at near, may bring about visual quality dysfunction. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine the frequency of vision diagnoses after concussion in adolescents and evaluate the sensitivity and specificity of physician-administered screening for detecting convergence and accommodative disorders post-concussion. We enrolled participants 11 to 17 years old, assessed 4 to 12 weeks following a diagnosed concussion. During the initial concussion examination, a sports medicine physician measured the near point of convergence (NPC), monocular accommodative amplitude (AA), and symptoms using the Convergence Insufficiency Symptom Survey (CISS). A comprehensive oculomotor evaluation was performed by an optometrist. One hundred and thirteen adolescents were enrolled, with a mean age of 15.2 years. Seventy-nine of the 113 (70%) participants had at least one oculomotor diagnosis after concussion, with the most common problems being vergence disorders (60%) and accommodative disorders (57%). The most common vergence disorder was convergence insufficiency (35%). Among accommodative disorders, the most common problem was accommodative insufficiency (35%). In all, 47% of the participants had more than one oculomotor diagnosis following concussion. The sensitivity of physician screening using measures of NPC, AA, and CISS for detecting convergence and accommodative insufficiency was 63%, 43%, 48%, respectively. The results of this study provide additional evidence that vision problems are common in adolescents with persistent concussion symptoms in the sub-acute phase 4 to 12 weeks post-concussion, and current physician screening methods using the NPC, AA, or the CISS underperform. Thus, it is prudent that adolescents with post-concussion symptoms lasting more than 4 weeks post injury receive a comprehensive oculomotor examination. [ABSTRACT FROM AUTHOR]

Classic studies of ocular dominance plasticity in early development showed that monocular deprivation suppresses the neural representation and visual function of the deprived eye. However, recent studies have shown that a short period of monocular deprivation (<3 h) in normal adult humans, shifts sensory eye dominance in favor of the deprived eye. How can these opposing effects be reconciled? Here we argue that there are two systems acting in opposition at different time scales. A fast acting, stabilizing, homeostatic system that rapidly decreases gain in the non-deprived eye or increases gain in the deprived eye, and a relatively sluggish system that shifts balance toward the non-deprived eye, in an effort to reduce input of little utility to active vision. If true, then continuous deprivation should produce a biphasic effect on interocular balance, first shifting balance away from the non-deprived eye, then towards it. Here we investigated the time course of the deprivation effect by monocularly depriving typical adults for 10 h and conducting tests of sensory eye balance at six intervening time points. Consistent with previous short-term deprivation work, we found shifts in sensory eye dominance away from the non-deprived eye up until approximately 5 h. We then observed a turning point, with balance shifting back towards the non-deprived eye, -, a biphasic effect. We argue that this turning point marks where the rapid homeostatic response saturates and is overtaken by the slower system responsible for suppressing monocular input of limited utility. [ABSTRACT FROM AUTHOR]

In this work, we examined the color tuning of units in the hidden layers of AlexNet, VGG-16 and VGG-19 convolutional neural networks and their relevance for the successful recognition of an object. We first selected the patches for which the units are maximally responsive among the 1.2 M images of the ImageNet training dataset. We segmented these patches using a k-means clustering algorithm on their chromatic distribution. Then we independently varied the color of these segments, both in hue and chroma, to measure the unit's chromatic tuning. The models exhibited properties at times similar or opposed to the known chromatic processing of biological system. We found that, similarly to the most anterior occipital visual areas in primates, the last convolutional layer exhibited high color sensitivity. We also found the gradual emergence of single to double opponent kernels. Contrary to cells in the visual system, however, these kernels were selective for hues that gradually transit from being broadly distributed in early layers, to mainly falling along the blue-orange axis in late layers. In addition, we found that the classification performance of our models varies as we change the color of our stimuli following the models' kernels properties. Performance was highest for colors the kernels maximally responded to, and images responsible for the activation of color sensitive kernels were more likely to be mis-classified as we changed their color. These observations were shared by all three networks, thus suggesting that they are general properties of current convolutional neural networks trained for object recognition. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to study online clothing consumers' behaviour and their visual attention mechanism to provide objective and quantitative evidences for the display and sales of online clothing. Design/methodology/approach: Firstly, this paper conducted a Focus Group Methodology and questionnaire survey to obtain concern factors of online clothing. Secondly, the online clothing's bottom-up visual stimulation and consumer's top-down expectations were analysed, and proposed the hypotheses about significant stimulus of clothing and consumer's emotional experience. Thirdly, the online clothing consumer's visual attention rules and related qualitative results were discussed, and proposed visual attention law for online clothing. Finally, took the company's 84th quarter clothing design practices as research projects, all the hypotheses were demonstrated through eye movement physiology experiments, online clothing trial release and node sales data. Findings: Online clothing has unique visual display ways compared with other online products such as online advertising, brands and food packaging. Clothing patterns of unfamiliar (fresh) font shapes are more attractive than the patterns of familiar fonts. The cause of the bottom-up visual attention bias is the contrast between clothing features, not the absolute stimulus intensity of the features themselves. Clothing factors can change their emotional experience from no difference to significant difference under the influence of other clothing factors. Originality/value: Put forward hypotheses of online clothing consumer behaviour and its visual attention mechanism, provided objective and quantitative evidences through eye tracker. [ABSTRACT FROM AUTHOR]

Introduction. To analyze the morphological and functional features of choroidal neovascularizations (CNVs) in eyes affected by pattern dystrophies (PD), evaluating their long-term response to intravitreal ranibizumab, and comparing them with CNVs in age-related macular degeneration (AMD). The mean goal is to identify possible disease biomarkers and to evaluate the long-term prognosis of CNVs in PD. Materials and Methods. A retrospective study of 42 patients with naïve CNV (26 PD and 16 AMD), for a total of 47 eyes (29 eyes in the PD group and 18 eyes in the AMD group). Each patient received a loading dose of ranibizumab (one monthly for three months) followed by pro re nata (PRN) reinjection protocol for a period of at least three years. Morphological OCT parameters (CRT, central retinal thickness; SRF, subretinal fluid; IRF, intraretinal fluid; SHRM, subretinal hyperreflective material; HRF, hyperreflective foci; HCD, hyperreflective crystalline deposits; cCT, central choroidal thickness; slCT, sublesional choroidal thickness; EZd, ellipsoid zone disruption; and best corrected visual acuity (BCVA in logMAR scale)) were reported at baseline and last follow-up. Results. At baseline, no significant differences were found between the two groups, except for choroidal thickness parameters that were significantly greater in the PD group (p = 0.009). Longitudinal PD analysis demonstrated reduction in BCVA (p = 0.009), decrease in CRT (p = 0.046), resolution of SRF in 61.6% of cases (p = 0.004) and SHRM in 30% (p = 0.034), and choroidal thinning both centrally (p = 0.004) and sublesional (p = 0.011) compared to baseline. At 3 years, the PD group received significantly more injections than the AMD (p = 0.011) and showed significantly thicker choroid (p = 0.033) and more frequent HRF (p = 0.006). Regarding the PD group, we found a negative correlation between age and choroidal thicknesses at baseline and at 3 years (p < 0.05); significant positive correlations were found between baseline BCVA and at 3 years (p < 0.001), BCVA at 3 years and IRF (p = 0.003) and SHRM at 3 years (p = 0.003); CRT baseline and CRT 3 years (p = 0.017); HCD at 3 years was associated with greater CRT (p = 0.04) and IRF at 3 years (p = 0.019). Conclusions. Early and long-term morphofunctional features of CNVs in PD and in AMD are overlapping. CNVs in PD have poorer long-term response to ranibizumab and higher choroidal thickness suggesting different pathogenetic and evolutionary mechanisms. [ABSTRACT FROM AUTHOR]

In the last larval instar, uncommitted progenitor cells in the Drosophila eye primordium start to adopt individual retinal cell fates, arrest their growth and proliferation, and initiate terminal differentiation into photoreceptor neurons and other retinal cell types. To explore the regulation of these processes, we have performed mRNA-Seq studies of the larval eye and antennal primordial at multiple developmental stages. A total of 10,893 fly genes were expressed during these stages and could be adaptively clustered into gene groups, some of whose expression increases or decreases in parallel with the cessation of proliferation and onset of differentiation. Using in situ hybridization of a sample of 98 genes to verify spatial and temporal expression patterns, we estimate that 534 genes or more are transcriptionally upregulated during retinal differentiation, and 1367 or more downregulated as progenitor cells differentiate. Each group of co-expressed genes is enriched for regulatory motifs recognized by co-expressed transcription factors, suggesting that they represent coherent transcriptional regulatory programs. Using available mutant strains, we describe novel roles for the transcription factors SoxNeuro (SoxN), H6-like homeobox (Hmx), CG10253, without children (woc), Structure specific recognition protein (Ssrp), and multisex combs (mxc). [ABSTRACT FROM AUTHOR]

The purpose of the present study is to explore the characteristics of the postural control in Kung-Fu trained young boys, in comparison with non-trained age-matched ones. Two groups of 11–13-year old boys (10 practicing Kung-Fu and 10 controls) were asked to maintain upright bipedal and unipedal stances on a force platform with eyes open and closed in a static and two dynamic postures. Postural control was assessed with centre of pressure excursions. Muscle response characteristics were recorded during maintaining a bipedal stance on an unstable platform with eyes open and closed. Kung-Fu practitioners had significantly (P <.05) better balance than controls in dynamic postures. Removal of vision significantly (P <.001) decreased the balance of both groups similarly. In dynamic conditions, controls were affected by removal of vision in both postures, but Kung-Fu practitioners depended on vision in unipedal posture only. Kung-Fu group showed significantly (P <.01) better neuromuscular responses than controls. Removal of vision significantly (P <.05) increased muscle-response amplitude for the two groups. Kung-Fu trained young boys seems to have better postural control in dynamic (unipedal-eyes open and bipedal-eyes closed) postures and better neuromuscular responses compared to non-trained ones. [ABSTRACT FROM AUTHOR]

A key element of contact lens practice involves clinical evaluation of anterior eye health, including the cornea and limbus, conjunctiva and sclera, eyelids and eyelashes, lacrimal system and tear film. This report reviews the fundamental anatomy and physiology of these structures, including the vascular supply, venous drainage, lymphatic drainage, sensory innervation, physiology and function. This is the foundation for considering the potential interactions with, and effects of, contact lens wear on the anterior eye. This information is not consistently published as academic research and this report provides a synthesis from all available sources. With respect to terminology, the report aims to promote the consistent use of nomenclature in the field, and generally adopts anatomical terms recommended by the Federative Committee for Anatomical Terminology. Techniques for the examination of the ocular surface are also discussed. [ABSTRACT FROM AUTHOR]

This paper outlines changes to the ocular surface caused by contact lenses and their degree of clinical significance. Substantial research and development to improve oxygen permeability of rigid and soft contact lenses has meant that in many countries the issues caused by hypoxia to the ocular surface have largely been negated. The ability of contact lenses to change the axial growth characteristics of the globe is being utilised to help reduce the myopia pandemic and several studies and meta-analyses have shown that wearing orthokeratology lenses or soft multifocal contact lenses can reduce axial length growth (and hence myopia). However, effects on blinking, ptosis, the function of Meibomian glands, fluorescein and lissamine green staining of the conjunctiva and cornea, production of lid-parallel conjunctival folds and lid wiper epitheliopathy have received less research attention. Contact lens wear produces a subclinical inflammatory response manifested by increases in the number of dendritiform cells in the conjunctiva, cornea and limbus. Papillary conjunctivitis is also a complication of all types of contact lenses. Changes to wear schedule (daily disposable from overnight wear) or lens materials (hydrogel from SiHy) can reduce papillary conjunctivitis, but the effect of such changes on dendritic cell migration needs further study. These changes may be associated with decreased comfort but confirmatory studies are needed. Contact lenses can affect the sensitivity of the ocular surface to mechanical stimulation, but whether these changes affect comfort requires further investigation. In conclusion, there have been changes to lens materials, design and wear schedules over the past 20+ years that have improved their safety and seen the development of lenses that can reduce the myopia development. However, several changes to the ocular surface still occur and warrant further research effort in order to optimise the lens wearing experience. [ABSTRACT FROM AUTHOR]

• In foveal crowding, impact of symmetry and similarity depends in the stimulus size. • Different mechanisms underlie foveal crowding for large and just resolvable targets. • Voluntary and involuntary attention interact in foveal crowding for brief tests. We compare the recognition of foveal crowded Landolt Cs of two sizes: brief (40 ms), large, low-contrast Cs and high-contrast (1 sec) tests at the resolution limit of the visual system. In different series, the test Landolt C was surrounded by two identical distractors located symmetrically along the horizontal or by a single distractor. The distractors were Landolt Cs or rings. At the resolution limit , the critical spacing was similar in the two series and did not depend on the type of distractor. The result supports the hypothesis that crowding at the resolution limit occurs when both the test and the distractors fall into the same smallest receptive field responsible for the target recognition. For large stimuli , at almost all separations distractors of the same shape caused greater impairment than did rings, and recognition errors were non-random. The critical spacing was equal to 0.5 test diameters only in the presence of one distracting Landolt C. This result suggests that attention is involved: When one distractor is added, involuntary attention, which is directed to the centre of gravity of the stimulus, can lead to confusion of features that are present in both tests and distractors and thus to non-random errors. [ABSTRACT FROM AUTHOR]

The epidemiology of the second half of the 20th century has been marked by a transition from infectious to non‐communicable diseases. Instead of having a unique etiological cause, the non‐communicable diseases are believed to develop by the temporal confluence of several risk factors on a given individual. Risk factors of genetic origin are considered non‐modifiable nowadays. In contrast, behavioural risk factors, including lifestyle, are considered modifiable, and, therefore the preventive and adjuvant interventions aimed to reduce the risk or modify the natural course of non‐communicable diseases are based in lifestyle changes. Since the seminal work of Jeremy Morris in the 50's (the so‐called "London Bus Study") epidemiological evidences have been accumulating over time on the potential role of a reduced physical activity in every domain of daily life as a risk factor for several non‐modifiable diseases. This is aggravated by the progressive trend of a reduced physical activity performed by the worldwide population during the last decades. The relationship of physical inactivity and/or sedentarism with several systemic diseases is clearly proven nowadays, and the underlying pathophysiological explanations are starting to be understood. In contrast what it happens in other organs or systems the potential effects of physical activity on ocular physiology and/or pathophysiology are still almost unknown. The design and development of future studies focused on these topics would need that the eye and vision research community is familiarized with: a) the current terminology on the field of physical activity and exercise; b) the hormetic properties of exercise, and consequently, the differences among acute responses and chronic adaptations to it; and, c) the potential physiological mechanisms ‐ranging from classical neuroendocrine responses to the recent concept of exerquines‐ that may explain them. All of them will be presented and discussed at this talk. [ABSTRACT FROM AUTHOR]

Aims/Purpose: To determine the presence of Interleukin 1‐beta (IL1‐β) and Transforming growth factor‐beta (TGF‐β) in the tears of neophytes contact lens wearers; and investigate the relationship between their concentration, tear stability, and ocular physiology findings. Methods: In this clinical trial, 12 neophytes (5 males, 24.0 ± 5.0 years) were dispensed with delefilcon A contact lenses. Physiological responses (bulbar and limbal hyperemia), non‐invasive tear break‐up times, and tear sample collections were obtained in the morning (before lens insertion; 9–10 a.m.) and afternoon (before lens removal; 7–8 p.m.) of the same day. The tear samples were assayed for IL1‐β and TGF‐β concentrations using Enzyme‐Linked Immunoabsorbent Assay kits. A parallel control group of 11 individuals (6 males, 25.0 ± 5.0) was also assessed to determine the levels of the biomarkers in the tears of non‐contact lens wearers. Results: Patients wore lenses for an average of 7:20 [6,9] h. Bulbar and limbal hyperemia increased throughout the day (p < 0.001). Tear break‐up times were lower in the afternoon compared to the morning assessment (4.7 ± 2.0 Vs. 12.2 ± 8.8 seconds; p < 0.001). The IL1‐β levels were higher in neophytes compared to controls (3.2 ± 4.7 Vs. 0.1 ± 0.1 ρg/ml; p = 0.05) but only in the afternoon. A significant correlation was found between IL1‐β concentration, bulbar (r = 0.405, p = 0.008), and limbal hyperemia (r = 0.499, p = 0.027) in the morning period. No substantial changes were reported for TGF‐β. Conclusions: The use of contact lenses might alter the IL1‐β regulatory mechanisms and disturb ocular surface homeostasis. However, more clinical evidence is needed to understand this phenomenon. [ABSTRACT FROM AUTHOR]

Background: Pseudomyopia is caused by increased refractive power by ciliary muscle spasm. Most patients cannot overcome pseudomyopia spontaneously; therefore, treatment of pseudomyopia is fastidious and needs a multidisciplinary approach. We report a case of unusual pseudomyopia with paradoxical accommodation, straining eyes to induce emmetropia at far distance and relaxing eyes to focus at near objects, contrary to physiological accommodation.Case Presentation: A 33-year-old woman experienced intermittent distant vision discomfort. This occurred at least a few hundred times daily. She could see near objects clearly; however, distant objects could be seen clearly only when she strained her eyes. Uncorrected distance visual acuity was 20/20 and manifest refraction (MR) in both eyes in the relaxed state was approximately - 2.5 D. MR changed to approximately - 0.5 D when she grimaced and strained her eyes when attempting to focus on distant letters. Her response was contrary to the physiological accommodative response. Cycloplegic refraction was approximately 0.0 D. Binocular autorefractor/keratometer was used to objectively evaluate her refractive response and pupil reaction according to accommodative stimulation. The IOL Master was used to evaluate the anterior chamber depth (ACD), lens thickness (LT), and pupil diameter with relaxed and strained eyes. For stepwise static accommodative stimuli (1-5 D), the refractive responses were correspondingly stepwise, similar to those elicited by healthy individuals. However, contrary to physiological accommodation, she strained her eyes to see distant objects and relaxed them to see near objects. There was no change in pupil diameter despite the accommodative stimuli being maximum. Biometry results showed that ACD deepened and LT flattened with eye strain, which were contrary to those during physiological accommodation.Conclusions: We report a rare case with reverse of physiological accommodative response. When patients complain of unusual distant visual discomfort, pseudomyopia with paradoxical accommodation should be considered. [ABSTRACT FROM AUTHOR]

Objects differ from one another along a multitude of visual features. The more distinct an object is from other objects in its surroundings, the easier it is to find it. However, it is still unknown how this distinctiveness advantage emerges in human vision. Here, we studied how visual distinctiveness signals along two feature dimensions—shape and surface texture—combine to determine the overall distinctiveness of an object in the scene. Distinctiveness scores between a target object and distractors were measured separately for shape and texture using a search task. These scores were then used to predict search times when a target differed from distractors along both shape and texture. Model comparison showed that the overall object distinctiveness was best predicted when shape and texture combined using a Euclidian metric, confirming the brain is computing independent distinctiveness scores for shape and texture and combining them to direct attention. [ABSTRACT FROM AUTHOR]

The skate retina provides a native all-rod retina suited for investigating a single type of photoreceptor regarding its properties and signaling to second order cells. Using the aspartate-induced isolated A-wave of the skate eyecup electroretinogram (ERG), it has been shown that adaptation in rods remains Weber-Fechner-like over a 6-log unit increase in background light intensity. Zinc, which can block calcium channels, has been found in the rod synaptic terminal and the synaptic cleft. Histidine is a zinc chelator. Voltage signals from neurons post-synaptic to rods indicate that histidine increases the dark release of glutamate and increases the horizontal cell light response. In histidine, the A-wave response to various light intensities in the dark-adapted retina increased more than fifty percent, corresponding to the effect on horizontal cells. In the presence of background light, although histidine-treated rod light responses remained Weber-Fechner-like, their increment threshold was raised significantly. This indicates that endogenous zinc feedback serves to increase rod sensitivity in a light-adapted retina, despite a corresponding reduction of threshold sensitivity in the dark. We propose that the increase in A-wave amplitude is a result of the increased conductance at the synaptic terminal and that the A-wave can be used to monitor changes in rod transmitter release. Furthermore, endogenous zinc may also provide the benefit of reducing metabolic stress and the risk of glutamate toxicity in the dark. [ABSTRACT FROM AUTHOR]

Purpose. This meta-analysis aimed to compare the efficacy and safety of phacoemulsification with goniosynechialysis (Phaco-GSL) with those of phacoemulsification alone (Phaco-alone) in patients with angle-closure glaucoma and cataract. Methods. Randomized controlled trials (RCTs) were selected through a search of electronic databases. Trial eligibility and risk of bias were assessed using Cochrane review methods. Primary measures included the intraocular pressure (IOP), number of antiglaucoma medications, peripheral anterior adhesion (PAS) extent, and their pre- and postoperative changes. For continuous parameters, we calculated weighted mean differences and 95% confidence intervals. Statistical analysis was performed using RevMan 5.3 software. Results. Eight RCTs were included, where 224 and 236 eyes were in the Phaco-GSL and Phaco-alone groups, respectively. Both postoperative IOP and number of medications were not significantly different between the study groups at the six- and twelve-month follow-up. However, the 12-month postoperative PAS extent was significantly smaller in the Phaco-GSL group than in the Phaco-alone group. Similarly, changes from the preoperative to 12-month postoperative PAS extent were significantly greater in the Phaco-GSL group than in the Phaco-alone group, but IOP and the number of medication changes were not different. Conclusions. Our results provide evidence that Phaco-GSL provides advantages over Phaco-alone treatment regarding PAS reduction. In terms of IOP and medication reduction, both groups were comparable. Thus, Phaco-GSL can be considered for the treatment of patients with angle-closure glaucoma and cataract due to its ease, safety, and potential benefit for the anterior chamber angle. [ABSTRACT FROM AUTHOR]

The eye is host to myriad bacterial, fungal, and viral organisms that likely influence ocular surface physiology in normal and diseased states. The ocular surface mycobiota of horses has not yet been described using NGS techniques. This study aimed to characterize the ocular surface fungal microbiota (mycobiota) in healthy horses in 2 environmental conditions (stalled versus pasture). Conjunctival swabs of both eyes were obtained from 7 adult stallions stabled in an open-air pavilion and 5 adult mares living on pasture. Genomic DNA was extracted from ocular surface swabs and sequenced using primers that target the Internal Transcribed Spacer 1 (ITS1) region of the fungal genome on an Illumina platform. Sequences were processed using Quantitative Insights Into Molecular Ecology (QIIME 2.0) and taxonomy assigned with the Findley et al. 2013 ITS1 database. The most abundant genera identified were Leptosphaerulina (22.7%), unclassified Pleosporaceae (17.3%), Cladosporium (16.2%), Alternaria (9.8%), unclassified Pleosporales (4.4%), unclassified Montagnulaceae (2.9%), Fusarium (2.5%), and Pestalotiopsis (1.4%). Fungal community composition (Jaccard, R = 0.460, p = 0.001) and structure (Bray-Curtis, R = 0.811, p = 0.001) were significantly different between pastured mares and stabled stallions. The ocular surface of pastured mares had significantly increased fungal species richness and diversity compared to stabled stallions (Shannon p = 0.0224, Chao1 p = 0.0118, Observed OTUs p = 0.0241). Relative abundances of Aspergillus (p = 0.005) and Alternaria spp. (p = 0.002) were significantly increased in the mycobiota of pastured mares. This is the first report to describe the mycobiota of the equine ocular surface. Environmental factors such as housing influence the composition, structure, and richness of the equine ocular surface mycobiota. [ABSTRACT FROM AUTHOR]

Estimates of detection and discrimination thresholds are often used to explore broad perceptual similarities between human subjects and animal models. Pupillometry shows great promise as a non-invasive, easily-deployable method of comparing human and animal thresholds. Using pupillometry, previous studies in animal models have obtained threshold estimates to simple stimuli such as pure tones, but have not explored whether similar pupil responses can be evoked by complex stimuli, what other stimulus contingencies might affect stimulus-evoked pupil responses, and if pupil responses can be modulated by experience or short-term training. In this study, we used an auditory oddball paradigm to estimate detection and discrimination thresholds across a wide range of stimuli in guinea pigs. We demonstrate that pupillometry yields reliable detection and discrimination thresholds across a range of simple (tones) and complex (conspecific vocalizations) stimuli; that pupil responses can be robustly evoked using different stimulus contingencies (low-level acoustic changes, or higher level categorical changes); and that pupil responses are modulated by short-term training. These results lay the foundation for using pupillometry as a reliable method of estimating thresholds in large experimental cohorts, and unveil the full potential of using pupillometry to explore broad similarities between humans and animal models. [ABSTRACT FROM AUTHOR]

Background: Visual functioning is often affected in persons with aphasia following stroke and other brain injuries. Characterizing the visual functioning of persons with aphasia is imperative in both clinical and research domains; however, visual functioning of persons with aphasia is infrequently assessed or described in either domain. Aims: This study aims to examine the utility of various visual screening measures and document the results of the screening tools for a cohort of persons with aphasia. Methods & Procedures: Twenty-three individuals with chronic aphasia completed a detailed vision screening using a visual case history, the Visual Activities Questionnaire, the McDowell Vision Screening Kit, an Amsler grid, the line bisection task, and the National Institutes of Health Stroke Scale item 3-visual. Outcomes & Results: Two-thirds of the participants reported significant visual histories with only one participant reporting stroke-related visual deficits. On average, the group rated visual difficulty during daily activities as never or rarely occurring, with the least difficulty reported for color discrimination and the most difficulty with visual acuity and visual search, though still only occurring rarely. All participants passed the cover/uncover screening task measuring ocular alignment and motility, the color perception screening task, and several tasks measuring ocular function. Failing scores, however, were assigned for about half of the participants for distance visual acuity, and only three participants for near visual acuity. Visual fields were normal for about two-thirds of the participants and all participants presented with normal visual attention. Conclusions: The results suggest that visual deficits are common in persons with aphasia, but are not necessarily related to the stroke that the person experienced. The results highlight the need to screen the vision of persons with aphasia both for clinical purposes and research protocols to ensure visual deficits are treated, compensated for, or controlled. [ABSTRACT FROM AUTHOR]

The lid margins are essential to maintain a healthy tear film and distribute it over the ocular surface to achieve an optimal refractive interface. Alterations in the lid margin structures and function may lead to significant ocular surface problems. Meibomian gland dysfunction is usually attributed to be the most common reason for ocular surface disease. However, the lid margin disease cannot be fully understood and adequately addressed if the function of the meibomian glands is not evaluated in relation to other lid margin structures. This review aims to emphasize that the lid margin requires a full assessment in order to address ocular surface diseases associated with lid margin disease. The different zones of the lid margin and their roles in the maintenance of ocular surface health are delineated. Alterations in the lid margin structures due to increasing age or underlying etiology and their potential impact are discussed. If structural abnormalities are not recognized and properly addressed, the treatment of meibomian gland dysfunction will likely fail. Future studies focusing on the underlying etiology of structural alterations will hopefully lead to the development of more effective therapeutic options. [ABSTRACT FROM AUTHOR]

Purpose. To investigate the difference between the eyes from the same human with respect to the biomechanical properties of fresh corneal tissues and investigate the assumption of similarity of the corneal biomechanical properties between the eyes. Methods. Strip specimens extracted through a small incision lenticule extraction (SMILE) surgery were tested using a uniaxial tensile test. The specimens were extracted vertically. Low-strain tangent modulus (LSTM), high-strain tangent modulus (HSTM), and tensile strength ( σ b ) were the biomechanical parameters used in the comparison of the eyes from the same human. Results. Ninety corneal specimens from 45 persons were included in this study. The LSTM of the left and right eyes were 1.34 ± 0.52 and 1.37 ± 0.46 MPa, while the HSTM were 50.53 ± 7.51 and 49.41 ± 7.01 MPa, respectively. There was no significant difference between the eyes in terms of LSTM, HSTM, and σ b P = 0.813 , 0.335 , and 0.605 , resp. . The LSTM and HSTM were significantly correlated with the spherical equivalent (SE) (P ≤ 0.01 , P = 0.001 , resp.). Conclusions. The assumption that the corneal biomechanical properties of the eyes from the same human are similar has been confirmed for the first time using fresh human corneal tissue. This finding may be useful in further biomechanical studies. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to investigate the extent to which the lexical tone can affect spoken-word recognition in Chinese using a printed-word paradigm. Participants were presented with a visual display of four words—namely, a target word (e.g., 象限, xiang4xian4, "quadrant"), a tone-consistent phonological competitor (e.g., 相册, xiang4ce4, "photo album"), or a tone-inconsistent phonological competitor (e.g., 香菜, xiang1cai4, "coriander"), and two unrelated distractors. Simultaneously, they were asked to listen to a spoken target word presented in isolation (Experiment 1) or embedded in neutral/predictive sentence contexts (Experiment 2), and then click on the target word on the screen. Results showed significant phonological competitor effects (i.e., the fixation proportion on the phonological competitor was higher than that on the distractors) under both tone conditions. Specifically, a larger phonological competitor effect was observed in the tone-consistent condition than in the tone-inconsistent condition when the spoken word was presented in isolation and the neutral sentence contexts. This finding suggests a partial role of lexical tone in constraining spoken-word recognition. However, when embedded in a predictive sentence context, the phonological competitor effect was only observed in the tone-consistent condition and absent in the tone-inconsistent condition. This result indicates that the predictive sentence context can strengthen the role of lexical tone. [ABSTRACT FROM AUTHOR]

To assess the mediating role of strength levels, hand dominance and participants´ sex on the intraocular pressure (IOP) behaviour during the execution of a maximal isometric handgrip test. One hundred and seventy-six sport science students (102 men and 74 women) performed a maximal isometric handgrip test with the dominant and non-dominant hands. A rebound tonometer was used to measure IOP before effort, during effort, and immediately after performing the handgrip test. Men and women were divided based on their handgrip strength in low- and high-strength groups using a median split analysis. There was an acute IOP rise during effort, returning to baseline levels immediately after exercise cessation (P <.001, ηp2 = 0.79). A greater increase in IOP during the execution of the handgrip test was observed for the dominant-hand compared to the non-dominant hand (P =.004, d = 0.30) and for men compared to women (P =.001, d = 0.90). The main effect of strength level did not reach statistical significance (P =.266). The IOP rise associated with a maximal isometric handgrip effort is affected by the participants´ sex (men > women) and hand dominance (dominant hand > non-dominant hand), but not on strength levels. These findings need to be corroborated in glaucoma patients. [ABSTRACT FROM AUTHOR]

Cerebral visual impairment is amongst the key pathological causes of pediatric visual abnormalities often resulted from hypoxic-ischemic brain injury. Such an injury results in profound visual impairments which severely impairs patients' quality of life. Given the nature of the pathology, treatments are currently limited to rehabilitation strategies such as transcranial electrical stimulation and visual rehabilitation therapy. Here, we discussed an 11-year-old girl with cerebral visual impairment who underwent concurrent visual rehabilitation therapy, transcranial electrical stimulation, and pharmacological therapy resulting in her improved visual function. Given its beneficial effects, transcranial electrical stimulation may be sought as a potential add-on modality when strategizing visual rehabilitation therapy. [ABSTRACT FROM AUTHOR]

New Findings: What is the topic of this review?This review describes the effect of extreme environments on the visual system.What advances does it highlight?The review highlights the way in which environmental stressors affect the eye and vision, both directly and indirectly. Much is known about the physiology and anatomy of the eye. Much less is known about the impact of different environments on the eye, and yet it is the pathophysiology that results from this interaction that is often the precursor to disaster. The present review focuses on the effect of different extreme environments on the visual system; in particular, the way in which such environments affect the sensory mechanism of that system. [ABSTRACT FROM AUTHOR]

Background: The purpose of this research was to investigate the diurnal effect of Ramadan fasting on the amplitude of accommodation and anterior segment parameters in visually healthy participants. Materials and Methods: The study included 68 healthy individuals, aged 26--42 years. The subjective accommodation amplitude was measured using the "minus lens" technique. Corneal refraction (K1, K2, and Kmax), central corneal thickness, corneal volume, anterior chamber volume, and anterior chamber depth parameters were evaluated using the Scheimpflug camera system. Participants were evaluated twice, at 08:00 and 16:00, while fasting during Ramadan. Data were analyzed by paired sample t-test. Results: The mean age of the participants, of which 28 were women and 40 were men, was 34.38±4.93 (range: 26--42). Comparison of measurements taken at 08:00 and 16:00 during fasting showed that at 16:00, the K1 values (08:00: 42.81±1.51 diopter and 16:00: 42.85±1.50 diopter, P = 0.016) and Kmax values (08:00: 44.29 ± 1.73 diopter and 16:00: 44.38±1.78 diopter, P = 0.020) were significantly steeper. When data collected at 08.00 and 16.00 were compared, there were no significant differences in diurnal changes: amplitude of accommodation (08:00: 7.39±1.40 diopter and 16:00: 7.37±1.40 diopter, P = 0.783), central corneal thickness (08:00: 535.60 ± 30.43 µm and 16:00: 535.25±30.66 µm, P = 0.694), corneal volume (08:00: 59.72±3.85 mm3 and 16:00: 59.60±3.98 mm3, P= 0.344), anterior chamber volume (08.00: 170.91±30.77 mm3 and 16.00: 171.22±32.61 mm3, P = 0.808) and anterior chamber depth (08:00: 2.91 ± 0.28 mm and 16:00: 2.92 ± 0.29 mm, P = 0.053). Conclusions: The results showed that dehydration due to fasting affects some anterior segment parameters, such as corneal refraction; however, it does not affect the diurnal changes of amplitude of accommodation, corneal pachymetry, or anterior chamber anatomy. [ABSTRACT FROM AUTHOR]

To calibrate stereoscopic depth from disparity our visual system must compensate for an object's egocentric location. Ideally, the perceived three-dimensional shape and size of objects in visual space should be invariant with their location such that rigid objects have a consistent identity and shape. These percepts should be accurate enough to support both perceptual judgments and visually-guided interaction. This theoretical note reviews the relationship of stereoscopic depth constancy to the geometry of stereoscopic space and seemingly esoteric concepts like the horopter. We argue that to encompass the full scope of stereoscopic depth constancy, researchers need to consider not just distance but also direction, that is 3D egocentric location in space. Judgements of surface orientation need to take into account the shape of the horopter and the computation of metric depth (when tasks depend on it) must compensate for direction as well as distance to calibrate disparities. We show that the concept of the horopter underlies these considerations and that the relationship between depth constancy and the horopter should be more explicit in the literature. [ABSTRACT FROM AUTHOR]

Eyes with the corneal ectasia keratoconus have performed better than expected (e.g. visual acuity) given their elevated levels of higher-order aberrations that cause rotationally asymmetric retinal blur. Adapted neural processing has been suggested as an explanation but has not been measured across multiple meridional orientations. Using a custom Maxwellian-view laser interferometer to bypass ocular optics, sinusoidal grating neural contrast sensitivity was measured in six eyes (three subjects) with keratoconus and four typical eyes (two subjects) at six spatial frequencies and eight orientations using a two-interval forced-choice paradigm. Total measurement duration was 24 to 28 hours per subject. Neural contrast sensitivity functions of typical eyes agreed with literature and generally showed the oblique effect on a linear-scale and rotational symmetry on a log-scale (rotational symmetry was quantified as the ratio of the minor and major radii of an ellipse fit to all orientations within each spatial frequency; typical eye mean 0.93, median 0.93; where a circle = 1). Mean sensitivities of eyes with keratoconus were 20% to 60% lower (at lower and higher spatial frequencies respectively) than typical eyes. Orientation-specific neural contrast sensitivity functions in keratoconus showed substantial rotational asymmetry (ellipse radii ratio: mean 0.84; median 0.86) and large meridional reductions. The visual image quality metric VSX was used with a permutation test to combine the asymmetric optical aberrations of the eyes with keratoconus and their measured asymmetric neural functions, which illustrated how the neural sensitivities generally mitigated the detrimental effects of the optics. [ABSTRACT FROM AUTHOR]

Background: Studies (particularly, optical coherence tomography angiography (OCTA) studies) on the peripheral microvascular bed in health are important because many retinal disorders involve its injury. Purpose: To improve the efficacy of diagnosing the changes in the retinal microvascular bed through its OCTA-based assessment at the zones ranging from the fovea to the periphery in normal eyes. Material and Methods: Fourteen healthy individuals were included in the study. Three sequential 3 mm x 3 mm OCTA scans with displacement from the center of the fovea to the periphery for each of the three directions (superior, inferior and temporal directions) were registered. Results: Superficial plexus vessel density and deep plexus vessel density were assessed at 1-9 mm from the center of the fovea. We found that superficial plexus vessel density progressively increased (38-46%) with distance from the center of the fovea, whereas deep plexus vessel density moderately decreased (18-25%) with distance from the center. Superficial plexus vessel density was significantly increased in the superior and inferior directions at the zones with the presence of vascular arcades, and these arcades are absent in the temporal direction; this makes the temporal direction most reliable and promising for studies on microcirculation at the ocular periphery. Conclusion: OCTA is an effective technique for assessing the retinal microvascular bed at the zones ranging from the fovea to the far periphery. [ABSTRACT FROM AUTHOR]

Purpose. This study investigated how a conscious change in ocular accommodation affects intraocular pressure (IOP) and ocular biometrics in healthy adult volunteers of different ages. Methods. Thirty-five healthy volunteers without ocular disease or past ocular surgery, and with refractive error between −3.50 and +2.50 diopters, were stratified into 20, 40, and 60 year old (y.o.) age groups. Baseline measurements of central cornea thickness, anterior chamber depth, anterior chamber angle, cornea diameter, pupil size, and ciliary muscle thickness were made by autorefraction and optical coherence tomography (OCT), while IOP was measured by pneumotonometry. Each subject's right eye focused on a target 40 cm away. Three different tests were performed in random order: (1) 10 minutes of nonaccommodation (gazing at the target through lenses that allowed clear vision without accommodating), (2) 10 minutes of accommodation (addition of a minus 3 diopter lens), and (3) 10 minutes of alternating between accommodation and nonaccommodation (1-minute intervals). IOP was measured immediately after each test. A 20-minute rest period was provided between tests. Data from 31 subjects were included in the study. ANOVA and paired t-tests were used for statistical analyses. Results. Following alternating accommodation, IOP decreased by 0.7 mmHg in the right eye when all age groups were combined (p = 0.029). Accommodation or nonaccommodation alone did not decrease IOP. Compared to the 20 y.o. group, the 60 y.o. group had a thicker ciliary muscle within 75 μm of the scleral spur, a thinner ciliary muscle at 125–300 μm from the scleral spur, narrower anterior chamber angles, shallower anterior chambers, and smaller pupils during accommodation and nonaccommodation (p 's < 0.01). Conclusion. Alternating accommodation, but not constant accommodation, significantly decreased IOP. This effect was not lost with aging despite physical changes to the aging eye. A greater accommodative workload and/or longer test period may improve the effect. [ABSTRACT FROM AUTHOR]

Purpose. To investigate the effects of chewing gum and tablet candy to reduce eyestrain in healthy individuals. Materials and Methods. A double-blinded crossover trial was conducted. Forty-six healthy individuals (23 men, 23 women) between 20 and 59 years old, feeling eyestrain, were enrolled. Each 10-year age group included 12 individuals except the 30s group, which included 10 individuals. A visual task was performed on reading material displayed on a computer screen at a fixed distance for 60 min. Gum or tablet candy of two pieces were chewed for two 15-min periods starting 15 and 45 min after starting to read. Subjects chewed gum on Day 1 and tablet candy on Day 2, and vice versa. Primary outcome is as follows: subjective eye fatigue (eye tiredness, eye heaviness, blurred vision, double vision, and eye dryness) using a visual analog scale (VAS). Secondary outcomes are as follows: subjective accommodation from near and far points of accommodation measured with a D'ACOMO, spherical equivalent refraction, and eye dryness by analyzing ring break-up time (RBUT) measured with the RT-7000 Auto Ref-Topographer. Results. The VAS scores of subjective eye fatigue were not significantly changed between chewing gum and tablet candy (P = 0.397 - P = 0.909). Those scores of eye tiredness and eye heaviness were significantly longer before and after the visual task with tablet candy (P = 0.013 and P = 0.025 , respectively) but not with chewing gum. The changes of subjective accommodation were significantly lower after the visual task between chewing gum and candy (P = 0.043). There were significant differences among each age group (20 s vs. 30 s, P = 0.594 ; 20 s vs. 40 s, P = 0.002 ; 20 s vs. 50 s, P = 0.002). After reading, the changes of spherical equivalent refraction did not indicate a shift toward myopia (P = 0.267). In the RBUT, there were no significant differences between the samples (P = 0.680). Conclusions. Chewing gum helps improve the ability of the eye to focus, especially in young adults. [ABSTRACT FROM AUTHOR]

Objectives: Heart, lens, and neuronal cells change significantly with age, and they are older than cells from renewable tissues. Near vision deterioration during aging results from a decrease in accommodation amplitude (AA). Cardiac aging is an independent risk factor for cardiovascular disease. We investigated the association between cardiac aging and AA.Methods: The subjects (500 mean 50-year-old subjects, with equal males and females) were divided into two groups according to AA measured with a Raf ruler. Biomicroscopy was used to capture images of the lens nucleus in the unaccommodated and accommodated state. The nucleus diameter change at 1 D accommodation was measured using ImageJ. Cardiac conduction system differences were evaluated using electrocardiography, and cardiac autonomic aging was assessed based on heart rate variability. Myocardial aging was assessed based on diastolic dysfunction.Results: For near distance vision, compared to subjects who could see clearly from 24 to 28 cm, subjects who could see clearly from 29 to 33 cm had a 2.104-fold higher risk of a lateral e' velocity <10 cm/s [95%CI: 1.312-3.374], 2.603-fold higher risk of diastolic dysfunction [95%CI: 1.453-4.662], 1.54-fold higher risk of a low/high frequency ratio >3.1 [95%CI: 1.085-2.197].Conclusions: As a simple screening test, subjective AA measurement can predict important heart aging parameters, including diastolic dysfunction.Clinicaltrials.gov Registry No: NCT04362215. [ABSTRACT FROM AUTHOR]

While fibroblasts constitute the main cell component of the sclera, the purpose of the present study was to investigate the cell densities of melanocytes at different regions of the sclera, and to compare them with associated scleral fibroblast densities in human donor eye sections.. Paraffin-embedded sections of sclera from 21 human eyes were stained with hematoxylin-eosin (H&E) and immunohistochemical staining (S-100/AEC). Scleral melanocyte and fibroblast numbers were counted in different regions of the sclera. The relationship between the melanocyte density and iris pigmentation was also analyzed.. Melanocytes were found in the posterior region of the sclera, especially around the vessels and nerves in emmissarial canals, whereas no or rare melanocytes were found in equatorial and anterior regions. In H&E sections, melanocyte densities in eyes with light-colored irides were significantly less than in eyes with medium or dark-colored irides (P <.05). In S-100-stained sections, more melanocytes could be detected than those in the H&E sections in light-colored eyes (P <.05), but not in medium or dark-colored eyes (P >.05). The numbers of scleral fibroblasts were relatively stable in different regions. In the posterior scleral region, the numbers of fibroblasts were slightly higher than the number of melanocytes, however, this differences were not statistically significant (P >.05).. Notable numbers of melanocytes were present in the posterior sclera suggesting that these cells may play a role in ocular physiology and in the pathogenesis of various disorders of the sclera. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate perceptual eye position (PEP) and to evaluate the effect of dichoptic visual perceptual training in postoperative intermittent exotropia [X(T)]. We enrolled 30 non-strabismus children (control group) and 54 postoperative X(T) children [divided into training group (33 patients) and non-training group (21 patients)]. All subjects received measurements of PEP, and the postoperative X(T) children were measured both in the third postoperative day and the third postoperative month. All patients in training group received 3-month dichoptic visual perceptual training based on a unique virtual reality platform. The results showed that the postoperative X(T) children with normal eye position still had an abnormal PEP. After a period of visual perceptual training, the PEP pixels in postoperative children dramatically decreased. The results revealed that PEP could evaluate fixation disparity and binocular visual function perceptively and precisely, and the dichoptic visual perceptive training may rebuild binocular visual function. [ABSTRACT FROM AUTHOR]

The environment and the physiological conditions play a vital role in the thermal processes in the human tissues, such as the multi-layered human-eye. In this work, a mathematical model of the human eye concerning the change in blood perfusion, porosity, evaporation rate, and ambient temperatures has been formulated based on non-Fourier heat conduction law with appropriate boundary and interface conditions. A direct method and MAPLE 17 software was used to get the numerical solution, and the results have been shown in figures. The temperature distribution based on various values of the relaxation times parameters has been discussed first to stand on its effect on the value of the temperature in each layer of the human eye. The impact of the blood perfusion, porosity, evaporation rate, time, and ambient temperatures have been discussed; they have significant effects on the thermal wave passing through the human eye layers. For validity, the results of this model have agreed with the results of some other works. [ABSTRACT FROM AUTHOR]

The present natural preference study investigated infants 4 and 7 months of age for their ability to respond to phantom contoubrs, illusory surfaces generated by half‐occlusions in a stereoscopic display consisting of a pair of parallel vertical lines. The left line in the half‐image for the right eye and the right line in the half‐image for the left eye have a gap in the middle. The visual system accounts for the binocular unmatched gaps by perceiving an illusory contour. Infants in the experimental condition were presented with a standard phantom stereogram displaying a phantom contour versus a non‐standard phantom stereogram, the half‐images of which were exchanged. This stereogram evokes the impression of two small separate illusory contours. In both stereograms, the gaps moved up and down. The participants aged 7 but not 4 months preferred looking at the standard phantom stereogram. A control condition supported the hypothesis that the infants 7 months of age in the experimental condition indeed responded to the coherent illusory surface instead of simply detecting differences in the geometric arrangement of the half‐occlusions. The results hence indicate that infants are able to extract spatial information from monocular regions in a binocular display. [ABSTRACT FROM AUTHOR]

Background: The degree of alpha attenuation from eyes-closed (EC) to eyes-open (EO) has been suggested as a neural marker of cognitive health, and its disruption has been reported in patients with clinically defined Alzheimer's disease (AD) dementia.Objective: We tested if EC-to-EO alpha reactivity was related to cerebral amyloid-β (Aβ) deposition during the early stage of AD.Methods: Non-demented participants aged ≥55 years who visited the memory clinic between March 2018 and June 2019 (N = 143; 67.8% female; mean age±standard deviation, 74.0±7.6 years) were included in the analyses. Based on the [18F]florbetaben positron emission tomography assessment, the participants were divided into Aβ+ (N = 70) and Aβ- (N = 73) groups. EEG was recorded during the 7 min EC condition followed by a 3 min EO phase, and a Fourier transform spectral analysis was performed.Results: A significant three-way interaction was detected among Aβ positivity, eye condition, and the laterality factor on alpha-band power after adjusting for age, sex, educational years, global cognition, depression, medication use, and white matter hyperintensities on magnetic resonance imaging (F = 5.987, p = 0.016); EC-to-EO alpha reactivity in the left hemisphere was significantly reduced in Aβ+ subjects without dementia compared with the others (F = 3.984, p = 0.048).Conclusion: Among mild cognitive impairment subjects, alpha reactivity additively contributed to predict cerebral Aβ positivity beyond the clinical predictors, including vascular risks, impaired memory function, and apolipoprotein E ɛ4. These findings support that EC-to-EO alpha reactivity acts as an early biomarker of cerebral Aβ deposition and is a useful measurement for screening early-stage AD. [ABSTRACT FROM AUTHOR]

Purpose: To establish the optimum grading increment which ensured parity between practitioners while maximising clinical precision.Methods: Second year optometry students (n = 127, 19.5 ± 1.4 years, 55 % female) and qualified eye care practitioners (n = 61, 40.2 ± 14.8 years, 52 % female) had 30 s to grade each of bulbar, limbal and palpebral hyperaemia of the upper lid of 4 patients imaged live with a digital slit lamp under 16× magnification, diffuse illumination, with the image projected on a screen. The patients were presented in a randomised sequence 3 times in succession, during which the graders used the Efron printed grading scale once to the nearest 0.1 increment, once to nearest 0.5 increment and once to the nearest integer grade in a randomised order. Graders were masked to their previous responses.Results: For most grading conditions less than 20 % of clinicians showed a ≤0.1 difference in grade from the mean. In contrast, more than 50 % of the student graders and 40 % of experienced graders showed a difference in grade from the mean within 0.5 for all conditions under measurement. Student precision in grading was better with both 0.1 and 0.5 grading increments than grading to the nearest unit, except for limbal hyperaemia where they performed more accurately with 0.5 unit increment grading. Limbal grading precision was not affected by grading step increment for experienced practitioners, but 0.1 and 0.5 grading increments were both better than the 1.0 grading increment for bulbar hyperaemia and the 0.1 grading increment was better than the 0.5 grading increment and both were better than the 1.0 grading increment for palpebral hyperaemia.Conclusion: Although narrower interval scales maximise the ability to detect smaller clinical changes, the grading increment should not exceed one standard deviation of the discrepancy between measurements. Therefore, 0.5 grading increments are recommended for subjective anterior eye physiology grading (limbal, bulbar and palpebral redness). [ABSTRACT FROM AUTHOR]

Purpose: Accommodative micro-fluctuations (AMF) are small dioptric changes during accommodation. The aim of this study was to evaluate and compare changes in AMF when wearing silicone hydrogel contact lenses of two different optical designs.Methods: A multi-centre, randomised, cross-over, non-dispensing study was conducted on 68 adapted contact lens wearers aged 25-35 years to compare AMF responses to a spherical and aspheric silicone hydrogel (comfilcon A) lens designs. A Righton Speedy "i" series Auto Refractometer in accommodation analyser mode was utilized before and after reading a standard text in font size 8 on an iPhone 5 for 20 min at a 25 cm viewing distance. Phone screen brightness was set by automatic adjustment mode and ambient illumination was controlled at all sites.Results: Mean ± SD AMF change from before to after the reading task was 2.25 ± 5.6 and 0.13 ± 5.7 (relative values) for the spherical and aspheric lens designs, respectively. The difference was statistically significant (P = 0.017, Paired t-test).Conclusions: The smaller change in AMF when using an aspheric lens design suggests reduced ciliary muscle stress when reading print on a smart phone at a close distance for short periods (20 min). Contact lens wearers who frequently use digital devices and are experiencing eye strain may benefit from switching from a spherical design to one that incorporates aspheric optics. [ABSTRACT FROM AUTHOR]

• Solubility of dexamethasone in the polymeric solution was increased by 5.2-fold. • The thermogel solution form a rigid gel at physiological temperature at eyes. • Dexamethasone was released in a sustained manner from the thermogel over 28 days. • Subconjunctivally injected DEX-thermogel could suppress the CNV development. Challenges of ophthalmic drug delivery arise not only from the limited solubility of hydrophobic therapeutics, but also the restricted permeability and fast clearance of drugs due to the complex anatomy and physiology of eyes. Excellent biocompatibility of a thermosensitive polymer, PLGA-PEG-PLGA (1800–1500–1800, LA:GA ratio = 3:1), as an ophthalmic delivery system was demonstrated in our previous work. In this study, delivery of dexamethasone using this thermogel via a single subconjunctival injection for prolonged treatment was evaluated with corneal neovascularization using an alkali-burn diseased model in rat. Solubility of dexamethasone in the polymeric solution was increased by 5.2-fold and the resulting drug-loaded solution formed in situ rigid gel at body temperature. Prolonged in vitro release of dexamethasone from the gel structure was noted. Dexamethasone gel formulation was demonstrated to be more effective in reducing the burn stimulus and neovascularization in the rat diseased model. The findings suggest the PLGA-PEG-PLGA in situ gelling system can be applied for ophthalmic drug delivery to achieve sustained drug release and improved efficacy. [ABSTRACT FROM AUTHOR]

Binocular rivalry is the phenomenon that when two incompatible images are simultaneously presented, one to each eye, the two images compete with each other to be the dominant percept. Studying the underlying neural mechanisms of binocular rivalry is useful for understanding the mechanisms of interocular inhibition. Levelt's Propositions, a set of four propositions that were originally published over fifty years ago, are not only useful for characterizing the perceptual dynamics of binocular rivalry, but can also provide a metric for assessing the common or differential neural mechanisms of binocular rivalry when diverse stimulus types are used. In the present study, we conducted a series of psychophysics experiments, where we compared the rivalry dynamics of two quite different types of stimuli. Orthogonal gratings, a classic type of rivalry stimulus, were contrasted with luminance patches, a type of rivalry stimulus that is relatively less studied. Our results showed that, similar to the orthogonal gratings, the alternate percepts in luminance-only rivalry were described by the modified Levelt's Propositions, despite the clearly slower alternation rates for luminance patches. However, unlike the mixed percepts observed during transitions between oriented gratings, fusion percepts during luminance rivalry were common, could be lustrous, and obeyed the same Propositions, suggesting a regime of tri-stability. Overall, both types of rivalry are consistent with recent models that posit separate binocular and monocular channels embedded within neural circuits that also accomplish contrast normalization. Finally, luminance rivalry is discussed in the contexts of binocular summation and suppression, as well as Fechner's paradox. [ABSTRACT FROM AUTHOR]

Individuals with attention deficit hyperactivity disorder (ADHD) frequently exhibit different types of visual deficits. This study investigates the dynamics of ocular accommodation and pupil size in a population of children with ADHD (6-14 years old) and assesses the association between these ocular variables with behavioural performance during a continuous performance task. The accommodation and pupil dynamics (magnitude and variability) were objectively measured, using the WAM-5500 auto-refractor, during the execution of a ~14-min continuous performance task in a sample of twenty-three non-medicated children with ADHD and thirty-one controls of a similar age range. Our data revealed that children with ADHD present a reduced accommodative response (higher lags of accommodation) during the execution of a continuous performance task. However, no group-differences were observed for the other ocular indices. Both groups experienced changes in all ocular variables as a function of time-on-task. The variability of accommodation and pupil diameter were associated with several indicators of behavioural performance for the ADHD group. However, no bivariate correlations were found for the control group. The current outcomes suggest that the accommodation and pupil dynamics may be considered as potential predictors of behavioural performance, which could help to improve the robustness of ADHD diagnosis. [ABSTRACT FROM AUTHOR]