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Background/aims To quantify the longitudinal changes of the macular microvasculature and the foveal avascular zone (FAZ) parameters in patients recovered from coronavirus disease-2019 (COVID-19) using optical coherence tomography angiography (OCTA) analysis. Methods This observational, longitudinal study was performed on patients recovered from COVID-19. The OCTA images were recorded at baseline and after 1 and 3 months at the follow-up examination. Vessel density (VD) of the retinal superficial (SCP) and deep capillary plexus (DCP), as well as the area of the FAZ of patients who had recovered from COVID-19, were measured. Results In total, 36 eyes of 18 patients (62.2% female) with a mean age of 34.5 ± 7.5 years old were included. Regarding SCP, while the VDs of the whole image, fovea, and parafovea were comparable at different time points, the mean VDs in inferior hemifield, as well as superior and inferior regions of perifovea, underwent significant reductions at month 3, compared to the baseline. In DCP, the mean of VD in the whole image was 54.3 ± 2.7 at the first visit which significantly decreased to 52.1 ± 3.8(P = 0.003) and 51.4 ± 2.7(P = 0.001) after 1 and 3 months, respectively. The VDs in all regions of parafovea and perifovea revealed a significant reduction after 1 and 3 months, compared to the first visit. The mean FAZ area was 0.27 ± 0.08 mm2, 0.26 ± 0.08 mm2, and 0.27 ± 0.08 mm2 at the baseline, month 1, and month 3, respectively (P > 0.05). Conclusion Based on the results, the patients who had recovered from COVID-19 had a progressive decrease of VD at the follow-up visit 3 months after COVID-19 infection.

Much of the evidence for morphological decomposition accounts of complex word identification has relied on the masked-priming paradigm. However, morphologically complex words are typically encountered in sentence contexts and processing begins before a word is fixated, when it is in the parafovea. To evaluate whether the single word-identification data generalize to natural reading, Experiment 1 investigated the contribution of morphological structure to the very earliest stages of lexical processing indexed by preview effects during sentence reading in the gaze-contingent boundary paradigm. Preview conditions systematically assessed the impact of prefixed and suffixed nonword previews that manipulated stem and affix overlap, and affix status, against an orthographically legal control baseline. Initial fixations on suffixed target words showed a preview benefit from nonwords that combined the target stem with a legitimate affix, but not with a nonaffix, whereas prefixed targets only benefited from an identical preview. When presented in a masked prime lexical-decision task in Experiment 2, the same stimuli yielded equivalent stem priming from suffixed and prefixed primes regardless of affix status, consistent with previous masked priming studies using similar nonword primes. The early effects of morphological structure selectively observed on parafoveal processing of suffixed words are inconsistent with recent nonmorphological, position-invariant accounts of embedded stem activation. These results provide the first evidence of morphological parafoveal processing in English and contribute to recent evidence that readers extract a higher level of information from the parafovea during natural reading than was previously assumed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Purpose: To examine the quantitative measurements of OCTA in children with amblyopia using the meta-analysis methodology.Methods: PubMed, Embase, and Cochrane library were searched for available papers up to March 2021. Weighted mean differences (WMD) were used to compare the retina parameters between the eyes with amblyopia and the contralateral eyes or healthy control eyes.Results: Twelve studies were included. When considering the parafovea, the microvessel density was reduced in amblyopic eyes compared with healthy control eyes in the superficial capillary plexus (SCP) in 6 × 6 volume scan (WMD = −2.12, 95%CI: −3.24, −0.99) but not SCP in 3 × 3 volume scan (WMD = −1.43, 95%CI: −2.96, 0.11). In the deep capillary plexus (DCP), amblyopia did not decrease vessel density in the 6 × 6 volume scan (WMD = −2.22, 95%CI: −5.86, 1.42; I2 = 79.6%, P = 0.008), but a difference was observed in the whole eye 3 × 3 (WMD = −1.95, 95%CI: −3.23, −0.67; I2 = 27.5%, P = 0.252). There were no significant differences in the foveal avascular zone area and foveal thickness between amblyopic eyes and healthy control eyes. There were no significant differences in microvessel density, foveal avascular zone area, and foveal thickness between amblyopic eyes and fellow eyes.Conclusion: According to OCTA, amblyopic eyes had lower vessel density in parafoveal SCP and DCP compared with healthy control eyes, but not compared with fellow eyes. There were no significant differences regarding the foveal avascular zone area and foveal thickness between amblyopic and non-amblyopic eyes.

Summary The human visual system has a high-resolution fovea and a low-resolution periphery. When actively searching for a target, humans perform a covert search during each fixation, and then shift fixation (the fovea) to probable target locations. Previous studies of covert search under carefully controlled conditions provide strong evidence that for simple and small search displays, humans process all potential target locations with the same efficiency that they process those locations when individually cued on each trial. Here, we extend these studies to the case of large displays, in which the target can appear anywhere within the display. These more natural conditions reveal an attentional effect in which sensitivity in the fovea and parafovea is greatly diminished. We show that this "foveal neglect" is the expected consequence of efficiently allocating a fixed total attentional sensitivity gain across the retinotopic map in the visual cortex. We present a formal theory that explains our findings and the previous findings.

SIGNIFICANCE: Contrast sensitivity changes across the visual field with age and is often measured clinically with various forms of perimetry on plain backgrounds. In daily life, the visual scene is more complicated, and therefore, the standard clinical measures of contrast sensitivity may not predict a patient's visual experience in more natural environments. PURPOSE: This study aims to determine whether contrast thresholds in older adults are different from younger adults when measured on a 1/f noise background (a nonuniform background whose spatial frequency content is similar to those present in the natural vision environments). METHODS: Twenty younger (age range, 20 to 35 years) and 20 older adults (age range, 61 to 79 years) with normal ocular health were recruited. Contrast thresholds were measured for a Gabor patch of 6 cycles per degree (sine wave grating masked by a Gaussian envelope of standard deviation 0.17°) presented on 1/f noise background (root-mean-square contrast, 0.05 and 0.20) that subtended 15° diameter of the central visual field. The stimulus was presented at four eccentricities (0°, 2°, 4°, and 6°) along the 45° meridian in the noise background, and nine contrast levels were tested at each eccentricity. The proportion of correct responses for detecting the target at each eccentricity was obtained, and psychometric functions were fit to estimate the contrast threshold. RESULTS: Older adults demonstrate increased contrast thresholds compared with younger adults. There was an eccentricity-dependent interaction with age, with the difference between groups being highest in the fovea compared with other eccentricities. Performance was similar for the two noise backgrounds tested. CONCLUSIONS: Our results revealed a strong eccentricity dependence in performance between older and younger adults, highlighting age-related differences in the contrast detection mechanisms between fovea and parafovea for stimuli presented on nonuniform backgrounds.

Purpose: To evaluate the effect of the weight loss, 3 months after bariatric surgery on the macular thickness and macular vascular density by optical coherence tomography angiography (OCTA).Methods: Forty obese patients were included in this prospective study. Body mass index (BMI), macular thickness (whole, fovea, parafovea and perifovea), macular vascular density (VD) in superficial capillary plexus (whole, fovea, parafovea and perifovea), and macular vascular density in deep capillary plexus (whole, fovea, parafovea and perifovea) were measured before and 3 months after bariatric surgery.Results: The BMI was significantly reduced postoperatively to 43.75±4.4 kg/m2 compared to the preoperative results 55.31±5.1 kg/m2 (p). There was significant increase in the macular thickness in the fovea and parafovea postoperatively (p ), but was not significant in the perifovea. There was significant increase in the macular vascular density in the deep capillary plexus postoperatively (p), but, there was no significant increase in the macular vascular density in the superficial capillary plexus postoperatively (p = 0.4). Significant correlations were detected between the BMI changes and changes in different macular parameters.Conclusion: Bariatric surgery showed significant effect on certain indices in the macular thickness and macular vascular density especially in the deep capillary plexus. Therefore, OCTA is considered a valuable tool to assess the short term changes in the macular microcirculation following significant weight reduction.

The aim of the study was to assess the relationship between hypertensive target organ damage and vessel density (VD), foveal thickness, thickness of retinal nerve fiber layer, ganglion cell complex, and foveal avascular zone (FAZ) using optical coherence tomography angiography in a nonselected group of hypertensive children. One hundred fifty-seven children (56 girls) in mean age 14.9±2.9 years, in whom arterial hypertension was ultimately diagnosed were included in the study. FAZ, whole, fovea, parafovea superficial VD, whole, fovea, parafovea deep VD, foveal thickness, retinal nerve fiber layer, and ganglion cell complex were taken into analysis. Both absolute and standardized values of carotid intima-media thickness correlated with the larger FAZ area ( P =0.035, r =0.17; P =0.01, r =0.2, respectively). Subjects with increased carotid intima-media thickness had significantly larger FAZ ( P =0.024), reduced fovea superficial VD ( P =0.039), and foveal thickness ( P =0.007). Left ventricular hypertrophy and increased carotid-femoral pulse wave velocity were not associated with optical coherence tomography angiography parameters. Multiple linear regression revealed that the only determinant of FAZ and foveal thickness was higher carotid intima-media thickness–SD score, and for fovea superficial VD, the only determinant was central systolic blood pressure. In conclusion, hypertensive children present with signs of remodeling of microcirculation and decreased neural layer of retina associated with hypertensive macrocirculation remodeling expressed as increased carotid intima-media thickness and elevated central systolic blood pressure.

Although previous research has demonstrated that for adults external letters of words are more important than internal letters for lexical processing during reading, no comparable research has been conducted with children. This experiment explored, using the boundary paradigm during silent sentence reading, whether parafoveal pre-processing in English is more affected by the manipulation of external letters or internal letters, and whether this differs between skilled adult and beginner child readers. Six previews were generated: identity (e.g., monkey); external letter manipulations where either the beginning three letters of the word were substituted (e.g., rackey) or the last three letters of the word were substituted (e.g., monhig); internal letter manipulations; e.g., machey, mochiy); and an unrelated control condition (e.g., rachig). Results indicate that both adults and children undertook pre-processing of words in their entirety in the parafovea, and that the manipulation of external letters in preview was more harmful to participants’ parafoveal pre-processing than internal letters. The data also suggest developmental change in the time course of pre-processing, with children’s pre-processing delayed compared to that of adults. These results not only provide further evidence for the importance of external letters to parafoveal processing and lexical identification for adults, but also demonstrate that such findings can be extended to children.

WOS:000609589900001 PMID: 33445974 Purpose: This study aimed to evaluate the retinal blood vessel parameters and the foveal avascular zone (FAZ) area using optical coherence tomography angiography (OCTA) in patients with acromegaly in comparison with healthy controls. Methods: A total of 45 patients with acromegaly and 45 healthy controls were included in this study. In all patients, the vessel density (VD) of the deep and superficial macular vascular networks and the foveal avascular zone (FAZ) were measured using OCTA. The correlation of insulin-like growth factor 1 (IGF-1) level and disease duration with deep macular VD and FAZ values was analyzed. All parameters were registered. Results were assessed and compared between the two groups. Results: Deep macular plexus VD values were lower in patients with acromegaly compared to the control group. No significant differences in VD values in the superficial segment, except for that in the inferior parafovea (P = .01) were found between the two groups. Furthermore, patients with acromegaly showed enlargement in the superficial (P = .30) and deep FAZ areas (P < .001). IGF-1 level and disease duration showed a significant negative correlation with the deep whole image (R = -0.216, P = .041, R = -0.339, P = .001, respectively), deep parafovea (R = -0.271, P = .01; R = -0.372, P < .001, respectively), deep parafovea superior hemi (R = -0.342, P = .001; R = -0.350, P = .001, respectively), deep parafovea temporal (R = -0.224, P = .034; R = -0.234, P = .026, respectively), deep parafovea nasal (R = -0.320, P = .002; R = -0.361, P < .001, respectively), and deep parafovea superior VD values (R = -0.293, P = .005; R = -0.307, P = .003, respectively) and a significant positive correlation with the deep FAZ area values (R = 0.244, P = .02; R = 0.329, P = .002, respectively). Conclusion: VD values in the deep macular capillary plexus were lower in patients with acromegaly, and the superficial and deep FAZ area enlarged. Patients with acromegaly may have an increased risk of developing ocular vascular complications. OCTA can be used to evaluate retinal blood VD in patients with acromegaly.

Available online 19 January 2021 During reading, we can process and integrate information from words allocated in the parafoveal region. However, whether we extract and process the meaning of parafoveal words is still under debate. Here, we obtained Fixation-Related Potentials in a Basque-Spanish bilingual sample during a Spanish reading task. By using the boundary paradigm, we presented different parafoveal previews that could be either Basque non-cognate translations or unrelated Basque words. We prove for the first time cross-linguistic semantic preview benefit effects in alphabetic languages, providing novel evidence of modulations in the N400 component. Our findings suggest that the meaning of parafoveal words is processed and integrated during reading and that such meaning is activated and shared across languages in bilingual readers. This study was partially funded by Spanish government (Ram´on y Cajal Fellowship 2017-2205, Juan de la Cierva-Incorporaci´on Postdoctoral Grant; FPI-MINECO Predoctoral Grant BES-2017-081797), Basque government (BERC 2018-2021 program, PIBA_2020_1_0024 grant), BCBL Severo Ochoa excellence accreditation SEV-2015-0490, and Grant RTI2018-093547-B-I00 from the Agencia Estatal de Investigaci´on.

We investigated the extent to which accuracy in word identification in foveal and parafoveal vision is determined by variations in the visibility of the component letters of words. To do so we measured word identification accuracy in displays of three three-letter words, one on fixation and the others to the left and right of the central word. We also measured accuracy in identifying the component letters of these words when presented at the same location in a context of three three-letter nonword sequences. In the word identification block, accuracy was highest for central targets and significantly greater for words to the right compared with words to the left. In the letter identification block, we found an extended W-shaped function across all nine letters, with greatest accuracy for the three central letters and for the first and last letter in the complete sequence. Further analyses revealed significant correlations between average letter identification per nonword position and word identification at the corresponding position. We conclude that letters are processed in parallel across a sequence of three three-letter words, hence enabling parallel word identification when letter identification accuracy is high enough.

The purpose of this study was to evaluate central and parafoveal inner retinal layer thickness in patients with subretinal drusenoid deposits (SDD) or conventional drusen (CD). Participants underwent comprehensive ophthalmoscopic examination. Evidence of SDD or CD was evaluated with near infrared reflectance and spectral domain optical coherence tomography. Quantification of subfoveal lesions was made through a qualitative analysis of vertical and horizontal SD-OCT scans centered on the fovea. Inner retinal layer macular thickness measurements were obtained for central circles with 1, 3, and 5 mm diameter. Continuous variables were compared by the analysis of covariance (ANCOVA) with post-hoc Tukey HSD correction for multiple comparison analysis. Fifty-five patients were included in the study, 18 eyes with SDD alone, 19 eyes with CD alone, and 18 eyes of healthy age-matched subjects. Eight eyes with SDD (44%) and 13 eyes with CD (68%) had subfoveal lesions. There was significant reduction in the inner retinal layer thickness in the central 1mm area and in the superior 3 mm area in the SDD and CD group compared to controls. In conclusion the inner retinal layer is thinner in the central macula and in the superior parafovea in eyes.

PURPOSE To examine angiographic risk factors for the recurrence of macular edema associated with branch retinal vein occlusion. METHODS We consecutively included 51 patients with treatment-naive branch retinal vein occlusion involving the macular area. Each eye initially received 3 monthly ranibizumab injections, with additional injections as necessary. At Month 3, we examined parafoveal vessel diameter indexes (VDI) in all sectors using optical coherence tomography angiography and determined the association with retinal thickness changes (Month 3-Month 5) and the number of ranibizumab injections during 12 months. RESULTS Parafoveal VDIs in the affected, nasal, and temporal sectors at Month 3 were significantly associated with corresponding parafoveal thickening (P = 0.020, 0.010, and

This study explores whether semantic processing in parafoveal reading in the Italian language is modulated by the perceptual and lexical features of stimuli by analyzing the results of the rapid parallel visual presentation (RPVP) paradigm experiment, which simultaneously presented two words, with one in the fovea and one in the parafovea. The words were randomly sampled from a set of semantically related and semantically unrelated pairs. The accuracy and reaction times in reading the words were measured as a function of the stimulus length and written word frequency. Fewer errors were observed in reading parafoveal words when they were semantically related to the foveal ones, and a larger semantic facilitatory effect was observed when the foveal word was highly frequent and the parafoveal word was short. Analysis of the reaction times suggests that the semantic relation between the two words sped up the naming of the foveal word when both words were short and highly frequent. Altogether, these results add further evidence in favor of the semantic processing of words in the parafovea during reading, modulated by the orthographic and lexical features of the stimuli. The results are discussed within the context of the most prominent models of word processing and eye movement controls in reading.

While reading is an essential human skill, many of the neuronal mechanisms supporting reading are not well understood. In spite of the reduced visual acuity, parafoveal information plays a critical role in natural reading1; however, it is strongly debated whether words are previewed parafoveally at the lexical level2–9. This is a key dispute for competing models on reading and of great significance since lexical retrieval is important for guiding eye movements. We found evidence for parafoveal previewing at the lexical level by combining a novel rapid invisible frequency tagging (RIFT)10, 11 approach with magnetoencephalography (MEG) and eye-tracking. In a silent reading task, target words of either low or high lexical frequency were tagged (flickered) subliminally at 60 Hz. The tagging response measured when fixating on the pre-target word reflected parafoveal previewing of the target word. We observed a stronger tagging response as early as 100 ms following fixations on pre-target words that were followed by target words of low compared with high lexical frequency. Moreover, the difference in tagging response with respect to target lexicality predicted individual reading speed. Our findings demonstrate that reading unfolds in the fovea and parafovea simultaneously to support fluent reading.

Purpose Because preterm birth and retinopathy of prematurity (ROP) are associated with poor visual acuity (VA) and altered foveal development, we evaluated relationships among the central retinal photoreceptors, postreceptor retinal neurons, overlying fovea, and VA in ROP. Methods We obtained optical coherence tomograms (OCTs) in preterm born subjects with no history of ROP (none; n = 61), ROP that resolved spontaneously without treatment (mild; n = 51), and ROP that required treatment by laser ablation of the avascular peripheral retina (severe; n = 22), as well as in term born control subjects (term; n = 111). We obtained foveal shape descriptors, measured central retinal layer thicknesses, and demarcated the anatomic parafovea using automated routines. In subsets of these subjects, we obtained OCTs eccentrically through the pupil (n = 46) to reveal the fiber layer of Henle (FLH) and obtained adaptive optics scanning light ophthalmograms (AO-SLOs) of the parafoveal cones (n = 34) and measured their spacing and distribution. Results Both VA and foveal depth decreased with increasing ROP severity (term, none, mild, severe). In severe subjects, foveae were broader than normal and the parafovea was significantly enlarged compared to every other group. The FLH was thinner than normal in mild (but not severe) subjects. VA was associated with foveal depth more than group. Density of parafoveal cones did not differ significantly among groups. Conclusions Foveal structure is associated with loss of VA in ROP. The preserved FLH in severe (relative to mild) eyes suggests treatment may help cone axon development. The significantly larger parafovea and increased outer nuclear layer (ONL) thickness in ROP hint that some developmental process affecting the photoreceptors is not arrested in ROP but rather is supranormal.

Purpose Delayed rod-mediated dark adaptation (RMDA) is a functional biomarker for incipient age-related macular degeneration (AMD). We used anatomically restricted spectral domain optical coherence tomography (SD-OCT) imaging data to localize de novo imaging features associated with and to test hypotheses about delayed RMDA. Methods Rod intercept time (RIT) was measured in participants with and without AMD at 5 degrees from the fovea, and macular SD-OCT images were obtained. A deep learning model was trained with anatomically restricted information using a single representative B-scan through the fovea of each eye. Mean-occlusion masking was utilized to isolate the relevant imaging features. Results The model identified hyporeflective outer retinal bands on macular SD-OCT associated with delayed RMDA. The validation mean standard error (MSE) registered to the foveal B-scan localized the lowest error to 0.5 mm temporal to the fovea center, within an overall low-error region across the rod-free zone and adjoining parafovea. Mean absolute error (MAE) on the test set was 4.71 minutes (8.8% of the dynamic range). Conclusions We report a novel framework for imaging biomarker discovery using deep learning and demonstrate its ability to identify and localize a previously undescribed biomarker in retinal imaging. The hyporeflective outer retinal bands in central macula on SD-OCT demonstrate a structural basis for dysfunctional rod vision that correlates to published histopathologic findings. Translational relevance This agnostic approach to anatomic biomarker discovery strengthens the rationale for RMDA as an outcome measure in early AMD clinical trials, and also expands the utility of deep learning beyond automated diagnosis to fundamental discovery.

To assess the progression of primary open-angle glaucoma (POAG) and to study the role of retinal microcirculation in its progression.In this 2-year prospective study, the rate of POAG progression was determined using perimetry (ROP1) and spectral domain optical coherence tomography (SD-OCT) by thinning of retinal nerve fiber layer (RNFL) (ROP2) and ganglion cell complex (GCC) (ROP3). The vessel density of parafoveal superficial plexus (VD parafovea) and peripapillary retina (VD ppr) was assessed using OCT angiography, peripheral resistance index (RI), and blood flow velocity in the posterior short ciliary arteries (PSCA) and central retinal artery (CRA) with the use of color Doppler mapping. The predictive properties of each parameter were calculated using the area under receiver operating curve (AUC).Progression was detected in 9.8% cases by perimetry and in 19.7% cases by OCT. The combination of these two methods increased the detection up to 32.8%. Circulatory parameters - VD parafovea (AUC 0.70±0.07), VD ppr (0.715±0.07), PSCA RI (0.801±0.12), CRA RI (0.798±0.11) - had similar high predictive properties as IOP max (0.79±0.05), corneal hysteresis (0.755±0.07), thickness of inner parafoveal layers (0.728±0.07) and RNFL (0.692±0.06). The study revealed the following correlations: ROP1 with maximum IOP (The obtained data demonstrates the importance of combining perimetry with OCT for detecting the progression of glaucoma and indicates its relationship with reduced ocular hemoperfusion.Оценить прогрессирование первичной открытоугольной глаукомы (ПОУГ) и исследовать роль в нем ретинальной микроциркуляции.В проспективном 2-летнем исследовании определена скорость прогрессирования ПОУГ (Rate of Progression) методом периметрии (ROPПрогрессирование выявлено в 9,8% случаев методом периметрии и в 19,7% — методом ОКТ. Сочетание двух методов повысило частоту выявления прогрессирования до 32,8%. Циркуляторные параметры: VD парафовеа (AUC 0,70Полученные данные демонстрируют важность сочетания периметрии с ОКТ для выявления прогрессирования глаукомы и указывают на его связь со снижением глазной гемоперфузии.

Optical Coherence Tomography Angiography (OCT-A) is regarded as a non-invasive approach for imaging the blood vessels. New investigations on OCT-A are developed to extract structural features useful in the diagnosis and treatment of ocular diseases. Raw OCT-A is capable of providing qualitative microvascular data, but our mentioned features are intended to provide quantitative information and trustable comparison during follow ups and between different people. In this paper, we proposed an easy-to-use software to remove spurious blood vessel shadows and extract numerical features from OCT-A images. The features are expected to play an important role in the diagnosis and understanding of blood conditions. For this purpose, we used blood flow information as vessel density (VD) map (%) in a 4.5 × 4.5 mm rectangle scan centered on the optic disk for deep optic nerve data. Information from original image and image with small vessels were measured in whole-image (WI), peripapillary (PP) areas and theirs superior and inferior sectors. Furthermore, we also used blood flow information at parafoveal capillary as VD map in order to remove the projection artifact of superficial macular vessels from deep macular images, compatible with different analysis protocols for macula (3 × 3 , 4 × 4 , 5 × 5 , 6 × 6, and 7 × 7 mm). Similarly, information from whole image and small vessels were measured in whole-image (Wi) and sector-based parafovea areas.

International audience; When reading, orthographic information is extracted not only from the word the reader is looking at, but also from adjacent words in the parafovea. Here we examined, using the recently introduced OB1-reader computational model, how orthographic information can be processed in parallel across multiple words and how orthographic information can be integrated across time and space. Although OB1-reader is a model of text reading, here we used it to simulate single-word recognition experiments in which parallel processing has been shown to play a role by manipulating the surrounding context in flanker and priming paradigms. In flanker paradigms, observers recognize a central word flanked by other letter strings located left and right of the target and separated from the target by a space. The model successfully accounts for the finding that such flankers can aid word recognition when they contain bigrams of the target word, independent of where those flankers are in the visual field. In priming experiments, in which the target word is preceded by a masked prime, the model accounts for the finding that priming occurs independent of whether the prime and target word are in the same location or not. Crucial to these successes is the key role that spatial attention plays within OB1-reader, as it allows the model to receive visual input from multiple locations in parallel, while limiting the kinds of errors that can potentially occur under such spatial pooling of orthographic information.

To investigate the relationship between visual resolution and cone parameters in eyes with different levels of best corrected visual acuity (BCVA). Seventeen eyes of 10 volunteers with BCVA of 20/12.5 or better (group 1) and 16 eyes of 10 volunteers with BCVA of 20/16 (group 2) were investigated in the study. Images of the cone photoreceptors at 1.5° from the fovea were obtained using an adaptive optics (AO) retinal camera. The BCVA was obtained following a subjective refraction using a standardized logMAR visual acuity chart. The mean cone density (29,570.96 ± 2489.94 cells/mm2) at 1.5° from the fovea in group 1 (BCVA ≥ 20/12.5, n = 17) was significantly greater (P

cinar, esat/0000-0002-8257-6884 WOS: 000579702900002 PubMed: 33074437 Purpose To evaluate the retinal vascular structure before and after the epiretinal membrane (ERM) surgery by optical coherence tomography angiography (OCTA). Methods Twenty-two eyes with ERM (study eyes) had been evaluated by OCTA for superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD) at foveal and parafoveal regions and foveal avascular zone (FAZ) before and after ERM removal surgery. Twenty-two fellow eyes were selected as control group. Results Preoperative VD of SCP and DCP were significantly lower in ERM eyes than in controls in both foveal and parafoveal areas (p < 0.05, for all). The difference regressed in SCP (fovea: 18.04 +/- 3.1 vs 19.98 +/- 18p = 0.002 and parafovea: 47.33 +/- 3.54 vs 49.71 +/- 28p = 0.001), but persisted in DCP (fovea: 17.25 +/- 3.52 vs 17.57 +/- 4.01p = 0.856 and parafovea: 50.12 +/- 4.35 vs 50.93 +/- 3.24p = 0.791) in study eyes, postoperatively. Superficial and deep FAZ areas were significantly smaller in study eyes than controls. Postoperatively, superficial FAZ area enlarged (0.288 +/- 0.10 vs 0.307 +/- 0.08p = 0.012), whereas deep FAZ area did not (0.324 +/- 0.09 vs 0.338 +/- 0.07p = 0.435). FAZ area was correlated with the best-corrected visual acuity in ERM eyes. Conclusion Vascular damage in SCP and DCP was demonstrated by OCTA in eyes with ERM. ERM removal surgery mainly improves superficial changes caused by ERM. Changes in deep retinal flow may be associated with visual outcomes after ERM removal surgery.

Purpose The purpose of this study was to compare perfusion parameters of the parafovea with scans outside the parafovea to find an area most susceptible to changes secondary to diabetic retinopathy (DR). Methods Patients with different DR severity levels as well as controls were included in this cross-sectional clinical trial. Seven standardized 3 × 3 mm areas were recorded with Swept Source Optical Coherence Tomography Angiography: one centered on the fovea, three were temporal to the fovea, and three nasally to the optic disc. The capillary perfusion density (PD) of the superficial capillary complex (SCC) and deep capillary complex (DCC) as well as the fractal dimension (FD) were generated. Statistical analyses were done with R software. Results One hundred ninety-two eyes (33 controls, 51 no-DR, 41 mild DR, 37 moderate/severe DR, and 30 proliferative DR), of which 105 patients with diabetes and 25 healthy controls were included (59 ± 15 years; 62 women). Mean PD of the DCC was significantly less in patients without DR (parafovea = 0.48 ± 0.03; temporal = 0.48 ± 0.02; and nasal = 0.48 ± 0.03) compared to controls (parafovea = 0.49 ± 0.02; temporal = 0.50 ± 0.02; and nasal = 0.50 ± 0.03). With increasing DR severity, PD and FD of the SCC and DCC further decreased. Conclusions Capillary perfusion of the retina is affected early by diabetes. PD of the DCC was significantly reduced in patients with diabetes who did not have any clinical signs of DR. The capillary network outside the parafovea was more susceptible to capillary perfusion deficits compared to the capillaries close to the fovea. Trial registration clinicaltrial.gov, NCT03765112, https://clinicaltrials.gov/ct2/show/NCT03765112?term=NCT03765112&rank=1.

BackgroundTo explore the role of foveal and parafoveal Müller cells in the morphology and pathophysiology of tractional macular disorders with a mathematical model of mechanical force transmission.MethodsIn this retrospective observational study, spectral-domain optical coherence tomography images of tractional lamellar macular holes and patients with myopic foveoschisis were reviewed and analysed with a mathematical model of force transmission. Parafoveal z-shaped Müller cells were modelled as a structure composed of three rigid rods, named R1, R2 and R3. The angle formed between the rods was referred to as θ . R1, R2 and R3 lengths as well as the variation of the angle θ were measured and correlated with best corrected visual acuity (BCVA).ResultsIn tractional lamellar macular holes, there was a significant reduction of the angle θ towards the foveal centre (pConclusionParafoveal Müller cells in the Henle fibre layer may guarantee structural stability of the parafovea by increasing retinal compliance and resistance to mechanical stress. Small values of the angle θ were related to worse BCVA possibly due to damage to Müller cell processes and photoreceptor’s axons.

PURPOSE To explore regional variation of the macular microvasculature in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD), also to detect the association between retinal macular microvascular parameters and the progress of preclinical AD. METHODS Prospective study of healthy controls, patients with MCI and patients with AD by using Optical coherence tomography angiography (OCT-A). We quantified foveal avascular zone (FAZ) areas, densities of the superficial retinal capillary plexuses (SRCP) and deep retinal capillary plexuses (DRCP). The SRCP and DRCP were divided into inner (3 mm) and external (6 mm) annular rings, each containing four quadrants (SI, II, TI, NI, SE, IE, TE and NE). The data were analysed statistically by using SPSS 22 software. RESULTS Totally, 60 subjects including 21 HC (33 eyes), 21 patients with MCI (32 eyes) and 18 AD patients (28 eyes) were recruited. The microvascular densities of DRCP at all quadrants of the parafovea and perifovea were significantly lower in AD patients compared to HC group (p

Macular pigment (MP), which is composed of lutein/zeaxanthin/mezo-zeaxanthin, is concentrated in the central part of the retina, the macula. It protects the macula by absorbing short-wavelength light and suppressing oxidative stress. To evaluate whether MP levels are related to retinal neural protection and resulting health, we analyzed the association between the MP optical density (MPOD), and the macular thickness and volumes. Forty-three eyes of 43 healthy adult volunteers (21 men and 22 women, age: 22&ndash, 48 (average 31.4 &plusmn, 1.1) years) were analyzed. Highly myopic eyes (&lt, 6 diopters) were excluded. MPOD was measured using MPS2&reg, and the neural retinal thickness and volume were measured using optical coherence tomography. The mean MPOD was 0.589 &plusmn, 0.024, and it positively correlated with the central retinal thickness (P = 0.017, R = 0.360) and retinal volume of the fovea (1-mm diameter around the fovea, P = 0.029, R = 0.332), parafovea (1&ndash, 3-mm diameter, P = 0.002, R = 0.458), and macula (6-mm diameter, P = 0.003, R = 0.447). In the macular area (diameter: 6 mm), MPOD was correlated with the retinal neural volume of the ganglion cell layer (P = 0.037, R = 0.320), inner plexiform layer (P = 0.029, R = 0.333), and outer nuclear layer (P = 0.020, R = 0.353). Thus, MPOD may help in estimating neural health. Further studies should determine the impact of MP levels on neuroprotection.

Retinal photoreceptors modulate the pupil diameter to regulate retinal illumination. At early stage the pupil-response is formed by intrinsically-photosensitive-Retinal-Ganglion-Cells (ipRGCs) expressing melanopsin, activated by blue light. ipRGCs’ axons pass through the optic nerve head, corresponding to the blind-spot. No photoreceptors except melanopsin appear to exist in the blind-spot. Contributions of melanopsin to pupil constriction in absence of classical photoreceptors in the blind-spot is not fully understood. We investigated how blue light in the blind-spot changes melanopsin-pupil-response compared to parafovea and periphery. The Post-Illumination-Pupil-Response (PIPR) amplitude reflecting melanopsin was analyzed for standardized time windows (1s1.8s and 2–6s) and expressed as pupillary-change. Bayesian analysis showed a BF>3 that PIPR>1.8s for blind-spot and periphery is not different. At times 2s–6s, a t-test comparison in the blind-spot condition showed a sign ificantly larger PIPR to blue compared to red light, confirming a melanopsin-pupil-response in the blind-spot. Taken together, equivalent stimulation in the blind-spot and periphery revealed comparable PIPR, although there are no rods and cones in the blind-spot. In absence of classical photoreceptors in the blind-spot, melanopsin seems to be responsible for pupil constriction in similar manner as in the periphery, which supports the presence of melanopsin on the axons of ipRGCs.

In two eye-tracking studies we investigated whether readers can detect a violation of the phonological-grammatical convention for the indefinite article an to be followed by a word beginning with a vowel when these two words appear in the parafovea. Across two experiments participants read sentences in which the word an was followed by a parafoveal preview that was either correct (e.g. Icelandic), incorrect and represented a phonological violation (e.g. Mongolian), or incorrect without representing a phonological violation (e.g. Ethiopian), with this parafoveal preview changing to the target word as participants made a saccade into the space preceding an. Our data suggests that participants detected the phonological violation while the target word was still two words to the right of fixation, with participants making more regressions from the previewed word and having longer go-past times on this word when they received a violation preview as opposed to a non-violation preview. We argue that participants were attempting to perform aspects of sentence integration on the basis of low-level orthographic information from the previewed word.

Models of eye movement control during reading assume that the difficulty of processing word n in a sentence modulates the depth of processing of the upcoming word/s (word n + 1) in the parafovea. This foveal load hypothesis is widely accepted in the literature despite surprisingly few clear replications of the basic effect. We sought to establish whether observing a foveal load effect depends on the type of parafoveal preview used in the boundary paradigm. Participants’ eye movements were recorded in two experiments as they read sentences in which a low- or high-frequency word n—a typical manipulation of foveal load—preceded a critical target word. Prior to the reader making a saccade to word n + 1, the parafoveal preview was either identical to word n + 1; an orthographically similar word or nonword; or an unrelated word or nonword. The results revealed that the critical evidence for a foveal load effect—an interaction between word n frequency and word n + 1 preview—was limited to conditions in which the invalid preview baseline was an orthographically illegal nonword. The remaining conditions produced completely additive effects of the two factors. These findings raise questions about the mechanisms underlying the spillover of foveal processing difficulty to parafoveal words. The implications for theories of reading are discussed. Australian Research Council

PURPOSE: To evaluate pre-operative and post-operative morphologic characteristics in idiopathic macular epiretinal membrane (ERM) by optical coherence tomography angiography (OCTA). METHODS: Thirty-three subjects with unilateral idiopathic ERM were enrolled and the contralateral eyes served as controls. Vascular parameters including superficial capillary plexus (SCP), deep capillary plexus (DCP), outer capillary plexus (OCP), and choroidal capillary plexus (CCP) were evaluated by OCTA. RESULTS: The superficial foveal avascular zone (FAZ) was significantly smaller in eyes with ERM (P

During reading, binocular visual input results in superior performance and is particularly important in the pre-processing of parafoveal text prior to direct fixation. It is not yet clear whether binocular vision in the parafovea is necessary for accurate saccadic targeting, or for efficient pre-processing of upcoming text, prior to direct fixation. In the present sentence reading experiment, we used a dichoptic gaze-contingent moving window paradigm in order to establish 1) how much parafoveal binocular input is necessary for fluent reading and 2) which aspect of parafoveal processing is more reliant on binocular vision. Eye movement measures revealed that reading was disrupted unless word N + 1 was entirely binocular in the parafovea, though no additional benefit was observed when word N + 2 was also binocular. Additionally, while fixation durations and reading times were clearly affected by the manipulation, similarly pronounced changes in binocular saccadic parameters such as accuracy, speed, amplitude and velocity were not observed. We concluded that the disruption to reading caused by presenting monocular text to the right of fixation cannot be attributed to difficulties in targeting binocular saccacdes, but instead results from a decreased efficiency in the pre-processing of parafoveal text. These results provide further demonstration for the importance of binocular vision during written text processing.

Recently, Belanger, Slattery, Mayberry and Rayner (2012) showed, using the moving window paradigm, that profoundly deaf adults have a wider perceptual span during reading relative to hearing adults matched on reading level. This difference might be related to the fact that deaf adults allocate more visual attention to simple stimuli in the parafovea (Bavelier, Dye & Hauser, 2006). Importantly, this reorganization of visual attention in deaf individuals is already manifesting in deaf children (Dye, Hauser & Bavelier, 2009). This leads to questions about the time course of the emergence of an enhanced perceptual span (which is under attentional control; Rayner, 2014; Miellet, O'Donnell, & Sereno, 2009) in young deaf readers. The present research addressed this question by comparing the perceptual spans of young deaf readers (age 7-15) and young hearing children (age 7-15). Young deaf readers, like deaf adults, were found to have a wider perceptual span relative to their hearing peers matched on reading level, suggesting that strong and early reorganization of visual attention in deaf individuals goes beyond the processing of simple visual stimuli and emerges into more cognitively complex tasks, such as reading.

To make graphical user interfaces look more fashionable, designers often make use of high-stroke-contrast fonts. We are yet to understand how these fonts affect reading. We examined the effect of letter-stroke contrast on three bold fonts, one with extreme contrast between thick and thin strokes, one with no contrast, and one in between. The fonts were designed for this experiment to enable control of font variables. Participants identified the middle letter in a lowercase letter trigram in each trial, briefly presented in the parafovea (at 2° left and right of fixation) and at the foveal fixation point. There was evidence for letter recognition impairment for the font with high stroke contrast compared to the fonts with low and medium stroke contrast, while there was no significant difference in performance between the medium- and low-stroke-contrast fonts. The results suggest that bold fonts with high stroke contrast should not be considered for designs where letter recognition is a priority.

The conventional stimulus for standard automated perimetry is fixed in size, giving elevated contrast thresholds and reduced test reliability in the periphery. Here, we test the hypothesis that appropriate scaling of the size of perimetric stimuli will return fixed thresholds and reduced variability across the visual field. We derived frequency-of-seeing (FOS) curves in five healthy subjects at central (3 degrees) and peripheral (27 degrees) locations with a method of constant stimuli (MOCS) using a desktop LCD display. FOS curves for a Goldmann III (GIII) stimulus were compared with those for size scaled spots. To consider clinical translation, we tested a further five healthy subjects (22-24 years) with the Melbourne Rapid Fields (MRF) tablet perimeter at several locations spanning 1 degree to 25 degrees from fixation, deriving FOS curves (MOCS) and also conducting repeated adaptive clinical thresholding to assess intra- and interobserver variability. We found that GIII contrast thresholds were significantly elevated in the periphery compared with the parafovea, with concomitant reduction of FOS slope. Using appropriately size scaled spots, threshold and slope differences between these locations were significantly reduced. FOS data collected with the tablet perimeter confirmed that size scaling confers broad equivalence of the shape of the FOS curve across the visual field. Repeated adaptive thresholding with size scaled stimuli gave relatively constant intra-observer variability across the visual field, which compares favorably with published normative data obtained with the GIII stimulus. The reduced variability will improve signal-to-noise ratio for correct classification of normal visual field test results, whereas the lower contrast thresholds yield greater dynamic range, which should improve the ability to reliably monitor moderate defects.

Human brain can be divided into multiple brain regions based on anatomical and functional properties. Recent studies showed that resting‐state connectivity can be utilized for parcellating brain regions and identifying their distinctive roles. In this study, we aimed to parcellate the primary and secondary visual cortices (V1 and V2) into several subregions based on functional connectivity and to examine the functional characteristics of each subregion. We used resting‐state data from a research database and also acquired resting‐state data with retinotopy results from a local site. The long‐range connectivity profile and three different algorithms (i.e., K‐means, Gaussian mixture model distribution, and Ward's clustering algorithms) were adopted for the parcellation. We compared the parcellation results within V1 and V2 with the eccentric map in retinotopy. We found that the boundaries between subregions within V1 and V2 were located in the parafovea, indicating that the anterior and posterior subregions within V1 and V2 corresponded to peripheral and central visual field representations, respectively. Next, we computed correlations between each subregion within V1 and V2 and intermediate and high‐order regions in ventral and dorsal visual pathways. We found that the anterior subregions of V1 and V2 were strongly associated with regions in the dorsal stream (V3A and inferior parietal gyrus), whereas the posterior subregions of V1 and V2 were highly related to regions in the ventral stream (V4v and inferior temporal gyrus). Our findings suggest that the anterior and posterior subregions of V1 and V2, parcellated based on functional connectivity, may have distinct functional properties.

Purpose To present ophthalmic imaging findings in the case of a 40-year-old male with sustained visual loss after a single episode of acute central serous retinopathy (CSR). Observations A male subject presented with visual acuity decline to 20/50 OS and was diagnosed with acute CSR. The initial pigment epithelial detachment and subretinal fluid resolved within 6 weeks, but visual acuity remained impaired. Using directional optical coherence tomography (D-OCT) and confocal and split-detector adaptive optics scanning light ophthalmoscopy (AOSLO), we imaged pathologic alterations in the photoreceptor mosaic of the affected eye. A foveal region of intermittent missing cones, a temporal parafoveal region of confluent missing cones, and a nasal parafoveal region of misdirected cones were observed. Conclusions and Importance Pathologic alterations in photoreceptor microanatomy underlie residual visual acuity deficits in this case of acute CSR. Observations of missing cones correlated well across all imaging modalities in the fovea and the temporal parafoveal region of missing cones. However, in the nasal parafovea where cones were present but misdirected, D-OCT and AOSLO may be able to identify and image photoreceptors with greater fidelity as compared to non-directional SDOCT (spectral domain OCT). D-OCT may thus have a clinical role in rapidly assessing photoreceptor mosaic integrity in pathology.

International audience; Prior research has shown that processing of a given target word is facilitated by the simultaneous presentation of orthographically related stimuli in the parafovea. Here we investigate the nature of such spatial integration processes by presenting orthographic neighbours of target words in the parafovea, considering that neighbours have been shown to inhibit, rather than facilitate, recognition of target words in foveal masked priming research. In Experiment 1, we used the gaze-contingent boundary paradigm to manipulate the parafoveal information subjects received while they fixated a target word within a sentence. In Experiment 2, we used the Flanking Letters Lexical Decision paradigm to manipulate parafoveal information while subjects read isolated words. Parafoveal words were either a higher-frequency orthographic neighbour of targets words (e.g., blue-blur) or a high-frequency unrelated word (e.g., hand-blur). We found that parafoveal orthographic neighbours facilitated, rather than inhibited, processing of the target. Thus, the present findings provide further evidence that orthographic information is integrated across multiple words and suggest that either the integration process does not enable simultaneous access to those words' lexical representations, or that lexical representations activated by spatially distinct stimuli do not compete for recognition.

This study was designed to perform psychophysical assessment of koniocellular pathway in patients with schizophrenia versus healthy controls. A total of 26 patients diagnosed with schizophrenia and 15 healthy controls were included. Snellen Visual Acuity Chart scores and Short Wavelength Automated Perimetry (SWAP) visual field testing including global visual field indices [mean deviation (MD), pattern standard deviation (PSD), test time (min)], reliability parameters [false negative responses (%), false positive responses (%) and fixed losses (%)] and average threshold sensitivity [central (parafovea), peripheral area, and four quadrants] were recorded in both groups. Significantly lower MD scores, higher PSD scores and lower average threshold sensitivity at each location across the visual field were noted in schizophrenia relative to control group. In conclusion, our findings revealed a deficit in koniocellular pathway with impaired SWAP global indices and lower threshold sensitivity at each location across the visual field among chronic schizophrenic patients as compared with control subjects. Our findings emphasize potential application of SWAP outside its original intended purpose as a glaucoma test, to provide deeper understanding of the specific contribution of lateral geniculate nucleus to the visual and cognitive disturbances of schizophrenia.

Purpose To examine the capability of optical coherence tomography-derived retinal thickness measures in detecting 4-year incident diabetic peripheral neuropathy (DPN). Methods 145 eyes of 145 participants with diabetes but no DPN at baseline were examined for incident DPN. HbA1c levels, nephropathy, neuropathy (DPN), cardiovascular measures, and various retinal thickness measures were examined at baseline and after 4 years. Incidence of DPN was defined as newly developed DPN at follow-up. Baseline factors were assessed by univariate and a step-wise multiple logistic regression, and the predictors were examined for diagnostic capabilities. Results Of the 145 participants without DPN at baseline, 51 had developed DPN when examined after 4 years (35% incidence). Of the ophthalmic variables, the mean (S.D.) of the overall thickness in the parafovea at baseline was 315 (18) μm in the no DPN group and 306 (18) μm in the ‘incidence’ group, and the differences were significant, p = 0.005. The superior hemisphere parafovea (mean (S.D.): 318 (17) μm vs 310 (20) μm, p = 0.02) and inferior hemisphere parafovea (313 (19) μm vs 302 (18) μm, p = 0.002) were different in the incident DPN group compared with the no DPN group. When adjusted for age, retinal thickness in the parafovea (AUC = 0.65, p = 0.003, 86% sensitivity and 44% specificity at 321 μm criterion), and body mass index or BMI (AUC = 0.65, p = 0.003, 49% sensitivity and 83% specificity at 29.3 kg m−2 criterion) at baseline were significant predictors for 4-year incident DPN. Conclusions A lower retinal thickness at the parafovea and a higher BMI can predict 4-year incident neuropathy in patients with diabetes, with acceptable diagnostic accuracies. This OCT-derived measure may serve as a potential ophthalmic marker in the screening of patients at risk of developing DPN.