Inferotemporal Region Research Articles

Clinical Characteristics and Associated Factors to the Development of Glaucoma in Eyes With Myopic Optic Neuropathy

PurposeTo observe the development of glaucoma in myopic eyes with and without myopic optic neuropathy (MON) and analyze associated factors to the development of typical glaucomatous damage. DesignA prospective, observational, cohort study MethodsA total of 233 myopic eyes with no definite evidence of glaucomatous damage were included in the study. Myopic patients without any retinal nerve fiber layer (RNFL) or visual field (VF) abnormalities were classified as myopic eyes without MON. Myopic patients with decreased RNFL at the superonasal (SN) or nasal area, and with corresponding VF defects either in the temporal or inferotemporal (IT) region, which is different from glaucomatous damage, were classified as myopic eyes with MON. Myopic eyes that developed glaucoma were defined by the presence of glaucomatous VF in the SN region including defects in Bjerrum area, or a new localized RNFL defect in the IT region on red-free photography or RNFL OCT. Disc morphological features and optic nerve head (ONH) parameters of two groups were compared. Hazard ratios for the association between baseline factors and conversion to glaucoma were obtained using Cox regression analysis. ResultsMean follow-up period was 11.66 ± 2.86 years. Myopic eyes with MON had a thinner average peripapillary RNFL thickness (P < 0.001), worse MD of the VF (P = 0.031), a higher percentage of IT VF defects (P < 0.001), smaller torsion degree (P = 0.047), and greater LCD (P = 0.022). Myopic eyes with MON who developed glaucoma had a thinner average peripapillary RNFL thickness (P = 0.009), greater PPA area (P = 0.049), greater LCD (P < 0.001), and thinner LCT (P < 0.001). Thinner baseline temporal RNFL thickness (HR, 0.956; 95% CI, 0.928–0.986; P = 0.004), greater baseline LCD (HR, 1.003; 95% CI, 1.000–1.005; P = 0.022), and greater PPA area (HR, 1.000; 95% CI, 1.000–1.003; P = 0.050) were significantly associated factors with glaucoma development in the Cox regression analysis. ConclusionMyopic eyes with MON have a greater risk to develop glaucoma compared to myopic eyes without MON. Myopic eyes with MON had larger PPA area, greater LCD, and thinner temporal peripapillary RNFL, indicating that accompanying structural weakness due to myopia, especially at the temporal side of the optic nerve head and the peripapillary sclera, increases the risk of glaucoma in myopic eyes with MON.

Evaluation of ganglion cell-inner plexiform layer thickness in the diagnosis of pre-perimetric glaucoma and comparison to retinal nerve fiber layers.

Evaluation of ganglion cell-inner plexiform layer thickness in the diagnosis of pre-perimetric glaucoma (PPG) and comparison to retinal nerve fiber layers. This study was a prospective hospital-based study. A total of 30 PPG and control patients were studied for retinal nerve fiber layer thickness (RNFL) and ganglion cell-inner plexiform layer complex (GC-IPL) by spectral-domain optical coherence tomography. PPG was defined as eyes with a normal visual field and one or more localized RNFL defects that were associated with a typical glaucomatous disc appearance. Diagnostic abilities of GC-IPL, optic nerve head (ONH), and RNFL parameters were computed using area under receiver-operating curve (AUROC), sensitivity, and specificity. GC-IPL parameters showed significant changes in PPG cases as compared to normal subjects in each region ( P value < 0.001). RNFL parameters also differed significantly from normal subjects in all quadrants ( P value 0.003 to < 0.001). Within GC-IPL parameters, the superotemporal region had the maximum area under the curve (AUC), followed by inferior, superior, and inferotemporal regions. Within RNFL parameters, the inferior quadrant had the maximum AUC, followed by superior and nasal quadrants. the GC-IPL parameters in PPG showed that the AUC of the GC-IPL parameters was much higher than those of the ONH and RNFL values. Although both the parameters RNFL and GC-IPL showed significant changes in PPG patients compared to healthy subjects, a higher AUC of GC-IPL points toward the higher sensitivity of GC-IPL than RNFL for detecting glaucoma in early stages.

Inference of Capillary Nonperfusion Progression on Widefield OCT Angiography in Diabetic Retinopathy.

The purpose of this study was to explore the spatial patterns of the nonperfusion areas (NPAs) on widefield optical coherence tomography angiography (OCTA) images in diabetic retinopathy (DR) and to investigate their associations with NPA progression and DR severity. We prospectively enrolled 201 eyes from 158 patients with DR. Widefield images were obtained using a swept-source OCTA device (Xephilio OCT-S1), followed by the creation of 20-mm (1614 pixels) en face images. Nonperfusion squares (NPSs) were defined as 10 × 10-pixel squares without retinal vessels. Eyes with high-dimensional spatial data were mapped onto a two-dimensional space using the uniform manifold approximation and projection algorithm and divided by clustering. The patterns of NPA distribution were statistically compared between clusters. All eyes were mapped onto a two-dimensional space and divided into six clusters based on the similarity of NPA distribution. Eyes in clusters 1 and 2 had minimal and small NPAs, respectively. Eyes in clusters 3 and 4 exhibited NPAs in the temporal and inferotemporal regions, respectively. Eyes in cluster 5 displayed NPAs in both superonasal and inferonasal areas. The unique NPA distributions in each cluster encouraged us to propose eight possible pathways of NPA progression. DR severity was not equal between clusters (P < 0.001), for example, 8 (15.7%) of 51 eyes and 15 (65.2%) of 23 eyes had PDR in clusters 1 and 5, respectively. Dimensionality reduction and subsequent clustering based on the NPA distribution on widefield OCTA enabled the inference of possible NPA progression in DR.

Food Choice Preferences: A Study on University Cafeterias’ Food in Terengganu

According to Campo et al. (2017), food presentation, also known as food visual, is one of the factors that can affect a person’s decision to eat. According to Imram (1999), “People eat first with their eyes” is a common proverb. It is considered an essential feature since it significantly explains or influences how consumers perceive food or drink (Delwiche, 2004). LaBar et al. (2001) also examined the amygdala and surrounding inferotemporal regions to see how food-related imagery could elicit emotional reactions. Two hundred twenty-eight respondents from a local university in Terengganu, Malaysia, took part in the survey that served as the basis for the study. This study aims to identify the important variables that affect how students choose their meals at the university cafeteria and to find the most important variables from the four food-related factors. The results of this study demonstrate that students consider each of the four food-related factors—presentation, colour, pricing, and variety—critically while making meal decisions. This study has set out to alert the cafeteria manager to improve on the particular component found via this analysis. The research’s conclusions will significantly influence the university’s students and the cafeteria staff who run the university’s eateries.

Comparing the Optical Coherence Tomography Outcomes of Intravitreal Injection Anti Vascular Endothelial Growth Factor in Branch Retinal Vein Occlusion (BRVO)

Background: BRVO is a blockage of the branches of the retinal vein due to a thrombus. The prevalence of 10-year BRVO is 1.6 per 100 subjects. The effect of anti-VEGF injection on BRVO management is effective in improving visual acuity and reducing macular oedema.&#x0D; Case presentation: A man, 32 years old, presented to the ophthalmology clinic at the Dr. M. Djamil General Hospital with a chief complaint of blurred vision in his left eye 1 week before admission. The blurred vision began suddenly. Visual acuity in LE was 20/50 and did not advance with a pinhole. Funduscopic examination of LE showed clear media, rounded papillae with well-defined borders, blood vessels aa:vv = 1:3, venous tortuosity (+) increased in the inferotemporal quadrant; retina: Bleeding (+) with dot blot and flame-shaped inferiorly, exudate (+) cotton wool spots at the inferotemporal region; foveal reflex (+)↓ on the macula. OCT LE examination showed macular intraretinal hypo-reflection and macular thickening with a central macular thickness of 617 μm. The physical examination showed a body weight of 114.9 kg, a height of 173 cm, and a body mass index of 38.4. Within 5 months after 3 times administrations of intravitreal injections of anti-VEGF bevacizumab and ranibizumab, visual acuity of LE: 20/25 was obtained, and increased appearance of the retinal fundus and OCT LE.&#x0D; Conclusion: Intravitreal injection therapy of anti-VEGF bevacizumab and ranibizumab is effective in reducing macular oedema and restoring visual acuity in BRVO.

Eye Banking a Boon in Eye Health Care Services and Vision Restoration and Corneal Tattooing for Aesthetic Purposes

Eye donation and eye banking are a boon in eye health care services for visual rehabilitation and corneal tattooing aesthetic purpose in post-trauma corneal opacities. A young female reported to our hospital with a complaint of corneal opacity and difficulty in closing her left eye. On examination, she was diagnosed with a “Corneal scar with an Inadvertent bleb”. The patient reported a history of corneoscleral injury for more than four years. A slit lamp examination showed a corneal scar with a micro leak at the inferotemporal scleral region.

Backward masking reveals coarse-to-fine dynamics in human V1

Natural images exhibit luminance variations aligned across a broad spectrum of spatial frequencies (SFs). It has been proposed that, at early stages of processing, the coarse signals carried by the low SF (LSF) of the visual input are sent rapidly from primary visual cortex (V1) to ventral, dorsal and frontal regions to form a coarse representation of the input, which is later sent back to V1 to guide the processing of fine-grained high SFs (i.e., HSF). We used functional resonance imaging (fMRI) to investigate the role of human V1 in the coarse-to-fine integration of visual input. We disrupted the processing of the coarse and fine content of full-spectrum human face stimuli via backward masking of selective SF ranges (LSFs: <1.75cpd and HSFs: >1.75cpd) at specific times (50, 83, 100 or 150 ms). In line with coarse-to-fine proposals, we found that (1) the selective masking of stimulus LSF disrupted V1 activity in the earliest time window, and progressively decreased in influence, while (2) an opposite trend was observed for the masking of stimulus’ HSF. This pattern of activity was found in V1, as well as in ventral (i.e. the Fusiform Face area, FFA), dorsal and orbitofrontal regions. We additionally presented subjects with contrast negated stimuli. While contrast negation significantly reduced response amplitudes in the FFA, as well as coupling between FFA and V1, coarse-to-fine dynamics were not affected by this manipulation. The fact that V1 response dynamics to strictly identical stimulus sets differed depending on the masked scale adds to growing evidence that V1 role goes beyond the early and quasi-passive transmission of visual information to the rest of the brain. It instead indicates that V1 may yield a ‘spatially registered common forum’ or ‘blackboard’ that integrates top-down inferences with incoming visual signals through its recurrent interaction with high-level regions located in the inferotemporal, dorsal and frontal regions.

Maternal smoking during pregnancy negatively affects brain volumes proportional to intracranial volume in adolescents born very preterm.

Maternal smoking during pregnancy has been shown to associate with smaller frontal lobe and cerebellar volumes in brain magnetic resonance imaging (MRI) at term age in very preterm infants. The aim of this study was to examine the effect of maternal smoking during pregnancy on volumetric brain MRI findings at 13 years. We hypothesized that adverse effects of smoking during pregnancy on brain volumes are still seen during adolescence. Included adolescents were born very preterm (gestational age < 32 weeks and/or birth weight ≤ 1,500 g) between April 2004 and December 2006 at the Turku University Hospital, Finland. Information on maternal smoking status (yes or no) during pregnancy was collected from medical records and maternal questionnaires before discharge. Adolescents underwent volumetric brain MRI at 13 years of age. Image post-processing was performed with FreeSurfer. Regional volumes, cortical thickness, surface area, and curvature were computed from 33 cortical regions of interest (ROIs). Additionally, volumes were calculated for 18 subcortical regions, as well as for white matter, gray matter, and intracranial volume. We normalized quantified absolute volumes for head size by dividing volumes with corresponding intracranial volumes. false discovery rate (FDR) correction for multiple comparisons across regions was used. A total of 9/44 (21%) adolescents had been exposed to maternal smoking during pregnancy. No statistically significant differences in absolute volumes were observed between the groups (p > 0.05). Regarding volumes proportional to intracranial volume, the adolescents in the exposed group exhibited smaller gray matter volumes in the inferotemporal (FDR corrected p = 0.022) and parahippocampal (p = 0.018) regions compared to the unexposed group. The surface area in the exposed group was also smaller in the parahippocampal (p = 0.046) and postcentral (p = 0.046) regions compared to the unexposed group. No statistically significant differences after correction for multiple comparisons were found for either curvature or cortical thickness between the groups. Maternal smoking exposure during pregnancy may have long-term effects on brain volumes up to 13 years in adolescents born very preterm. Our findings emphasize the importance of smoking-free pregnancy.

Evaluation of efficacy of peribulbar block with the combination of 2% lidocaine and 0.5% bupivacaine in comparison with 2% lidocaine and 0.75% ropivacaine in cataract surgery.

Cataract surgery is performed under peribulbar or retrobulbar block. Majority of the patients posted for cataract have some form of medical diseases like diabetes, hypertension, angina, ischaemic heart disease etc. Lidocaine and bupivacaine are the most commonly used local anesthetic for the block procedure. Here we compare the efficacy of peribulbar block in cataract surgery using the combination of 1:1 mixture of 2% lidocaine with 0.5% bupivacaine and 1:1 mixture of 2% lidocaine with 0.75% ropivacaine. It is a prospective, randomized, double blinded study including 60 patients were devided into two groups of 30 each, Group-R received 8 ml of 1:1 mixture of 4 ml of 2% lidocaine, 4 ml of 0.75% ropivacaine and 15 IU/ml of hyaluronidase and group-B received 8 ml of 1:1 mixture of 4 ml of 2% lidocaine, 4 ml of 0. 5% bubivacaineand 15 IU/ml of hyaluronidase. Peribulbar block was performed as per Bloomberg's modification of the Davis and Mandel technique where 5 ml of local anesthetic was injected in the infero temporal region and 3 ml of drug was injected in the superi nasal area. Patients were assessed for sensory block, eyelid and occular movements at an interval of 2 minutes. Systolic, diastolic and mean arterial pressures, heart rate, oxygen saturation, ECG were monitored non invasively at 1,3,5,8,10,15 and then every 10 minutes till the end of the surgery. Mean time for the onset of sensory blockade was 2.70 ± 6.5 minutes in Group B and 2.63 ± 0.57 minutes in group R with P-value 0.671, showing no significant difference in the onset of sensory blockade. Onset of motor blockade was 6.53 ± 1.81 minutes in group B, and 7.57 ± 1.46 minutes in the group R, the P-value being 0.018 was statistically significant. Regarding the duration of analgesia, our study showed mean time for analgesia lasted for 295 ± 54.63 minutes in group B and 414.67 ± 99.47 in group R with P value 0.001 showing statistically significant prolongation of duration of analgesia with group R. We observed a significant increase of mean IOP in bupivacaine group from 13.333 ± 1.582 mm Hg to 21.966 ± 2.697 mm Hg, whereas in ropivacaine group it increased from 12.766 ± 1.222 mm Hg to 13.0 ± 1.341 mm Hg after peribulbar anaesthesia.

Quantitatively Evaluating the Relationships between Insulin Resistance and Retinal Neurodegeneration with Optical Coherence Tomography in Early Type 2 Diabetes Mellitus

Introduction: The aim of this study was to quantitatively assess retinal neurodegenerative changes with optical coherence tomography (Cirrus HD-OCT) in type 2 diabetes mellitus (T2DM) patients without diabetic retinopathy (DR) and evaluate their relationships with insulin resistance (IR) and associated systemic indicators. Methods: 102 T2DM patients without DR and 48 healthy controls were included in this observational cross-sectional study. The OCT parameters of macular retinal thickness (MRT) and ganglion cell-inner plexiform layer (GCIPL) thicknesses were evaluated between diabetic and normal eyes. The receiver operating characteristics (ROC) curve was generated to evaluate the discrimination power of early diabetes. Correlation and multiple regression analysis were performed between ophthalmological parameters and T2DM-related demographic and anthropometric variables, and serum biomarkers and homeostasis model assessment of insulin resistance (HOMA-IR) scores. Results: MRT and GCIPL thicknesses showed significant thinning in patients, especially in inferotemporal area. High body mass index (BMI) correlated with decreased GCIPL thicknesses and elevated intraocular pressure (IOP). A negative correlation between waist-to-hip circumference ratio (WHR) and GCIPL thicknesses was also found. High-density lipoprotein (HDL) and fasting C-peptide (CP0) were associated with GCIPL thickness but only in inferotemporal region (r = 0.20, p = 0.04; r = −0.20, p = 0.05, respectively). Multiple regression analysis showed that increased HOMA-IR scores independently predicted both average (β = −0.30, p = 0.05) and inferotemporal (β = −0.34, p = 0.03) GCIPL thinning. Conclusion: Retinal thinning in early T2DM was associated with obesity-related metabolic disorders. IR as an independent risk factor for retinal neurodegeneration may increase the risk of developing glaucoma.

Longitudinal change of peripapillary vessel density and retinal nerve fibre layer thickness in normal tension and primary angle closure glaucoma

PurposeTo compare the rates of peripapillary vessel density (pVD) loss and retinal nerve fibre layer (RNFL) thinning in normal tension glaucoma (NTG) and primary angle closure glaucoma (PACG).MethodsBaseline age and...

Three-dimensional choroidal vascularity index in central serous chorioretinopathy using ultra-widefield swept-source optical coherence tomography angiography.

BackgroundTo map and compare the three-dimensional choroidal vascularity index (3D-CVI) in eyes with unilateral central serous chorioretinopathy (CSC), fellow eyes and control eyes using ultra-widefield swept source optical coherence tomography (UWF SS-OCTA).MethodsIn this prospective observational study, the 3D-CVIs were measured in 9 subfields or 1 × 1 mm grids by the UWF SS-OCTA with a viewing angle of horizontal 24 × vertical 20 mm. The proportions of vortex vein anastomoses and their corresponding CVI in the central regions were compared among the CSC, fellow and control eyes. Correlations of CVI and vascular density of the large choroidal vessel layer/choriocapillaris layer/choroidal thickness (CT) were also assessed.ResultsThirty-two eyes in 32 patients with unilateral CSC and 32 normal eyes were included in the study. The mean CVI in the eyes with CSC was significantly greater than that in the fellow eyes of CSC and control eyes (41.99 ± 3.56% vs. 40.38 ± 3.855%, P = 0.003; 41.99 ± 3.56% vs. 38.93 ± 4.067%, P = 0.004, respectively). The CVIs in superotemporal, inferotemporal and inferonasal regions were significantly higher in CSC eyes than control eyes (P = 0.03, P = 0.02, P = 0.008). In CSC eyes, there was a linear positive correlation between 3D-CVI and vascular density of the large choroidal vessel layer and CT in all subfields. The proportion of vortex vein anastomoses in CSC was 25/32 (78.1%), and significantly higher in fellow and control eyes (P < 0.001). The average central CVI was significantly higher in CSC eyes with anastomoses than in CSC eyes without anastomoses (42.8 ± 5.1% vs. 38.4 ± 2.7%, P = 0.039). CVIs in superior, central, inferior, superonasal, nasal and inferonasal regions were significantly correlated with vortex vein anastomoses (P < 0.05), regardless of CSC, fellow or healthy eyes. In addition, whether there were vortex vein anastomoses, CVI in superotemporal region was significantly higher in eyes with CSC (P = 0.002) and fellow eyes (P = 0.014), compared to control eyes. No significant correlation was found between hypertension and CVIs in the three groups.ConclusionRemodeling of choroidal drainage routes by venous anastomosis between superior and inferior vortex veins may be common in CSC. The 3D-CVI could be a comprehensive parameter to evaluate the choroid vasculature and help understand the pathogenesis of pachychoroid spectrum disease.

Decrease in Tear Film Lipid Layer Thickness in Patients with Keratoconus.

Keratoconus (KC) is a progressive corneal disorder characterized by thinning and protrusion, mostly of the inferotemporal and central corneal regions. Dysfunction of the meibomian gland, the excretions of which form the lipid layer of the tear film, has been reported to be associated with KC. Thus, this manuscript investigates the correlation among lipid layer thickness (LLT), partial blink rate (PBR), and KC of different degrees. This retrospective study included 54 patients and 24 healthy controls. The anterior corneal curvature, LLT, and PBR were taken from the unilateral eye of all 78 participants. The difference in those ocular parameters between the moderate and severe groups and the control group is significant. No significant association was found between anterior corneal curvature and LLT (r = −0.2, p = 0.15) across all the patients. However, there was a significant negative correlation between anterior corneal curvature and LLT in moderate (r = −0.6, p < 0.05) and severe (r = −0.7, p < 0.05) keratoconus cases. The results also show a significant negative correlation between anterior corneal curvature and PBR (r = −0.41, p < 0.05). Therefore, we conclude that the severity of keratoconus is associated with the thinning of LLT and the reduction of PBR. This may relate to a further epithelial abnormality with the reduced protection of tear film from the air, leading to the release of proteolytic enzymes that degrade stromal collagen and weaken the cornea.

Advanced ultrawide-field optical coherence tomography angiography identifies previously undetectable changes in biomechanics-related parameters in nonpathological myopic fundus.

Purpose: To detect previously undetectable changes in vessel density and structural thickness, the two biomechanics-related parameters reflecting hemodynamics and tensile strength, respectively, in the peripheral and central fundi of nonpathological myopic eyes with an advanced ultrawide-field optical coherence tomography angiography (OCTA) system. Methods: A cross-sectional observational clinical study was carried out by recruiting 155 eyes from 79 college students aged 18–28 years. The eyes were stratified into normal, low-myopia, medium-myopia, and high-myopia groups according to diopter. A newly developed OCTA system with scanning dimensions of 24 mm × 20 mm, acquisition speed of 400 kHz, and imaging range of 6 mm was used to examine the vessel densities of superficial vascular complex (SVC), deep vascular complex (DVC), choriocapillary (ChC), and choroidal vessel (ChV) layers, as well as the thicknesses of the inner retina, outer retina, and choroid in the nonpathological myopic eyes. Results: The vessel densities in ChV at the temporal, inferotemporal, inferior, and inferonasal regions in the fundus periphery were significantly reduced in myopic subjects as compared to normal controls (all p < 0.05). The thicknesses of the inner retinal segments in most peripheral regions of the fundus became attenuated along with myopia severity (all p < 0.05). The thicknesses of the outer retinal segments were diminished at the superior and supranasal regions of the peripheral fundi of myopic subjects as compared to normal controls (all p < 0.05). At the central macular region, the decreased vessel densities of SVC and DVC were correlated with the attenuated thicknesses of inner retinal segments, respectively (all p < 0.05). Conclusion: As revealed for the first time by the advanced ultrawide-field OCTA system, the two biomechanics-related parameters that include the densities of the choroidal vessels and thicknesses of the inner retina segments were significantly reduced in the periphery of nonpathological myopic fundi and the reductions were associated with myopia severity. At the central macular region, the newly developed device provides consistent results with the previous findings. Therefore, it is important to use the noninvasive, ultrawide-field OCTA with high resolution for early detection of fundus changes in subjects with nonpathological high myopia. Clinical Trial Registration: clinicaltrials.gov, identifier ChiCTR2100054093.

Microvasculature Dropout and Development of Normal Tension Glaucoma in Glaucoma Suspects: The Normal Tension Glaucoma Suspect Cohort Study

To investigate the contribution of vessel parameters to identify normal tension glaucoma (NTG) suspects at risk of NTG development. Multicenter prospective cohort study. A total of 307 eyes of 307 NTG suspects having intraocular pressure within the normal range; a suspicious optic disc, but without definite localized retinal nerve fiber layer (RNFL) defects; and a normal visual field (VF). To measure laminar vessel density (VD), the VD was measured in the intradisc region from images of the deep vascular layers of optical coherence tomography angiography (OCT-A). Conversion to NTG was defined either by a new localized RNFL defect in the superotemporal or inferotemporal region, or the presence of a glaucomatous VF defect on 2 consecutive tests according to the pattern deviation plots. Conversion to NTG. In total, 73 (23.8%) of the 307 NTG suspects converted to NTG during the follow-up period of 59.84 ± 12.44 months. Detection rate of microvasculature dropout (MvD) was significantly higher in NTG suspects who progressed to NTG (50.7%) than in those who did not (6.4%; P < .001). The macular deep VD (P=.006) and laminar deep VD (P=.004) were significantly lower in NTG suspects who progressed to NTG. The presence of MvD (P < .001) and lower laminar deep VD (P=.006) were significantly associated with NTG conversion. NTG suspects with baseline MvD or a lower laminar deep VD on OCT-A had a higher risk of conversion.

Correlation of Clinical Fibrillar Layer Detection and Corneal Thickness in Advanced Fuchs Endothelial Corneal Dystrophy.

Central subendothelial geographic deposits are formed as a fibrillar layer (FL) in advanced Fuchs endothelial corneal dystrophy (FECD). Previous studies demonstrated a significant decrease in corneal endothelial cell (CEC) density and an increase in focal corneal backscatter in the FL area. The present study investigated the association of the FL with edema formation and its localization. Patients (n = 96) presenting for Descemet membrane endothelial keratoplasty (DMEK) for advanced FECD were included. Slit-lamp biomicroscopy with FECD grading was followed by Scheimpflug imaging with en face backscatter analysis and pachymetric analysis. FL dimensions were measured, and correlation with pachymetric values was performed. An FL was detected in 74% of all eyes (n = 71). Pachymetric values in FL-positive versus FL-negative eyes were for corneal thickness at the apex (ACT) 614 ± 52 µm and 575 ± 46 µm (p = 0.001), for peripheral corneal thickness at 1 mm (PCT1mm) 616 ± 50 µm and 580 ± 44 µm (p = 0.002), for PCT2mm 625 ± 48 µm and 599 ± 41 µm (p = 0.017), for PCT3mm 651 ± 46 µm and 635 ± 40 µm (p = 0.128) and for PCT4mm 695 ± 52 µm and 686 ± 43 µm (p = 0.435), respectively. Correlation analysis indicated a weak correlation for the FL maximum vertical caliper diameter with ACT and PCT1mm values but no further relevant correlations. In FL-positive eyes, increased focal corneal backscatter and increased corneal thickness showed primarily central and inferotemporal localization. In conclusion, Scheimpflug imaging shows an association of the FL with increased corneal thickness in advanced FECD and shows localization of the FL and increased corneal thickness in the central and inferotemporal region. This may provide important information for progression assessment and therapeutic decision making in FECD patients in the future.

Activity in perirhinal and entorhinal cortex predicts perceived visual similarities among category exemplars with highest precision.

Vision neuroscience has made great strides in understanding the hierarchical organization of object representations along the ventral visual stream (VVS). How VVS representations capture fine-grained visual similarities between objects that observers subjectively perceive has received limited examination so far. In the current study, we addressed this question by focussing on perceived visual similarities among subordinate exemplars of real-world categories. We hypothesized that these perceived similarities are reflected with highest fidelity in neural activity patterns downstream from inferotemporal regions, namely in perirhinal (PrC) and anterolateral entorhinal cortex (alErC) in the medial temporal lobe. To address this issue with functional magnetic resonance imaging (fMRI), we administered a modified 1-back task that required discrimination between category exemplars as well as categorization. Further, we obtained observer-specific ratings of perceived visual similarities, which predicted behavioural discrimination performance during scanning. As anticipated, we found that activity patterns in PrC and alErC predicted the structure of perceived visual similarity relationships among category exemplars, including its observer-specific component, with higher precision than any other VVS region. Our findings provide new evidence that subjective aspects of object perception that rely on fine-grained visual differentiation are reflected with highest fidelity in the medial temporal lobe.

Relationship of macular ganglion cell complex thickness to choroidal microvasculature drop-out in primary open-angle glaucoma

Background/aimsTo investigate the rate of ganglion cell complex (GCC) thinning in primary open-angle glaucoma (POAG) patients with and without deep-layer microvasculature drop-out (MvD).MethodsPOAG patients who had at least 1.5 years...

GlauNet: Glaucoma Diagnosis for OCTA Imaging Using a New CNN Architecture

Glaucoma is a neurodegenerative disease that affects the optic nerve head and causes visual field defect. Current investigations focus on neural component which may overlook other important factors such as the vascular cause. The optical coherence tomography angiography (OCTA) imaging has been developed and provided quantitative parameters that showed good diagnostic accuracy to detect glaucoma. However, those parameters are based on image processing of observed clinical findings, therefore, some image information can be lost. Convolutional neural network has been successfully applied for automatic feature extraction and object classification. In this study, the glaucoma diagnosis network, namely GlauNet, has been proposed. GlauNet consists of two sections: the feature-extraction section and the classification section. The feature-extraction section has three convolutional layers. Each convolutional layer is followed by rectified linear unit and maximum pooling layer. The classification section contains five fully connected layers. GlauNet was trained with 258 glaucomatous and 439 non-glaucomatous eyes. The visualization of the feature-extraction section showed the highlight in the area of optic nerve head and retinal nerve fiber layer in the superotemporal and inferotemporal regions. It was then tested on 27 glaucomatous and 48 non-glaucomatous eyes. Its sensitivity and specificity were 88.9% with 89.6%, respectively. The area under receiver operating characteristic curve of GlauNet was 0.89. GlauNet was robust against the artifacts. Its sensitivity and specificity were still higher than 80% (82.4% and 80.3%, respectively) when tested on 88 poor-quality images.

REGIONAL VARIATION IN FLUID RESERVOIR THICKNESS, OXYGEN TRANSMISSIBILITY AND CORNEAL OEDEMA DURING SCLERAL LENS WEAR

Purpose: To determine if regional variation in post lens fluid reservoir thickness (PLFT) during scleral lens wear leads to regional variation in oxygen transmissibility and corneal edema during 4 hours of non-fenestrated scleral lens wear.Methods: About 20 healthy subjects (mean age, 28.8 ± 4.2 years) were fitted with nonfenestrated rotationally symmetric scleral lenses. Anterior segment optical coherence tomography was used to measure cornea thickness before and after lens wear, PLFT 10 minutes and 4 hours after lens application, and scleral lens thickness (with the scleral lens in situ) 4 hours after scleral lens application. These measurements were limited to the central 6 mm and divided into three zones (central, mid-peripheral, and peripheral zones). In the mid-peripheral and peripheral zones, eight principal meridians were measured, generating 17 measurement points in total. Scleral lens thickness and PLFT measurements were corrected for optical distortions by a series of equations. Oxygen transmissibility was calculated by dividing the scleral lens oxygen permeability by the optically-corrected scleral lens thickness, taking into account the oxygen permeability of saline and fluid reservoir thickness.Results: A significant regional variation in PLFT (F = 12.860, P = 0. 012) was observed after 10 minutes of the lens application, PLFT was thickest and thinnest in the inferotemporal and the superonasal region of the peripheral zones( 322.6 ± 161.8 µm and 153.8 ± 96.4 µm, respectively); however, this variation was not statistically significant at 4 hours of scleral lens wear (F = 4.692; P = 0.073). Despite significant regional variation in oxygen transmissibility (F = 48.472; P = 0.001) and relatively low oxygen transmissibility through the scleral lens, induced corneal edema did not vary significantly in different regions (F = 3.346; P = 0.126). In the central corneal region, the induced corneal edema correlated moderately with PLFT (r = 0.468; P = 0.037) and oxygen transmissibility (r = -0.528; P = 0.017). This relationship was insignificant in the peripheral cornea.Conclusion: The inferotemporal peripheral region had the thickest PLFT and least oxygen transmissibility, and the superonasal region had the vice versa. Despite significant variation in PLFT and oxygen transmissibility initially, in healthy corneas, this variation does not seem to induce statistically significant regional variation in corneal edema. Increased central PLFT and decreased oxygen transmissibility moderately correlate with central corneal edema.