Eccentricity Effect of Deformation Detection for Radial Frequency Patterns With Their Centers at Fixation Point

We measured the eccentricity effect of deformation thresholds of circular contours for two types of the radial frequency (RF) patterns with their centers at the fixation point: constant circular contour frequency (CCF) RF patterns and constant RF magnified (retino-cortical scaling) RF patterns. We varied the eccentricity by changing the mean radius of the RF patterns while keeping the centers of the RF patterns at the fixation point. Our peripheral stimulus presentation was distinguished from previous studies which have simply translated RF patterns at different locations in the visual field. Sensitivity for such shape discrimination fell off as the moderate and high CCF patterns were presented on more eccentric sites but did not as the low CCF patterns. However, sensitivity held constant as the magnified RF patterns were presented on more eccentric sites, indicating that the eccentricity effects observed for the high and moderate CCF patterns were neutralized by retinocortical mapping. Notably, sensitivity for the magnified RF patterns with large radii (4°–16°) presented in the peripheral field revealed a similar RF dependence observed for RF patterns with small radii (0.25°–1.0°) presented at the fovea in previous studies.

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Optical coherence tomography angiography and Humphrey field analyser for macular capillary non-perfusion evaluation in branch retinal vein occlusion

Scientific Reports ◽

10.1038/s41598-021-84240-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hiroko Terashima ◽

Fumiki Okamoto ◽

Hiruma Hasebe ◽

Eriko Ueda ◽

Hiromitsu Yoshida ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Visual Field ◽

Retinal Vein Occlusion ◽

Branch Retinal Vein Occlusion ◽

Oct Angiography ◽

Vein Occlusion ◽

Field Sensitivity ◽

Field Analyser ◽

Capillary Plexus ◽

The Mean

AbstractWe non-invasively evaluated macular non-perfused areas (m-NPAs) of branch retinal vein occlusion (BRVO) using optical coherence tomography (OCT) angiography and the Humphrey visual field analyser 10-2 programme (HFA 10-2). We enrolled 30 patients (30 eyes) with macular oedema secondary to BRVO. OCT angiography was used to photograph the macula at 6 × 6-mm; sizes of m-NPAs in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were measured in four areas. For HFA 10-2, we divided the actual measurement threshold of 68 points into four areas and calculated the mean central visual field sensitivity (CVFS). The correlation between the mean m-NPA and mean CVFS (dB) in each area was examined. There was a strong correlation between the m-NPA of each region detected in SCP and DCP, and the mean CVFS of each corresponding area (SCP: r = − 0.83, r = − 0.64, r = − 0.73, and r = − 0.79; DCP: r = − 0.82, r = − 0.71, r = − 0.71, and r = − 0.70), p values were < 0.001 for all. m-NPAs were associated with decreased visual field sensitivity in BRVO. Non-invasive m-NPA evaluation was possible using OCT angiography and HFA 10-2.

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Correlation between fundus autofluorescence and visual function in patients with cone-rod dystrophy

Scientific Reports ◽

10.1038/s41598-021-81597-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Satoru Kanda ◽

Takumi Hara ◽

Ryosuke Fujino ◽

Keiko Azuma ◽

Hirotsugu Soga ◽

...

Keyword(s):

Visual Field ◽

Significant Relationship ◽

Fundus Autofluorescence ◽

Univariate Analysis ◽

Retrospective Chart Review ◽

Mean Deviation ◽

Wide Field ◽

The Mean ◽

The Relationship ◽

Field Imaging

AbstractThis study aimed to investigate the relationship between autofluorescence (AF) signal measured with ultra-wide field imaging and visual functions in patients with cone-rod dystrophy (CORD). A retrospective chart review was performed for CORD patients. We performed the visual field test and fundus autofluorescence (FAF) measurement and visualized retinal structures with optical coherence tomography (OCT) on the same day. Using binarised FAF images, we identified a low FAF area ratio (LFAR: low FAF/30°). Relationships between age and logMAR visual acuity (VA), central retinal thickness (CRT), central choroidal thickness (CCT), mean deviation (MD) value, and LFAR were investigated. Thirty-seven eyes of 21 CORD patients (8 men and 13 women) were enrolled. The mean patient age was 49.8 years. LogMAR VA and MD were 0.52 ± 0.47 and − 17.91 ± 10.59 dB, respectively. There was a significant relationship between logMAR VA and MD (p = 0.001). LogMAR VA significantly correlated with CRT (p = 0.006) but not with other parameters. Conversely, univariate analysis suggested a significant relationship between MD and LFAR (p = 0.001). In the multivariate analysis, LFAR was significantly associated with MD (p = 0.002). In conclusion, it is useful to measure the low FAF area in patients with CORD. The AF measurement reflects the visual field deterioration but not VA in CORD.

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What do patients with glaucoma see: a novel iPad app to improve glaucoma patient awareness of visual field loss

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-317034 ◽

2020 ◽

pp. bjophthalmol-2020-317034

Author(s):

Meghal Gagrani ◽

Jideofor Ndulue ◽

David Anderson ◽

Sachin Kedar ◽

Vikas Gulati ◽

...

Keyword(s):

Visual Field ◽

Vision Loss ◽

Peripheral Vision ◽

Glaucoma Patient ◽

Visual Field Loss ◽

Sensitivity Threshold ◽

Roc Curve Analysis ◽

The Mean ◽

Ipad App ◽

Field Defects

PurposeGlaucoma patients with peripheral vision loss have in the past subjectively described their field loss as ‘blurred’ or ‘no vision compromise’. We developed an iPad app for patients to self-characterise perception within areas of glaucomatous visual field loss.MethodsTwelve glaucoma patients with visual acuity ≥20/40 in each eye, stable and reliable Humphrey Visual Field (HVF) over 2 years were enrolled. An iPad app (held at 33 cm) allowed subjects to modify ‘blur’ or ‘dimness’ to match their perception of a 2×2 m wall-mounted poster at 1 m distance. Subjects fixated at the centre of the poster (spanning 45° of field from centre). The output was degree of blur/dim: normal, mild and severe noted on the iPad image at the 54 retinal loci tested by the HVF 24-2 and was compared to threshold sensitivity values at these loci. Monocular (Right eye (OD), left eye (OS)) HVF responses were used to calculate an integrated binocular (OU) visual field index (VFI). All three data sets were analysed separately.Results36 HVF and iPad responses from 12 subjects (mean age 71±8.2y) were analysed. The mean VFI was 77% OD, 76% OS, 83% OU. The most common iPad response reported was normal followed by blur. No subject reported dim response. The mean HVF sensitivity threshold was significantly associated with the iPad response at the corresponding retinal loci (For OD, OS and OU, respectively (dB): normal: 23, 25, 27; mild blur: 18, 16, 22; severe blur: 9, 9, 11). On receiver operative characteristic (ROC) curve analysis, the HVF retinal sensitivity cut-off at which subjects reported blur was 23.4 OD, 23 OS and 23.3 OU (dB).ConclusionsGlaucoma subjects self-pictorialised their field defects as blur; never dim or black. Our innovation allows translation of HVF data to quantitatively characterise visual perception in patients with glaucomatous field defects.

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Functional Monitoring after Trabeculectomy or XEN Microstent Implantation Using Spectral Domain Optical Coherence Tomography and Visual Field Indices—A Retrospective Comparative Cohort Study

Biology ◽

10.3390/biology10040273 ◽

2021 ◽

Vol 10 (4) ◽

pp. 273

Author(s):

Marc Schargus ◽

Catharina Busch ◽

Matus Rehak ◽

Jie Meng ◽

Manuela Schmidt ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Cohort Study ◽

Visual Field ◽

Spectral Domain ◽

Optical Coherence ◽

Treatment Groups ◽

Rnfl Thickness ◽

Comparative Cohort Study ◽

The Mean ◽

All Treatment

The aim of this study was to compare the efficacy of trabeculectomy (TE), single XEN microstent implantation (solo XEN) or combined XEN implantation and cataract surgery (combined XEN) in primary open-angle glaucoma cases, naïve to prior surgical treatment, using a monocentric retrospective comparative cohort study. Intraocular pressure (IOP) and the number of IOP-lowering drugs (Meds) were monitored during the first 24 months after surgery. Further disease progression was monitored using peripapillary retinal nerve fiber layer (RNFL) thickness examinations using spectral domain optical coherence tomography (OCT) as well as visual acuity (VA) and visual field (VF) tests. In the TE group (52 eyes), the mean IOP decreased from 24.9 ± 5.9 to 13.9 ± 4.2 mmHg (p < 0.001) and Meds decreased from 3.2 ± 1.2 to 0.5 ± 1.1 (p < 0.001). In the solo XEN (38 eyes) and the combined XEN groups, the mean IOP decreased from 24.1 ± 4.7 to 15.7 ± 3.0 mmHg (p < 0.001) and 25.4 ± 5.6 to 14.7 ± 3.2 mmHg (p < 0.001), while Meds decreased from 3.3 ± 0.8 to 0.8 ± 1.2 (p < 0.001) and 2.7 ± 1.2 to 0.4 ± 1.0 (p < 0.001), respectively. The VF and VA indices showed no sign of further deterioration, the RNFL thickness further decreased in all treatment groups after surgery. TE and XEN led to comparable reductions in IOP and Meds. Although the VA and VF indices remained unaltered, the RNFL thickness continuously decreased in all treatment groups during the 24-month follow-up.

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Relationship between mean follow-up intraocular pressure, rates of visual field progression and current target intraocular pressure guidelines

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-317406 ◽

2020 ◽

pp. bjophthalmol-2020-317406

Author(s):

Bruna Melchior ◽

Carlos Gustavo De Moraes ◽

Jayter S Paula ◽

George A Cioffi ◽

Christopher A Girkin ◽

...

Keyword(s):

Intraocular Pressure ◽

Visual Field ◽

Treatment Guidelines ◽

Evaluation Study ◽

Mean Deviation ◽

Racial Groups ◽

Current Guideline ◽

Registration Number ◽

The Mean

AimsTo investigate if eyes presenting intraocular pressure (IOP) within the limits of current guideline-driven target IOP indeed experience slow rates of glaucomatous visual field (VF) progression.MethodsA total of 8598 24-2 VF tests from 603 eyes from the African Descent and Glaucoma Evaluation Study with manifest glaucoma were included. The sample was split into three groups based on baseline VF mean deviation (MD): G1 (better than −5.0 dB), G2 (−5.0 to −10 dB) and G3 (worse than −10 dB). We investigated the relationship between existing target IOP guidelines and rates of MD progression in these groups.ResultsFor stable eyes, the medians and IQR of the mean follow-up IOP were G1=15.0 mmHg (IQR: 13.1 to 17.7), G2=13.2 mmHg (IQR: 11.6 to 14.3) and G3=11.9 mmHg (IQR: 10.1 to 13.8) (p<0.01). When considering the mean follow-up IOP within the limits proposed by current guidelines, the median MD slopes were: −0.20 dB/y (IQR: −0.43 to −0.02) for G1<21 mmHg, −0.19 dB/y (IQR: −0.51 to −0.01) for G2<18 mmHg and −0.15 dB/y (IQR: −0.47 to 0.05) for G3<15 mmHg (p=0.63). There were no significant differences between racial groups.ConclusionIn a sample of patients with manifest glaucoma, despite substantial variability between eyes, adherence to treatment guidelines helped slow the rates of global VF progression at various stages of disease.Trial registration numberclinicaltrials.gov Identifier: NCT00221923.

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Milling Force Prediction for Circular Contour Machining

Materials Science Forum ◽

10.4028/www.scientific.net/msf.800-801.243 ◽

2014 ◽

Vol 800-801 ◽

pp. 243-248

Author(s):

Kai Zhao ◽

Zhan Qiang Liu

Keyword(s):

Prediction Model ◽

Milling Process ◽

Machining Process ◽

Curvature Radius ◽

Force Model ◽

Milling Force ◽

Circular Contour ◽

The Mean ◽

Contour Machining ◽

Matlab Programming

When machining the complex parts of aircraft engines, the milling force for the circular contour must be accurately predicted to reduce machining vibration. In this paper, the prediction model of the mean milling force per tooth during machining circular contour is developed. Firstly, the formulas of the entry angle, the exit angle and the equivalent feed per tooth are established through the analysis of circular contour milling process. Then, the equation of the mean milling force per tooth is deduced based on mechanistic force model during the circular contour machining process. Finally, the prediction model of mean milling force per tooth during machining circular contour is developed using MATLAB programming. The relationship between the milling force per tooth and surface curvature radius of the machined workpiece is also analyzed in this paper.

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Deficits in Complex Visual Perception Following Unilateral Temporal Lobectomy

Journal of Cognitive Neuroscience ◽

10.1162/089892998562816 ◽

1998 ◽

Vol 10 (3) ◽

pp. 395-407 ◽

Cited By ~ 11

Author(s):

Krystel R. Huxlin ◽

William H. Merigan

Keyword(s):

Visual Field ◽

Visual Perception ◽

Temporal Cortex ◽

Stimulus Presentation ◽

Texture Segmentation ◽

Temporal Lobectomy ◽

Long Term Memory ◽

Additional Control ◽

Short And Long Term ◽

Visual Discriminations

Although human temporal cortex is known to be important for short- and long-term memory, its role in visual perception is not well understood. In this study, we compared the performance of three patients with unilateral temporal lobectomies to that of normal controls on both fisimplefl and ficomplexfl visual discriminations that did not involve explicit memory components. Two types of complex tasks were tested that involved discriminations secondary to texture segmentation. These were contrasted with simple discriminations using luminance-defined stimuli. Patients showed impaired thresholds only on tasks involving texture segmentation, performing as well as controls when the targets were defined by luminance rather than texture. The minimum stimulus presentation times for threshold performance were also measured for all tasks and found to be elevated in temporal lobectomy patients relative to controls. Although the magnitude of the deficits observed was substantial, loss was equivalent in ipsi- and contra-lesional regions of the visual field. Additional control experiments showed that the patients' perceptual deficits were not due, even in part, to disturbances of basic visual capacities such as acuity and contrast sensitivity. Our results indicate that temporal lobe damage disrupts complex, but not simple, visual discriminations throughout the visual field.

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