Frequency Doubling Technology Research Articles

MODERN METHODS FOR DIAGNOSTICS OF GLAUCOMA

Glaucoma is a chronic optical neuropathy characterized by loss of ganglion cells with the development of specific changes in the optic nerve head (ONH) and retinal nerve fiber layer (RNFL). Early detection of the disease plays an important role in preventing the development structural abnormalities and irreversible vision loss. Diagnosis of glaucoma is based on assessing the safety of optic nerve structures and visual functions results clinical examination of the optic disc and RNFL are subjective and vary greatly. In connection with this, research in recent years has been aimed at developing additional objective methods for diagnosing glaucoma. The possibility of using confocal scanning laser ophthalmoscopy, scanning laser perimetry and optical coherence tomography to assess the condition of the optic disc. In order to ensure early detection of visual field defects options are currently being considered replacing standard automated perimetry (SAP) with selective, which includes short-wavelength automated perimetry (SWAP) and perimetry with the illusion of spatial doubling frequencies (frequency-doubling technology perimetry, FDT). The article is an overview modern method for diagnosing glaucoma in the context of their use in clinical practice.

New possibilities of perimetry in screening and early diagnosis of glaucoma

PURPOSE. To study the diagnostic effectiveness of an improved software version of the well-known authors' modification of Frequency Doubling Technology (FDT) perimetry by comparing it with the previous software version and standard automated perimetry on the same contingent of healthy individuals and patients with primary open-angle glaucoma (POAG).METHODS. The study included 56 patients (105 eyes) (mean age 61±13.2 years) with POAG. Patients were divided into three groups depending on the stage of glaucoma: group 1 — early stage (39 eyes), group 2 — moderate (25 eyes), and group 3 — advanced (9 eyes) stage. The fourth (control) group included 32 eyes of 16 healthy people (average age 48.2±6.2 years). All study subjects underwent standard automated perimetry (SAP) on the Humphrey III visual field analyzer and non-standard perimetry in the form of our own modification of FDT perimetry and its improved software version — FDT VR version based on the new portable automatic perimeter "Stimulus" (OOO Total Vizhen, Russia). The optic nerve disc was evaluated on the Heidelberg Retina Tomograph 3.RESULTS. The software version of the authors' modification of FDT perimetry has been improved for liquid crystal monitors and adapted to the portable perimeter "Stimulus". When comparing diagnostic effectiveness, both variants of FDT perimetry are not inferior to SAP in sensitivity (87.6; 87.8 and 86.7%, respectively), and in terms of specificity (98.2; 98.1 and 84.4%, respectively) they are superior. A strong (r=0.99988) and reliable (p<0.05) correlation was found between the average values of light sensitivity for both variants of FDT perimetry.CONCLUSION. The introduction of FDT perimetry based on the new portable automatic perimeter "Stimulus" into widespread ophthalmological practice can contribute to improving the effectiveness of screening and early diagnosis of glaucoma.

Relationship of structural and functional visual biomarkers with measures of amyloid, tau, and neurodegeneration across the AD continuum

AbstractBackgroundThe eye often reflects changes seen in the brain in neurodegenerative diseases. This study sought to examine the relationship of contrast sensitivity measured using frequency doubling technology (FDT) and retinal thickness measured using optical coherence tomography (OCT) with temporal lobe neurodegeneration, cerebral tau deposition, and mean plasma ptau181 in older adults along the Alzheimer’s disease (AD) continuum.MethodParticipants included 28 individuals with subjective cognitive decline (SCD), 18 mild cognitive impairment (MCI), 4 with AD, and 30 age‐matched cognitive normal (CN) from the Indiana Memory and Aging Study at the Indiana ADRC. Participants were excluded from the study if they had significant eye disease determined to interfere with OCT, FDT, non‐AD dementia, or exclusion for MRI or PET. Mean deviation (MD) and pattern standard deviation (PSD) from FDT were used as measures of contrast sensitivity. OCT scans from each eye to measure retinal thickness in the retinal nerve fiber layer (RNFL) and macula. MRI scans were processed using Freesurfer v6 to measure medial (MTL) and lateral temporal lobe (LTL) volumes. LTL SUVR values were extracted from [18F]flortaucipir PET scans. Plasma ptau 181 was measured using a SIMOA assay. Finally, the association between contrast sensitivity, average RNFL thickness, macular volumes with temporal lobe volumes, LTL tau, and mean plasma ptau181 was assessed using a partial Pearson correlation, covaried for age, sex, and diagnosis. p<0.05 was considered significant.ResultRNFL thickness was decreased in patients with AD. Hippocampal volume correlated with RNFL thickness and macular volume in both eyes and with PSD in the left eye. The inferior temporal volume correlated with MD in both eyes, while mean plasma ptau181 with PSD in both eyes. Finally, lateral temporal lobe tau was correlated with the inner retinal layers of ganglion cell layer plus inner plexiform layer thickness.ConclusionContrast sensitivity correlates with temporal lobe volumes and mean plasma ptau181. RNFL thinning and macular volumes are associated with hippocampal atrophy, and inner retinal nuclear layers correlate with lateral temporal tau. Imaging of the eye may represent a useful biomarker to screen patients at risk for AD prior to more invasive and prolonged testing.

All-fiber laser system for all-optical 87Rb Bose Einstein condensate to space application.

In the development of the Cold Atom Physics Research Rack (CAPR) on board the Chinese Space Station, the laser system plays a critical role in preparing the all-optical 87 R b Bose-Einstein condensates (BECs). An all-fiber laser system has been developed for CAPR to provide the required optical fields for atom interaction and to maintain the beam pointing in long-term operation. The laser system integrates a 780nm fiber laser system and an all-fiber optical control module for sub-Doppler cooling, as well as an all-fiber 1064nm laser system for evaporative cooling. The high-power, single-frequency 780nm lasers are achieved through rare-Earth doped fiber amplification, fiber frequency-doubling, and frequency stabilization technology. The all-fiber optical control module divides the output of the 780nm laser system into 15 channels and regulates them for cooling, trapping, and probing atoms. Moreover, the power consistency of each pair of cooling beams is ensured by three power tracking modules, which is a prerequisite for maintaining stable MOT and molasses. A high-power, compact, controlled-flexible, and highly stable l064nm all-fiber laser system employing two-stage ytterbium-doped fiber amplifier (YDFA) technology has been designed for evaporative cooling in the optical dipole trap (ODT). Finally, an all-optical 87 R b BEC is realized with this all-fiber laser system, which provides an alternative solution for trapping and manipulating ultra-cold atoms in challenging environmental conditions.

The Association Between Frailty and Visual Field Loss in US Adults

To describe the association between visual field loss and frailty in a nationally representative cohort of US adults. Retrospective cross-sectional study. The cohort included adults 40 years or older with complete eye examination data from the 2005-2006 and 2007-2008 National Health and Nutrition Examination Surveys (NHANES). Visual field loss (VFL) was determined by frequency doubling technology and a 2-2-1 algorithm. A 36-item deficit accumulation-based frailty index was used to divide subjects into 4 categories of increasing frailty severity. Of the 4897 participants, 4402 (93.2%) had no VFL, 301 (4.1%) had unilateral VFL, and 194 (2.73%) had bilateral VFL. Within the sample, 2 subjects197 (53.1%) were categorized as non-frail, 1659 (31.3%) as vulnerable, 732 (11.3%) as mildly frail, and 312 (4.3%) as most frail. In multivariable models adjusted for demographics, visual acuity, and history of cataract surgery, subjects with unilateral VFL had higher adjusted odds of being in a more frail category (adjusted odds ratio [aOR], 2.07; 95% CI, 1.42-3.02) than subjects without VFL. Subjects with bilateral VFL also had higher odds of a more frail category compared to subjects without VFL (aOR, 1.74; 95% CI, 1.20-2.52). In the 2005-2008 NHANES adult population, VFL is associated with higher odds of frailty, independent of central visual acuity loss. Frail individuals may be more susceptible to diseases that can cause VFL, and/or VFL may predispose to frailty. Additional studies are needed to determine the directionality of this relationship and to assess potential interventions.

Prevalence and Cause of Loss of Visual Acuity and Visual Field in Highly Myopic Eyes: The Beijing Eye Study

To explore prevalence and causes of loss of visual acuity and visual field in highly myopic eyes. Population-based study. The participants (n=4439) of the Beijing Eye Study underwent an ophthalmological and systemic examination including frequency doubling technology perimetry (FDT). High myopia was defined by a refractive error of ≤-6Dpt or axial length >26.0 mm. Prevalence of vision impairment causes. The study included 212 highly myopic eyes (154 participants;mean age:56.2±9.6 years;refractive error:-9.87±3.70 Dpt;range:-20.87 to -6.00Dpt; axial length:27.2±1.3mm;range:26.01-30.88mm). Moderate/severe vision impairment (MSVI) (best corrected visual acuity (BCVA) from <6/18 to 3/60) and blindness (BCVA <3/60 or <10° visual field around central fixation) was present in 40/212 (18.9%;95%CI:13.6,24.2) eyes, and in 10/212 (4.7%;95%CI:1.8, 7.6) eyes, respectively. BCVA decreased with more myopic refractive error (beta:-0.55;B:-0.08;95%CI:-0.09,-0.06;P<0.001). Primary (i.e., most influential) causes for MSVI and blindness were myopic macular degeneration (MMD) (29/50;58%), age-related macular degeneration (1/50;2%), and branch macular retinal vein occlusion (1/50;2%). Secondary causes were MMD (4/50;8%) and optic nerve atrophy (14/50 (28%), differentiated into a non-glaucomatous type (NGOA) (9/50;18%) and glaucomatous type (GOA) (5/50;10%). Prevalence of MMD as vision impairment cause (mean:40/212 (18.9%;95%CI:13.6,24.2) increased from 1/61 (1.6%;95%CI:0.00,4.9) in the group of -6.00 to ≥-7.00Dpt, to 16/25 (64.0%;95%CI:43.8,84.2) in the group of <-15.0Dpt. Higher MMD prevalence correlated with higher myopic refractive error (OR:0.70;95%CI:0.61;0.81;P<0.001) and higher prevalence of concomitant optic neuropathy (OR:86.2;95%CI:16.1,463;P<0.001). Optic neuropathy prevalence as cause of vision impairment (mean:19/212;9.0%;95%CI:5.0,13.0) increased from 0/61 (0%) in the refractive error group of -6.00Dpt to ≥-7.00Dpt, to 9/25 (36.0%;95%CI:16.0,56.0) in the group of <-15.0Dpt. Higher optic neuropathy prevalence correlated with more myopic refractive error (P<0.001) and older age (P=0.02). GOA prevalence (mean:6/212;2.8%;95%CI:1.0,5.0) and NGOA prevalence (mean:13/212 (6.1%;95%CI:3.0,9.0) increased from 0/61 (0%) in the group of -6.00 to ≥-7.00Dpt, to 4/25 (16.0%;95%CI:1.0,31.0) and 5/25 (20%;95%CI:3.0,37.0), respectively, in the group of <-15.0Dpt. In this population-based recruited, highly myopic cohort, prevalence of optic neuropathy (9.0%) as vision impairment cause was lower than MMD prevalence (18.9%), and it was an important reason for vision impairment in the group of <-15Dpt. MMD was vision impairment cause in 16/25 (64.0%) eyes with <-15.0Dpt refractive error.

High-Efficiency Second-Harmonic Generation Using Quasi-Bound State in LiNbO3 Metasurface

We numerically demonstrated a high-efficiency second-harmonic generation (SHG) using quasi-bound state in the continuum (quasi–BIC) in thin film LiNbO3 (TFLN) metasurface. The TFLN possessed exceptionally high second-order nonlinear coefficients, contributing to the enhanced SHG performance. An eccentric cylinder unit cell was presented to achieve high Q–factor resonances associated with the asymmetric parameter introduced. Simulations showed that the high efficiency of the second-harmonic conversion was obtained by using the high Q–factor of the asymmetric dielectric cylinder metasurface, and it achieved a high SHG efficiency of 6.5% at pump intensities as low as 1 MW/cm2 at a normal incident. Furthermore, the simulation results indicated that breaking the symmetry through oblique incidence was more effective in achieving a higher Q–factor compared to altering the structural parameters. Specifically, under 1° oblique incidences, the conversion efficiency could reach 1.2% at an incident power of 1 kW/cm². We have proposed a method to achieve a high conversion efficiency of second-harmonic generation in low-refractive-index materials. Our work not only offers theoretical support but also provides valuable insights for the advancement of efficient nonlinear frequency doubling technology, optical communication, and sensing applications.

The effect of surgical weight loss on diabetes complications in individuals with class II/III obesity.

The aim of this study was to determine the effect of bariatric surgery on diabetes complications in individuals with class II/III obesity (BMI > 35 kg/m2). We performed a prospective cohort study of participants with obesity who underwent bariatric surgery. At baseline and 2 years following surgery, participants underwent metabolic phenotyping and diabetes complication assessments. The primary outcomes for peripheral neuropathy (PN) were a change in intra-epidermal nerve fibre density (IENFD, units = fibres/mm) at the distal leg and proximal thigh, the primary outcome for cardiovascular autonomic neuropathy (CAN) was a change in the expiration/inspiration (E/I) ratio, and the primary outcome for retinopathy was a change in the mean deviation on frequency doubling technology testing. Among 127 baseline participants, 79 completed in-person follow-up (age 46.0 ± 11.3 years [mean ± SD], 73.4% female). Participants lost a mean of 31.0 kg (SD 18.4), and all metabolic risk factors improved except for BP and total cholesterol. Following bariatric surgery, one of the primary PN outcomes improved (IENFD proximal thigh, +3.4 ± 7.8, p<0.01), and CAN (E/I ratio -0.01 ± 0.1, p=0.89) and retinopathy (deviation -0.2 ± 3.0, p=0.52) were stable. Linear regression revealed that a greater reduction in fasting glucose was associated with improvements in retinopathy (mean deviation point estimate -0.7, 95% CI -1.3, -0.1). Bariatric surgery may be an effective approach to reverse PN in individuals with obesity. The observed stability of CAN and retinopathy may be an improvement compared with the natural progression of these conditions; however, controlled trials are needed.

Assessment of the Effectiveness of Different Variants of Frequency Doubling Technology Perimetry in Monitoring the Glaucoma Process

Purpose: To compare the diagnostic effectiveness of non-standard perimetry and standard automated perimetry (SAP) during earlystage monitoring of primary open-angle glaucoma (POAG).Patients and methods. The study involved 30 patients (46 eyes) with early-stage of POAG, aged 30 to 65 years (54.9 ± 1.3), who were under ongoing monitoring for 3 to 4 years (3.50 ± 0.68 years). All subjects, in addition to the standard ophthalmological examination, performed the threshold program “24-2” perimetry using the Humphrey II, the own modification of Frequency Doubling Technology (FDT) Perimetry, in the form of 2 threshold strategies: the wellknown “FDT-16” and the new “FDT-64”. The condition of the optic nerve head (ONH) was assessed using HRT 3 (Heidelberg Retina Tomograph, Germany) and OCT — Topcon 3D OCT- 2000 (TOPCON, Japan). During monitoring, RTVue FD-OCT (Optovue, USA) was additionally performed, evaluating the parameters of the retinal ganglion cell complex (GCC).Results. Regular follow-up, the implementation of the prescribed treatment contributed to the stabilization of glaucoma, as evidenced by the stability of the average MD index values according to all 3 threshold strategies, but reliably (p = 0.000) only according to SAP data. According to the criterion of the number of scotomas, there was a weakly expressed, but statistically significant negative dynamics for all the compared strategies. According to the results of the structural assessment of the ONH (the size of the excavation), a weakly pronounced negative dynamics was obtained in dynamics according to both HRT and OCT data. The average MD index values, the number of scotomas according to the three perimeter strategies and the excavation size based on HRT and OCT in patients with early-stage of POAG turned out to be stronger and more significant using the “FDT-16”, and the correlation characteristics with the results of “24-2” HFA II, “FDT-64” largely coincided.Conclusion. A reliable correlation between structural and functional parameters indicates the feasibility of using “FDT-64” in combination with SAP not only in for the diagnosis of the early-stage of glaucoma, but also in assessing its course. The sensitivity level of the results of “FDT-64” (100 %) compared to “FDT-16” (88 %) in patients with POAG was higher, therefore, “FDT-64” is advisable to use in complex diagnostic cases and in monitoring glaucoma.

Diagnostic Accuracy of Frequency-Doubling Technology and the Moorfields Motion Displacement Test for Glaucoma

Portable perimetric testing could be useful for community-based glaucoma screening programs. Frequency-doubling technology (FDT) and the Moorfields motion displacement test (MDT) are portable perimeters that have shown promise as potential screening tools for glaucoma. This study's goal was to determine the diagnostic accuracy of FDT and MDT for visual field defects and glaucoma. Prospective, cross-sectional, diagnostic accuracy study. A consecutive series of patients aged ≥ 50 years who presented to a glaucoma clinic in South India and had never undergone Humphrey field analyzer (HFA) visual field testing in the past. Participants underwent 24-2 Swedish Interactive Thresholding Algorithm (SITA)Standard HFA perimetry, FDT perimetry, MDT perimetry, and iPad perimetry using visualFields Easy in random order. Ophthalmologist grades of HFA and optic nerve head photographs were used as reference standards for glaucoma and field defect presence. Receiver operating characteristic curves were constructed to assess the diagnostic accuracy of various parameters for each test. Sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). Overall, 292 eyes from 173 participants were included, with 112 eyes classified as moderate or worse glaucoma. For moderate or worse glaucoma detection, the best parameter on FDT was mean deviation (MD) (AUROC, 0.84; 95% confidence interval [CI], 0.79-0.89) and the best parameter on MDT was global probability of true damage (GPTD) (AUROC, 0.87; 95% CI, 0.82-0.91). When specificity was set to 90%, the sensitivity for detection of moderate or worse glaucoma was 55% (95% CI, 39%-68%) for FDT MD and 62% (95% CI 52%-71%) for MDT GPTD. Frequency-doubling technology and MDT perimetry had fair diagnostic accuracy for glaucoma detection when administered to naïve test takers in this South Indian population. Although not appropriate for use as a sole glaucoma screening test, these perimetric tests may be useful as ancillary tests. Proprietary or commercial disclosure may be found after the references.

Case Report: Retinal nerve fiber layer and ganglion cell thinning on spectral domain optical coherence tomography following multiple strokes

A 62-year-old Caucasian male presented for a routine exam with a history of a significant stroke suffered 5 years prior resulting in temporary aphasia and persistent visual field loss. At presentation, best correctable acuities were 20/20+ OU through mild hyperopic astigmatic correction. Visual field testing with frequency doubling technology revealed an incongruous left superior quandrantanopia. Anterior segments demonstrated mild bilateral mixed blepharitis but were otherwise unremarkable. Dilated fundus examination with spectral domain optical coherence tomography revealed moderate disc cupping and marked, symmetric inferior and temporal RNFL thinning, as well as diffuse bilateral ganglion cell thinning. This case demonstrates how OCT can be used as an objective test to detect retrograde neve fiber and ganglion cell loss secondary to post-chiasmal pathology.

Risk factors for glaucoma are reflected in abnormal responses to frequency-doubling technology screening in both normal and glaucoma eyes

The frequency-doubling technology (FDT) screening test (FDT-C-20-1) has adopted in many recent population-based glaucoma surveys, but factors associated with false-positive (FP) responses to FDT-C-20-1 in normal eyes and false-negative (FN) responses in glaucoma eyes were not known. These factors were investigated in a population-based setting using the data from 3805 normal eyes (2381 subjects) and 272 eyes with definite glaucoma (215 subjects) in the Kumejima Study participants with reliable FDT-C-20-1 results. Considering the presence of at least one abnormal test point (P < 0.01) as abnormal, the specificity and sensitivity of FDT-C-20-1 for glaucoma were 91.8% (95% confidence interval, 91.1 ~ 92.5) and 56.3% (47.0 ~ 62.5), respectively. Multivariate linear mixed-model logistic regression analysis showed correlations with older age, worse visual acuity, greater β-peripapillary area (P < 0.001 for all comparisons) and more myopic refraction (P = 0.030) with the FP responses in normal eyes, and normal-tension glaucoma (P = 0.043), a better mean deviation value of Humphrey perimetry (P = 0.001), larger rim area (P = 0.041), and absence of disc hemorrhage (P = 0.015) with the FN responses in glaucoma eyes. In a population-based setting, abnormal responses to FDT-C-20-1 indicate the presence of a risk factor for glaucoma in normal eyes and risk factors for more rapid progression in glaucoma eyes.

Comparison between frequency-doubling technology perimetry and standard automated perimetry in early glaucoma

This study aimed to find out the significance of the difference between frequency-doubling technology perimetry (FDT) and standard automated perimetry (SAP) in terms of the detected visual field (VF) damage, and evaluate associated factors to SAP–FDT difference in early glaucoma. Glaucoma patients in early stage (MD better than − 6.0 decibel, 96 eyes) were included in this cross-sectional study. We subtracted mean deviation (MD) and pattern standard deviation (PSD) of FDT from those of SAP, respectively. Additionally, we counted significantly depressed points of P < 5% and P < 1% on the pattern deviation probability plot of both FDT and SAP and defined eyes with significant SAP–FDT difference when the number of abnormal points were greater than 4 points on FDT. We measured lamina cribrosa depth (LCD) and lamina cribrosa curvature index (LCCI) for structural parameters of the optic nerve head from images using enhanced depth imaging of the optical coherence tomography (OCT). Peripapillary vessel density (VD) and presence of microvasculature dropout (MvD), the complete loss of choriocapillaris in localized regions of parapapillary atrophy, was evaluated using deep layer map of OCT angiography (OCT-A) for vascular parameters. Peripheral nasal step (PNS) group had an isolated glaucomatous VF defect within nasal periphery outside 10° of fixation. Parafoveal scotoma (PFS) group had an isolated glaucomatous VF defect within 12 points of a central 10˚ radius. Eyes with significant SAP–FDT difference showed higher detection of MvD on deep layer map of OCT-A, greater LCD, and greater LCCI (all P < 0.05, respectively). In logistic regression analysis, frequent presence of MvD, less presence of disc hemorrhage, and greater LCD were significantly associated with significant SAP–FDT difference. Sub-analysis was performed in eyes with PNS (50 eyes) and PFS (46 eyes). SAP–FDT difference of MD value showed positive association with peripapillary VD on deep layer of OCT-A, which was significant in eyes with PFS compared to eyes with PNS. SAP–FDT difference of PSD value showed negative association with LCCI and LCD, which was significant in eyes with PNS compared to eyes with PFS. Glaucomatous eyes classified by the difference of the detected VF damage on FDT versus SAP showed different clinical features. Greater SAP–FDT difference was significantly associated with structural parameters such as LCD and LCCI. Less SAP–FDT difference was associated with presence of disc hemorrhage and lower deep layer peripepillary VD. There is possibility to use the difference of SAP and FDT to identify associated risk factors in glaucoma patients.

Frequency Doubling Technology Visual Field Loss in Fabry Subjects Related to Retinal Ganglion Cell Function as Explored by ERG and OSOME.

PurposeThis study aims to evaluate potential causes of FDT visual field loss in a selected group of Fabry subjects.Patients and MethodsThis is a pilot observational study. Subjects were assessed during 2 visits. The following tests were performed: visual acuity, tonometry, optical coherence tomography (OCT) optic nerve scan, frequency doubling time (FDT) and threshold (SAP) VF, ERG, and Online Spectro-reflectometry Oxygenation Measurement in the Eye (OSOME). Results are compared across visits and, when indicated, interpreted against those collected on non-Fabry population matched for age and sex.ResultsThe study population was composed of 3 males (34.3 ± 8.9 y.o.) and 5 females (46.4 ± 6.5 y.o). For all subjects, BCVA remained 6/6 OU throughout the study and OCT optic nerve scans were normal. FDT showed a defect in at least 1 quadrant for all participants, in contrast with SAP. FDT PSD value was found different vs SAP. For ERG, the i-wave (52.1 + 2.7 ms) and B-waves (31.6 ± 2.1 ms) peak times were significantly longer compared to a non-Fabry population (p < 0.05). Overall blood oxygenation varied from 61.3% ± 4% to 68.1% ± 4% at the second visit, suggesting a loss of capillary perfusion. Blood volume varied based on location (superior/inferior), eye tested (OD/OS) and time (visit 1/2). The range of values exceeds normal subjects findings (p < 0.05). Blood volume was correlated to FDT PSD value for the superior area of the optic nerve.ConclusionThe results suggest that Fabry subjects present FDT deficits and abnormal ERG patterns that may be explained by a retinal dysfunction affecting retinal ganglion cells (RGCs), second to vascular alterations.

1158-P: The Effect of Surgical Weight Loss on Diabetic Complications in the Severely Obese

The aim of this study was to determine the effect of surgical weight loss on chronic kidney disease (CKD) , retinopathy, and cardiovascular autonomic neuropathy (CAN) in people with severe obesity. We completed a prospective cohort study of participants with severe obesity who underwent bariatric surgery. At baseline and at 2 years following bariatric surgery, participants had outcome measurements and underwent metabolic phenotyping. The updated National Cholesterol Education Program (NCEP) criteria were used to define the metabolic syndrome (MetS) and its individual components. The primary outcome for CKD was the estimated Glomerular Filtration Rate (eGFR) , retinopathy was mean deviation on frequency doubling technology testing, and CAN was the expiration/inspiration (E/I) ratio. Among 138 baseline participants, 80 (mean (standard deviation) age: 45.6 (11.2) years, 72.5% female) completed 2 years of follow-up. Participants lost 31.9 (17.5) kg. All metabolic syndrome components improved with the exception of blood pressure. CKD worsened (eGFR: baseline: 85.6 (19.7) , 2-year: 82.6 (23.1) , p=0.04) , retinopathy was stable (mean deviation: baseline: −1.2 (4.3) , 2-year: −1.6 (4.2) , p=0.53) , and CAN was stable (E/I ratio: baseline: 1.18 (0.12) , 2-year: 1.18 (0.11) , p=0.95) following bariatric surgery. Greater reduction in fasting glucose was associated with significant improvements to primary CKD (eGFR: point estimate (PE) : -0.22, 95% Confidence Interval (CI) : −0.38, −0.06) and retinopathy (mean deviation: PE: -0.04, 95%CI: −0.08, −0.004) , after adjusting for age, sex, and baseline BMI. Surgical weight loss was associated with improvements in all metabolic parameters except blood pressure. Despite the improvement to metabolic risk factors, CKD significantly worsened during follow-up, whereas retinopathy and CAN outcomes remained stable. This stability may be an improvement compared to the natural progression of these conditions, however controlled trials are needed to confirm. Disclosure E.L.Reynolds: None. M.Watanabe: None. M.Elafros: None. E.L.Feldman: None. B.C.Callaghan: None. Funding The project described was supported by Grant Number P30DK020572 (MDRC) from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) . Dr. Callaghan is currently funded by a NIH NIDDK R-award (DK115687) . Dr. Reynolds was supported by NIH T32 (NS0007222) . Dr. Feldman was supported by an NIH NIDDK DP3 award (DK094292) and is currently funded by NIH NIDDK (R24082841 and R21 NS102924) and the Novo Nordisk Foundation Center for Basic Metabolic Research (NNF14°C0011633) . Dr. Reynolds, Dr. Callaghan, and Dr. Feldman receive support from the NeuroNetwork for Emerging Therapies and the A. Alfred Taubman Research Institute at the University of Michigan.

Multiple Sclerosis: What Methods are Available for the Assessment of Subclinical Visual System Damage?

ABSTRACT We aimed to assess the visual fields and optical coherence tomography (OCT) measurements in patients with multiple sclerosis (MS) to detect subclinical visual system disease. The study included 15 MS patients with previous optic neuritis (Group I), 17 MS patients without previous optic neuritis (Group II), and 14 healthy controls (Group III). Each subject underwent standard automated perimetry (SAP), frequency doubling technology perimetry (FDTP), and OCT. The mean deviation of SAP in Group I was lower than those in Groups II (p = .018) and III (p = .001). The pattern standard deviation of SAP in Group I was higher than those in Group III (p < .0001). The mean deviation of FDTP in Groups I and II was lower than those in Group III (p = .0001 and p = .016, respectively). The temporal quadrant of the retinal nerve fibre layer in Group I was thinner than those in Groups II and III (p = .005 and p = .003, respectively). The mean macular volume in Group I was thinner than those in Groups II and III (p = .004 and p = .002, respectively). A single method is inadequate for establishing early and/or mild visual impairment in MS. All conventional and non-conventional techniques are complementary in demonstrating subclinical visual damage in MS.

Evaluation of the effectiveness of frequency doubling technology perimetry in the diagnosis of optic neuropathies

PURPOSE. To compare the diagnostic effectiveness of two perimetric threshold strategies with frequency-doubling technology in patients with early primary open-angle glaucoma (POAG), the optical form of multiple sclerosis (MS) and papilledema in an open-label comparative clinical study.MATERIAL AND METHODS. The study involved 78 patients (105 eyes) with optic neuropathies (ON). The patients were divided into 3 groups depending on the etiology of optic neuropathy: the first group included 30 patients (46 eyes) with early POAG aged 30 to 65 years (54.9±1.3); the second group included 26 patients (26 eyes) diagnosed with the optic form of MS (an episode of retrobulbar optic neuritis in the medical history) aged 22 to 44 years (33.7±6.5); the third group consisted of 22 patients (33 eyes) aged from 18 to 66 years (35.7±14.9) with papilledema caused in the majority of cases by various brain tumors (25 eyes or 75.7%). The fourth (control) group consisted of 60 healthy individuals (60 eyes) aged 20 to 65 years, who were divided into 2 equal subgroups – younger (24.8±4.4) and older (56.4±3.9).Standard and non-standard perimetry was performed on all subjects during a comprehensive ophthalmic examination using the Humphrey 745i Visual Field Analyzer II (HFA II, «24-2» threshold strategy) (Germany-USA) and the author's own modification of Frequency Doubling Technology (FDT) Perimetry, in the form of 2 threshold strategies: the well-known «FDT-16» and the new «FDT-64».RESULTS. Both the «FDT-16» and the «FDT-64» threshold strategies were more effective in diagnosing glaucomatous optic neuropathy (GON), as confirmed by the higher sensitivity of their results to two criteria — the number of identified scotomas (n of scotomas n≥2), and the number of scotoma clusters in patients with POAG (88 and 100%; 95 and 83%, respectively) compared with those in patients with MS (61 and 76%; 85 and 54%, respectively) and papilledema (51 and 78%; 88 and 70%, respectively). The specificity of the «FDT-16» and «FDT-64» threshold strategies was significantly higher than the specificity of Humphrey perimetry (100, 80 and 63%, respectively).CONCLUSION. Both perimetric threshold strategies with frequency-doubling technology were found to be the most effective in detecting GON. This confirms that they are more sensitive in patients with early POAG when compared with the sensitivity in patients with MS and papilledema. The level of specificity of both FDT perimetry strategies far exceeds the level of specificity of Humphrey perimetry data, which indicates the advantage of FDT perimetry in separating healthy people from patients with ON, and not only of glaucoma genesis.

Comparison of the Automated Pattern-Noise (PANO) Glaucoma Test with the HFA, an FDT Stimulus, and the Fundus Area Cup-to-disk Ratio.

Aim and objectiveTo compare the results of a new automated glaucoma test—Pattern–Noise (PANO)—to the Humphrey Visual Field Analyzer-II (HFA), the fundus area cup-to-disk ratio (CDR), and a frequency doubling technology (FDT) stimulus.Materials and methodsThis was a prospective study performed in the West-Region of Cameroon. Two hundred and nineteen eyes of 122 adult patients were included with a clinical suspicion of normal-tension or primary open-angle glaucoma and no other major ocular pathology. Eyes were examined with PANO, HFA (24-2 SITA standard), and FDT-stimulus in a randomized order followed by clinical assessment of the CDR.ResultsParametric correlation of the mean contrast threshold of PANO with the mean contrast threshold of FDT-stimulus, total deviation of HFA, and area CDR was 0.94, −0.85, and 0.62, respectively (p < 0.001 for all values). Spatial distribution of sensitivity thresholds is highly correlated (p < 0.001) at all points in the visual field between PANO and HFA. With cut-off values of 3 ± 1 dB for HFA mean deviation and 4 ± 1 for PANO mean contrast threshold and after eliminating borderline cases, PANO's sensitivity was 95% and specificity 60%. The mean patient age was 45.2 ± 15.8 years. Mean thresholds of PANO and FDT-stimulus decreased with increasing age. Mean examination time was 7.1 ± 1.8 minutes for PANO, 5.9 ± 1.3 minutes for HFA, and 4.7 ± 1.3 minutes for FDT-stimulus. The mean percentage of false-positives per examination was 4.95% for PANO, 4.62% (p = 0.025) for FDT-stimulus, and 2.10% for HFA.ConclusionThe results showed that PANO was successful in suspecting the presence of glaucoma. Pattern–Noise examination led to findings that were significantly correlated to HFA, FDT stimulus, and area CDR. Some patterns of defect were also correlated. Furthermore, PANO showed a reasonable examination time and error rate.Clinical significanceAffordable and robust visual field devices are lacking in large parts of the developing world. Comparing them to established methods is a prerequisite to their clinical use.How to cite this articleHannen T, El-Khoury S, Patel R, et al. Comparison of the Automated Pattern–Noise (PANO) Glaucoma Test with the HFA, an FDT Stimulus, and the Fundus Area Cup-to-disk Ratio. J Curr Glaucoma Pract 2021;15(3):132–138.

Generation of 5.2 fs, energy scalable blue pulses.

In this Letter, ultrashort blue pulses spanning 350-500 nm are generated by combining the broadband frequency doubling technology with the two-stage multiplate continuum (MPC) generation scheme. We prepare relatively broadband input pulses and use a two-stage configuration for MPC generation, allowing us to employ thinner and less solid plates for further spectral broadening. Therefore, the deteriorations of the spectral phase, energy conversion efficiency, and beam quality, which occur more easily for 400 nm pulses, are effectively suppressed. After fine dispersion management, we obtain clean 5.2 fs blue pulses with a root-mean-square energy stability of 0.69% over one hour and excellent beam quality. Furthermore, lower than 8% energy loss during the spectral broadening process at each stage is achieved. The overall optimized performances and energy scalability of this blue pulse, as well as the possibility of further compressing the pulse duration, are likely to motivate more strong-field research with sub-cycle time resolution in this extended wavelength range.

New options for the diagnosis of normal tension glaucoma in the light of Professor V.V. Volkov’s concept of its pathogenesis

PURPOSE:To measure lamina cribrosa thickness (LCT) and lamina cribrosa depth (LCD), optic nerve subarachnoid space width (ONSASW) in patients with normal tension glaucoma and in healthy individuals and to compare these data with the results of our own pilot study.&#x0D; MATERIALS AND METHODS:The 1st group included 13 patients (22 eyes) with normal tension glaucoma aged 39 to 88 years (59.8 10.9 years). The 2nd (control) group included 10 healthy people (20 eyes) aged 40 to 59 years (47.9 5.5 years). All subjects underwent structural and functional assessment of the optic nerve head using optical coherent tomograph (OCT) RTVue-100 (Optovue, USA), Humphrey perimeter (HFA II 745i, Germany-USA), and our own modification of Frequency Doubling Technology perimetry. LCT and LCD were measured by OCT RS-3000 Advance (Nidek, Japan). To measure ONSASW we used a cross-sectional image of the optic nerve taken with Magnetic Resonance Imaging (GE Optima MR450w MRI, USA).&#x0D; RESULTS:Differences in the 1st and 2nd groups between the mean values of LCT (234.14 27.73 and 336.25 21.0 m, respectively;p= 0.0000), LCD (461.8 101.7 and 361.65 58.2 m, respectively;p= 0.0004) and ONSASW (1.371 0.035 and 1.52 0.133 mm, respectively;p= 0.011) were statistically significant.&#x0D; CONCLUSION:Patients with normal tension glaucoma had significantly higher LCD value with significantly lower LCT and ONSASW values compared to healthy individuals, which is comparable with the results of our pilot study, and confirms the importance of these morphometric criteria in normal tension glaucoma diagnosis verification.