Inferior Hemisphere Research Articles

Retinal oximetry in branch retinal vein occlusion.

To measure retinal oxygen saturation (SO2 ) in eyes with branch retinal vein occlusion (BRVO). Retinal oximetry was performed using the Oxymap T1 retinal oximeter in 50 eyes (50 patients) with resolved BRVO. SO2 was calculated in each major retinal artery and vein in four quadrants. The superior or inferior hemisphere with BRVO was categorized as the affected hemisphere and the other as the unaffected hemisphere. Oxymap T1 allowed us to measure SO2 in major retinal vessels. Both arterial and venous SO2 in the affected hemisphere were significantly higher than those in the unaffected hemisphere. However, there was no significant difference in arteriovenous (A-V) difference in SO2 between the affected and unaffected hemispheres. Of the 50 included eyes, 32 had non-ischemic BRVO and 18 had ischemic BRVO. In the affected hemisphere, arterial SO2 was significantly higher in ischemic BRVO (106.9±8.8%) than in non-ischemic BRVO (101.3±9.2%, p=0.044). There were no significant differences in venous SO2 between non-ischemic and ischemic BRVO. Consequently, the A-V difference in SO2 was significantly higher in ischemic BRVO (51.9±13.9%) than in non-ischemic BRVO (43.4±11.5%, p=0.028). In multiple regression analysis, the type of perfusion (non-ischemic or ischemic) had associations with arterial SO2 (β=0.365, p=0.013) and with A-V differences in SO2 in the affected hemisphere (β=0.406, p=0.006). In ischemic BRVO, arterial SO2 and the A-V difference in SO2 in the affected hemisphere were significantly higher than in non-ischemic BRVO.

Diagnostic ability of macular ganglion cell asymmetry in Preperimetric Glaucoma

BackgroundTo evaluate the diagnostic ability of macular ganglion cell asymmetry to diagnose preperimetric glaucoma (PPG), using Cirrus spectral domain optical coherence tomography (OCT).MethodsThis prospective study included 67 eyes of 67 patients with PPG and 67 eyes of 67 age- and refractive error-matched controls. We measured circumpapillary RNFL (cpRNFL) thickness, macular ganglion cell-inner plexiform layer (GCIPL) thickness and optic nerve head (ONH) parameters using OCT. Macular ganglion cell asymmetries were expressed as absolute difference and ratios between inferior hemisphere and superior hemisphere, inferotemporal (IT) and superotemporal (ST), IT and superonasal (SN), IT and inferonasal (IN), ST and IN as well as temporal and nasal. An asymmetry index was assigned by taking the absolute value of log10 of the ratio. The area under the receiver operating characteristics curve (AUROC), partial AUROC (pAUROC) ≥ specificities 90 and 95%, cutoff values and sensitivities at specificities 90 and 95% was analyzed.ResultsParameters with largest AUROCs were IT GCIPL thickness (0.784), average RNFL thickness (0.767), and average C/D (0.746). For macular asymmetry parameters, log IT/SN index had the largest AUROC (0.734), followed by log IT/IN index (0.725), and absolute difference of IT−SN GCIPL thickness (0.715). Performance was comparable between the best measures of asymmetry analysis (log IT/SN index) and those of cpRNFL, GCIPL, and ONH parameters (all P > 0.05). The IT/SN asymmetry index not only had the largest pAUROC based on the pAUROCs ≥90 and 95% specificity (0.044 and 0.019) but also had the highest diagnostic sensitivity at 90 and 95% specificities (52.2 and 46.3%).ConclusionsGCIPL asymmetry measurements have diagnostic ability comparable to cpRNFL, GCIPL, and ONH analysis for PPG. The best macular ganglion cell asymmetry parameter was IT/SN asymmetry index, which could be a new parameter to detect early structural changes in PPG.

Circumscribed choroidal haemangioma: clinical and topographical features

AimsTo characterise the clinical and topographical features of circumscribed choroidal haemangioma (CCH) and to visualise the patterns of tumour extent in the ocular fundus.MethodsData on the size, shape and location...

Spatial and Temporal Characteristics of Visual Field Progression in Glaucoma Assessed by Parallel Factor Analysis.

PurposeTo explore spatial and temporal characteristics of glaucomatous visual field (VF) progression through multi-way decomposition of data.MethodsSix serial VF exams with intervals of 6.0 ± 1.0 months in 121 pre-perimetric glaucoma eyes and 80 perimetric glaucoma eyes were arranged into a three-dimensional cube. The data were decomposed using parallel factor analysis.ResultsThree tri-linear components (i.e., spatial scores, temporal loadings, and subject-specific loadings) were identified. Component 1 clearly showed differences between superior and inferior hemispheres, linear trends over time, and wide variability in perimetric glaucoma. Findings were compatible with well-known characteristics of glaucomatous VF defects. Component 2 showed nasal and central areas in contrast with superior, inferior, and temporal peripheral locations, whereas component 3 showed a contrast between nasal and temporal hemispheres. Both components 2 and 3 failed to show clear temporal trends.ConclusionsIdentification of spatio-temporal patterns shows new possibilities for a multi-way decomposition methodology for earlier diagnosis and prediction of glaucomatous VF progression.

Peripapillary microvasculature in the retinal nerve fiber layer in glaucoma by optical coherence tomography angiography: focal structural and functional correlations and diagnostic performance.

PurposeTo quantify peripapillary microvasculature within the retinal nerve fiber layer (RNFL) in primary open-angle glaucoma (POAG) and normal eyes, determine association of perfusion parameters with structural and functional measures, and report diagnostic accuracy of perfusion parameters.Patients and methodsPOAG and normal patients underwent 6×6 mm2 optic nerve head scans (Angioplex optical coherence tomography angiography [OCTA]; Cirrus HD-OCT 5000) and Humphrey Field Analyzer II-i 24-2 visual field (VF) testing. Prototype software performed semiautomatic segmentation to create RNFL en face images and quantified vessel area density (VAD), vessel skeleton density (VSD), and vessel complexity index (VCI) in the optic nerve head globally and focally. Generalized estimating equations models assessed association of OCTA parameters with VF mean deviation (MD) and RNFL thickness.ResultsThirty-eight POAG and 17 normal eyes were studied. Global VAD, VSD, and VCI were reduced in mild POAG vs normal (P<0.02) and moderate-severe vs mild POAG (P<0.04). Stepwise focal reductions across disease stage were demonstrated for OCTA parameters in the inferior hemisphere (P<0.05); reduction in OCTA parameters in mild POAG vs normal was demonstrated in inferior and superior quadrants (P<0.05). Reduced global VF MD was associated with reduced VAD, VSD, and VCI (P=0.0007, 0.0013, <0.0001; R2=0.449, 0.312, 0.399, respectively), and global RNFL thickness was associated with VAD, VSD, and VCI (P<0.0001; R2=0.499, 0.524, 0.542), superior and inferior hemifield MD were associated with corresponding VAD, VSD, and VCI (P≤0.001; R2 from 0.208 to 0.513). RNFL thickness in all quadrants was associated with corresponding OCTA parameters (P<0.05; R2 from 0.213 to 0.394), except temporal VAD and VCI. Area under curves for VAD, VSD, and VCI demonstrated good diagnostic ability (0.868, 0.855, 0.868; P<0.0001).ConclusionGlaucomatous eyes showed stepwise reductions in RNFL microcirculation across severity; focal reductions in the inferior hemisphere and inferior and superior quadrants were most significant. OCTA parameters had stronger associations with structural rather than functional measures of glaucoma.

Macular ganglion cell asymmetry for detecting paracentral scotoma in early glaucoma.

PurposeWe evaluated macular ganglion cell asymmetry as a tool for diagnosing paracentral scotoma (PCS) in early glaucoma.Patients and methodsThis prospective study compared 58 patients with early glaucoma and PCS to 58 age-matched control individuals. All glaucomatous eyes had scotoma within the central 12 degrees of fixation and confined to one hemifield. We measured circumpapillary retinal nerve fiber layer (cpRNFL) thickness, macular ganglion cell-inner plexiform layer (GCIPL) thickness, and optic nerve head (ONH) parameters with Cirrus spectral domain optical coherence tomography. Macular ganglion cell asymmetry was expressed as the absolute differences and the ratios between the inferior and superior hemispheres, inferotemporal (IT) and superotemporal (ST) areas, IT and superonasal (SN) areas, IT and inferonasal (IN) areas, and ST and IN areas. The asymmetry index was the absolute log10 of the ratio. The area under the receiver operating characteristics curve (AUROC) and partial AUROC (pAUROC, specificities ≥90%) were analyzed for each parameter.ResultsAll GCIPL parameters and most cpRNFL parameters were significantly lower in early glaucoma than in controls. The best discriminating parameters were inferior RNFL thickness, average RNFL thickness, and minimum GCIPL thickness. The macular ganglion cell asymmetry parameters with the largest AUROCs were the log IT/ST index, the absolute difference in IT−ST GCIPL thicknesses, and the log IT/SN index. Performance was comparable between the log IT/ST index and the cpRNFL (inferior RNFL thickness, P=0.129), GCIPL (minimum GCIPL thickness, P=0.358), and ONH parameters (vertical cup-to-disc ratio, P=0.475).ConclusionThe IT/ST asymmetry index may be useful as a new parameter for detecting structural changes in glaucoma patients with PCS.

Intraocular retinal thickness asymmetry in early stage of primary open angle glaucoma and normal tension glaucoma.

To investigate the intraocular retinal thickness asymmetry of peripapillary retinal nerve fiber layer (pRNFL) and macular layers measured by spectral-domain optical coherence tomography (SD-OCT) in patients with early stage of primary open angle glaucoma (POAG) and normal tension glaucoma (NTG). A total of 117 patients with early stage of glaucoma (54 patients with POAG and 63 patients with NTG) and 32 normal subjects were recruited for the study. The pRNFL thickness, total macular layer (TML) thickness, and isolated inner macular layer (IML) thickness were measured by SD-OCT. Hemisphere TML thickness asymmetry measured by the posterior pole asymmetry scan was evaluated. Thickness differences of pRNFL and IML between superior and inferior quadrants were calculated. Asymmetry indices (AIs) of the pRNFL, TML and isolated IML were also computed. Areas under the receiver-operating characteristic curves (AROCs) were generated to determine the diagnostic capabilities of different parameters. Intraocular pRNFL thickness differences and AIs between the superior and inferior quadrants were significantly different between normal and NTG groups (P=0.009 and P<0.001, respectively). Intraocular pRNFL thickness differences and AIs between the temporal-superior and temporal-inferior sectors were also significantly different between normal and NTG groups (P=0.035 and P<0.001, respectively). The thickness differences and AIs of TML between superior and inferior hemispheres were significantly different between normal and NTG groups (P=0.001 and P=0.001, respectively) and between normal and POAG groups (P=0.032 and P=0.020, respectively). The thickness differences and AIs of macular ganglion cell layer (mGCL) between superior and inferior quadrants were significantly different between normal and NTG groups (P=0.013 and P=0.004, respectively), and between NTG and POAG groups (P=0.015 and P=0.012, respectively). The thickness difference of TML between superior and inferior hemispheres showed the highest diagnostic capability for early NTG eyes (AROC=0.832). Intraocular retinal thickness asymmetry in pRNFL, TML and mGCL are found in early stage of NTG. Hemisphere TML thickness asymmetry is also found in POAG eyes. Asymmetry analysis of retinal thickness can be an adjunctive modality for early detection of glaucoma.

Mapping the thickness changes on retinal layers segmented by spectral-domain optical coherence tomography using the posterior pole program in glaucoma

Abstract Objectives To evaluate changes in retinal layers of the macula (mRLs) using OCT posterior pole program (PPP) in primary open-angle glaucoma (POAG). Material and methods The study included 128 patients with POAG and 103 healthy controls who had PPP maps (macular grid 8 × 8) drawn by SD-OCT. Only one eye per patient was studied. The 9 mRLs were automatically segmented by prototype software, obtaining: a macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform + nuclear layer, photoreceptor layer, retinal pigment epithelium (RPE), outer retina and RPE + outer retina. Thickness values were obtained on 64 cells of the grid for each mRL, and mean thickness of superior and inferior hemispheres were calculated. Comparisons of mean thickness of these hemispheres and thickness of each cell between groups were determined. Differences in the cell by cell comparisons were represented quantitatively by heat maps for each mRL. Results Photoreceptors and RPE were found in POAG group when comparing thickness of hemispheres, thinning of mRNFL, GCL, IPL, and thickening of INL. Heat maps showed symmetrical thinning patters between superior and inferior hemispheres in inner retinal layers (except for INL) and asymmetrical thickening patters in outer retinal layers in GPAA group. Conclusions There are thickness changes in all mRLs in POAG, when studied by PPP. Thinning of inner layers (except for INL), and thickening of outer layers in POAG show different symmetry patterns in relation to horizontal meridian.

A Sectoral Analysis of Vessel Density Measurements in Perimetrically Intact Regions of Glaucomatous Eyes: An Optical Coherence Tomography Angiography Study.

To study sectoral vessel density (VD) and structural alterations in the peripapillary and parafoveal hemiretina corresponding to perimetrically intact regions of glaucomatous eyes with hemifield defects and to compare these with healthy eyes using optical coherence tomography. This cross-sectional study included 37 eyes with open-angle glaucoma having visual fields defects restricted to 1 hemifield and 45 age-matched controls. Peripapillary VD and retinal nerve fiber layer (RNFL) thickness were measured in 8 sectors. Parafoveal VD and ganglion cell complex thickness were measured in the superior and inferior hemispheres of the macula. These parameters were compared between the intact hemiretinae of glaucomatous eyes and corresponding sectors of healthy eyes using the t test. Within the perimetrically intact regions of glaucomatous eyes, the mean VD and RNFL thickness were significantly reduced in inferotemporal, superonasal, and nasal upper peripapillary sectors as compared with healthy eyes (P<0.008). The temporal upper sector had reduced mean VD (60.3% vs. 62.9%, P=0.04) despite similar mean RNFL thickness (P=0.18). The superotemporal sector had decreased mean RNFL thickness (121 vs. 138 µm, P=0.0001) despite similar VD (P=0.06). At the macula, ganglion cell complex thickness was reduced in the superior and inferior hemispheres, but mean VD was reduced in the superior parafoveal region only. Peripapillary and parafoveal vascular changes precede functional decline. The extent of VD reduction and RNFL thinning varies in different peripapillary sectors and longitudinal studies are required to better understand the temporal relationship of vascular and RNFL loss.

Effect of duration and severity of migraine on retinal nerve fiber layer, ganglion cell layer, and choroidal thickness.

To investigate the factors in migraine that have the highest significance on retinal and choroidal layers' thickness. Ninety patients with migraine and 40 age-matched healthy participants were enrolled in this observational, cross-sectional study. After full ophthalmological examination, spectral domain-optical coherence tomography was done for all patients measuring the thickness of ganglion cell layer and retinal nerve fiber layer. Enhanced depth imaging technique was used to measure the choroidal thickness. There was significant thinning in the superior and inferior ganglion cell layers, all retinal nerve fiber layer quadrants, and all choroidal quadrants (except for the central subfield) in migraineurs compared to controls. The duration of migraine was significantly correlated with ganglion cell layer, retinal nerve fiber layer, and all choroidal quadrants, while the severity of migraine was significantly correlated with ganglion cell layer and retinal nerve fiber layer only. Multiregression analysis showed that the duration of migraine is the most important determinant factor of the superior retinal nerve fiber layer quadrant (β = -0.375, p = 0.001) and in all the choroidal quadrants (β = -0.531, -0.692, -0.503, -0.461, -0.564, respectively, p < 0.001), while severity is the most important determinant factor of inferior, nasal, and temporal retinal nerve fiber layer quadrants (β = -0.256, -0.335, -0.308; p = 0.036, 0.005, 0.009, respectively) and the inferior ganglion cell layer hemisphere (β = -0.377 and p = 0.001). Ganglion cell layer, retinal nerve fiber layer, and choroidal thickness are significantly thinner in patients with migraine. The severity of migraine has more significant influence in the thinning of ganglion cell layer and retinal nerve fiber layer, while the duration of the disease affected the choroidal thickness more.

Mapeo de los cambios de grosor en el glaucoma de las capas retinianas maculares segmentadas usando el programa de polo posterior de la tomografía de coherencia óptica de dominio espectral

ObjectivesTo evaluate changes in retinal layers of the macula (mRLs) using OCT posterior pole program (PPP) in primary open-angle glaucoma (POAG). Material and methodsThe study included 128 patients with POAG and 103 healthy controls who had PPP maps (macular grid 8×8) drawn by SD-OCT. Only one eye per patient was studied. The 9 mRLs were automatically segmented by prototype software, obtaining: a macular retinal nerve fibre layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform+nuclear layer, photoreceptor layer, retinal pigment epithelium (RPE), outer retina and RPE+outer retina. Thickness values were obtained on 64 cells of the grid for each mRL, and mean thickness of superior and inferior hemispheres were calculated. Comparisons of mean thickness of these hemispheres and thickness of each cell between groups were determined. Differences in the cell by cell comparisons were represented quantitatively by heat maps for each mRL. ResultsPhotoreceptors and RPE were found in POAG group when comparing thickness of hemispheres, thinning of mRNFL, GCL, IPL, and thickening of INL. Heat maps showed symmetrical thinning patters between superior and inferior hemispheres in inner retinal layers (except for INL) and asymmetrical thickening patters in outer retinal layers in GPAA group. ConclusionsThere are thickness changes in all mRLs in POAG, when studied by PPP. Thinning of inner layers (except for INL), and thickening of outer layers in POAG show different symmetry patterns in relation to horizontal meridian.

Asymmetry of Peak Thicknesses between the Superior and Inferior Retinal Nerve Fiber Layers for Early Glaucoma Detection: A Simple Screening Method.

PurposeTo assess whether the asymmetry in the peripapillary retinal nerve fiber layer (pRNFL) thickness between superior and inferior hemispheres on optical coherence tomography (OCT) is useful for early detection of glaucoma.Materials and MethodsThe patient population consisted of Training set (a total of 60 subjects with early glaucoma and 59 normal subjects) and Validation set (30 subjects with early glaucoma and 30 normal subjects). Two kinds of ratios were employed to measure the asymmetry between the superior and inferior pRNFL thickness using OCT. One was the ratio of the superior to inferior peak thicknesses (peak pRNFL thickness ratio; PTR), and the other was the ratio of the superior to inferior average thickness (average pRNFL thickness ratio; ATR). The diagnostic abilities of the PTR and ATR were compared to the color code classification in OCT. Using the optimal cut-off values of the PTR and ATR obtained from the Training set, the two ratios were independently validated for diagnostic capability.ResultsFor the Training set, the sensitivities/specificities of the PTR, ATR, quadrants color code classification, and clock-hour color code classification were 81.7%/93.2%, 71.7%/74.6%, 75.0%/93.2%, and 75.0%/79.7%, respectively. The PTR showed a better diagnostic performance for early glaucoma detection than the ATR and the clock-hour color code classification in terms of areas under the receiver operating characteristic curves (AUCs) (0.898, 0.765, and 0.773, respectively). For the Validation set, the PTR also showed the best sensitivity and AUC.ConclusionThe PTR is a simple method with considerable diagnostic ability for early glaucoma detection. It can, therefore, be widely used as a new screening method for early glaucoma.

IRIDEX MicroPulse P3: innovative cyclophotocoagulation

Purpose: To present the new IRIDEX MicroPulse P3 (MP3) technology in patients with refractory glaucoma and our preliminary results at 1 week and 1 month postoperatively. Methods: IRIDEX MP3 laser cyclophotocoagulation was performed in 7 eyes of 7 patients under retrobulbar anaesthesia with lidocaine 2% in the operating room. Each eye received two treatments of 80-90s over the superior and inferior hemisphere, avoiding the temporal- and nasal-most clock hours. 810nm IRIDEX MP3 was set to 31,3% duty cycle (0,5ms treatment pulse followed by 1,1 ms of rest). Postoperative topical steroids were prescribed for 1 week. Results: Mean IOP decrease at 1 week was 60,3% and 33,4% at 1 month, with a mean topical hypotensive treatment reduction of 0,71 therapeutic agents. The procedure was safe in all cases and effective in 71% of the patients. Neovascular glaucoma patients registered high IOP levels 1 month postoperatively in spite of medical and MP3 laser treatment. BCVA remained unchanged after undertaking the laser procedure. No significant inflammation, discomfort, or pain was reported. There were no complications such as hypotony, phthisis bulbi, and macular edema. Conclusions: IRIDEX MP3 represents an innovation in cyclophotocoagulation. It is non-destructive, repeatable, non-invasive, with a high safety profile. A mean IOP decrease of 33,4% was registered at 1 month. Patient comfort and recovery are favorable. Long-term results will prove its efficacy in the future.

Paravascular inner retinal abnormalities in healthy eyes.

To investigate the prevalence and characteristics of paravascular inner retinal abnormalities in healthy eyes. In this prospective observational case series, we included 178 healthy eyes (178 patients) with no ocular diseases. Eyes with co-existing ocular diseases, e.g., epiretinal membrane, glaucoma, or high myopia, were excluded from the current study. The posterior pole and paravascular areas of the temporal arcade vessels were comprehensively examined by dense radial scanning of optical coherence tomography (OCT) with the extended field imaging technique. On fundus photography, no inner retinal abnormalities were detected along the temporal arcade vessels. On OCT sections, paravascular inner retinal abnormalities were seen in 77 (43.3%) eyes. In 71 (39.9%) eyes, inner retinal cystoid or fissure-like spaces that had no connection to the vitreous cavity were seen adjacent to the temporal arcade vessels. Most of these lesions were detected only on several consecutive OCT sections. In four (2.2%) eyes, inner retinal cleavages with openings to the vitreous cavity were seen adjacent to the temporal arcade vessels. These lesions were more frequently detected in the inferior hemisphere and along the major retinal veins. No eyes showed typical broad defects of the inner retinal tissue. There were no significant differences in age, gender, visual acuity, refractive error, or axial length between eyes with or without paravascular inner retinal abnormalities. Paravascular cystoid or fissure-like spaces were frequently seen in the inner retina of healthy eyes. However, we detected no typical paravascular inner retinal defects in healthy eyes.

Optical coherence tomography predicts 4-year incident diabetic neuropathy.

To examine the capability of optical coherence tomography-derived retinal thickness measures in detecting 4-year incident diabetic peripheral neuropathy (DPN). 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 4years. 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. Of the 145 participants without DPN at baseline, 51 had developed DPN when examined after 4years (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 321μm criterion), and body mass index or BMI (AUC=0.65, p=0.003, 49% sensitivity and 83% specificity at 29.3kgm-2 criterion) at baseline were significant predictors for 4-year incident DPN. 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.

Peripapillary Retinal Nerve Fiber Layer Vascular Microcirculation in Eyes With Glaucoma and Single-Hemifield Visual Field Loss

Understanding the differences in vascular microcirculation of the peripapillary retinal nerve fiber layer (RNFL) between the hemispheres in eyes with glaucoma with single-hemifield visual field (VF) defects may provide insight into the pathophysiology of glaucoma. To investigate the changes in the microcirculation of the peripapillary RNFL of eyes with glaucoma by using optical microangiography. Eyes with glaucoma and single-hemifield VF defect and normal eyes underwent scanning using an optical microangiography system covering a 6.7 × 6.7-mm2 area centered at the optic nerve head. The RNFL microcirculation was measured within an annulus region centered at the optic nerve head divided into superior and inferior hemispheres. Blood flux index (the mean flow signal intensity in the vessels) and vessel area density (the percentage of the detected vessels in the annulus) were measured. Differences in microcirculation between the hemispheres in eyes with glaucoma and normal eyes and correlations among blood flow metrics, VF thresholds, and clinical optical coherence tomography structural measurements were assessed. Twenty-one eyes from 21 patients with glaucoma (7 men and 14 women; mean [SD] age, 63.7 [9.9] years) and 20 eyes from 20 healthy control individuals (9 men and 11 women; mean [SD] age, 68.3 [10.7] years) were studied. In eyes with glaucoma, the abnormal hemisphere showed a thinner RNFL (mean [SE] difference, 23.5 [4.5] μm; 95% CI, 15.1-32.0 µm; P < .001), lower RNFL blood flux index (mean [SE] difference, 0.04 [0.01]; 95% CI, 0.02-0.05; P < .001), and less vessel area density (mean [SE] difference, 0.08% [0.02%]; 95% CI, 0.05%-0.10%; P < .001) than did the normal hemisphere. Compared with normal eyes, reduced RNFL microcirculation was found in the normal hemisphere of eyes with glaucoma, measured by mean [SE] differences in blood flux index (0.06 [0.01]; 95% CI, 0.04-0.09; P < .001) and vessel area density (0.04% [0.02%]; 95% CI, 0.02%-0.08%; P = .003) but not in RNFL thickness (3.4 [4.7] μm; 95% CI, -6.2 to 12.9 µm; P = .48). Strong correlations were found between the blood flux index and VF mean deviation (Spearman ρ = 0.44; P = .045) and RNFL thickness (Spearman ρ = 0.65; P = .001) in the normal hemisphere of the eye with glaucoma. Reduced RNFL microcirculation was detected in the normal hemisphere of eyes with glaucoma, with strong correspondence with VF loss and RNFL thinning. Although the results suggest that vascular dysfunction precedes structural changes seen in glaucoma, longitudinal studies would be needed to confirm this finding.

Novel Computational Analysis of Left Atrial Anatomy Improves Prediction of Atrial Fibrillation Recurrence after Ablation.

The left atrium (LA) can change in size and shape due to atrial fibrillation (AF)-induced remodeling. These alterations can be linked to poorer outcomes of AF ablation. In this study, we propose a novel comprehensive computational analysis of LA anatomy to identify what features of LA shape can optimally predict post-ablation AF recurrence. To this end, we construct smooth 3D geometrical models from the segmentation of the LA blood pool captured in pre-procedural MR images. We first apply this methodology to characterize the LA anatomy of 144 AF patients and build a statistical shape model that includes the most salient variations in shape across this cohort. We then perform a discriminant analysis to optimally distinguish between recurrent and non-recurrent patients. From this analysis, we propose a new shape metric called vertical asymmetry, which measures the imbalance of size along the anterior to posterior direction between the superior and inferior left atrial hemispheres. Vertical asymmetry was found, in combination with LA sphericity, to be the best predictor of post-ablation recurrence at both 12 and 24 months (area under the ROC curve: 0.71 and 0.68, respectively) outperforming other shape markers and any of their combinations. We also found that model-derived shape metrics, such as the anterior-posterior radius, were better predictors than equivalent metrics taken directly from MRI or echocardiography, suggesting that the proposed approach leads to a reduction of the impact of data artifacts and noise. This novel methodology contributes to an improved characterization of LA organ remodeling and the reported findings have the potential to improve patient selection and risk stratification for catheter ablations in AF.

Regional Relationship between Macular Retinal Thickness and Corresponding Central Visual Field Sensitivity in Glaucoma Patients.

Purpose. To investigate the relationship between macular retinal thickness (MRT) and central visual field sensitivity (VFS) in patients with glaucoma. Methods. This retrospective study enrolled patients diagnosed with open-angle glaucoma. All study patients underwent Humphrey 10-2 visual field (VF) test and Spectralis spectral-domain optical coherence tomography (SD-OCT) exam for MRT measurement. Results. Sixty-eight eyes of 68 patients were examined. The correlation coefficients between VFS and MRT were 0.331 (P = 0.006) and 0.491 (P = 0.000) in the superior and inferior hemispheres, respectively. The average MRT in the eyes with abnormal 10-2 VF hemifields was significantly thinner than that in the eyes without abnormal hemifields in both hemispheres (P = 0.005 and 0.000 in the superior and inferior hemisphere, resp.). The average MRT values with an optimal sensitivity-specificity balance for discriminating the abnormal VF hemifield from the normal hemifield were 273.5 μm and 255.5 μm in the superior and inferior hemisphere, respectively. The area under the receiver operating characteristic curve was 0.701 in the superior hemisphere and 0.784 in the inferior hemisphere (both P < 0.05). Conclusions. MRT measured through SD-OCT was significantly correlated with central VFS. Lower MRT values might be a warning sign for central VF defects in glaucoma patients.

Comparative analysis of the value of information provided by anterior segment optical coherence tomography and confocal laser scanning microscopy for identifying the palisades of Vogt in normal limbus

to conduct a comparative analysis of the value of information provided by anterior segment optical coherence tomography (AS-OCT) and in vivo confocal laser scanning microscopy (CLSM) for identifying the palisades of Vogt (POV) in normal limbus. POV were studied in 15 healthy participants (30 eyes) without any anterior segment disease. Two examination methods were used: AS-OCT En Face imaging (RTVue XR Avanti, 3D Cornea protocol) and CLSM (HRT3). Concordance of the results was then analyzed. Structural features of POV were distinguishable by both methods. CLSM was able to visualize POV in both the superior and inferior limbi of all the 15 patients (30 eyes). Within the inferior corneal hemisphere, POV had the appearance of well-differentiated hyperreflective double-contoured structures organized in parallel lines at the level of basal epithelium. The structure of the superior limbus, as judged from CLSM data, varied significantly: «classic» palisades were seen in only 13 eyes (43%), while in the other 17 cases (57%) POV were atypical. On OCT, POV structure was seen in detail in 29 eyes. By comparing the abilities of CLSM and OCT to visualize POV, a strong positive correlation (rS=0.99, p<0.05) was revealed between the results obtained in both the superior and inferior limbi. OCT data provide a detailed understanding of POV structure and strongly correlate with CLSM results. Taking into consideration the noninvasiveness, demonstrativeness, and repeatability of AS-OCT En Face imaging as well as the high value of provided information, the method cay be recommended as an alternative in POV diagnostics.

Circumferential flow of particles in the suprachoroidal space is impeded by the posterior ciliary arteries

Microneedle injection into the suprachoroidal space (SCS) enables targeted drug delivery for treatment of posterior segment diseases. This study sought to identify and characterize anatomical barriers to circumferential spread of particles in the SCS of rabbit and human cadaver eyes. These barriers could make targeting specific regions within the SCS challenging. A hollow microneedle (33-gauge, 750 μm long) was used to inject fluorescent particles into albino New Zealand White rabbit eyes ex vivo at six different positions around the limbus and a limited number of conditions in vivo. SCS injections were also performed in human cadaver eyes 8 mm and 2 mm from the optic nerve (ON). Eyes were dissected and particle distribution was quantified. In rabbit eyes, injections made in the superior or inferior hemispheres (even when injected temporally immediately adjacent to the long posterior ciliary artery (LPCA)) did not significantly cross into the other hemisphere, apparently due to a barrier formed by the LPCA. The vortex veins had a minor effect on particle deposition, limited to only around the vortex vein root. In human eyes, the short posterior ciliary arteries (SPCAs) prevented circumferential spread towards the macula and ON. In conclusion, the rabbit LPCA and the human SPCA were anatomical barriers to particle spread within the SCS. Therefore, design of drug delivery protocols targeting the SCS need to account for barriers formed by anatomical structures in order for injected drug to reach target tissues.