Inferior Hemisphere Research Articles

Comparison of retinal nerve fiber layer, macular ganglion cell complex and choroidal thickness in patients with migraine with and without aura by using optical coherence tomography

BackgroundWe compared the choroidal thickness (CT), peripapillary retinal nerve fibre layer thickness (pRNFLT) and macular ganglion cell complex thickness (mGCCT) by using spectral domain optic coherence tomography (SD−OCT) in patients with migraine with aura (MWA), migraine without aura (MWoA), and healthy controls. MethodsThirty-seven patients with MWA, 40 patients with MWoA, and age and sex-matched 50 healthy controls were included in this cross-sectional study. CTs at fovea, nasal to fovea and temporal to fovea, global pRNFLT, four quadrants of pRNFLTs, mGCCTs in superior and inferior hemisphere were measured by SD−OCT. The duration of migraine, monthly attack number and the migraine disability assessment (MIDAS) questionnaire scores were recorded. ResultsThe mean foveal CT, nasal CT, and temporal CT in patients with MWA were significantly thinner than those of patients with MWoA and control (p < 0.001) while CTs of patients with MWoA were similar with those of controls. Patients with MWA and MWoA had thinner global pRNFLT, superior and inferior pRNFLT compared to controls but there were no significant differences between two migraineurs groups. Only nasal quadrant of pRNFLT was significantly thinner in patients with MWA than other groups. The superior and inferior mGCCTs were significantly thinner in patients with MWA and MWoA than controls. ConclusionOur results suggested that dysregulation of blood flow in ocular tissues caused by impairment of autoregulation in migraine. Patients with MWA might have an additional risk of choroidal and retinal ischemia than patients with MWoA and healthy controls.

PICA injury secondary to anterior odontoid screw fixation: Case report of an exceptional complication

BackgroundOdontoid fracture is a common injury in the upper cervical spine that can sometimes be managed by anterior odontoid screw fixation. Case descriptionWe report the first case of iatrogenic postero-inferior cerebellar artery (PICA) injury while performing anterior odontoid screw fixation for a type II odontoid fracture in a 22-year-old man. Fisher grade 4 subarachnoid hemorrhage secondary to iatrogenic pseudoaneurysm formation was managed by the endovascular neuroradiologist. Odontoid fracture was then managed posteriorly using Harm's technique. Postoperative 12-month follow-up revealed good clinical and radiological results. CT scan showed fusion. Complete exclusion of the pseudo aneurysm with a mild stroke in the inferior left cerebellar hemisphere were noted on the MRI. There were no cerebellar ataxia or swallowing disorders. ConclusionTo the best of our knowledge, this is the first case report of iatrogenic PICA injury in anterior odontoid screw fixation. The patient was well managed in our institution within a multidisciplinary team. We recommend that surgical management of odontoid fractures should be performed in expert centres.

Retinal Thickness Asymmetry in Highly Myopic Eyes with Early Stage of Normal-Tension Glaucoma.

Purpose To investigate the retinal thickness asymmetry parameters of circumpapillary retinal nerve fiber layer (cpRNFL) and macular layers measured by spectral-domain optical coherence tomography in highly myopic (HM) patients with an early stage of normal-tension glaucoma (NTG). Methods This cross-sectional study included 55 eyes of HM patients with early NTG and 37 eyes of HM normal participants. High myopia was defined as spherical equivalence more myopic than −6 diopters. Thickness differences and asymmetry indices (AIs) of cpRNFL between superior and inferior corresponding parts and thickness differences and AIs of the total macular layer (TML) and inner macular layers between superior and inferior hemispheres were calculated. The areas under the receiver operating characteristic curves (AROCs) were analyzed and compared. Results In the cpRNFL asymmetry analysis, the thickness differences and AIs of cpRNFL between temporal-superior and temporal-inferior sectors (P < 0.0001 and P < 0.0001, respectively) and between superior and inferior quadrants (P = 0.002 and P < 0.0001, respectively) were significantly different between HM control subjects and HM NTG patients. In the macular asymmetry analysis, the thickness difference and AI of TML were significantly different between superior and inferior hemispheres (P < 0.0001 and P < 0.0001, respectively). The thickness difference and AI of the macular ganglion cell layer (mGCL) were significantly different between superior and inferior hemispheres (P < 0.0001 and P < 0.0001, respectively). The AROCs for thickness difference of TML (0.845) and thickness difference of mGCL (0.773) were comparable to AROCs for average cpRNFL thickness (0.842), macular retinal nerve fiber layer thickness (mRNFL) thickness (0.871), and mGCL thickness (0.822). Conclusion In our study, HM NTG patients had retinal thickness asymmetry in cpRNFL, TML, and mGCL. The diagnostic capabilities for thickness asymmetry of TML and mGCL were comparable to the diagnostic capabilities for cpRNFL thickness, mRNFL thickness, and mGCL thickness. Asymmetry analysis of retinal thickness can be an adjunctive tool for the early detection of HM NTG.

Examination of patients with glaucoma during the COVID-19 pandemic

To evaluate the efficacy of the optimal examination technique for patients with glaucoma during the COVID-19 pandemic that includes one of the safest methods of tonometry [transpalpebral tonometry (TPT), contour dynamic tonometry (CDT) and Icare rebound tonometry (RBT)] in combination with spectral domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCTA). The study included 65 patients with primary open-angle glaucoma (POAG) who sought medical aid at the Ophthalmological Center of FMBA during the COVID-19 pandemic; they were examined using three tonometry methods: RBT, TPT and CDT. All patients underwent central corneal thickness measurement, perimetry, OCT and OCTA with assessment of vessel density (VD) of the superficial plexus in the macula (whole image macula) and peripapillary retina (PPR). High correlation was found between the results obtained with RBT, TPT and CDT. None of the methods showed a correlation between IOP and corneal thickness. The correlations between IOP and OCTA parameters were obtained: IOPTPT and VDPPR in the inferior temporal sector (r= -0.386, p=0.027), IOPRBT and VD whole image macula (r= -0.69, p=0.019), and in the macula inferior hemisphere (r= -0.75, p=0.008), as well as between the ocular pulse amplitude (OPA) and VD in the macular inferior hemisphere (r=0.380, p=0.039). The OCTA parameters had a moderate, but significant correlation with the perimetric indices. Tonometry methods (TPB, CDT and RBT) exhibit high correlation with each other and no correlation with corneal thickness. IOP parameters measured by different methods, especially using the Icare tonometer, correlate with OCTA parameters, and the latter - with perimetric indices. The combination of these tonometry methods with SD-OCT and OCTA is optimal for examining patients during the pandemic.

Profile of macular ganglion cell-inner plexiform layer thickness in healthy 6.5\u2009year- old Swedish children

BackgroundThe purpose was to study the macular ganglion cell- inner plexiform layer (GC-IPL) thickness in healthy 6.5 year- old Swedish children using Optical Coherence Tomography (OCT) and to study topography symmetry within eyes and between eye pairs.MethodsA total of 181 eyes of 92 healthy children (39 girls, 53 boys) aged 6.5 and serving as a term-born control group in the Extremely Preterm Infants in Sweden Study (EXPRESS), were examined with Cirrus HD-OCT. Main outcome measures were average and minimum values of GC-IPL thickness of the device’s predefined macular sectors. Single sectors, combined sectors defined as superior and inferior hemispheres and temporal and nasal sectors were evaluated. Intra-individual GC-IPL thickness between eye pairs was analyzed. Visual acuity, refraction and general cognition were assessed and correlated to GC-IPL outcome.ResultsEighty-five children completed the OCT examination and 155 out of 181 scans (86%) were analyzed. The mean average GC-IPL thickness was 85.9 μm (± 5.3; 5th and 95th percentiles were 76.0 and 94.6 μm). The mean minimum GC-IPL thickness was 83.6 μm (± 4.9; 5th and 95th percentiles were 75.4 and 92.3 μm). The difference in thickness between nasal and temporal sectors and between superior and inferior hemisphere sectors were less than 2 μm. The difference between average GC-IPL thickness and minimum GC-IPL thickness was 2.3 μm (± 1.9; 5th and 95th percentiles were 0.0 and 6.0 μm). The difference between the thickest and thinnest sector within eye was 6.4 μm (± 2.2; 5th and 95th percentiles were 3.0 and 10.0 μm). There was a moderate correlation in the difference between the nasal combined and the temporal combined sectors within eye pairs (p < 0.0001, Spearman’s ρ 0.58). The average GC-IPL thickness was weakly positively correlated with SE (spherical equivalent; combined sphere and ½ cylinder) (p = 0.031, Spearman’s ρ 0.23).ConclusionsThis study provides normative GC-IPL thickness values for healthy 6.5 year- old Swedish children. The GC-IPL thickness variations within eyes and within eye pairs are generally small. It could therefore be assumed that larger variations are sensitive markers of focal GC-IPL thinning due to damage to the primary visual pathways in children.

Are Retinal and Peripapillary Blood Flows Affected during Migraine Attack?

ABSTRACT Migraine pathophysiology is complex and partially includes the vasculature. This study compared retinal and peripapillary blood flow parameters in migraine patients during an attack with healthy controls using optical coherence tomography angiography (OCTA). A prospective clinical study was conducted including 52 eyes from 26 migraineurs and 48 eyes from 24 healthy controls. OCTAs were performed with RTVue XR Avanti using AngioVue software. OCTA imaging was performed during the attack period in migraineurs before any treatment for the attack. Vascular densities in the whole image, fovea, superior hemisphere, inferior hemisphere, and temporal, superior, nasal, and inferior regions of the parafoveal area and in the superficial and deep capillary plexuses were acquired and statistically analysed. The flow density parameters were measured in the superficial retinal capillary plexus, deep retinal capillary plexus, outer retinal capillary plexus, and choriocapillaris layers of the macula in a 3-mm diameter area. The peripapillary flow densities were measured for the optic nerve head, vitreous, radial peripapillary capillaries, and choroid in a 4.50-mm diameter area around the optic disc. Vascular density measurements in the superficial plexus were similar between migraineurs and controls (p > .05). Vascular densities in the deep capillary plexus were similar between groups (p > .05), except in the deep superior area (p = .05). Flow areas in the nerve head, vitreous, peripapillary capillary, and choroid segments were similar between migraineurs and controls (p > .05). Macular thickness parameters were also similar between groups (p > .05). The results suggest that an acute migraine attack does not affect retinal or peripapillary blood flow.

Subclinical retinal microvascular alterations assessed by optical coherence tomography angiography in children with systemic hypertension

To compare the foveal avascular zone (FAZ) macular and peripapillary vessel density between children with high blood pressure and healthy subjects. A total of 40 eyes of 20 children with hypertension and 40 eyes of 20 age- and sex-matched healthy controls were included. Capillary vessel density (CVD) in superficial (SCP) and deep (DCP) retinal capillary plexus, peripapillary region, and FAZ were analyzed by optical coherence tomography angiography. The mean ages were 15.2±1.5years (range, 10-18) in patients with hypertension and 14.4±2.8years (range, 10-18) in healthy controls (P=0.742). The mean FAZ area measured 0.25±0.10mm2 in children with hypertension and 0.25±0.09mm2 in healthy controls (P=0.765). There was no significant difference between study groups in any measure of the macular SCP (P>0.05 for all); however, the mean whole image, inferior hemisphere, and para- and perifoveal measurements of the macular DCP were significantly lower in children with hypertension than in controls (P<0.05 for all). Although there was no evidence of hypertensive retinopathy, subthreshold microvascular alterations were found in the DCP of the retinal circulation in pediatric hypertensives. These alterations should be considered as prognostic cues when defining whole systemic response to high blood pressure in childhood.

Glaucomatous Maculopathy: Thickness Differences on Inner and Outer Macular Layers between Ocular Hypertension and Early Primary Open-Angle Glaucoma Using 8 × 8 Posterior Pole Algorithm of SD-OCT.

The purpose of this study was to compare the thickness of all inner and outer macular layers between ocular hypertension (OHT) and early primary open-angle glaucoma (POAG) using spectral domain optical coherence tomography (SD-OCT) 8 × 8 posterior pole algorithm (8 × 8 PPA). Fifty-seven eyes of 57 OHT individuals and fifty-seven eyes of 57 early POAG patients were included. The thickness of macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform and nuclear layer, photoreceptor layer (PRL) and retinal pigment epithelium were obtained in 64 cells for each macular layer and mean thickness of superior and inferior hemispheres was also calculated. Thinning of superior and inferior hemisphere mean thickness in mRNFL, GCL and IPL and thickening of superior and inferior hemisphere mean thickness in PRL and inferior hemisphere in INL were found in early GPAA group. Otherwise, heatmaps representing cell-to-cell comparisons showed thinning patterns in inner retinal layers (except for INL) and thickening patterns in outer retinal layers in GPAA group. We found that 8 × 8 PPA not only allows the detection of significant thinning patterns in inner retinal layers, but also thickening patterns in outer retinal layers when comparing early POAG eyes to OHT eyes.

Optical coherence tomography angiography findings of multiple sclerosis with or without optic neuritis

ABSTRACTObjective: Nowadays, retinal microvascular structures can be investigated using optical coherence tomography angiography (OCTA). We aimed to evaluate the probable vascular changes in the foveal and peripapillary regions of patients with multiple sclerosis (MS).Methods: A total of 20 patients with relapsing remitting multiple sclerosis (RRMS) and 24 healthy controls were recruited in this study. All participants’ superficial and deeper retinal and peripapillary layers were evaluated using OCTA after a total ophthalmologic examination.Results: In the superficial plexus, the whole image (49.53 ± 3.9% and 51.83 ± 2.1%, p = 0.009), superior hemisphere (49.44 ± 4.11% and 51.63 ± 2.3%, p = 0.018), inferior hemisphere (49.75 ± 3.9% and 52.03 ± 2.2%, p = 0.012), parafoveal (51.87 ± 3.9% and 53.08 ± 3.46%, p = 0.048) and perifoveal (50.41 ± 3.86% and 52.76 ± 2.1%, p = 0.007) vascular densities were statistically significant lesser in patients with RRMS than in controls. In the optic disc OCTA parameters, the vessel density of the inferior (50.15 ± 6.99% and 53.04 ± 3.63% p = 0.043) and temporal sector (48.09 ± 5.47% and 50.85 ± 5.24%, p = 0.045) were statistically significantly lesser in patients with RRMS than in controls.Conclusion: The reductions in vessel density of the retinal or peripapillary area of patients with RRMS shown in this study should be investigated further to determine whether it is a secondary lesion to optic neuritis (ON) or a primary vasculopathic condition of MS.

Profiles of Ganglion Cell-Inner Plexiform Layer Thickness in a Multi-Ethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

To examine the normative profile and determinants of macular ganglion cell-inner plexiform layer (GCIPL) thickness based on spectral-domain OCT (SD-OCT) in a nonglaucoma, multi-ethnic Asian population. Population-based, cross-sectional study. Ethnic Chinese, Malay, and Indian adults aged ≥40 years recruited from the Singapore Epidemiology of Eye Diseases Study. All participants underwent standardized examinations. The GCIPL thickness was measured using Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA). Participants with glaucoma or poor-quality scans were excluded. Eye-specific data were used. Associations of ocular and systemic factors with GCIPL thickness parameters were investigated using multivariable linear regression with generalized estimating equation models to account for correlation between both eyes. GCIPL thickness. A total of 4464 participants (7520 eyes) consisting of 1625 Chinese, 1212 Malay, and 1627 Indian adults contributed to this analysis. Average GCIPL thickness was 82.6±6.1 μm in Chinese, 81.5±6.8 μm in Malays, and 78.0±6.9 μm in Indians (P < 0.001 by analysis of variance). The 5th percentile limit of average GCIPL thickness was 72 μm in Chinese, 70 μm in Malays, and 67 μm in Indians. In multivariable analysis adjusting for age, gender, axial length, presence of cataract, OCT signal strength, disc area, hypertension, diabetes, and hyperlipidemia, eyes of Indians were observed to have 3.43 μm thinner GCIPL on average compared with Chinese (P < 0.001) and 3.36 μm thinner GCIPL compared with Malays (P<0.001). In addition, older age (per decade; β=-2.51), female (β=-1.57), longer axial length (per mm; β=-1.54), and presence of chronic kidney disease (β=-1.49) were significantly associated with thinner average GCIPL (all P ≤ 0.008). Larger optic disc area (per mm2; β= 0.78; P < 0.001) was associated withthicker GCIPL. These factors were consistently observed to be significant for superior and inferior hemisphere GCIPL thickness. GCIPL thickness profiles were significantly thinner in Indians compared with Chinese and Malays. Our findings further highlight the need of a more refined, ethnic-specific normative database for GCIPL thickness, which in turn may improve the detection and diagnosis of glaucoma in Asians.

Brain activity associated with the rubber foot illusion

The internal representation of the body is constantly updated by sensory information based on interactions with the environment. The internal representation of the hand can be experimentally manipulated with the rubber hand illusion (RHI) paradigm. Brain activity during the RHI provides insight into the neural mechanisms underpinning the reconstruction of the internal representation of the hand. Recently, the RHI paradigm has been employed for the lower limb, revealing that the illusion is also induced in the lower limb (rubber foot illusion; RFI). However, the neural correlates of the RFI remain unknown. We used functional magnetic resonance imaging (fMRI) to examine brain activity during the RFI. Forty-four healthy volunteers participated in the fMRI experiment. Significant increases in activation were observed in the bilateral medial and middle frontal gyri, left supplemental motor area, bilateral inferior parietal lobuli, precunei, calcarine cortices, and cerebellar hemispheres; and in the vermis and bilateral thalami during the right RFI. During the left RFI, significant increases in activation were observed in the bilateral medial, middle, and superior frontal gyri; left inferior frontal gyrus and supplemental motor area, bilateral inferior parietal lobuli and middle temporal gyri, and in the left cerebellar hemisphere, vermis, and bilateral thalami. Conjunction analysis revealed that the prefrontal cortex including the bilateral medial and middle frontal gyri, parietal cortex including the bilateral inferior parietal lobuli, and cerebellum including the bilateral cerebellar hemispheres and vermis were conjointly activated during the right and left RFIs. The distribution of co-activated brain areas during the RFI was similar to the previously reported distribution of brain areas activated during the RHI. Co-activation of these brain areas may be associated with the reconstruction of the internal representation of the body. The fact that these areas are activated both in the RFI and RHI will have implications for the treatment of patients with disturbed internal bodily representation.

Abstract WP64: Perfusion Imaging Can Identify Basilar Occlusion Patients With a Favorable Response to Thrombectomy

Introduction: Perfusion imaging can identify patients who respond favorably to endovascular therapy (EVT) in the anterior circulation; no data are available for the posterior circulation. We evaluated perfusion patterns, assessed with RAPID software, in a consecutive cohort of patients with basilar artery occlusion treated with EVT and assessed the association between reperfusion and favorable clinical outcome based on the perfusion profile. Hypothesis: We hypothesized that patients with limited regions of severe hypoperfusion (Tmax &gt; 10s) would have a favorable response (mRS 0-2) to reperfusion (mTICI 2b-3) while patients with multiple critical brain regions severely hypoperfused would have poor outcome (mRS 4-6) despite reperfusion. Methods: From a multicenter cohort of perfusion imaging in posterior circulation stroke, we included patients with basilar artery occlusion and EVT. We pre-specified a Critical Area Perfusion Score (CAPS, 0 - 8 points) to identify severe hypoperfusion (Tmax &gt;10s) in the following regions: inferior and/or superior cerebellar hemisphere (1-4 points), pons (2 points), midbrain/thalamus (2 points). We compared the outcome between reperfusers and non reperfusers based on the CAP score with univariate and multivariate analysis. Results: 38 patients met the inclusion criteria. Mean age was 63±17, 34% female, NIHSS 17±11. In patients who reperfused (n=30, 79%) 63% had favorable outcome, while no patient without reperfusion survived, p=0.003 OR=29 (95%CI 1.5-547). Ninety percent (19/21) of reperfused patients with CAPS ≤2 had a favorable outcome, while none of the 9 with reperfusion and a score &gt;2 survived, p&lt;0.001, OR=148 (95%CI 6.5-3,333). In univariate analysis, favorable outcome was associated with NIHSS OR=0.87 (95% CI 0.80-0.96), p=0.003, and mismatch volume OR=0.98 (95% CI 0.97-0.997) p=0.013. In the multivariate analysis, only CAPS was an independent predictor of favorable outcome. Conclusions: Patients with limited regions of severe hypoperfusion (Tmax &gt; 10s) had a robust response to basilar artery EVT, however, all patients with multiple critical brain regions severely hypoperfused died despite successful reperfusion. Perfusion imaging profiles may help identify optimal patients for basilar EVT.

Effects of CPAP for patients with OSA on visual sensitivity and retinal thickness

ObjectiveObstructive sleep apnea/hypopnea syndrome (OSA) could compromise oxygenation of the optic nerve and cause glaucomatous optic neuropathy; there has been no study to investigate the microstructure changes of the optic nerve and retina in OSA patients before and after continuous positive airway pressure (CPAP) therapy. In this study, we assess whether treatment with CPAP might improve visual sensitivity and retinal thickness in patients with OSA. MethodsPatients with OSA were prospectively recruited and referred for ophthalmologic evaluation at baseline and three months after CPAP treatment. Each patient underwent an ophthalmological exam, standard automated perimetry (SAP), and optical coherence tomography (OCT) exam. Peripapillary retinal nerve fiber layer (RNFL) and macular layer (ML) thickness parameters were measured. The SAP, RNFL, and ML thickness parameters before and after treatment were compared. ResultsA total of 32 OSA patients were consecutively enrolled. At baseline, the mean deviation (MD) of SAP was −2.15 ± 1.90 dB (dB). After CPAP treatment, the MD was −1.38 ± 1.37 dB (p = 0.017). Regarding the OCT parameters, the inferior quadrant and nasal-inferior sector of RNFL thickness significantly improved after treatment (p = 0.025 and 0.004, respectively). The ML thickness in the superior-inner sector, inferior-outer sector, nasal-outer sector, superior hemisphere, and inferior hemisphere were also significantly improved after treatment. Improvement of ML thickness in the superior-inner sector positively correlated with the apnea/hypopnea index (r = 0.405, p = 0.022) and desaturation index (r = 0.473, p = 0.006) on pre-treatment polysomnography. ConclusionThe treatment of CPAP could improve visual sensitivity and increase retinal thickness in patients with OSA.

The Horizontal Raphe of the Human Retina and its Watershed Zones.

The horizontal raphe (HR) as a demarcation line dividing the retina and choroid into separate vascular hemispheres is well established, but its development has never been discussed in the context of new findings of the last decades. Although factors for axon guidance are established (e.g., slit-robo pathway, ephrin-protein-receptor pathway) they do not explain HR formation. Early morphological organization, too, fails to establish a HR. The development of the HR is most likely induced by the long posterior ciliary arteries which form a horizontal line prior to retinal organization. The maintenance might then be supported by several biochemical factors. The circulation separate superior and inferior vascular hemispheres communicates across the HR only through their anastomosing capillary beds resulting in watershed zones on either side of the HR. Visual field changes along the HR could clearly be demonstrated in vascular occlusive diseases affecting the optic nerve head, the retina or the choroid. The watershed zone of the HR is ideally protective for central visual acuity in vascular occlusive diseases but can lead to distinct pathological features.

Influence of Choroidal Microvasculature Dropout on the Rate of Glaucomatous Progression: A Prospective Study

To determine the prognostic significance of choroidal microvasculature dropout (MvD) to predict the future rate of progressive retinal nerve fiber layer (RNFL) thinning in eyes with primary open-angle glaucoma (POAG). Prospective, longitudinal case series. This study enrolled 101 eyes of 101 patients with POAG who underwent OCT angiography (OCTA) imaging of the optic nerve head at baseline and were followed up for at least 2 years thereafter, during which RNFL thickness was measured by serial spectral-domain OCT. The peripapillary microvasculature was evaluated by examining en face OCTA images. Choroidal MvD was defined as a focal sectoral capillary dropout with no visible microvascular network in the choroidal layer. The rate of RNFL thinning was determined by linear regression of serial OCT RNFL thickness measurements. Influence of the presence of an MvD on the rate of subsequent RNFL thinning. Microvasculature dropout was identified in 48 eyes (47.5%). The rate of global RNFL thinning was significantly faster in eyes with MvD than eyes without MvD (-1.6±0.8 vs.-1.2±0.9 μm/year, P= 0.018). Eyes with MvD in the inferior hemisphere (n= 41) showed a faster rate of inferior RNFL thinning than eyes without MvD (P= 0.036). Eyes with MvD in both the superior and inferior hemispheres (n= 5) showed faster rates of superior (P= 0.027) and inferior (P= 0.016) RNFL thinning than eyes without MvD. Multivariate regression analysis showed that MvD at baseline (P= 0.003) and the presence of disc hemorrhage during follow-up (P= 0.001) were independently associated with a faster rate of global RNFL thinning. Microvasculature dropout was an independent predictor of a faster rate of progressive RNFL thinning in patients with POAG. Microvasculature dropout location was topographically associated with the location of faster RNFL thinning.

57-Year-Old Man With Vertigo

57-Year-Old Man With Vertigo

The influence of visual field position induced by a retinal prosthesis simulator on mobility.

Our aim is to develop a new generation of suprachoroidal-transretinal stimulation (STS) retinal prosthesis using a dual-stimulating electrode array to enlarge the visual field. In the present study, we aimed to examine how position and size of the visual field-created by a retinal prosthesis simulator-influenced mobility. Twelve healthy subjects wore retinal prosthesis simulators. Images captured by a web camera attached to a head-mounted display (HMD) were processed by a computer and displayed on the HMD. Three types of artificial visual fields-designed to imitate phosphenes-obtained by a single (5 × 5 electrodes; visual angle, 15°) or dual (5 × 5 electrodes ×2; visual angle, 30°) electrode array were created. Visual field (VF)1 is an inferior visual field, which corresponds to a dual-electrode array implanted in the superior hemisphere. VF2 is a superior visual field, which corresponds to a single-electrode array implanted in the inferior hemisphere. VF3 is a superior visual field, which corresponds to a dual-electrode array implanted in the inferior hemisphere. In each type of artificial visual field, a natural circular visual field (visual angle, 5°) which imitated the vision of patients with advanced retinitis pigmentosa existed at the center. Subjects were instructed to walk along a black carpet (6m long × 2.2m wide) without stepping on attached white circular obstacles. Each obstacle was 20cm in diameter, and obstacles were installed at 40-cm intervals. We measured the number of footsteps on the obstacles, the time taken to complete the obstacle course, and the extent of head movement to scan the area (head-scanning). We then compared the results recorded from these 3 types of artificial visual field. The number of footsteps on obstacles was lowest in VF3 (One-way ANOVA; P = 0.028, Fisher's LSD; VF 1 versus 3 P = 0.039, 2 versus 3 P = 0.012). No significant difference was observed for the time to complete the obstacle course or the extent of head movement between the 3 visual fields. The superior and wide visual field (VF3) obtained by the retinal prosthesis simulator resulted in better mobility performance than the other visual fields.

Intereye and intraeye asymmetry analysis of retinal microvascular and neural structure parameters for diagnosis of primary open-angle glaucoma.

To investigate the diagnostic values of intereye or intraeye asymmetry of retinal perfused vessel density and neural structure parameters for detection of glaucoma. In total, 152 healthy subjects and 72 bilateral primary open-angle glaucoma (POAG) patients were enrolled. Total POAG group contains all glaucoma patients. Early to moderate POAG group contains patients whose binocular mean defect values were larger than -12 dB. The retinal perfused vessel densities were acquired using optic coherence tomography angiography. The neural structure parameters include RNFL, GCC thickness and its derivative indices like focal loss volume percentage (FLV%) and global loss volume percentage (GLV%). Intereye asymmetry equaled to the absolute difference of parameters between paired eyes. Intraeye asymmetry was defined as absolute difference between the inferior and superior hemisphere values from one random selected eye. The areas under the receiver operating characteristic curves (AUROCs) were calculated to evaluate diagnostic ability. From pairwise comparison analysis of ROC curves, the intereye asymmetric parameters with the largest diagnostic accuracy were FLV and GLV% (AUROC = 0.944), which were significantly superior to the intereye asymmetry of perfused vessel density in peripapillary area and parafoveal area (P < 0.05). Particularly, the intereye asymmetry of FLV% (AUROC = 0.926) and GLV% (AUROC = 0.950) showed excellent diagnostic precision for detecting early to moderate glaucoma patients. However, the intraeye asymmetry of microvascular parameters and neural structure parameters showed fair diagnostic ability for identifying POAG patients. The intereye asymmetry of neural structure parameters, particularly the FLV% and GLV%, outperformed the microvascular parameters for identifying POAG patients.

Two-year observation of posterior corneal elevations after small incision lenticule extraction (SMILE) for myopia higher than −10 dioptres

AimTo investigate the change in posterior corneal elevations (PCEs) of eyes with extremely high myopia 2 years after small incision lenticule extraction (SMILE).MethodsWe evaluated 39 eyes of 39 patients with...

Anterior Corneal Curvature and Aberration Changes After Scleral Lens Wear in Keratoconus Patients With and Without Ring Segments.

To evaluate changes in the anterior corneal curvature and aberrometry after scleral contact lens wear in keratoconus (KC) subjects with and without intracorneal ring segments (ICRS). Twenty-six subjects diagnosed with keratoconus were selected to participate in the study. Subjects were divided into 2 groups, those with ICRS (KC-ICRS group) and those without ICRS (KC group). Subjects were instructed to wear 16.5-mm scleral lenses for 8 hours. Topographic and aberrometric parameters were evaluated before lens wear and immediately after lens removal. Anterior corneal curvature was evaluated at corneal diameters of 2, 4, 6, and 8 mm, and corneal aberrations were measured at 4-, 6-, and 8-mm pupil diameters. The mean age of subjects was 36.95±8.95 years. In KC group, there was a statistically significant flattening of the central corneal curvature, from 6.98 to 7.09 mm (P<0.05). No changes were found in the central corneal curvature in the KC-ICRS group. The KC group showed anterior corneal curvature flattening, mainly in the nasal quadrant. The KC-ICRS group showed flattening primarily in the inferior hemisphere. In the KC group, spherical aberration for 6-mm pupil increased significantly. In the KC-ICRS group, changes in aberrations were significant for high-order root mean square at 4- and 6-mm pupil diameters (P<0.05), for oblique astigmatism for 4 mm and 6 mm, and for vertical coma for 4-mm pupil (P<0.05). Short-term scleral lens wear showed flattening of the anterior corneal surface in all subjects. In the KC group, the flattening was more pronounced in the nasal quadrant while changes were more pronounced inferiorly in KC-ICRS group.