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Gait disorders are a disabling feature of Parkinson’s disease (PD). To avoid falls, people with PD should be able to adequately adapt their gait. This requires correct response inhibition and integration of visual information. In this small pilot study, we investigated PD-related impairments in gait adaptability and the influence of ocular disorders thereon.Compared with controls, persons with PD were less able to adapt their gait in unexpected situations (U?=?21.5, p?=?0.013), with only a small influence of ocular disorders on precision stepping (U?=?6, p?=?0.012 in the ML-direction and in the AP-direction, (U?=?20, p?=?0.456).This shows that people with PD have more difficulty with precision stepping than healthy controls and experience more problems with adapting their gait. We found only a small impact of ocular disorders on successfully execute precision stepping. The ability to adapt gait, particularly in challenging environmental conditions or with impaired vision, may provide a useful assessment and training option for fall prevention in PD.

Gait disorders are a disabling feature of Parkinson’s disease (PD). To avoid falls, people with PD should be able to adequately adapt their gait. This requires correct response inhibition and integration of visual information. In this small pilot study, we investigated PD-related impairments in gait adaptability and the influence of ocular disorders thereon. Compared with controls, persons with PD were less able to adapt their gait in unexpected situations (U = 21.5, p = 0.013), with only a small influence of ocular disorders on precision stepping (U = 6, p = 0.012 in the ML-direction and in the AP-direction, (U = 20, p = 0.456). This shows that people with PD have more difficulty with precision stepping than healthy controls and experience more problems with adapting their gait. We found only a small impact of ocular disorders on successfully execute precision stepping. The ability to adapt gait, particularly in challenging environmental conditions or with impaired vision, may provide a useful assessment and training option for fall prevention in PD.

Visual disorders like double vision, dry eyes, and visual field deficits are common but frequently missed in Parkinson’s disease. Here, we aim to increase awareness for these visual disorders in Parkinson patients by discussing several common problems that can be easily diagnosed using comprehensive history taking and a basic neuro-ophthalmological examination. We offer practical guidance for the patient interview and physical exam that can facilitate a timelier recognition of visual disorders. Such recognition has immediate therapeutic relevance, because Parkinson patients are strongly dependent on an adequate vision, for example to optimally benefit from visual cueing strategies.

To study long-term macular changes by spectral-domain (SD) OCT in patients with Sjögren–Larsson syndrome (SLS).

AimsTo investigate retinal microaneurysms in patients with diabetic macular oedema (DME) by optical coherence tomography angiography (OCTA) according to their location and morphology in relationship to their clinical properties, leakage on fundus fluorescein angiography (FFA) and retinal thickening on structural OCT.MethodsOCTA and FFA images of 31 eyes of 24 subjects were graded for the presence of microaneurysms. The topographical and morphological appearance of microaneurysms on OCTA was evaluated and classified. For each microaneurysm, the presence of focal leakage on FFA and associated retinal thickening on OCT was determined.ResultsOf all microaneurysms flagged on FFA, 295 out of 513 (58%) were also visible on OCTA. Microaneurysms with focal leakage and located in a thickened retinal area were more likely to be detected on OCTA than not leaking microaneurysms in non-thickened retinal areas (p=0.001). Most microaneurysms on OCTA were seen in the intermediate (23%) and deep capillary plexus (22%). Of all microaneurysms visualised on OCTA, saccular microaneurysms were detected most often (31%), as opposed to pedunculated microaneurysms (9%). Irregular, fusiform and mixed fusiform/saccular-shaped microaneurysms had the highest likeliness to leak and to be located in thickened retinal areas (p<0.001, p<0.001 and p=0.001).ConclusionsRetinal microaneurysms in DME could be classified topographically and morphologically by OCTA. OCTA detected less microaneurysms than FFA, and this appeared to be dependent on leakage activity and retinal thickening. Morphological appearance of microaneurysms (irregular, fusiform and mixed saccular/fusiform) was associated with increased leakage activity and retinal thickening.

We developed a deep learning algorithm for the automatic segmentation and quantification of intraretinal cystoid fluid (IRC) in spectral domain optical coherence tomography (SD-OCT) volumes independent of the device used for acquisition. A cascade of neural networks was introduced to include prior information on the retinal anatomy, boosting performance significantly. The proposed algorithm approached human performance reaching an overall Dice coefficient of 0.754 ± 0.136 and an intraclass correlation coefficient of 0.936, for the task of IRC segmentation and quantification, respectively. The proposed method allows for fast quantitative IRC volume measurements that can be used to improve patient care, reduce costs, and allow fast and reliable analysis in large population studies.

We propose a method for automatic detection of the foveal center in optical coherence tomography (OCT). The method is based on a pixel-wise classification of all pixels in an OCT volume using a fully convolutional neural network (CNN) with dilated convolution filters. The CNN-architecture contains anisotropic dilated filters and a shortcut connection and has been trained using a dynamic training procedure where the network identifies its own relevant training samples. The performance of the proposed method is evaluated on a data set of 400 OCT scans of patients affected by age-related macular degeneration (AMD) at different severity levels. For 391 scans (97.75%) the method identified the foveal center with a distance to a human reference less than 750 μm, with a mean (± SD) distance of 71 μm ± 107 μm. Two independent observers also annotated the foveal center, with a mean distance to the reference of 57 μm ± 84 μm and 56 μm ± 80 μm, respectively. Furthermore, we evaluate variations to the proposed network architecture and training procedure, providing insight in the characteristics that led to the demonstrated performance of the proposed method.

We developed a fully automated system using a convolutional neural network (CNN) for total retina segmentation in optical coherence tomography (OCT) that is robust to the presence of severe retinal pathology. A generalized U-net network architecture was introduced to include the large context needed to account for large retinal changes. The proposed algorithm outperformed qualitative and quantitatively two available algorithms. The algorithm accurately estimated macular thickness with an error of 14.0 ± 22.1 µm, substantially lower than the error obtained using the other algorithms (42.9 ± 116.0 µm and 27.1 ± 69.3 µm, respectively). These results highlighted the proposed algorithm’s capability of modeling the wide variability in retinal appearance and obtained a robust and reliable retina segmentation even in severe pathological cases.

Supplemental Digital Content is available in the text.

A growing body of evidence suggests that phototransduction can be studied in the human eye in vivo by imaging of fast intrinsic optical signals (IOS). There is consensus concerning the limiting influence of motion-associated imaging noise on the reproducibility of IOS-measurements, especially in those employing spectral-domain optical coherence tomography (SD-OCT). However, no study to date has conducted a comprehensive analysis of this noise in the context of IOS-imaging. In this study, we discuss biophysical correlates of IOS, and we address motion-associated imaging noise by providing correctional post-processing methods. In order to avoid cross-talk of adjacent IOS of opposite signal polarity, cellular resolution and stability of imaging to the level of individual cones is likely needed. The optical Stiles-Crawford effect can be a source of significant IOS-imaging noise if alignment with the peak of the Stiles-Crawford function cannot be maintained. Therefore, complete head stabilization by implementation of a bite-bar may be critical to maintain a constant pupil entry position of the OCT beam. Due to depth-dependent sensitivity fall-off, heartbeat and breathing associated axial movements can cause tissue reflectivity to vary by 29% over time, although known methods can be implemented to null these effects. Substantial variations in reflectivity can be caused by variable illumination due to changes in the beam pupil entry position and angle, which can be reduced by an adaptive algorithm based on slope-fitting of optical attenuation in the choriocapillary lamina.

Supplemental Digital Content is available in the text.

OBJECTIVE To describe the clinical and genetic findings in 15 patients with multifocal vitelliform lesions. METHODS All patients and, if possible, affected family members underwent an ophthalmic examination and their genomic DNA was analyzed for mutations in the vitelliform macular dystrophy 2 (VMD2) gene. Patients who did not have a mutation in the VMD2 gene were screened for mutations in the peripherin/RDS gene. RESULTS Patient age at onset of the disease was highly variable, ranging from 5 to 59 years. The peripheral lesions varied in number, size, and overall appearance but showed similar characteristics at autofluorescence imaging and optical coherence tomography compared with the central vitelliform lesion. Mutations in the VMD2 gene were identified in 9 of 15 patients. One patient without a VMD2 mutation carried a sequence variant in the 5′ untranslated region of the peripherin/RDS gene. CONCLUSIONS Multifocal vitelliform dystrophy is a clinically and genetically heterogeneous retinal disease that can be caused by mutations in the VMD2 gene. Other genes associated with this phenotype remain to be identified. CLINICAL RELEVANCE Clinical and molecular genetic characterization of multifocal vitelliform dystrophy may lead to better understanding of the pathophysiological mechanisms underlying this phenotype and may enable a more accurate prognosis in individual patients.Arch Ophthalmol. 2007;125(8):1100-1106--

Purpose To study the clinical appearance and surgical results of autosomal dominantly inherited rhegmatogenous retinal detachments (RRDs). Methods After prospective examination of all but two family members, the medical records of 16 affected patients (21 eyes) of two families from the Netherlands with autosomal dominantly inherited RRD were retrospectively evaluated. Special attention was paid to the age at onset, the ocular morphology and the clinical appearance of the RRD. The type and number of the various surgical procedures were analyzed with respect to preoperative appearance of the RRD, postoperative results and final visual acuity. Results The mean age at onset of RRD of affected individuals in families A and B was 37±18 years and 19±10 years, respectively. The mean ocular axial length in the two families was 24.7 mm and 26.7 mm. The mean number of retinal defects preoperatively found was 2.2 in family A and 7.1 in family B. Round, atrophic retinal holes predominated. Two of 21 affected eyes showed significant preoperative proliferative vitreoretinopathy. Pars plana vitrectomy was the primary procedure in 4 cases; extra ocular buckling was the initial procedure in 15 cases. One eye received scleral folding with diathermy as primary surgery. Redetachment following surgery occurred in 5 of 10 cases in family A and 4 of 10 eyes in family B. Anatomical success could be achieved in 9 of 10 and 8 of 10 eyes in families A and B, respectively. Conclusions In these families the prevalence of RRD is high. Most patients were affected at a relatively young age compared with non-genetically linked forms of RRD. Because of the low success rate of surgical intervention and, subsequently, the high number of operations necessary to achieve reattachment of the retina, the use of diagnostic genetic techniques to identify individuals at risk would be advisable. In these subjects measures to prevent RRD are an option, even when anatomical substrates of precursors of RRD are absent.

Background The use of a mixture of silicone oil and partially fluorinated alkanes (high-density silicone oil) has recently been suggested as intraocular tamponade in complicated retinal detachment of the inferior quadrants. We describe a series of patients who developed a clinical picture resembling anterior granulomatous uveitis following endotamponade with high-density silicone oil. Methods We evaluated 19 eyes of 18 patients who underwent pars plana vitrectomy and intraocular tamponade with high-density silicone oil (Oxane HD ®). The indication for this type of intraocular tamponade was limited to cases with complicated retinal detachment of the inferior quadrants. Oxane HD ® was removed after a mean period of 3 months. Results One to eight weeks following vitrectomy with high-density silicone oil, an intraocular inflammation was observed in 7 of 19 eyes (37%). These eyes presented with keratic precipitates (KP), pigmented clumps in the inferior part of the anterior chamber and increased anterior chamber cellular reaction. This inflammatory response did not react to topical steroids. In addition to KP a considerable amount of cellular precipitation was noted on the surface of the oil bubble. Strikingly, the intraocular inflammatory signs completely resolved following removal of the high-density silicone oil. Conclusions An inflammatory response, resembling granulomatous uveitis, occurs in a significant number of patients after high-density silicone oil endotamponade. It is likely that this vitreous substitute is an immunogenic agent, given the complete resolution of the inflammation after removal of the high-density silicone oil. The routine use of this newly developed silicone oil should therefore await the outcome of additional controlled clinical trials.

Proteases and their inhibitors play a pivotal role in developmental and differentiative processes. In the present report we investigated the immunohistochemical localization of a1-antitrypsin, a1-antichymotrypsin and inter-a-trypsin inhibitor in first trimester as well as in term human placentas. For this purpose polyclonal antibodies against these serine-protease inhibitors were used. All inhibitors were expressed in the villous syncytiotrophoblast of first and last trimester placentas. Placental fibrinoid was positively stained for a1-antitrypsin and inter-a-trypsin inhibitor throughout gestation. a1-Antitrypsin and a1-antichymotrypsin showed a strong immunostaining in the Hofbauer cells (first trimester and full term placentas). Extravillous cytotrophoblast was negative for the three protease inhibitors throughout gestation. The presence of the three inhibitors in the syncytiotrophoblast suggests a role in coagulative, invasive and immunomodulatory processes. Fibrinoid, staining for a1-antitrypsin and inter-a-trypsin inhibitor, could also have an important immunoprotective function. The presence of protease inhibitors in the Hofbauer cells suggests an involvement of these cells in villous remodelling and differentiative processes.