Visual exploration behaviour during clock reading in Alzheimer's disease

Eye movement behaviour during visual exploration of 24 patients with probable Alzheimer's disease and 24 age-matched controls was compared in a clock reading task. Controls were found to focus exploration on distinct areas at the end of each clock hand. The sum of these two areas of highest fixation density was defined as the informative region of interest (ROI). In Alzheimer's disease patients, visual exploration was less focused, with fewer fixations inside the ROI, and the time until the first fixation was inside the ROI was significantly delayed. Changes of fixation distribution correlated significantly with the ability to read the clock correctly, but did not correlate with dementia severity. In Alzheimer's disease patients, fixations were longer and saccade amplitudes were smaller. The altered visual exploration in Alzheimer's disease might be related to parietal dysfunction or to an imbalance between a degraded occipito-parietal and relatively preserved occipito-temporal visual network.

Stem cell-based therapeutic applications in retinal degenerative diseases

Retinal degenerative diseases that target photoreceptors or the adjacent retinal pigment epithelium (RPE) affect millions of people worldwide. Retinal degeneration (RD) is found in many different forms of retinal diseases including retinitis pigmentosa (RP), age-related macular degeneration (AMD), diabetic retinopathy, cataracts, and glaucoma. Effective treatment for retinal degeneration has been widely investigated. Gene-replacement therapy has been shown to improve visual function in inherited retinal disease. However, this treatment was less effective with advanced disease. Stem cell-based therapy is being pursued as a potential alternative approach in the treatment of retinal degenerative diseases. In this review, we will focus on stem cell-based therapies in the pipeline and summarize progress in treatment of retinal degenerative disease.

Application of the specular and diffuse reflection analysis for in vitro diagnostics of dental erosion: correlation with enamel softening, roughness, and calcium release

We present assembly and application of an optical reflectometer for the analysis of dental erosion. The erosive procedure involved acid-induced softening and initial substance loss phases, which are considered to be difficult for visual diagnosis in a clinic. Change of the specular reflection signal showed the highest sensitivity for the detection of the early softening phase of erosion among tested methods. The exponential decrease of the specular reflection intensity with erosive duration was compared to the increase of enamel roughness. Surface roughness was measured by optical analysis, and the observed tendency was correlated with scanning electron microscopy images of eroded enamel. A high correlation between specular reflection intensity and measurement of enamel softening (r(2) ? -0.86) as well as calcium release (r(2) ? -0.86) was found during erosion progression. Measurement of diffuse reflection revealed higher tooth-to-tooth deviation in contrast to the analysis of specular reflection intensity and lower correlation with other applied methods (r(2) = 0.42-0.48). The proposed optical method allows simple and fast surface analysis and could be used for further optimization and construction of the first noncontact and cost-effective diagnostic tool for early erosion assessment in vivo.

The link between visual exploration and neuronal activity: A multi-modal study combining eye tracking, functional magnetic resonance imaging and transcranial magnetic stimulation

In the present multi-modal study we aimed to investigate the role of visual exploration in relation to the neuronal activity and performance during visuospatial processing. To this end, event related functional magnetic resonance imaging er-fMRI was combined with simultaneous eye tracking recording and transcranial magnetic stimulation (TMS). Two groups of twenty healthy subjects each performed an angle discrimination task with different levels of difficulty during er-fMRI. The number of fixations as a measure of visual exploration effort was chosen to predict blood oxygen level-dependent (BOLD) signal changes using the general linear model (GLM). Without TMS, a positive linear relationship between the visual exploration effort and the BOLD signal was found in a bilateral fronto-parietal cortical network, indicating that these regions reflect the increased number of fixations and the higher brain activity due to higher task demands. Furthermore, the relationship found between the number of fixations and the performance demonstrates the relevance of visual exploration for visuospatial task solving. In the TMS group, offline theta bursts TMS (TBS) was applied over the right posterior parietal cortex (PPC) before the fMRI experiment started. Compared to controls, TBS led to a reduced correlation between visual exploration and BOLD signal change in regions of the fronto-parietal network of the right hemisphere, indicating a disruption of the network. In contrast, an increased correlation was found in regions of the left hemisphere, suggesting an intent to compensate functionality of the disturbed areas. TBS led to fewer fixations and faster response time while keeping accuracy at the same level, indicating that subjects explored more than actually needed.

[Adapted and Standardised Patient Management in the Treatment of Neovascular AMD in the Outpatient Setting of a University Eye Hospital.]

Visual results in treating neovascular age-related macular degeneration (AMD) using intravitreal injected anti-VEGF (IVT) clearly depend on injection frequency. Regarding to the European approval Ranibizumab has to be used only in cases of recurrent visual loss after the loading phase. In contrast monthly treatment--as also provided in the ANCHOR and MARINA studies--is generally allowed in Switzerland. However, it is commonly tried to reduce the injection frequency because of the particular cost situation in all health systems and of cause also due to the necessary strict monitoring and reinjection regimes, which raise management problems with increasing patient numbers. In this article the special treatment regimes of our University Eye Hospital is presented, in which a reduced injection frequency basically leads to the same increased and stable visual results as in ANCHOR and MARINA; however, needing significantly more injections as generally provided in other countries of Europe. The main focus for achieving this in a large number of patients is placed on re-structuring our outpatient flow for IVT patients with particular emphasis on patient separation and standardisation of treatment steps leading to significantly reduced time consumption per patient. Measurements of timing and patient satisfaction before and after restructuring underline its importance in order to be able to treat more patients at a high quality even in the future. The exceptional importance of spectral domain OCT measurements as the most important criterium for indicating re-treatment is illustrated.

Visual hallucinations

Research into visual hallucinations has accelerated over the last decade from around 350 publications per year in 2000 to over 500 in 2010. Increased recognition of the frequent occurrence of visual hallucinations in a number of common disorders, coupled with improvements in the measurement of phenomenology, and more sophisticated imaging techniques have allowed the development and initial testing of sophisticated models. However, key questions remain unanswered. Amongst these are: whether there is a satisfactory definition of hallucinations in a constructive visual system; whether there are one, two or several core varieties of hallucinations; what are the underlying brain mechanisms for hallucinations; and what, if anything, can be done to treat them when they lead to distress? Looking across research in several clinical areas suggests a tentative integrative model that allows the possibility of answering these questions, but much work remains to be done.

Communication in troubled waters: responses of fish communication systems to changing environments

Fish populations are increasingly being subjected to anthropogenic changes to their sensory environments. The impact of these changes on inter- and intra-specific communication, and its evolutionary consequences, has only recently started to receive research attention. A disruption of the sensory environment is likely to impact communication, especially with respect to reproductive interactions that help to maintain species boundaries. Aquatic ecosystems around the world are being threatened by a variety of environmental stressors, causing dramatic losses of biodiversity and bringing urgency to the need to understand how fish respond to rapid environmental changes. Here, we discuss current research on different communication systems (visual, chemical, acoustic, electric) and explore the state of our knowledge of how complex systems respond to environmental stressors using fish as a model. By far the bulk of our understanding comes from research on visual communication in the context of mate selection and competition for mates, while work on other communication systems is accumulating. In particular, it is increasingly acknowledged that environmental effects on one mode of communication may trigger compensation through other modalities. The strength and direction of selection on communication traits may vary if such compensation occurs. However, we find a dearth of studies that have taken a multimodal approach to investigating the evolutionary impact of environmental change on communication in fish. Future research should focus on the interaction between different modes of communication, especially under changing environmental conditions. Further, we see an urgent need for a better understanding of the evolutionary consequences of changes in communication systems on fish diversity.

Intravitreal triamcinolone acetonide for serous retinal pigment epithelial detachments in exudative age-related macular degeneration

BACKGROUND: Due to the high risk of RPE tears PDT is usually not performed in eyes with serous RPE detachments (sRPED). For this reason this subform of exudative AMD was so far untreatable. PATIENTS AND METHODS: We report on a prospective uncontrolled observational case series. 20 eyes of 20 patients with subfoveal sRPED demonstrated by OCT were treated between June 2005 and April 2006 with intravitreal triamcinolone acetonide (IVTA). In 15 cases there was a primary sRPED, in 5 cases it had developed after one or more sessions of photodynamic therapy with Visudyne. RESULTS: There was a trend for better average visual acuity in the group with primary sRPED from 0.73 logMAR (0.19 Snellen equivalent) at baseline (n = 15) to 0.68 logMAR (0.21 Snellen) after one month (n = 15) (p = 0.19) and to 0.60 logMAR (0.25 Snellen) after three months (n = 14) (p = 0.41). The maximal height of sRPED decreased to an average of 35.3 % after one month (n = 15) and increased again to 56.9 % after 3 months (n = 14). One patient was lost to follow-up. In the group of eyes with sRPED after PDT, one eye developed an RPE tear with severe vision loss two weeks after IVTA. In the remaining four eyes average visual acuity improved from 0.90 logMAR (0.13 Snellen) at baseline to 0.73 logMAR (0.19 Snellen) after one month and to 0.80 logMAR (0.16 Snellen) after 3 months. Complete resolution of sRPED was observed in 8/20 eyes (4/5 eyes with sRPED after PDT and 4/15 eyes with primary sRPED). CONCLUSIONS: IVTA seems to be a therapeutic option in otherwise untreatable eyes with sRPED.

Increased plasma endothelin-1 levels in patients with progressive open angle glaucoma

AIM: To compare the plasma levels of endothelin-1 (ET-1) between patients with primary open angle glaucoma with visual field progression despite normal or normalised intraocular pressure and patients with stabile visual fields in a retrospective study. METHODS: The progressive group consisted of 16 primary open angle glaucoma patients and the group with stable visual field consisted of 15 patients. After a 30 minute rest in a supine position, venous blood was obtained for ET-1 dosing. Difference in the plasma level of ET-1 between two groups was compared by means of analysis of covariance (ANCOVA), including age, sex, and mean arterial blood pressure as covariates. RESULTS: ET-1 plasma levels were found to be significantly increased in patients with deteriorating (3.47 (SD 0.75) pg/ml) glaucoma when compared to those with stable (2.59 (SD 0.54) pg/ml) visual fields (p = 0.0007). CONCLUSIONS: Glaucoma patients with visual field progression in spite of normal or normalised intraocular pressure have been found to have increased plasma endothelin-1 levels. It remains to be determined if this is a secondary phenomenon or whether it may have a role in the progression of glaucomatous damage.

Safety and feasibility of percutaneous closure of patent foramen ovale without intra-procedural echocardiography in 825 patients

BACKGROUND: Percutaneous closure of patent foramen ovale (PFO) is generally performed using intra-procedural guidance by transoesophageal (TEE) or intracardiac (ICE) echocardiography. While TEE requires sedation or general anaesthesia, ICE is costly and adds incremental risk, and both imaging modalities lengthen the procedure. METHODS: A total of 825 consecutive patients (age 51 +/- 13 years; 58% male) underwent percutaneous PFO closure solely under fluoroscopic guidance, without intra-procedural echocardiography. The indications for PFO closure were presumed paradoxical embolism in 698 patients (95% cerebral, 5% other locations), an embolic event with concurrent aetiologies in 47, diving in 51, migraine headaches in 13, and other reasons in 16. An atrial septal aneurysm was associated with the PFO in 242 patients (29%). RESULTS: Permanent device implantation failed in two patients (0.2%). There were 18 procedural complications (2.2%), including embolization of the device or parts of it in five patients with successful percutaneous removal in all cases, air embolism with transient symptoms in four patients, pericardial tamponade requiring pericardiocentesis in one patient, a transient ischaemic attack with visual symptoms in one patient, and vascular access site problems in seven patients. There were no long-term sequelae. Contrast TEE at six months showed complete abolition of right-to-left shunt via PFO in 88% of patients, whereas a minimal, moderate or large residual shunt persisted in 7%, 3%, and 2%, respectively. CONCLUSIONS: This study confirms the safety and feasibility of percutaneous PFO closure without intra-procedural echocardiographic guidance in a large cohort of consecutive patients.

Verteporfin therapy in occult with no classic CNV due to AMD: results of the Photodynamic Therapy in Occult-Only Lesions study

PURPOSE: To provide further information on verteporfin photodynamic therapy in occult with no classic choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD). METHODS: Verteporfin therapy was administered at baseline and then at months 3, 6, and 9, if fluorescein leakage from CNV was evident on angiography. RESULTS: Of 202 patients enrolled, 184 completed 12 months. Each patient was treated in one eye only. All study eyes received verteporfin therapy at baseline, with a progressive decrease in the number treated at subsequent visits (mean 2.5 treatments during 12 months). The mean change in visual acuity letter score from baseline to month 12 was -11.9. At month 12, 164 eyes (82.4%) had lost <30 letters of visual acuity, 123 eyes (61.8%) had lost <15 letters, 78 eyes (39.2%) had lost <5 letters, 31 (15.6%) had >5-letter increase, and 7 (3.5%) had >15-letter improvement. The percentage of eyes with fluorescein leakage from CNV decreased from 75.5% at month 3 to 25.1% at month 12. Adverse events were documented for 54% patients. Few patients had treatment-associated adverse events (7%). Acute severe visual acuity decrease occurred in two eyes (1%), one of which had visual acuity that returned to baseline by the next follow-up visit. CONCLUSIONS: This study provides additional evidence that over 12 months, verteporfin is generally well tolerated and maintains or improves visual acuity in over one-third of eyes containing occult-only CNV. Verteporfin also improved anatomical outcomes by reducing leakage from CNV in at least two-thirds of eyes.