Angular momentum sensitive two-center interference

In quantum mechanics the Young-type double-slit experiment can be performed with electrons either traveling through a double slit or being coherently emitted from two inversion symmetric molecular sites. In the latter one the valence photoionization cross sections of homonuclear diatomic molecules were predicted to oscillate over kinetic energy almost 50 years ago. Beyond the direct proof of the oscillatory behavior of these photoionization cross sections σ, we show that the angular distribution of the emitted electrons reveals hitherto unexplored information on the relative phase shift between the corresponding partial waves through two-center interference patterns.

Development of a very large array for retinal stimulation

Retina degeneration is one of the leading causes of blindness nowadays and cannot be cured in most cases. It has been shown that electrical stimulation of retinal ganglion cells can generate visual perceptions and therefore implantable electrode arrays can be possible treatment for these patients. Most implants developed for that purpose use electrode arrays with a size of a few millimeters squared and therefore could restore only a very small field of vision and hardly improve orientation in an unknown environment. In this paper we present results of the development of an implantable electrode array covering about 100 mm(2) of retinal tissue.

[Retinal vasculitis as manifestation of multiple sclerosis]

Multiple sclerosis (MS) is the most common chronic disease of the central nervous system in Germany. In 80 % of patients early stages of the disease are characterized by a clinically isolated episodic course. Ocular manifestations are common and mostly affect the optic nerve or the uvea and in some cases the retinal vessels. Here we report on a bilateral retinal vasculitis as the first manifestation of MS in a 27-year-old patient. All symptoms resolved after high dose steroid treatment; however, intensive follow-up is crucial due to potential occlusive, ischemic complications.

[Ahmed glaucoma valve via pars plana access. Long-term results of implantation for therapy refractive glaucoma]

BACKGROUND

Aim of this study is the presentation of long-term results regarding the effectiveness and safety of the implantation of Ahmed glaucoma valve (AGV) devices using a pars plana approach after vitrectomy in the treatment of therapy refractive glaucoma.

METHODS

The implantation of AGV devices using a pars plana approach after vitrectomy was performed in 27 eyes of 22 patients with neovascular glaucoma (n = 7 patients), uveitis (n = 6), complex juvenile secondary glaucoma (n = 4), primary open angle glaucoma (n = 3), pseudoexfoliation glaucoma (n = 1) and nanophthalmus (n = 1). Intraocular pressure, visual acuity and subsequent complications were documented. The mean follow-up period was 23.6 months.

RESULTS

Intraocular pressure was significantly reduced from 30.2 mmHg preoperatively to 13 mmHg after a follow-up of 36 months. The mean visual acuity did not change significantly, five eyes required a subsequent explantation of which three were due to AGV-related complications.

CONCLUSIONS

The implantation of AGV devices using a pars plana approach permits an effective and permanent reduction of intraocular pressure (IOP) even in severe therapy refractive secondary glaucoma; however, the risk of serious sight-threatening complications has to be taken into account.

Implantation and explantation of an active epiretinal visual prosthesis: 2-year follow-up data from the EPIRET3 prospective clinical trial

PURPOSE

The EPIRET3 retinal prosthesis was implanted in six volunteers legally blind from retinitis pigmentosa (RP) and removed after 4 weeks. Two years later, these subjects were re-examined to investigate ocular side effects and potential changes to quality of life.

METHODS

Vision-related quality of life was recorded using the NEI-VFQ-25 questionnaire. Clinical data including interval history, visual acuity, and intraocular pressure were obtained. Anterior and posterior segments of the study eyes were examined and photographed; this included fluorescein angiography and optical coherence tomography (OCT).

RESULTS

Data from five patients could be analysed. Life-quality score was consistent with results obtained at baseline. No unexpected structural alteration could be found in the study eyes. A moderate epiretinal gliosis was present in areas where the epiretinal stimulator had been fixated using retinal tacks. Angiography revealed no leakage or neovascularisation; OCT showed no generalised increase of central retinal thickness.

CONCLUSIONS

Vision-related quality of life is low in patients suffering from end-stage RP. No further deterioration of life quality could however be detected within our monitoring period. Surgery was well tolerated by both patients and their eyes, without adverse events occurring during the follow-up period. Epiretinal gliosis is known to occur with retinal tacks, but seems of no major concern to the integrity of the study eyes. However, it may potentially interfere with functional aspects of active implants. Hence, alternative, possibly biochemical, fixation methods merit further research.

[Evaluation of the need for communication training of ophthalmologists for gaining telephone consent for cornea donation]

INTRODUCTION

Because of the gap between the high need for cornea tissue for transplantation and the current lower numbers of donors, there is high pressure to succeed in telephone calls to relatives of deceased for obtaining consent. Besides the attempt to increase the rate of donors, these telephone calls should be gentle for relatives and not overstrain professionals. This study assesses the need and expectations of physicians towards communication training in preparation for their task.

METHODS

In September-October 2009 a needs assessment for communication training among physicians who currently work or have worked for the eye bank took place. Personal data were recorded and their estimate of the perceived burden as well as needs and potential benefits from a specific communication training for obtaining consent for cornea donation by telephone were assessed using numeric rating scales between 1 (minimum) and 10 (maximum). Results were expressed as mean and range.

RESULTS

The participants felt only moderately prepared for the task regarding information content, their emotions and personal convictions. They considered a specific training to be highly meaningful, necessary and helpful. Their highest burden during telephone calls previously experienced was documented as 8.4 and the average burden as 6.3. Accordingly, their willingness to continue working at an eye bank after their rotation was moderate.

DISCUSSION

Physicians involved in obtaining consent for cornea donation by telephone feel highly stressed and only moderately prepared for fulfilling the task both for the information content and on the emotional level. Accordingly, specific communication training is perceived as highly meaningful, necessary and helpful. An educational program was developed to meet the needs and expectations of physicians.

High efficiency non-viral transfection of retinal and iris pigment epithelial cells with pigment epithelium-derived factor

Transplantation of pigment epithelial cells in patients with age-related macular degeneration and Parkinson's disease has the potential to improve functional rehabilitation. Genetic modification of cells before transplantation may allow the delivery of neuroprotective factors to achieve functional improvement. As transplantation of cells modified using viral vectors is complicated by the possible dissemination of viral particles and severe immune reactions, we have explored non-viral methods to insert genetic material in pigment epithelial cells. Using lipofection or nucleofection ARPE-19 cells, freshly isolated and primary retinal and iris pigment epithelial (IPE) cells were transfected with plasmids encoding green fluorescent protein (GFP) and with three plasmids encoding recombinant pigment epithelium-derived factor (PEDF) and GFP. Transfection efficiency was evaluated by fluorescence microscopy and stability of protein expression by immunoblotting. Pigment epithelial cells were successfully transfected with plasmid encoding GFP. Expression of GFP in ARPE-19 was transient, but was observed for up to 1 year in IPE cells. Analysis of pigment epithelial cells transfected with PEDF plasmids revealed that PEDF fusion proteins were successfully expressed and functionally active. In conclusion, efficient transfer of genetic information in pigment epithelial cells can be achieved using non-viral transfection protocols.