Michael Völker

Full macular translocation (FMT) versus photodynamic therapy (PDT) with verteporfin in the treatment of neovascular age-related macular degeneration: 2-year results of a prospective, controlled, randomised pilot trial (FMT-PDT)

BackgroundThe purpose of this study was to compare full macular translocation (FMT) with photodynamic therapy (PDT) in the treatment of neovascular age-related macular degeneration (AMD).MethodsIn a prospective, randomised, non-masked, monocenter, pilot-trial, 50 eyes of 50 patients were assigned to either FMT or PDT. Baseline and control examinations in 3-monthly intervals over a 12-month period included standardized protocol refraction, visual acuity testing and fluorescein angiography. Primary outcome measurements were made to establish the change in distant visual acuity from the baseline to the 12-month examination. The statistical analyses were carried out on the intent-to-treat principle.ResultsThe improvement of one or more ETDRS lines was 56% (14/25) of the eyes in the FMT and 16% (4/25) of the eyes in the PDT arm (P=0.007). Twenty eyes (80%) in the FMT and 16 eyes (64%) in the PDT group had less than three ETDRS lines of vision loss (P=0.35). Retinal detachment (six eyes) and diplopia (five patients) were recorded in the FMT group. None of the eyes treated in the FMT group had phtysis.ConclusionThis pilot study showed that no statistically significant difference existed between the FMT and PDT in terms of the vision loss of less than three ETDRS lines in eyes with neovascular AMD. The chance of vision improvement was significantly higher for the patients in the FMT group. However, in the era of promising therapy with anti-vascular endothelial growth factor for neovascular AMD, FMT should not be offered as a standard primary procedure for neovascular AMD.

Early electroretinographic features of streptozotocin-induced diabetic retinopathy

Background:  This study set out to document the early electrophysiological and immunohistochemical changes that occur in the retina of experimentally induced diabetic rats.

In vivo assessment of subretinally implanted microphotodiode arrays in cats by optical coherence tomography and fluorescein angiography

BackgroundFollowing multiple promising investigations into restoration of vision in degenerative retinal disease by implantation of a sub- or epiretinal prosthesis, the step to clinical use in humans is impending. In this study we intended to establish optical coherence tomography (OCT) and fluorescein angiography (FA) first in research animals for noninvasive assessment of the condition of the posterior pole of eyes after intraocular implant surgery.MethodsThree adult cats that had undergone subretinal implant surgery were evaluated by OCT and FA between 1 and 470 days postoperatively. Eight adult cats served as control. In addition histology was performed.ResultsIn all three cats OCT demonstrated stable positioning of the implants in the subretinal space during the complete examination period. Transient retinal edema was found in the early postoperative period but decreased during follow-up. The retina over the implants was well attached at all times in cats 1 and 2; however, in cat 3 localized retinal detachment was demonstrated. FA showed intact retinal vasculature over the subretinal implant in high detail without interference from choroidal background fluorescence.ConclusionsOCT and FA have been fruitfully applied to cats to assess the morphological and circulatory conditions of the neuroretina and of its interface with the subretinal implant. The techniques may therefore provide a tool for objective, noninvasive in vivo evaluation of eyes that have undergone subretinal implant surgery, both in research animals and in humans.

Verteporfin photodynamic therapy induced apoptosis in choroidal neovascular membranes

Aim: To evaluate the impact of verteporfin photodynamic therapy (PDT) on the induction of apoptosis in choroidal neovascular membranes (CNV) secondary to age related macular degeneration. Methods: Retrospective review of 22 surgically excised CNV. 12 of these patients had been treated with PDT 3–146 days previously. Apoptotic cells were detected with the TUNEL technique and compared to the expression of CD34 (endothelial cells, EC), CD105 (activated endothelial cells), Ki-67 (proliferation marker), and cytokeratin18 (retinal pigment epithelial cells, RPE). Results: CNV excised 3 days after PDT were characterised both by collapsed and patent vessels. The EC displayed a statistical significant positive TUNEL reaction when compared to the remaining treated CNV (p<0.001) and untreated CNV (P = 0.002). The proliferative activity was reduced. CNV excised 1–5 months after PDT displayed a patent vascularisation and high proliferative activity. All membranes either treated or untreated disclosed only sporadic TUNEL positive cells within the stroma and the RPE. Conclusions: Verteporfin PDT leads to selective and effective damage of EC within CNV. Both patent and occluded vessels were lined by apoptotic EC. This finding and the increased expression of proliferation marker at later time points suggest that revascularisation after PDT is caused by angiogenesis rather than recanalisation.

Proliferative response of cultured human tenon's capsule fibroblasts to platelet-derived growth factor isoforms

Abstract• Background: Although platelet-derived growth factor (PDGF) has been thought to be critical in the wound-healing response of Tenons capsule fibroblasts after glaucoma filtration surgery, no information is currently available concerning the proliferative effect of PDGF isoforms on this cell type. The aim of the present study was to evaluate the proliferative effect of PDGF-AB heterodimer and PDGF-AA and -BB homodimers on cultured human Tenons capsule fibroblasts. • Methods: Human Tenons capsule fibroblasts, cultured under serum-free conditions, were stimulated with PDGF-AA, -AB and -BB isoforms in concentrations ranging from 1 to 100 ng/ml. Cell numbers were determined on days 1, 3, 5 and 7, using a cell counter. • Results: Addition of PDGF-AB and -BB led to a dosedependent increase in cell proliferation. A maximal response (79.9% over control) was obtained after 7 days with 30 ng/ml of PDGF-BB, with an EC50 of 8.9 ng/ml. The maximal increase in cell proliferation caused by PDGF-AB (30 ng/ml) was 54.9%, with an EC50 of 12.5 ng/ml. Stimulation with PDGF-AA revealed a significant effect only with concentrations higher than 30 ng/ml. • Conclusion: Our results indicate that PDGF-AB and -BB isoforms are potent stimulators of proliferation of human Tenons capsule fibroblasts, suggesting that PDGF-AB and -BB isoforms play an important role in the wound-healing response after glaucoma filtration surgery.

CHORIORETINAL NEOVASCULARIZATION AFTER RADIAL OPTIC NEUROTOMY FOR CENTRAL RETINAL VEIN OCCLUSION

Radial optic neurotomy was recently introduced for the treatment of central retinal vein occlusion. Two patients developed chorioretinal neovascularization through the radial cut of the optic disc after pars plana vitrectomy, radial optic neurotomy, and endophotocoagulation. Patients undergoing radial optic neurotomy should be closely observed to minimize the risk of this complication.

Epiretinal Deposit of Triamcinolone Acetonide at the Posterior Pole After Intravitreal Injection

The anatomic response to intravitreal bevacizumab injection in three patients with aggressive, posterior retinopathy of prematurity is described. In all cases, the worse eye was treated with a single intravitreal injection of 0.75 mg of bevacizumab as monotherapy or complementary to laser therapy. In 24 hours, all injected eyes showed regression of the tunica vasculosa lentis and iris vessel engorgement and disappearance of iris rigidity. In addition, plus disease and retinal proliferation began to regress. None of the eyes required additional treatment. Follow-up of up to 10 months

Photodynamic therapy with double duration for circumscribed choroidal haemangioma: functional and anatomical results based on initial parameters: Photodynamic therapy for haemangioma

Pre‐treatment symptoms longer than 12 months and foveal cystoid changes are indicators for poor anatomical and functional outcome after photodynamic therapy (PDT).

Human Vision-Motivated Algorithm Allows Consistent Retinal Vessel Classification Based on Local Color Contrast for Advancing General Diagnostic Exams.

PURPOSE Abnormalities of blood vessel anatomy, morphology, and ratio can serve as important diagnostic markers for retinal diseases such as AMD or diabetic retinopathy. Large cohort studies demand automated and quantitative image analysis of vascular abnormalities. Therefore, we developed an analytical software tool to enable automated standardized classification of blood vessels supporting clinical reading. METHODS A dataset of 61 images was collected from a total of 33 women and 8 men with a median age of 38 years. The pupils were not dilated, and images were taken after dark adaption. In contrast to current methods in which classification is based on vessel profile intensity averages, and similar to human vision, local color contrast was chosen as a discriminator to allow artery vein discrimination and arterial-venous ratio (AVR) calculation without vessel tracking. RESULTS With 83% ± 1 standard error of the mean for our dataset, we achieved best classification for weighted lightness information from a combination of the red, green, and blue channels. Tested on an independent dataset, our method reached 89% correct classification, which, when benchmarked against conventional ophthalmologic classification, shows significantly improved classification scores. CONCLUSIONS Our study demonstrates that vessel classification based on local color contrast can cope with inter- or intraimage lightness variability and allows consistent AVR calculation. We offer an open-source implementation of this method upon request, which can be integrated into existing tool sets and applied to general diagnostic exams.