Photodynamic therapy of choroidal neovascularization with enlargement of the spot size to include the feeding complex

This is a case report of a 83-year-old man with choroidal neovascularization (CNV), due to age-related macular degeneration (AMD) in his right eye. Digital fluorescein (FA) and indocyanine green angiography (ICG) were performed, which disclosed predominantly classic subfoveal CNV and a dilated and tortuous feeding complex. The visual acuity was 20/800. Anti-vascular endothelial growth factor (anti-VEGF) treatment was suggested, however, the patient was not keen to receive an intraocular injection. Modified photodynamic therapy (PDT) with spot size enlarged, to include not only the CNV lesion but the feeding complex as well, was performed. Ten days after one session of PDT, ICG showed absence of leakage from the CNV and complete occlusion of the feeding complex. The visual acuity gradually improved to 20/100 and remained stable during the following 23 months. No evidence of CNV leakage was seen in the FA and ICG during the follow up period. Adjustment of the PDT spot size to include the detectable by ICG feeding complex might be an additional option in order to close the subfoveal CNV and might be considered as an alternative to intravitreal injection of anti-VEGF in selected cases where anti-VEGF treatment is not available

Quantitative determination of glycosaminoglycans in tears of diabetic patients

Marilita M Moschos1, Alexandros A Rouvas1, Spyridon Papadimitriou1, Athanasios Kotsolis1, Nikolaos Sitaras2, Michael Apostolopoulos11Department of Ophthalmology; 2Department of Pharmacology, University of Athens, GreecePurpose: To determine the amount of glycosaminoglycans (GAGs) in tears of patients with diabetic retinopathy (DR) and to compare it with normal subjects.Methods: 38 patients with DR and 24 normal volunteers were included. Thirty subjects suffered from background diabetic retinopathy (BDR) and 8 from proliferate diabetic retinopathy (PDR). For the GAGs assay, the uronic carbazole reaction was used.Results: The mean concentration of GAGs was significantly higher in patients with DR than in normal subjects. The GAGs concentration in patients with BDR or PDR was significantly higher than in normal subjects.Conclusion: The measurement of GAGs in tears of diabetic patients could be a tool in order to assess the stability or not of the disease.Keywords: glycosaminoglycans, tears, diabetic retinopath

What Is Stochastic Resonance? Definitions, Misconceptions, Debates, and Its Relevance to Biology

Stochastic resonance is said to be observed when increases in levels of unpredictable fluctuations—e.g., random noise—cause an increase in a metric of the quality of signal transmission or detection performance, rather than a decrease. This counterintuitive effect relies on system nonlinearities and on some parameter ranges being “suboptimal”. Stochastic resonance has been observed, quantified, and described in a plethora of physical and biological systems, including neurons. Being a topic of widespread multidisciplinary interest, the definition of stochastic resonance has evolved significantly over the last decade or so, leading to a number of debates, misunderstandings, and controversies. Perhaps the most important debate is whether the brain has evolved to utilize random noise in vivo, as part of the “neural code”. Surprisingly, this debate has been for the most part ignored by neuroscientists, despite much indirect evidence of a positive role for noise in the brain. We explore some of the reasons for this and argue why it would be more surprising if the brain did not exploit randomness provided by noise—via stochastic resonance or otherwise—than if it did. We also challenge neuroscientists and biologists, both computational and experimental, to embrace a very broad definition of stochastic resonance in terms of signal-processing “noise benefits”, and to devise experiments aimed at verifying that random variability can play a functional role in the brain, nervous system, or other areas of biology

Twelve months of follow-up after intravitreal injection of ranibizumab for the treatment of idiopathic parafoveal telangiectasia

Alexandros Rouvas,1 Panagiotis Malamos,2 Maria Douvali,1 Amalia Ntouraki,1 Nikos N Markomichelakis1 12nd Department of Ophthalmology, Medical School of Athens University, Athens, Greece; 2Department of Ophthalmology, NHS, “G Gennimatas” General Hospital, Athens, Greece Aims: To report the anatomic and functional outcomes of intravitreal ranibizumab in idiopathic parafoveal telangiectasia (IPT). Material and methods: Four eyes of three patients were included in this interventional case series. One patient (two eyes) had bilateral IPT (type 2) and two patients (two eyes) had unilateral (type 1) IPT. Retreatment was scheduled in case of leakage persistence in combination with visual acuity (VA) deterioration. Fluorescein angiography and optical coherence tomography were performed together with a full ophthalmic examination at baseline, 1, 3, 6, 9, and 12 months after injection. Results: One intravitreal injection of ranibizumab was performed in all four eyes. Complete cessation of leakage was documented postintervention in three eyes and partial cessation in one eye, followed by improvement of best corrected VA in one of them. In all eyes, structural changes of the photoreceptor layer were detected in tomography and were responsible for visual loss, which was in most cases, refractory to the applied therapy. Conclusion: Use of ranibizumab might be efficient in eliminating leakage activity in the macular region in patients with IPT. Nevertheless, improvement in VA was infrequent. Preexisting early photoreceptor alteration in IPT might render such patients unable to improve VA. Keywords: idiopathic parafoveal telangiectasis, intravitreal ranibizumab, fluorescein angiography, high-definition optical coherence tomograph

Retinal arterial occlusive diseasein a young patient with cat scratch disease

Purpose: To report an unusual case of a branch retinal arterial occlusion and bilateral multifocal retinitis in a young woman with cat scratch disease. Methods: A 23-year-old woman was referred to our clinic complaining of a sudden scotoma in the upper part of the visual field of her left eye. Fundoscopy revealed occlusion of an inferior temporal branch of the retinal artery in the left eye and bilateral multifocal retinitis, which was confirmed by fluorescein angiography. Subsequent indocyanine angiography did not reveal choroidal involvement. Laboratory analysis showed rising IgG titers for Bartonellahenselae. Results: Cat scratch disease was diagnosed, and a 4-week course of doxycycline was initiated. The patient responded well to the antibiotics. Both retinitis and arterial occlusion were resolved, the visual field was regained and the patient reported elimination of her symptoms. Conclusions: Cat scratch disease should be considered in the differential diagnosis in young patients with retinal occlusive disease. © 2013 S. Karger AG, Basel