BackgroundGene silencing in the retina using RNA interference could open broad possibilities for functional studies of genes in vivo and for therapeutic interventions in eye disorders. Therefore, there is a considerable demand for protocols to deliver siRNA into the vertebrate retina. In this work we explored a possibility to deliver synthetic 21 bp siRNA into the mouse retina after intravitreal application using a non-viral carrier.MethodsFluorescently labelled synthetic 21 bp siRNA duplex was combined with Transit-TKO transfection reagent and injected intravitreally into adult mice eyes. Eyes cryostat sections and whole mount retinas were prepared 24-48 h post-injection, stained with either Hoechst 33342 (cell nuclei) or immunostained with anti-GFAP antibody (astroglia cells marker). Distribution of fluorescent siRNA signal in the retina was investigated.ResultsSingle intravitreal injection of as little as 5 ng of siRNA combined with Transit-TKO transfection reagent by a modified protocol provided robust and non-toxic delivery of the siRNA into the retina. However, siRNA accumulation was predominantly confined to ganglion cells layer as analysed 24 h post-injection. Furthermore, siRNA containing particles were localized along GFAP cytoskeleton of retinal astroglial cells hinting on intracellular localization of the siRNAConclusionsIn this work we demonstrated that siRNA can be efficiently delivered into the vertebrate retina in vivo with low-toxicity using a non-viral carrier, specifically Transit-TKO transfection reagent. However, the capacity of siRNA delivered by our protocol to induce gene silencing in the retina has to be further evaluated. Our report could raise a closer look on Transit-TKO transfection reagent as a promising siRNA carrier in vivo and be of interest for the researchers and companies who work on development of ocular RNAi techniques.

BackgroundTo describe, a yet non-documented complication of GDI surgery (glaucoma drainage incision surgery) - anterior to posterior segment migration of Ahmed Glaucoma Valve (AGV) tube.Case PresentationWe report a young 9 year old boy, diagnosed with refractory glaucoma with Reiger anomaly. History included of poor vision in both eyes, left more than right with glare since childhood. He underwent GDI surgery with AGV implantation following which he developed posterior migration of AGV tube. The detailed ocular history, ophthalmic findings, clinical course, surgical management and development of the posterior tube migration is discussed.ConclusionPosterior Migration of AGV tube has yet not been described. Also there is a role of expectant management of the complication in this case as evidenced by the benign course of events.

BackgroundAlthough a leading cause of visual impairment and a treatable cause of blindness globally, the pattern of refractive errors in many populations is unknown. This study determined the pattern of refractive ocular conditions, reasons for spectacles renewal and the effect of correction on refractive errors in a resource-limited community.MethodsA retrospective review of case records of 1,413 consecutive patients seen in a private optometry practice, Nigeria between January 2006 and July 2007.ResultsA total number of 1,216 (86.1%) patients comprising of (486, 40%) males and (730, 60%) females with a mean age of 41.02 years SD 14.19 were analyzed. The age distribution peaked at peri-adolescent and the middle age years. The main ocular complaints were spectacles loss and discomfort (412, 33.9%), blurred near vision (399, 32.8%) and asthenopia (255, 20.9%). The mean duration of ocular symptoms before consultation was 2.05 years SD 1.92. The most common refractive errors include presbyopia (431, 35.3%), hyperopic astigmatism (240, 19.7%) and presbyopia with hyperopia (276, 22.7%). Only (59, 4.9%) had myopia. Following correction, there were reductions in magnitudes of the blind (VA<3/60) and visually impaired (VA<6/18-3/60) patients by (18, 58.1%) and (89, 81.7%) respectively. The main reasons for renewal of spectacles were broken lenses/frame/scratched lenses/lenses' falling off (47, 63.4%).ConclusionsAdequate correction of refractive errors reduces visual impairment and avoidable blindness and to achieve optimal control of refractive errors in the community, services should be targeted at individuals in the peri-adolescent and the middle age years.

BackgroundAlzheimer's disease (AD) and age-related macular degeneration (AMD) share several pathological features including β-amyloid (Aβ) peptide accumulation, oxidative damage, and cell death. The causes of AD and AMD are not known but several studies suggest disturbances in cholesterol metabolism as a culprit of these diseases. We have recently shown that the cholesterol oxidation metabolite 27-hydroxycholesterol (27-OHC) causes AD-like pathology in human neuroblastoma SH-SY5Y cells and in organotypic hippocampal slices. However, the extent to which and the mechanisms by which 27-OHC may also cause pathological hallmarks related to AMD are ill-defined. In this study, the effects of 27-OHC on AMD-related pathology were determined in ARPE-19 cells. These cells have structural and functional properties relevant to retinal pigmented epithelial cells, a target in the course of AMD.MethodsARPE-19 cells were treated with 0, 10 or 25 μM 27-OHC for 24 hours. Levels of Aβ peptide, mitochondrial and endoplasmic reticulum (ER) stress markers, Ca2+ homeostasis, glutathione depletion, reactive oxygen species (ROS) generation, inflammation and cell death were assessed using ELISA, Western blot, immunocytochemistry, and specific assays.Results27-OHC dose-dependently increased Aβ peptide production, increased levels of ER stress specific markers caspase 12 and gadd153 (also called CHOP), reduced mitochondrial membrane potential, triggered Ca2+ dyshomeostasis, increased levels of the nuclear factor κB (NFκB) and heme-oxygenase 1 (HO-1), two proteins activated by oxidative stress. Additionally, 27-OHC caused glutathione depletion, ROS generation, inflammation and apoptotic-mediated cell death.ConclusionsThe cholesterol metabolite 27-OHC is toxic to RPE cells. The deleterious effects of this oxysterol ranged from Aβ accumulation to oxidative cell damage. Our results suggest that high levels of 27-OHC may represent a common pathogenic factor for both AMD and AD.