Overexpression of Neuregulin-1 Type III Has Impact on Visual Function in Mice.

Schizophrenia is associated with several brain deficits, including abnormalities in visual processes. Neuregulin-1 (Nrg1) is a family of trophic factors containing an epidermal growth factor (EGF)-like domain. It is thought to play a role in neural development and has been linked to neuropsychiatric disorders. Abnormal Nrg1 expression has been observed in schizophrenia in clinical studies. Moreover, in schizophrenia, there is more and more evidence found about pathological changes of the retina regarding structural, neurochemical and physiological parameters. However, mechanisms of these changes are not well known. To investigate this, we analysed the function of the visual system using electroretinography (ERG) and the measurement of visual evoked potentials (VEP) in transgenic mice overexpressing Nrg1 type III of three different ages (12 weeks, 24 weeks and 55 weeks). ERG amplitudes tended to be higher in transgenic mice than in control mice in 12-week old mice, whereas the amplitudes were almost similar in older mice. VEP amplitudes were larger in transgenic mice at all ages, with significant differences at 12 and 55 weeks (p values between 0.003 and 0.036). Latencies in ERG and VEP measurements did not differ considerably between control mice and transgenic mice at any age. Our data show for the first time that overexpression of Nrg1 type III changed visual function in transgenic mice. Overall, this investigation of visual function in transgenic mice may be helpful to understand corresponding changes that occur in schizophrenia, as they may find use as biomarkers for psychiatric disorders as well as a potential tool for diagnosis in psychiatry.

A modified protocol for isolation of retinal microglia from the pig.

Microglia are the resident immune cells in the retina. To investigate their properties and behaviour, a reliable and yielding procedure to culture them is necessary. We here describe a way of isolation of microglial cells from the porcine retina, as pig eyes are similar to human eyes in size, structure and vasculature, including similarities in proteins and pathways. Retina was isolated from fresh pig eyes, dissociated by a mixture of collagenase, hyaluronidase and DNAse, and passed through a cell strainer. After triple centrifugation with decreasing velocity and re-suspension, cells were seeded into poly-d-lysine coated culture flasks and cultured using DMEM and macrophage-colony stimulating factor (M-CSF). Number of cells increased gradually during the first 10-14 days, till they could be split and used for experiments. Identity of isolated cells as microglia was assessed by immunostaining against the microglia/macrophage markers Iba1, CD11b, CD68, CD45 and TMEM119. Phagocytic function of microglia could be demonstrated by phagocytosis of fluorescence beads and their response to lipopolysaccharide (LPS). As a conclusion, we developed a protocol for isolation and cultivation of pig retinal microglial cells that are suitable for research in the laboratory.

Lack of WWC2 Protein Leads to Aberrant Angiogenesis in Postnatal Mice.

The WWC protein family is an upstream regulator of the Hippo signalling pathway that is involved in many cellular processes. We examined the effect of an endothelium-specific WWC1 and/or WWC2 knock-out on ocular angiogenesis. Knock-outs were induced in C57BL/6 mice at the age of one day (P1) and evaluated at P6 (postnatal mice) or induced at the age of five weeks and evaluated at three months of age (adult mice). We analysed morphology of retinal vasculature in retinal flat mounts. In addition, in vivo imaging and functional testing by electroretinography were performed in adult mice. Adult WWC1/2 double knock-out mice differed neither functionally nor morphologically from the control group. In contrast, the retinas of the postnatal WWC knock-out mice showed a hyperproliferative phenotype with significantly enlarged areas of sprouting angiogenesis and a higher number of tip cells. The branching and end points in the peripheral plexus were significantly increased compared to the control group. The deletion of the WWC2 gene was decisive for these effects; while knocking out WWC1 showed no significant differences. The results hint strongly that WWC2 is an essential regulator of ocular angiogenesis in mice. As an activator of the Hippo signalling pathway, it prevents excessive proliferation during physiological angiogenesis. In adult animals, WWC proteins do not seem to be important for the maintenance of the mature vascular plexus.

ALTERED RETINAL PERFUSION IN PATIENTS WITH INACTIVE GRAVES OPHTHALMOPATHY USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

Objective: The aim of this study was to evaluate retinal and optic nerve head (ONH) perfusion in patients with inactive Graves ophthalmopathy (GO) and compare it to healthy controls using optical coherence tomography angiography (OCTA). Methods: Twenty-nine eyes of 29 patients with inactive GO (study group) and 29 eyes of 29 healthy subjects (control group) were included in this study. The vessel density (VD) data in the superficial and deep retinal OCT angiogram of the macula and the radial peripapillary capillary network (RPC) were extracted and analyzed. OCTA was performed using RTVue XR Avanti with AngioVue (Optovue Inc, Fremont, CA). Clinical activity was evaluated using the clinical activity score, the severity assessment using the NOSPECS classification. Results: The VD in the superficial OCT angiogram and in the OCT angiogram of the ONH was significantly lower in the GO group when compared to the control group (whole en face, P = .016; parafovea, P = .026; RPC peripapillary, P = .027). There was no significant correlation between VD and functional parameters or the NOSPECS classification. Conclusion: Macular VD and ONH capillary density measured using OCTA were significantly lower in the study group compared to healthy controls. Noninvasive quantitative analysis of retinal perfusion using OCTA could be useful in monitoring patients with GO. Abbreviations: CAS = clinical activity score; GO = Graves ophthalmopathy; OCTA = optical coherence tomography angiography; ONH = optic nerve head; RPC = radial peripapillary capillary; rSp = Spearman's correlation coefficient; VD = vessel density.

Lipofuscin-dependent stimulation of microglial cells.

PURPOSE: To examine the reaction of microglial cells (MG) when incubated with lipofuscin (LP) in vitro with emphasis on the immunological reaction of the MG toward LP and the suppression of this reaction by immunomodulatory agents. MG are involved in the pathogenesis of degenerative eye disorders such as age-related macular degeneration (AMD). LP is a heterogeneous waste material that accumulates in the retinal pigment epithelium (RPE) cells with advancing age. LP is known to have toxic effects on RPE cells and therefore an elevated LP-derived fundus autofluorescence is a risk factor for AMD development. MG in the subretinal space have been reported in eyes affected by AMD. Moreover, in senescent mice, subretinal MG were found, which display an autofluorescence that may be derived from LP uptake. METHODS: In this study, we incubated MG (BV-2 cell line and primary cells from murine brain) in vitro with LP isolated from the human RPE. We observed phagocytosis, studied cell morphologies, and analyzed the cell culture supernatants. We also investigated the effect of the immunomodulatory agents hydrocortisone (HC), minocycline, and the tripeptide TKP. RESULTS: The MG phagocytosed the LP quickly and completely. We detected highly elevated levels of pro-inflammatory cytokines (especially of IL-6, IL-23p19, TNF-α, KC, RANTES, and IL-1α) in the cell culture supernatants. Furthermore, levels of vascular endothelial growth factor (VEGF) were raised in BV-2 cells. Anti-inflammatory agents added to the cell cultures inhibited the inflammatory reaction, in particular hydrocortisone (HC). Minocycline and TKP had less impact on the cytokine release. CONCLUSION: The interaction of MG and LP could play a role in the development of retinal degeneration by triggering an inflammatory reaction and angiogenesis.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN PATIENTS WITH RETINITIS PIGMENTOSA.

PURPOSE: To evaluate the correlation between the flow density measured by optical coherence tomography angiography and functional parameters in patients with retinitis pigmentosa. METHODS: Twenty eyes of 20 patients with retinitis pigmentosa and 21 eyes of 21 healthy subjects were prospectively included in this study. Optical coherence tomography angiography was performed using RTVue XR Avanti with AngioVue (Optovue Inc). The macula was imaged with a 6 × 6-mm scan, whereas for the optic nerve head a 4.5 × 4.5-mm scan was taken. Visual acuity, visual field parameters (mean deviation and visual field index), full-field electroretinography, and multifocal electroretinography were tested for correlation with flow density data. RESULTS: The flow density (whole en face) in the superficial/deep retinal OCT angiograms and in the optical coherence tomography angiography of the optic nerve head was significantly lower in the retinitis pigmentosa group when compared with the control group (P < 0.001). The flow density in the superficial retinal OCT angiogram (fovea) correlated significantly with the visual acuity (rSpearman = -0.77, P < 0.001) and the visual field parameters (visual field index: rSpearman = 0.56, P = 0.01; mean deviation: rSpearman = 0.54, P = 0.01). CONCLUSION: Patients with retinitis pigmentosa show a decreased macular and optic nerve head perfusion compared with healthy subjects. The flow density measured using optical coherence tomography angiography correlated with subjective and objective functional parameters.

Different effects of various anti-angiogenic treatments in an experimental mouse model of retinopathy of prematurity.

BACKGROUND: Anti-vascular endothelial growth factor (VEGF) drugs are an option for the treatment of retinopathy of prematurity (ROP). Blocking of other angiogenic factors is also of interest. We therefore investigated in which effects would result blocking of placental growth factor (PlGF). METHODS: C57BL/6 mice were exposed to 75% oxygen from P7 to P12. Intravitreal injections were performed at P12. Mice of control groups remained untouched after oxygen treatment, or phosphate buffered saline or neutral IgG molecules were injected. In the treatment groups, antibodies against VEGF or PlGF, a mixture of anti-VEGF and anti-PlGF, aflibercept or sunitinib were injected. On P17, electroretinographic (ERG) measurements were performed. Avascular zones and neovascularization were evaluated in retinal flat-mounts. Results are expressed as percent of total retinal area (median with median absolute deviation, MAD). RESULTS: Eyes of control groups showed similar neovascularization (1.4-3.3%, MAD 0.4-0.9%). Neovascularization was significantly less (0.5-0.7%, MAD 0.1-0.3%) in all treatment groups. Avascular zones in the retinas of control groups showed similar values (18.3-25.7%, MAD 4.8-8.8%). Avascular zones were significantly reduced down to 3.6 ± 1.3% after anti-VEGF injection, but they were not reduced significantly in the other treatment groups (13.3-22%, MAD 3.6-6.1%). ERG measurements did not reveal significant differences between the controls and the treatment groups. CONCLUSIONS: Blocking of PlGF or injection of sunitinib results in a similar inhibition of neovascularization as by anti-VEGF treatment in the mouse model of ROP. However, physiological angiogenesis that occurs after anti-VEGF treatment is blocked by anti-PlGF or sunitinib treatment, indicating that pathological neovascularization may follow different pathways than physiological angiogenesis.

Feasibility of optical coherence tomography angiography to assess changes in retinal microcirculation in ovine haemorrhagic shock.

BACKGROUND: This study aimed to investigate the feasibility of optical coherence tomography angiography (OCT-A) for quantitative analysis of flow density to assess changes in retinal perfusion in an experimental model of haemorrhagic shock. METHODS: Haemorrhagic shock was induced in five healthy, anaesthetized sheep by stepwise blood withdrawal of 3 × 10 ml∙kg- 1 body weight. OCT-A imaging of retinal perfusion was performed using an OCT device. Incident dark-field illumination microscopy videos were obtained for the evaluation of conjunctival microcirculation. Haemodynamic variables and flow density data in the OCT angiogram were analysed before and during progressive haemorrhage resulting in haemorrhagic shock as well as after fluid resuscitation with 10 ml∙kg- 1 body weight of balanced hydroxyethyl starch solution (6% HES 130/0.4). Videos of the conjunctival microcirculation were recorded at baseline, in haemorrhagic shock, and after resuscitation. Data are presented as median with interquartile range. Comparisons between time points were made using Friedman's test and the degree of correlation between two variables was expressed as Spearman's rank correlation coefficient. RESULTS: Mean arterial pressure and cardiac index (CI) decreased and lactate concentration increased after induction of shock, and haemodynamics recovered after resuscitation. The flow density in the superficial retinal OCT angiogram decreased significantly after shock induction (baseline 44.7% (40.3; 50.5) vs haemorrhagic shock 34.5% (32.8; 40.4); P = 0.027) and recovered after fluid resuscitation (46.9% (41.7; 50.7) vs haemorrhagic shock; P = 0.027). The proportion of perfused vessels of the conjunctival microcirculation showed similar changes. The flow density measured using OCT-A correlated with the conjunctival microcirculation (perfused vessel density: Spearman's rank correlation coefficient ρ = 0.750, P = 0.001) and haemodynamic parameters (CI: ρ = 0.693, P < 0.001). CONCLUSIONS: Retinal flow density, measured using OCT-A, significantly decreased in shock and recovered after fluid therapy in an experimental model of haemorrhagic shock. OCT-A is feasible to assess changes in retinal perfusion in haemorrhagic shock and fluid resuscitation.

Quantitative changes in flow density in patients with adult-onset foveomacular vitelliform dystrophy: an OCT angiography study.

PURPOSE: To quantitatively compare the flow density, the retinal thickness, and the area of the foveal avascular zone (FAZ) between patients with adult-onset foveomacular vitelliform dystrophy (AOFVD) and a healthy controls. METHODS: Thirteen eyes (eight patients) with AOFVD and 13 matched eyes (13 patients) without any ocular pathology were included in this study. A 6 × 6 mm optical coherence tomography angiography (OCTA) scan was performed for every included eye. The flow density (superficial retinal vascular layer, deep retinal vascular layer and choriocapillary layer), retinal thickness and FAZ (superficial retinal vascular layer and deep retinal vascular layer) were subsequently analyzed. RESULTS: The mean flow density was decreased in the AOFVD patients in all measured vascular layers. The difference from the control group was statistically significant in the parafoveal sector of the deep retinal vascular layer (P = 0.02), and a clear trend was found in the superficial retinal vascular layer (P = 0.05). Both groups had comparable FAZs in the superficial and deep retinal vascular layers. The retinal thickness values were higher in the fovea (P = 0.840) and lower in the parafoveal sectors (P = 0.125). The difference was significant in the superior parafoveal sector (P = 0.034). CONCLUSIONS: Flow densities as measured by OCTA are decreased in the superficial retinal vascular layer and the deep retinal vascular layer in patients with AOFVD. These findings could be helpful for diagnosing and understanding the pathogenesis of this disease.

Quantitative analysis of retinal perfusion in mice using optical coherence tomography angiography.

PURPOSE: To evaluate repeatability of the quantitative analysis of vessel density in the retinas of healthy mice using optical coherence tomography angiography (OCT-A). METHODS: Seventeen eyes of seventeen healthy mice aged 10-15 weeks (young) and 75-95 weeks (old) were included in this study. OCT-A was performed using RTVue XR Avanti (Optovue Inc., Fremont, California, USA) under general anaesthesia. The retina was imaged twice using a 3 × 3 mm2 scan. Retinal thickness and flow density data in the superficial and deep retinal OCT angiograms were extracted and analysed. RESULTS: The differences between the flow density values (whole en face) in the first and second sessions were non-significant (superficial retinal OCT angiogram: first session: 45.4 ± 4.1% (39.1-55.3%); second session: 46.1 ± 4.7% (39.1-59.1%); p = 0.14; deep retinal OCT angiogram: first session: 47.1 ± 3.8% (39.4-53.4%); second session: 47.3 ± 3.7% (39.4-53.8%); p = 0.50). The repeatability assessment of retinal thickness yielded intraclass correlation coefficient (ICC) values ranging between (0.86-0.99) while the ICCs for the flow density measurements ranged from 0.87 to 0.92 for the superficial retinal OCT angiogram and 0.68 to 0.93 for the deep retinal OCT angiogram. CONCLUSIONS: Repeated OCT-A measurement of mice retinal vessel density (VD) revealed valid repeatability, indicating that this non-invasive technology is sufficient for longitudinal assessment of vascular changes in various mouse models and thereby opening the way to in-depth, experimental analysis of the vascular aspects of different retinal diseases and monitoring of disease progression and the effects of treatments.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN PATIENTS WITH RETINITIS PIGMENTOSA.

PURPOSE: To evaluate the correlation between the flow density measured by optical coherence tomography angiography and functional parameters in patients with retinitis pigmentosa. METHODS: Twenty eyes of 20 patients with retinitis pigmentosa and 21 eyes of 21 healthy subjects were prospectively included in this study. Optical coherence tomography angiography was performed using RTVue XR Avanti with AngioVue (Optovue Inc). The macula was imaged with a 6 × 6-mm scan, whereas for the optic nerve head a 4.5 × 4.5-mm scan was taken. Visual acuity, visual field parameters (mean deviation and visual field index), full-field electroretinography, and multifocal electroretinography were tested for correlation with flow density data. RESULTS: The flow density (whole en face) in the superficial/deep retinal OCT angiograms and in the optical coherence tomography angiography of the optic nerve head was significantly lower in the retinitis pigmentosa group when compared with the control group (P < 0.001). The flow density in the superficial retinal OCT angiogram (fovea) correlated significantly with the visual acuity (rSpearman = -0.77, P < 0.001) and the visual field parameters (visual field index: rSpearman = 0.56, P = 0.01; mean deviation: rSpearman = 0.54, P = 0.01). CONCLUSION: Patients with retinitis pigmentosa show a decreased macular and optic nerve head perfusion compared with healthy subjects. The flow density measured using optical coherence tomography angiography correlated with subjective and objective functional parameters.

Behaviour of CD11b-Positive Cells in an Animal Model of Laser-Induced Choroidal Neovascularisation.

BACKGROUND/AIM: Immune cells, e.g. microglial cells of the retina, appear to be involved in pathological processes in neovascular age-related macular degeneration. Therefore, the purpose of this study was to immunohistochemically check the expression of various factors and cytokines by CD11b-positive (CD11b+) immune cells in an animal model of choroidal neovascularisation (CNV). METHODS: We used the animal model of laser-induced CNV in mice. Eyes were isolated at 1, 4, 7, and 14 days after laser treatment. Cryosections were prepared and checked immunohistochemically for the presence of different growth factors and cytokines on microglial cells and other immune cells identified by CD11b immunoreactivity. RESULTS: We found that the number of CD11b+ cells at the laser spots increased dramatically 4 days after laser treatment, the majority of them entering the laser spot most probably by migration. CD11b+ cells in the laser spot were positive for a variety of pro-angiogenic factors, such as PDGF-ß, FGF-1, FGF-2, and TGF-ß1. They were also positive for some inflammatory cytokines, in particular TNF-α, IL-6, and CXCL1. In non-treated retinas, CD11b+ cells showed almost no immunoreactivity for these proteins. CONCLUSION: Microglial cells, macrophages, and other CD11b+ cells may promote the neovascularisation in the laser spot and show a moderate inflammatory behaviour. Immunoreactivity for most of these molecules was found to decrease during the time of observation. Modulation of immune cell activity may thus be a tool to reduce the extent of CNV.

Comparison of Choriocapillaris Flow Measurements between Two Optical Coherence Tomography Angiography Devices.

PURPOSE: To evaluate choriocapillaris (CC) perfusion in healthy subjects using 2 different optical coherence tomography angiography (OCT-A) devices. PROCEDURES: Macular OCT-A imaging (36 eyes of 36 subjects) was performed using Optovue AngioVue and Zeiss AngioPlex devices. CC decorrelation signal index was assessed, and CC data were analyzed regarding intra-device variability, inter-device correlation, age, signal strength, and fields of view. RESULTS: The intra-device variability of CC measurements in the 3 × 3 mm2 field was 5.3 and 2.6% (Angiovue and Angioplex, coefficients of variation; 6 × 6 mm2: 8.0 and 2.8%, respectively). Mean CC decorrelation signal index in 3 × 3 mm2 was 104.3 ± 6.7 (Angiovue) and 81.3 ± 9.2 (Angioplex) (6 × 6 mm2: 95.6 ± 8.1, 81.1 ± 6.5) with high correlation between both devices (3 × 3 mm2: p = 0.0053; 6 × 6 mm2: p = 0.0139). CC decorrelation signal index in 3 × 3 mm2 was significantly higher in subjects aged ≤58 years compared to subjects aged ≥59 years (Angiovue: 107.3 ± 3.6, 101.3 ± 7.7, p = 0.0156; Angioplex: 84.6 ± 7.6, 78.0 ± 9.5, p = 0.0371). Signal strength was 64.6 ± 8.9 (Angiovue) and 9.5 ± 0.8 (Angioplex). CONCLUSION: Both devices showed low intra-device variability and a high inter-device correlation. CC decorrelation signal index was negatively correlated with advancing age.

OCT angiography in the mouse: A novel evaluation method for vascular pathologies of the mouse retina.

PURPOSE: To investigate the application of optical coherence tomography (OCT) angiography in the retinas of healthy mice and to evaluate choroidal neovascularization (CNV) in a mouse model of laser-induced CNV. METHODS: C57BL/6J mice aged 18-25 weeks were examined using the spectral-domain optical coherence tomography device RTVue XR Avanti (Optovue, Inc, Fremont, California, USA). Blood flow in different retinal layers was detected using the split-spectrum amplitude-decorrelation angiography algorithm. Fluorescein angiography (FA) images were obtained using the Heidelberg Spectralis device (Heidelberg, Germany). RESULTS: Using the RTVue XR Avanti, we were able to obtain high-quality OCT angiography images of normal vasculature in the superficial, deep capillary and choriocapillary layers in laser-treated mice and untreated controls. Whereas no blood flow was detectable in the outer retina of untreated mice, blood flow and hence neovascular vessels were found in laser-treated mice. CONCLUSIONS: OCT angiography can clearly visualize the normal vascular plexus in the different retinal layers in the mouse retina and choroid. With OCT angiography, it is possible to verify the choroidal neovascularization induced by laser treatment. Thus, OCT angiography is a helpful imaging tool for non-invasive, in vivo evaluation of laser-induced CNV in the mouse.

Deletion of myosin VI causes slow retinal optic neuropathy and age-related macular degeneration (AMD)-relevant retinal phenotype.

The unconventional myosin VI, a member of the actin-based motor protein family of myosins, is expressed in the retina. Its deletion was previously shown to reduce amplitudes of the a- and b-waves of the electroretinogram. Analyzing wild-type and myosin VI-deficient Snell's Waltzer mice in more detail, the expression pattern of myosin VI in retinal pigment epithelium, outer limiting membrane, and outer plexiform layer could be linked with differential progressing ocular deficits. These encompassed reduced a-waves and b-waves and disturbed oscillatory potentials in the electroretinogram, photoreceptor cell death, retinal microglia infiltration, and formation of basal laminar deposits. A phenotype comprising features of glaucoma (neurodegeneration) and age-related macular degeneration could thus be uncovered that suggests dysfunction of myosin VI and its variable cargo adaptor proteins for membrane sorting and autophagy, as possible candidate mediators for both disease forms.

Exploring choriocapillaris under reticular pseudodrusen using OCT-Angiography.

PURPOSE: To evaluate if choriocapillaris (CC) vessel density and CC decorrelation signal index are compromised in eyes with reticular pseudodrusen (RPD) using optical coherence tomography angiography (OCT-A). METHODS: Decorrelation values in OCT-A CC images of 20 RPD patients were measured in the outer superior and the outer inferior sector of the EDTRS grid and compared to age-matched healthy controls. CC vessel density and CC decorrelation signal index were measured within a 30 µm and a 10 µm OCT-A CC slab. CC data were correlated to number of RPD lesions, predominantly present RPD stage, predominantly present RPD type, retinal area affected by RPD and choroidal thickness (CT). RESULTS: CC vessel density and CC decorrelation signal index decreased in correlation to advancing age in healthy subjects particularly in subjects older than 60 years (CC vessel density: 30 µm: p=0.0019; 10 µm: p=0.0014; CC decorrelation signal index: 30 µm: p=0.0005; 10 µm: p=0.0003). In the RPD group, CC vessel density (outer superior sector, 10 µm: 98.299) and CC decorrelation signal index (89.07) were significantly reduced compared to controls (99.203, p=0.0002; 98.09, p=0.0010). The number of RPD lesions was correlated to a reduced CC vessel density (30 µm: p=0.0355) but not to changes in CC decorrelation signal index. No correlations were found between CC parameters and either RPD stage, RPD type, size of RPD affected area or CT. CONCLUSIONS: OCT-A reveals a distinct reduction in CC vessel density and CC decorrelation signal index in eyes affected by RPD, which emphasizes the relevance of the CC layer in RPD pathogenesis.

The microglia in healthy and diseased retina.

The microglia are the immune cells of the central nervous system and, also the retina. They fulfil several tasks of surveillance in the healthy retina. In case of an injury or disease, microglia become activated and tries to repair the damage. However, in a lot of cases it does not work, and microglia deteriorate the situation by releasing toxic and pro-inflammatory compounds. Moreover, they further promote degenerative processes by attacking and phagocytosing damaged neurones and photoreceptors that otherwise would possibly have the chance to survive. Such deleterious action of the microglia has been observed in degeneration of retinal ganglion cells and photoreceptors, and it takes place in hereditary diseases, infections as well as in case of traumatic or light injuries. Therefore, a number of attempts has been undertaken so far to inhibit the microglia, with varying success. The task remains to study behaviour of the microglia and their interaction with other retinal cell populations in more detail with respect to released factors and expressed receptors including the time points of the corresponding events. The goal has to be to find a better balance between helpful and detrimental actions of the microglia.

MORPHOLOGY SCORE AS A MARKER OF RETINAL FUNCTION IN DRUSENOID PIGMENT EPITHELIAL DETACHMENT.

PURPOSE: To evaluate a morphology score for drusenoid pigment epithelial detachment (dPED) regarding predictability of a decline in retinal function beyond best-corrected visual acuity. METHODS: Thirteen eyes of 10 patients with dPED due to age-related macular degeneration (AMD) were included (age 72.8 ± 4.2 years). All underwent volume spectral domain optical coherence tomography, fluorescence angiography, and confocal scanning laser ophthalmoscopy infrared imaging as well as multifocal electroretinography and microperimetry. The dPED morphology score suggested consists of five parameters: hyperreflective spots in infrared, lesion diameter, lesion height, presence of vitelliform-like material in the subretinal space or subretinal fluid, and integrity of the ellipsoid zone in spectral domain optical coherence tomography. Subsequently, a score value between 0 and 1 according to the extent of morphologic changes was correlated to foveal multifocal electroretinography and microperimetry measurements. RESULTS: The mean best-corrected visual acuity was 20/40. The mean height and mean diameter of dPED were 312.2 ± 111 µm and 2,535 ± 805 µm. Two dPED showed no hyperreflective spots in confocal scanning laser ophthalmoscopy infrared images, three displayed a moderate stage of hyperreflective spots, and eight had severe hyperreflective spots. Two eyes showed subretinal fluid, and five patients showed vitelliform-like material in the subretinal space. Eight eyes revealed a severe disruption of the ellipsoid zone. Although no correlation was found between dPED morphology score and best-corrected visual acuity, eyes with a dPED morphology score >0.5 revealed distinctly decreased values in functional measurements compared with those with a score ≤0.5. CONCLUSION: The dPED morphology score aggregates all currently known morphologic changes in dPED and represents a valuable tool for clinical lesion evaluation. Furthermore, it allows for assessing an estimate of functional decline beyond best-corrected visual acuity.

Intravitreal dexamethasone implant [Ozurdex] for the treatment of nonarteritic anterior ischaemic optic neuropathy.

PURPOSE: To evaluate structural and functional outcomes of intravitreal dexamethasone implant (IDI) in three patients presenting with nonarteritic anterior ischaemic optic neuropathy. METHODS: IDI was administered once in three patients. Best-corrected visual acuity (BCVA), perimetry, volume spectral-domain optical coherence tomography scan of the optic disc (ODV), retinal nerve fibre layer (RNFL) scan and visually evoked potential (VEP) measurements were assessed at baseline and after one and 3 months. RESULTS: Mean BCVA was 20/100 in patient 1 (patient 2: 20/100; patient 3: 20/50) at baseline, 20/60 (patient 2: 20/400) at 1 month and 20/80 (20/400; 20/60) at 3 months. Mean deviation in perimetry developed from -4.90 dB (-22.09 dB; -8.68 dB) to -7.60 dB (-30.75 dB) and -14.23 dB (-30.59 dB; -7.17 dB). ODV and RNFL decreased during follow-up. VEP measurements showed a reduction in amplitudes during the entire observation period. CONCLUSIONS: All patients showed a reduction in papilla oedema over time. A functional improvement was not observed.

Quantification of retinal pigment epithelium tear area in age-related macular degeneration.

PURPOSE: To compare different quantification tools based on confocal scanning laser ophthalmoscopy for assessment of retinal pigment epithelium (RPE) tear area size. METHODS: Confocal scanning laser ophthalmoscopy fundus autofluorescence (FAF) and near-infrared reflectance (IR) images were retrospectively evaluated in 23 patients with RPE tear after intravitreal injection for pigment epithelium detachment due to exudative age-related macular degeneration at baseline and additionally in 11 patients after 5.1 ± 1.8 months of follow-up. Retinal pigment epithelium tear area was measured by three independent readers using three methods: manually on confocal scanning laser ophthalmoscopy FAF images, manually on confocal scanning laser ophthalmoscopy IR images, and using an FAF-based semiautomated software. RESULTS: Confidence intervals were 0.08 and 0.12 for FAF, 0.11 and 0.09 for FAF-based semiautomated software, and 0.25 and 0.27 for IR for intraobserver (Reader 1) and interobserver agreements (Readers 1 and 2), respectively. The average values of the square errors of the quantification methods were 0.040 ± 0.033 mm (FAF), 0.035 ± 0.060 mm (software), and 0.187 ± 0.219 mm (IR). Mean area of RPE tears at baseline given as the average measurement of all 3 readers using FAF-based semiautomated software was 5.77 ± 4.62 mm (range, 0.13-14.74 mm). Follow-up measurements of unilobular RPE tears (8 patients) showed no change in lesion area size (0.14 ± 0.33 mm); in contrast, multilobular RPE tears (3 patients) showed a progression in lesion area size of 1.80 ± 0.74 mm. CONCLUSION: Manual FAF-based and semiautomated FAF-based quantifications of RPE tear area are accurate and reproducible and superior to manual IR-based measurement. Retinal pigment epithelium tear area quantification is clinically relevant regarding further intravitreal treatment, particularly in multilobular RPE tears.