Comparing the Efficacy of Bevacizumab and Ranibizumab in Patients with Diabetic Macular Edema (BRDME): The BRDME Study, a Randomized Trial.

PURPOSE: To generate conclusive evidence regarding the noninferiority of intravitreal bevacizumab compared with ranibizumab in patients with diabetic macular edema (DME). DESIGN: Comparative, randomized, double-masked, multicenter, noninferiority clinical trial. PARTICIPANTS: Eligible patients were older than 18 years, diagnosed with type 1 or type 2 diabetes mellitus, with glycosylated hemoglobin of less than 12%, central area thickness of more than 325 µm, and visual impairment from DME with a best-corrected visual acuity (BCVA) between 24 letters and 78 letters. METHODS: From June 2012 through February 2018, a total of 170 participants were randomized to receive 6 monthly injections of either 1.25 mg bevacizumab (n = 86) or 0.5 mg ranibizumab (n = 84). MAIN OUTCOME MEASURES: Primary outcome was change in BCVA from baseline to month 6 compared between the 2 treatment arms. The noninferiority margin was 3.5 letters. RESULTS: The difference in mean BCVA between treatment arms was 1.8 letters in favor of ranibizumab after 6 months of follow-up; BCVA improved by 4.9±6.7 letters in the bevacizumab group and 6.7±8.7 letters in the ranibizumab group. The lower bound of the 2-sided 90% confidence interval (CI) was -3.626 letters, exceeding the noninferiority margin of 3.5 letters. Central area thickness decreased more with ranibizumab (138.2±114.3 µm) compared with bevacizumab (64.2±104.2 µm). In a post hoc subgroup analysis, participants with a worse BCVA at baseline (≤69 letters) improved by 6.7±7.0 letters with bevacizumab and 10.4±10.0 letters with ranibizumab, and central area thickness decreased significantly more in the ranibizumab arm of this subgroup compared with the bevacizumab arm. Participants with an initially better BCVA at baseline (≥70 letters) did not demonstrate differences in BCVA or OCT outcomes between treatment arms. CONCLUSIONS: Based on change in BCVA from baseline to month 6, the noninferiority of 1.25 mg bevacizumab to 0.5 mg ranibizumab was not confirmed. Only the subgroup of patients with a lower BCVA at baseline showed better visual acuity and anatomic outcomes with ranibizumab. Our study confirmed the potential differential efficacy of anti-vascular endothelial growth factor agents in the treatment of DME as well as the difference in response between patient groups with different baseline visual acuities.

Comparing the Efficacy of Bevacizumab and Ranibizumab in Patients with Retinal Vein Occlusion: The Bevacizumab to Ranibizumab in Retinal Vein Occlusions (BRVO) study, a Randomized Trial.

PURPOSE: Comparing the efficacy of intravitreal injections of bevacizumab to ranibizumab in the treatment of macular edema (ME) resulting from retinal vein occlusion (RVO). DESIGN: Comparative, randomized, double-masked, multicenter, noninferiority clinical trial. The noninferiority margin was 4 letters. PARTICIPANTS: Patients with vision loss resulting from ME secondary to a branch or (hemi) central RVO who might benefit from anti-vascular endothelial growth factor treatment were eligible for participation. METHODS: From June 2012 through February 2018, 277 participants were randomized to receive injections of 1.25 mg bevacizumab (n = 139) or 0.5 mg ranibizumab (n = 138). The follow-up was 6 months with a monthly dosing interval. MAIN OUTCOME MEASURES: The primary outcome was a change in visual acuity from baseline at 6 months. Changes in the central area thickness and safety were studied as secondary outcomes. RESULTS: The mean visual acuity (±standard deviation) improved, with 15.3±13.0 letters for bevacizumab and 15.5±13.3 letters for ranibizumab after 6 months of monthly treatment. The lower limit of the 2-sided 90% confidence interval was -1.724 letters, which is within the noninferiority margin of 4 letters. Even in the branch and (hemi-)central RVO subgroups, minimal differences were found in visual acuity outcomes between treatment arms. Changes in central area thickness on OCT at 6 months did not differ significantly between treatment groups, with a decrease of 287.0±231.3 µm in the bevacizumab group and 300.8±224.8 µm in the ranibizumab group. Severe adverse events (SAEs) were also distributed equally over both treatment groups: 10 participants (7.1%) in the bevacizumab group and 13 participants (9.2%) in the ranibizumab group experienced SAEs. CONCLUSIONS: This study showed, based on the change in visual acuity, that bevacizumab is noninferior to ranibizumab for patients with ME resulting from RVO of either subtype when receiving monthly injections for a period of 6 months. In addition, anatomic and safety outcomes did not differ between treatment groups. Based on our findings, bevacizumab may be an effective alternative to ranibizumab.

Physico-chemistry of bacterial transmission versus adhesion.

Bacterial adhesion is a main problem in many biomedical, domestic, natural and industrial environments and forms the onset of the formation of a biofilm, in which adhering bacteria grow into a multi-layered film while embedding themselves in a matrix of extracellular polymeric substances. It is usually assumed that bacterial adhesion occurs from air or by convective-diffusion from a liquid suspension, but often bacteria adhere by transmission from a bacterially contaminated donor to a receiver surface. Therewith bacterial transmission is mechanistically different from adhesion, as it involves bacterial detachment from a donor surface followed by adhesion to a receiver one. Transmission is further complicated when the donor surface is not covered with a single layer of adhering bacteria but with a multi-layered biofilm, in which case bacteria can be transmitted either by interfacial failure at the biofilm-donor surface or through cohesive failure in the biofilm. Transmission through cohesive failure in a biofilm is more common than interfacial failure. The aim of this review is to oppose surface thermodynamics and adhesion force analyses, as can both be applied towards bacterial adhesion, with their appropriate extensions towards transmission. Opposition of surface thermodynamics and adhesion force analyses, will allow to distinguish between transmission of bacteria from a donor covered with a (sub)monolayer of adhering bacteria or a multi-layered biofilm. Contact angle measurements required for surface thermodynamic analyses of transmission are of an entirely different nature than analyses of adhesion forces, usually measured through atomic force microscopy. Nevertheless, transmission probabilities based on Weibull analyses of adhesion forces between bacteria and donor and receiver surfaces, correspond with the surface thermodynamic preferences of bacteria for either the donor or receiver surface. Surfaces with low adhesion forces such as polymer-brush coated or nanostructured surfaces are thus preferable for use as non-adhesive receiver surfaces, but at the same time should be avoided for use as a donor surface. Since bacterial transmission occurs under a contact pressure between two surfaces, followed by their separation under tensile or shear pressure and ultimately detachment, this will affect biofilm structure. During the compression phase of transmission, biofilms are compacted into a more dense film. After transmission, and depending on the ability of the bacterial strain involved to produce extracellular polymeric substances, biofilm left-behind on a donor or transmitted to a receiver surface will relax to its original, pre-transmission structure owing to the viscoelasticity of the extracellular polymeric substances matrix, when present. Apart from mechanistic differences between bacterial adhesion and transmission, the low numbers of bacteria generally transmitted require careful selection of suitably sensitive enumeration methods, for which culturing and optical coherence tomography are suggested. Opposing adhesion and transmission as done in this review, not only yields a better understanding of bacterial transmission, but may stimulate researchers to more carefully consider whether an adhesion or transmission model is most appropriate in the specific area of application aimed for, rather than routinely relying on adhesion models.

FACTORS ASSOCIATED WITH PENTOSIDINE ACCUMULATION IN THE HUMAN VITREOUS.

PURPOSE: To explore factors associated with pentosidine accumulation in the human vitreous. METHODS: Vitreous samples were obtained during trans pars plana vitrectomy for macular hole or rhegmatogenous retinal detachment. Patient characteristics included age, gender, and diabetes mellitus. Ocular characteristics included pseudophakia, posterior vitreous detachment, and presence of intraocular fibrosis (epiretinal membrane, proliferative vitreoretinopathy, or both). Pentosidine concentration as a measure of accumulation of advanced glycation end products was determined by high performance liquid chromatography. RESULTS: Pentosidine concentrations were measured in 222 vitrectomy samples (118 female and 104 male patients [median age 66 years], treated for macular hole [n = 105] or rhegmatogenous retinal detachment [n = 117]). Pentosidine was found to accumulate significantly with age (P < 0.001). After correction for age, a multivariable linear regression model revealed significantly higher pentosidine values in eyes with intraocular fibrosis (P = 0.001), in phakic as compared with pseudophakic eyes (P = 0.02), and in the absence of a complete posterior vitreous detachment (P = 0.018). The authors found no association with diabetes mellitus or gender. CONCLUSION: This study confirmed an age-related pentosidine accumulation in the vitreous and found new factors relating to pentosidine levels. Findings support the hypothesis of enzyme-induced vitreous liquefaction and the hypothesis of pentosidine as a pro-fibrotic factor.

Association of Circulating Markers With Outcome Parameters in the Bevacizumab and Ranibizumab in Diabetic Macular Edema Trial.

Purpose: The purpose of this study was to evaluate selected candidate biomarkers as potential markers for patients with diabetic macular edema (DME) who receive antivascular endothelial growth factor (VEGF) therapy. Methods: Selected biomarkers included blood levels of messenger RNA (mRNA) of retinoschisin, RPE65, rhodopsin, and endothelial progenitor cell markers CD34 and CD133. Blood samples were obtained from 89 patients with DME according to the study protocol of the Bevacizumab and Ranibizumab in Diabetic Macular Edema (BRDME) study. During each monthly visit, patients underwent optical coherence tomography scanning and visual acuity was measured. Anti-VEGF injections were administered at fixed monthly intervals over 6 months. Analyses of covariance using simplified and linear mixed models were used to examine the correlations between candidate markers and changes in visual acuity and central subfield thickness. Results: Plasma mRNA levels of retinoschisin were negatively associated with visual acuity, and plasma mRNA levels of rhodopsin were positively associated with visual acuity in patients with DME (P < 0.01 and P < 0.05, respectively). In addition, changes in central subfield thickness between baseline and months 1, 2, and 3 during anti-VEGF treatment were associated with mRNA levels of retinoschisin, rhodopsin, and the ratio of retinoschisin-to-rhodopsin (P < 0.01, all). Conclusions: This prospective, multicenter study found that circulating mRNA levels of retinoschisin and rhodopsin are associated with visual acuity and changes in central subfield thickness during anti-VEGF therapy in patients with DME. (ClinicalTrials.gov number: NCT01635790.).

Glaucoma drainage device surgery after vitreoretinal surgery: incidence and risk factors.

PURPOSE: The initial success of vitreoretinal surgery can be annihilated by an acceleration of preexisting glaucoma or the development of secondary glaucoma. Aim of this study was to determine the incidence of and risk factors for medically uncontrollable glaucoma after vitreoretinal surgery. METHODS: Case-control study amongst patients who underwent vitreoretinal surgery at the University Medical Center Groningen between 1991 and 2011 (in total 14,942 interventions). Cases were all patients who received a glaucoma drainage device after vitreoretinal surgery. Controls were a subset of the patients who underwent vitreoretinal surgery without a subsequent drainage device. Cases and controls were matched (three controls per case) with regard to the year of the (first) vitreoretinal intervention. The incidence rate was calculated from the number of cases and the number of person-years corresponding to all vitreoretinal interventions performed in the study period. Risk factors were analysed with logistic regression. RESULTS: Ninety-five cases were identified after a follow-up of 101,961 person-years (one per 1000 person-years). Cases were younger (p = 0.017), were more often men (p = 0.035), underwent more interventions (p < 0.001) or were treated with silicone oil (p = 0.021), had a higher intra-ocular pressure 1 week after the intervention (p < 0.001) and had more often a history of glaucoma or ocular hypertension (p < 0.001). CONCLUSION: Glaucoma after vitreoretinal surgery that requires a glaucoma drainage device is not very common and patients who need a device differ from those who do not. This gives the opportunity to monitor certain subgroups more closely.

Immunohistochemical Evaluation of Idiopathic Epiretinal Membranes and In Vitro Studies on the Effect of TGF-ß on Müller Cells.

PURPOSE: The purpose of this study was to investigate the presence of type VI collagen and glial cells in idiopathic epiretinal membrane (iERM) and the role of TGF-ß in the expression of collagens and α-smooth muscle actin (α-SMA) in retinal Müller cells. METHODS: Idiopathic ERM samples from vitrectomy were analyzed for glial acidic fibrillary protein (GFAP), cellular retinaldehyde-binding protein (CRALBP), α-SMA, and type VI collagen using flat-mount immunohistochemistry. To study intracellular collagen expression in relation to cellular phenotype, spontaneously immortalized human Müller cells (MIO-M1) were treated with TGF-ß1 for 48 hours, and the expression of α-SMA and intracellular type I, II, IV, and VI collagens was studied by using immunocytology. Findings in Müller cells were compared with those in fetal lung fibroblasts and newborn skin fibroblasts. RESULTS: A colocalization of GFAP/CRALBP and GFAP/α-SMA was found in iERM, indicating a dynamic process of activation of retinal Müller cells in vivo. Transforming growth factor-ß1 induced up-regulation of α-SMA stress fibers in retinal Müller cells and both types of fibroblasts in vitro. The intracellular staining intensity of type I, II, and VI collagens was decreased in retinal Müller cells containing α-SMA stress fibers, whereas the intracellular staining intensity of type I and VI collagens in both types of fibroblasts was not affected. CONCLUSIONS: Type VI collagen and activated retinal Müller cells are present in iERM. Transforming growth factor-ß1 induces an up-regulation of α-SMA stress fibers in retinal Müller cells and fibroblasts and appears to have a cell-specific effect on intracellular collagen expression.

Substrate Elastic Modulus Regulates the Morphology, Focal Adhesions, and α-Smooth Muscle Actin Expression of Retinal Müller Cells.

PURPOSE: The stiffness of the extracellular matrix has been shown to regulate cell adhesion, migration, and transdifferentiation in fibrotic processes. Retinal Müller cells have been shown to be mechanosensitive; they are involved in fibrotic vitreoretinal diseases. Since fibrosis increases the rigidity of the extracellular matrix, our aim was to develop an in vitro model for studying Müller cell morphology and differentiation state in relation to matrix stiffness. METHODS: A spontaneously immortalized human Müller cell line (MIO-M1) was cultured on type I collagen-coated polyacrylamide gels with Young's moduli ranging from 2 to 92 kPa. Cell surface area, focal adhesion, and the expression and morphology of α-smooth muscle actin induced by transforming growth factor ß (TGF-ß [10 ng/mL for 48 hours]) were analyzed by immunocytology. The images were documented by using fluorescence microscopy and confocal scanning laser microscopy. RESULTS: MIO-M1 cells cultured on stiff substrates exhibited a significant increase in cell surface area, stress fiber, and mature focal adhesion formation. Furthermore, Müller cells treated with TGF-ß1 and TGF-ß2 and cultured on stiff substrates showed an increased incorporation of α-smooth muscle actin into stress fibers when compared to those grown on soft surfaces. CONCLUSIONS: Compliance of the surrounding matrix seems to influence the morphology and contraction of retinal Müller cells in fibrotic conditions. Development of an in vitro model simulating both the normally compliant retinal tissue and the rigid retinal fibrotic tissue helps fill the gap between the results of petri-dish cell culture with rigid surfaces and in vivo findings.

The Ultrastructural Localization of Type II, IV, and VI Collagens at the Vitreoretinal Interface.

BACKGROUND: The vitreoretinal interface is the border of the cortical vitreous and the inner surface of the retina. The adhesion of the cortical vitreous to the ILM, namely vitreoretinal adhesion, involves a series of complex molecular adhesion mechanisms and has been considered as an important pathogenic factor in many vitreoretinal diseases. The presence of type VI collagen at the vitreoretinal interface and its possible interaction with collagens and glycoproteins indicates that type VI collagen may contribute to the vitreoretinal adhesion. PURPOSE: To clarify the ultrastructural location of type VI collagen and its relationship to type II and IV collagens at the vitreoretinal interface. METHODS: The ultrastructural localization of type II, IV and VI collagens in the adult human vitreoretinal interface of five donor eyes was evaluated by transmission electron microscopy using immunogold labeling. RESULTS: In the pre-equatorial region, we observed densely packed vitreous lamellae with a partly intraretinal course containing type II and VI collagens, reticular structures containing type IV and VI collagens and a thin inner limiting membrane (ILM) containing type IV and VI collagens in a linear distribution pattern. From the anterior to the posterior retina, the linear pattern of type IV and VI collagen labeling gradually became more diffusely present throughout the entire thickness of the ILM. CONCLUSIONS: The presence of type VI collagen in vitreous lamellae penetrating the ILM into the superficial retina suggests that type VI collagen may be involved in the organization of vitreous fibers into lamellae and in the adhesion of the vitreous fibers to the retina. The close relation of type VI to type IV collagen in the ILM suggests that type VI collagen is an important collagen type in the ILM. The topographic variations of type IV and VI collagens in the different regions of the ILM suggest a regional heterogeneity of the ILM. The reticular labeling pattern of type IV and VI collagens observed in the anterior vitreous are highly similar to labeling patterns of blood vessel walls. In the anterior vitreous, they may represent remnants of the regressed embryonic hyaloid blood vessel system. Their presence is in support of the theory on interactive remodeling of the developing vitreous as opposed to the main stream theory of displacement and compression of the primary by the secondary vitreous.

Postoperative metamorphopsia in macula-off rhegmatogenous retinal detachment: associations with visual function, vision related quality of life, and optical coherence tomography findings.

PURPOSE: To evaluate postoperative metamorphopsia in macula-off rhegmatogenous retinal detachment (RRD) and its association with visual function, vision related quality of life, and optical coherence tomography (OCT) findings. METHODS: 45 patients with primary macula-off RRD were included. At 12 months postoperatively, data on metamorphopsia using sine amsler charts (SAC), best corrected visual acuity (BCVA), letter contrast sensitivity, color vision (saturated and desaturated color confusion indexes), critical print size, reading acuity, the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25), and OCT, were obtained. RESULTS: Metamorphopsia was present in 39 patients (88.6%), with most of them (n = 35, 77.8%) showing only mild metamorphopsia (SAC score = 1). Patients with metamorphopsia had significantly worse postoperative BCVA (p = 0.02), critical print size (p<0.0005), and reading acuity (p = 0.001) compared to patients without metamorphopsia. Other visual function outcomes and NEI-VFQ-25 overall composite score were all also somewhat lower in patients with metamorphopsia, but this did not reach statistical significance. No association with OCT findings was present. CONCLUSION: The prevalence of postoperative metamorphopsia in macula-off RRD patients is high, however, the degree of metamorphopsia is relatively low. When metamorphopsia is present, visual functions seem to be compromised, while vision related quality of life is only mildly affected.

Prevention of posterior capsular opacification.

Posterior capsular opacification (PCO) is a common complication of cataract surgery. The development of PCO is due to a combination of the processes of proliferation, migration, and transdifferentiation of residual lens epithelial cells (LECs) on the lens capsule. In the past decades, various forms of PCO prevention have been examined, including adjustments of techniques and intraocular lens materials, pharmacological treatments, and prevention by interfering with biological processes in LECs. The only method so far that seems effective is the implantation of an intraocular lens with sharp edged optics to mechanically prevent PCO formation. In this review, current knowledge of the prevention of PCO will be described. We illustrate the biological pathways underlying PCO formation and the various approaches to interfere with the biological processes to prevent PCO. In this type of prevention, the use of nanotechnological advances can play a role.

Postoperative vision-related quality of life in macula-off rhegmatogenous retinal detachment patients and its relation to visual function.

OBJECTIVE: To determine the vision-related quality of life (VR-QOL) after surgery for macula-off rhegmatogenous retinal detachment (RRD) in relation to visual acuity, contrast acuity, and color vision. METHODS: In a prospective observational study, we included 55 patients with a macula-off RRD. Best corrected visual acuity (BCVA), color vision (saturated and desaturated color confusion indices (CCI)) and contrast acuity were measured at 12 months postoperatively in both the RRD eye and the fellow control eye, and the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) was filled out. RESULTS: Operated and fellow control eyes differed significantly in mean LogMAR BCVA (P<0.0001), median Log contrast acuity (P<0.0001), saturated CCI (P = 0.009), and desaturated CCI (P = 0.016). Significant correlations were observed between the NEI VFQ-25 overall composite score and postoperative LogMAR BCVA (R = -0.551, P<0.0001), contrast acuity (R = 0.472, P<0.0001), saturated CCI (R = -0.315, P = 0.023), and desaturated CCI (R = -0.283, P = 0.044). CONCLUSIONS: A lower VR-QOL was highly correlated to a worse postoperative BCVA and contrast acuity and to a lesser extent to color vision disturbances.

Idiopathic epiretinal membrane.

BACKGROUND: Idiopathic epiretinal membrane (iERM) is a fibrocellular membrane that proliferates on the inner surface of the retina at the macular area. Membrane contraction is an important sight-threatening event and is due to fibrotic remodeling. METHODS: Analysis of the current literature regarding the epidemiology, clinical features, and pathogenesis of iERM and fibrotic tissue contraction. RESULTS: Epidemiologic studies report a relationship between iERM prevalence, increasing age, and posterior vitreous detachment. Clinically, iERM progresses through different stages characterized by an increased thickness and wrinkling of the membrane. Pathophysiologically, iERM formation is a fibrotic process in which myofibroblast formation and the deposition of newly formed collagens play key roles. Anomalous posterior vitreous detachment may be a key event initiating the formation of iERM. The age-related accumulation of advanced glycation end products may contribute to anomalous posterior vitreous detachment formation and may also influence the mechanical properties of the iERM. CONCLUSION: Remodeling of the extracellular matrix at the vitreoretinal interface by aging and fibrotic changes, plays a significant role in the pathogenesis of iERM. A better understanding of molecular mechanisms underlying this process may eventually lead to the development of effective and nonsurgical approaches to treat and prevent vitreoretinal fibrotic diseases.

Postoperative recovery of visual function after macula-off rhegmatogenous retinal detachment.

PURPOSE: To determine which factors affect the recovery of visual function in macula off rhegmatogenous retinal detachment (RRD). METHODS: In a prospective study of forty-five patients with a primary macula-off RRD of 24 hours to 6 weeks duration, the height of the macular detachment was determined by ultrasonography. At 12 months postoperatively, best corrected visual acuity (BCVA), contrast acuity, and color confusion indexes (CCI) were obtained. RESULTS: Macular detachment was present for 2-32 (median 7) days before repair. A shorter duration of macular detachment was correlated with a better CCI saturé (p = 0.0026) and lower LogMAR BCVA (better Snellen visual acuity) (p = 0.012). Also, a smaller height of macular detachment was correlated with a lower LogMAR BCVA (p = 0.0034). A younger age and lower pre-operative LogMAR BCVA at presentation were both correlated with better postoperative contrast acuity in the total group (age: p = 1.7×10(-4) and pre-operative LogMAR BCVA: p = 0.0034). CONCLUSION: Functional recovery after macula-off RRD is affected by the duration and the height of the macular detachment. Recovery of contrast acuity is also affected by age and BCVA at presentation. MEETING PRESENTATION: ARVO annual meeting 2013, May 7, Seattle, Washington, United States of America. TRIAL REGISTRATION: trialregister.nl NTR839.

Glial cells and collagens in epiretinal membranes associated with idiopathic macular holes.

PURPOSE: To investigate the identity of collagens and cellular components in the epiretinal membrane (ERM) associated with full-thickness idiopathic macular hole and their clinical relevance. METHODS: Pars plana vitrectomy with the peeling of internal limiting membrane and ERM was performed by 2 surgeons in 40 eyes with idiopathic macular holes. The clinical data were reviewed and the surgical specimens were processed for flat-mount and immunohistochemical analysis. RESULTS: Epiretinal membrane is a GFAP-positive gliotic and fibrotic scar which contains newly formed Type I, III, and V collagens. Type VI collagen was not observed. Colocalization studies found cells coexpressing GFAP/CRALBP, GFAP/α-SMA, and α-SMA/CRALBP, which are consistent with transdifferentiation of Müller cells into fibroblasts and myofibroblasts. The clinically significant ERMs can be divided into two groups according to the amount of cells in ERM: sparse cellular proliferation and dense cellular proliferation. The latter group is associated with a higher chance of surgical difficulty during internal limiting membrane peeling (P = 0.006). Preoperative and postoperative visual function were not affected by the density of the cellular proliferation. CONCLUSION: Retinal glial cells, probably transdifferentiated Müller cells, are involved in the formation of full-thickness macular hole-associated ERMs by a gliotic and fibrotic process. Such ERMs contain newly formed Type I, III, and V collagen depositions. The cell density of ERM affects its biomechanical properties and determines the difficulty of ERM peeling.

Morphometric analyses of the visual pathways in macular degeneration.

INTRODUCTION: Macular degeneration (MD) causes central visual field loss. When field defects occur in both eyes and overlap, parts of the visual pathways are no longer stimulated. Previous reports have shown that this affects the grey matter of the primary visual cortex, but possible effects on the preceding visual pathway structures have not been fully established. METHODS: In this multicentre study, we used high-resolution anatomical magnetic resonance imaging and voxel-based morphometry to investigate the visual pathway structures up to the primary visual cortex of patients with age-related macular degeneration (AMD) and juvenile macular degeneration (JMD). RESULTS: Compared to age-matched healthy controls, in patients with JMD we found volumetric reductions in the optic nerves, the chiasm, the lateral geniculate bodies, the optic radiations and the visual cortex. In patients with AMD we found volumetric reductions in the lateral geniculate bodies, the optic radiations and the visual cortex. An unexpected finding was that AMD, but not JMD, was associated with a reduction in frontal white matter volume. CONCLUSION: MD is associated with degeneration of structures along the visual pathways. A reduction in frontal white matter volume only present in the AMD patients may constitute a neural correlate of previously reported association between AMD and mild cognitive impairment.

Design and validation of a method to determine the position of the fovea by using the nerve-head to fovea distance of the fellow eye.

PURPOSE: To measure the nerve-head to fovea distance (NFD) on fundus photographs in fellow eyes, and to compare the NFD between fellow eyes. METHODS: Diabetic patients without retinopathy, (n = 183) who were screened by fundus photography at the University Medical Center Groningen, the Netherlands from January 1(st) 2005 until January 1(st) 2006 were included. The NFD was measured in left and right eyes both from the center and from the rim of the nerve-head. To determine inter- and intra-observer agreement, repeated measurements by one observer (n = 3) were performed on all photographs and by two observers on 60 photographs (30 paired eyes). The effect of age, gender, and refractive error on NFD was analysed. RESULTS: The correlation of NFDs between the left and the right eye was 0.958 when measured from the center of the nerve head (mean difference 0.0078 mm. ±SD 0.079 (95% limits of agreement -0.147-0.163)) and 0.963 when measured from the rim (mean difference 0.0056±SD 0.073 (95% limits of agreement -0.137-0.149)). Using the NFD between fellow eyes interchangeably, resulted in a standard error of 0.153 mm. Intra- and inter-observer variability was small. We found a significant effect of age (center of the nerve-head (P = 0.006) and rim of the nerve head (P = 0.003)) and refractive error (center of nerve-head (P<0.001) and rim of nerve head (P<0.001)) on NFD. CONCLUSIONS: The NFD in one eye provides a confident, reproducible, and valid method to address the position of the fovea in the fellow eye. We recommend using the NFD measured from the center of the nerve-head since the standard error by this method was smallest. Age and refractive error have an effect on NFD.

Nonadhesive, silica nanoparticles-based brush-coated contact lens cases--compromising between ease of cleaning and microbial transmission to contact lenses.

Surface properties of lens cases are determinant for their cleanability and for microbial transmission from lens cases to contact lenses (CLs). PEG-polymer-brush-coatings are known to decrease microbial adhesion more than other surface-coatings. Here, we applied a robust, silica nanoparticles-based brush-coating to polypropylene cases to evaluate their ease of cleaning and probability of bacterial transmission to CLs. Adhesion forces of nine bacterial strains (Pseudomonas, Staphylococci, and Serratia) to rigid CLs, polypropylene, and silica nanoparticles-based brush-coated polypropylene were measured using atomic-force-microscopy and subjected to Weibull analyses to yield bacterial transmission probabilities. Biofilms of each strain were grown in coated and uncoated cases and rinsed with a NaCl or antimicrobial lens care solution. Residual, viable organisms were quantified. Bacterial adhesion forces of all strains were significantly, up to tenfold smaller on brush-coated than on uncoated polypropylene. This yielded, higher transmission probabilities to a CL, but mild-rinsing yielded 10-100 fold higher removal of bacteria from brush-coated than from polypropylene cases. Moreover, due to weak adhesion forces, bacteria on brush-coated cases were two-to-three fold more susceptible to an antimicrobial lens care solution than on polypropylene cases. Therewith, the design of lens case surfaces is a compromise between ease of cleaning and transmission probability to CLs.

Bacterial adhesion forces to Ag-impregnated contact lens cases and transmission to contact lenses.

PURPOSE: To measure adhesion forces of Pseudomonas aeruginosa, Staphylococcus aureus, and Serratia marcescens to a rigid contact lens (CL), standard polypropylene, and Ag-impregnated lens cases using atomic force microscopy and determine bacterial transmission from lens case to CL. METHODS: Adhesion forces of bacterial strains to Ag-impregnated and polypropylene lens cases and a rigid CL were measured using atomic force microscopy. Adhesion forces were used to calculate Weibull distributions, from which transmission probabilities from lens case to CL were derived. Transmission probabilities were compared with actual transmission of viable bacteria from a lens case to the CL in 0.9% NaCl and in an antimicrobial lens care solution. RESULTS: Bacterial transmission probabilities from polypropylene lens cases based on force analysis coincided well for all strains with actual transmission in 0.9% NaCl. Bacterial adhesion forces on Ag-impregnated lens cases were much smaller than that on polypropylene and CLs, yielding a high probability of transmission. Comparison with actual bacterial transmission indicated bacterial killing due to Ag ions during colony-forming unit transmission from an Ag-impregnated lens case, especially for P. aeruginosa. Transmission of viable bacteria from Ag-impregnated lens cases could be further decreased by use of an antimicrobial lens care solution instead of 0.9% NaCl. CONCLUSIONS: Bacterial transmission probabilities are higher from Ag-impregnated lens cases than from polypropylene lens cases because of small adhesion forces, but this is compensated for by enhanced bacterial killing due to Ag impregnation, especially when in combination with an antimicrobial lens care solution. This calls for a balanced combination of antimicrobial lens care solutions and surface properties of a lens case and CL.

The incidence of rhegmatogenous retinal detachment in The Netherlands.

OBJECTIVE: To estimate the incidence and characteristics of rhegmatogenous retinal detachment (RRD) in The Netherlands in 2009. DESIGN: Retrospective, observational case series. PARTICIPANTS: All patients with RRD in the Dutch population in 2009. METHODS: By reviewing surgical logs, cases of primary RRD repair in 2009 were identified. Exclusion criteria included RRD before 2009 and exudative, tractional, or traumatic retinal detachments. Patient demographics, date of surgery, and lens status were documented. Incidence of RRD and 95% confidence intervals (CIs) were calculated based on the Poisson distribution. Age distribution, male-to-female ratio, and proportion of RRD patients with prior cataract extraction (CE) were determined. A Student t test was used to examine differences in the incidence of RRD between groups. MAIN OUTCOME MEASURES: Annual RRD incidence in the population and per gender-adjusted age category and proportion of RRD patients with prior CE. RESULTS: The annual RRD incidence was 18.2 per 100 000 people (95% CI, 11.4-18.8), with a peak incidence of 52.5 per 100 000 people (95% CI, 29.4-56.8) between 55 and 59 years of age. The Bilateral RRD rate was 1.67%. Macula-off presentation occurred in 54.5% of all RRD patients. Prior CE was noted in 33.5% of RRD eyes. The male-to-female ratio was 1.3:1, and RRD incidence was statistically significantly more frequent in males (P<0.0001). CONCLUSIONS: Rhegmatogenous retinal detachment is predominantly a disease of the population older than 50 years, and males are more susceptible to RRD. The annual RRD incidence is highly dependent on demographic characteristics.