[Circumscribed choroidal hemangioma in Sturge-Weber syndrome]. / Umschriebenes choroidales Hämangiom bei Sturge-Weber-Syndrom.

We report on a 19-year-old patient with Sturge-Weber syndrome (SWS), accompanied by a Naevus flammeus, secondary glaucoma, and glaucomatous optic atrophy of the right eye. The painful and blind eye was enucleated. Histopathological analysis revealed a circumscribed choroidal hemangioma around the optic nerve and a smaller extrascleral hemangioma. Molecular genetic testing excluded GNA11, GNAQ, or GNAS mutations. Our work illuminates the clinical, histological, and molecular genetic aspects of this rare case, contributing to the differential diagnosis of ocular conditions in patients with SWS.

[Corneal wound healing-Pharmacological treatment]. / Wundheilung der Kornea ­ Pharmakologische Therapie.

Physiological wound healing of the cornea is a complex process and involves numerous multifactorial tissue processes. A proper wound healing, especially without the formation of light-scattering scars, is essential to preserve the integrity and function of the cornea. Misdirected wound healing is of vast clinical relevance as it can lead to corneal fibrosis and the loss of optical transparency with subsequent reduction of visual acuity, up to blindness. In addition to the understanding of the pathophysiological mechanisms, the knowledge of therapeutic concepts and options for treating corneal wound healing disorders and fibrosis is essential to counteract a permanent damage of the cornea as early as possible. Nowadays, various pharmacological and surgical options are available for treatment. The decision, appropriate selection and indication for the optimal treatment depend primarily on the genesis and clinical appearance of the corneal wound, fibrosis or scar. The treatment of wound healing disorders ranges from the use of topical therapy and supportive measures up to tissue replacement procedures. As long as the mechanical stability of the cornea is intact and wound healing processes are still ongoing, a pharmacological modulation is reasonable, which is discussed in this article.

Anatomical and functional results after vitrectomy with conventional ILM peeling versus inverted ILM flap technique in large full-thickness macular holes.

BACKGROUND: Aim of the study was to compare success rate and functional outcome following pars plana vitrectomy (PPV) with conventional internal limiting membrane (ILM) peeling versus ILM flap technique for full-thickness idiopathic macular holes (FTMH). METHODS: Retrospective analysis of consecutive eyes with FTMH having undergone vitrectomy with sulfur hexafluoride (SF6) endotamponade 25% at the University Medical Center Rostock, Germany (2009-2020). Eyes were divided according to applied surgical technique (ILM peeling [group P] versus ILM flap [group F]). Inclusion criteria were macular hole base diameters (MH-BD) ≥ 400 µm plus axial length ≤ 26.0 mm. Each group was divided into two subgroups based on macular hole minimum linear diameter (MH-MLD): ≤ 400 µm and > 400 µm. Exclusion criteria were FTMH with MH-BD < 400 µm, trauma, myopia with axial length > 26.0 mm or macular schisis. Demographic, functional, and anatomical data were obtained pre- and postoperatively. Preoperative MH-BD and MH-MLD were measured using optical coherence tomography (OCT; Spectralis®, Heidelberg Engineering GmbH, Heidelberg, Germany). Main outcome parameter were: primary closure rate, best-corrected visual acuity (BCVA), and re-surgery rate. RESULTS: Overall 117 eyes of 117 patients with FTMH could be included, thereof 52 eyes underwent conventional ILM peeling (group P) and 65 additional ILM flap (group F) technique. Macular hole closure was achieved in 31 eyes (59.6%) in group P and in 59 eyes (90.8%) in group F (p < 0.001). Secondary PPV was required in 21 eyes (40.4%) in group P and in 6 eyes (9.2%) in group F. Postoperative BCVA at first follow-up in eyes with surgical closure showed no significant difference for both groups (MH-MLD ≤ 400 µm: p = 0.740); MH-MLD > 400 µm: p = 0.241). CONCLUSION: Anatomical results and surgical closure rate following ILM flap technique seems to be superior to conventional ILM peeling for treatment of FTMH.

PREVALENCE OF SARS-CoV-2 RNA AND ANTIBODY DETECTION, AND VACCINATION STATUS IN PATIENTS WITH OCULAR VASCULAR OCCLUSION.

PURPOSE: To analyze the annual prevalence of ocular vascular occlusion in relation to COVID-19 infection and vaccination status in a prospective study. METHODS: All patients were examined for an active severe acute respiratory syndrome coronavirus 2 infection by RNA detection and for a previous infection by virus-specific antibody detection, and their vaccination status was documented. Data from pandemic year 2020 and previous years, before COVID-19 (2019, 2018, 2017), were retrospectively analyzed. RESULTS: In 2021, a total of 103 patients with the first diagnosis of ocular vascular occlusion were treated. Most frequent subdiagnoses were central retinal vein occlusion (20.4%), nonarteritic anterior ischemic optic neuropathy (18.4%), central retinal artery occlusion (13.6%), and branch retinal artery occlusion (12.6%). Thereof, only three patients (2.9%) presented with virus-specific severe acute respiratory syndrome coronavirus 2 antibodies, and none was PCR positive. Patients with preceded severe acute respiratory syndrome coronavirus 2 vaccination (59.2%) presented with comparable characteristics as unvaccinated patients with vascular occlusion regarding age, gender distribution, systemic risk factors, duration of symptoms, visual acuity, and the present subdiagnoses ( P > 0.05). The total number of cases in 2021 (103 cases) was comparable with the pandemic year 2020, at which no vaccination was available (114 cases), and to earlier years 2017, 2018, and 2019 without COVID-19 pandemic (100, 120, and 119 cases). Furthermore, we did not reveal any differences between pandemic and reference years regarding patients' characteristics ( P > 0.05). CONCLUSION: Our study did not reveal an increased annual prevalence of ocular vascular occlusions during COVID-19 pandemic years 2020 and 2021. Patients with previous COVID-19 vaccination did not present differences regarding the risk profile nor symptoms, compared with unvaccinated individuals.

Retinal and Choroidal Ultra-Widefield OCT - Technology, Insights, and Clinical Relevance. / Retinale und choroidale Ultra-Weitwinkel-OCT ­ Technologie, Einblicke und klinische Bedeutung.

As one of the most state-of-the-art procedures for retinal and choroidal imaging, ultra-widefield optical coherence tomography (UWF-OCT) offers significant gains in terms of information pertaining to peripheral retinal lesions and their differential diagnoses. In particular, it enables the presence of minimal accumulations of subretinal fluid to be assessed in detail and then documented. It also enables choroidal expansion of choroidal lesions to be precisely measured. Similar to conventional OCT, its only limitations relate to patient compliance and opacities of the ocular media. While the pupil width is somewhat less important here, the quality of the images is nevertheless better with the patient under medication-induced mydriasis. Used in combination with UWF fundus photography, UWF-OCT is a helpful tool for assessing and monitoring peripheral retinal and choroidal lesions.

Retinal Vascular Occlusion after COVID-19 Vaccination: More Coincidence than Causal Relationship? Data from a Retrospective Multicentre Study.

BACKGROUND: To investigate whether vaccination against SARS-CoV-2 is associated with the onset of retinal vascular occlusive disease (RVOD). METHODS: In this multicentre study, data from patients with central and branch retinal vein occlusion (CRVO and BRVO), central and branch retinal artery occlusion (CRAO and BRAO), and anterior ischaemic optic neuropathy (AION) were retrospectively collected during a 2-month index period (1 June-31 July 2021) according to a defined protocol. The relation to any previous vaccination was documented for the consecutive case series. Numbers of RVOD and COVID-19 vaccination were investigated in a case-by-case analysis. A case-control study using age- and sex-matched controls from the general population (study participants from the Gutenberg Health Study) and an adjusted conditional logistic regression analysis was conducted. RESULTS: Four hundred and twenty-one subjects presenting during the index period (61 days) were enrolled: one hundred and twenty-one patients with CRVO, seventy-five with BRVO, fifty-six with CRAO, sixty-five with BRAO, and one hundred and four with AION. Three hundred and thirty-two (78.9%) patients had been vaccinated before the onset of RVOD. The vaccines given were BNT162b2/BioNTech/Pfizer (n = 221), followed by ChadOx1/AstraZeneca (n = 57), mRNA-1273/Moderna (n = 21), and Ad26.COV2.S/Johnson & Johnson (n = 11; unknown n = 22). Our case-control analysis integrating population-based data from the GHS yielded no evidence of an increased risk after COVID-19 vaccination (OR = 0.93; 95% CI: 0.60-1.45, p = 0.75) in connection with a vaccination within a 4-week window. CONCLUSIONS: To date, there has been no evidence of any association between SARS-CoV-2 vaccination and a higher RVOD risk.

[Corneal wound healing-Pathophysiology and principles]. / Wundheilung der Kornea ­ Pathophysiologie und Grundlagen.

The cornea forms the anterior border of the eye and significantly contributes to a sharp optical image quality on the retina through its transparency, avascular nature and curvature. Because of its anatomical structure and as a barrier to the environment, the cornea is particularly exposed to various external factors, such as injuries and pathogens. A correct wound healing without the formation of light diverging scarring is therefore essential to preserve the integrity and function of the cornea. Misguided wound healing is of outstanding clinical relevance and can lead to corneal fibrogenesis. Corneal fibrosis results in scarring with a loss of optical transparency, which significantly reduces eyesight and can lead to blindness. Understanding the pathophysiological mechanisms of wound healing and fibrogenesis is of great importance for the diagnostics, treatment and evaluation of the subsequent healing process in order to prevent permanent damage as far as possible.

Screening for common eye diseases in the elderly with Optos ultra-wide-field scanning laser ophthalmoscopy: a pilot study with focus on ocular toxoplasmosis.

PURPOSE: Studies on the occurrence of ocular toxoplasmosis (OT) in a general population are rare. Therefore, we conducted this pilot study to assess whether a nonmydriatic ultra-wide-field (UWF) scanning laser ophthalmoscope (SLO) is suitable for a simple, rapid screening procedure. METHODS: The population of this cross-sectional study was randomly recruited from a cohort of hospital-based patients in an urban geriatric hospital. Ophthalmologic evaluation was performed on 201 eyes from 101 participants through nonmydriatic UWF-SLO (Optos Daytona) and assessed for suspicious lesions and other relevant ocular findings. All images were evaluated by two independent examiners. Individuals who presented lesions with a morphological appearance suggestive of OT underwent fundoscopy and serological analysis of Toxoplasma gondii-specific antibodies. RESULTS: The mean age of the study group was 76 years, and 63 (62%) were female. Despite many health restrictions, the SLO examination was carried out easily in this geriatric population. Three participants presented findings by SLO suspicious for T. gondii-related injury. Further clinical examination and serological investigation confirmed the diagnosis, with funduscopic evaluation and positive T. gondii ELISA testing. In addition, a high rate of arterial hypertension and dyslipidemias within the cohort led to a high incidence of vascular changes and age-related fundus findings. CONCLUSION: In our study, we confirm that UWF-SLO technology is helpful in the rapid detection of peripheral retinal injuries in elderly patients such as OT and may be used as a routine screening tool.

Vascular findings in primarily affected and fellow eyes of middle-aged patients with Coats' disease using multimodal imaging.

AIMS: To investigate the retinal vascular structure and capillary anomalies of affected and fellow eyes of patients with unilateral Coats' disease using multimodal imaging. METHODS: Clinical investigation of both eyes of each patient with diagnosed Coats' disease using ultra-widefield (UWF) fundus imaging, including UWF fluorescein angiography (UWFFA), spectral domain optical coherence tomography (OCT) and optical coherence tomography angiography (OCT-A). RESULTS: We analysed 38 eyes of 19 patients with unilateral Coats' disease and found that all fellow eyes (19/19; 100%) revealed vascular alterations, detected by UWFFA, predominantly located in the temporal periphery. Thereby, 89% of the fellow eyes (17/19) presented capillary bed abnormalities, that did not exceed the capillary level; 58% (11/19) presented tortuous abnormalities and 26% (5/19) presented microaneurysmatic abnormalities, exceeding the capillary level. If primarily affected eyes presented central Coats' specific vascular abnormalities, fellow eyes revealed tortuous vascular abnormalities twice as often (78% (7/9) vs 40% (4/10); P=0.096). In primarily affected eyes, a tendency towards larger foveal avascular zones was revealed, compared to fellow eyes (0.28±0.16 mm2 vs 0.20±0.10 mm2; P=0.123). CONCLUSION: The use of modern multimodal imaging allows the detection of even subtle vascular changes in fellow eyes of patients with Coats' disease. Coats' disease appears to be a bilateral ocular disease with a predominant manifestation in one eye of the affected patients.

[Pharmacotherapy of Non-neovascular AMD]. / Medikamentöse Therapieansätze für die nicht neovaskuläre AMD.

BACKGROUND: Non-neovascular age-related macular degeneration (AMD) is not yet treatable. This article summarises current clinical research approaches. The reasons for the current lack of success are analysed. METHODS: Literature and databank search. RESULTS: The number of therapeutic approaches and mechanisms is limited. Only reduction in lipofuscin containing deposits is specific for AMD. Further approaches include modulation of inflammation and neuroprotection. Confirmatory studies have failed to demonstrate efficacy in AMD, i.e. slowing or stopping AMD progression. DISCUSSION: To increase the probability of success for future developments, the pharmacological target space needs to be broadened. This may be achieved by application of molecular network analyses. As visual acuity is commonly not primarily affected by non-neovascular AMD, research on patient perspective is required to define reasonable target profiles for future therapies.

Radiation-Induced Optic Neuropathy: Observation versus Intravitreal Treatment: Can Visual Acuity Be Maintained by Intravitreal Treatment?

PURPOSE: To compare intravitreal therapy with the natural course of radiation optic neuropathy after primary proton beam therapy for choroidal melanoma with respect to long-term visual acuity and development of optic atrophy. DESIGN: Retrospective comparative case series. METHODS: Inclusion criteria: patients treated with primary proton beam therapy for choroidal melanoma with a minimum follow-up of 24 months after the occurrence of radiation optic neuropathy and optic disc imaging during follow-up. EXCLUSION CRITERIA: pathologic condition of the optic disc before irradiation and intravitreal therapy to treat cystoid macular edema not originating from the optic disc. RESULTS: Of 93 patients, 48 were observed only after radiation optic neuropathy, and 45 were treated with intravitreal therapy (triamcinolone, bevacizumab, and/or dexamethasone). Median follow-up was 55 months (29-187 months); median interval between onset of radiation optic neuropathy and the last patient visit was 34 months (24-125 months). Of 48 observed patients, 41 (85.4%) developed an optic atrophy after a median of 14 months (3-86 months) after radiation optic neuropathy; and of 45 intravitreally treated patients, 34 (75.5%) presented with an optic atrophy after a median of 12.5 months (1-55 months) following optic neuropathy, indicating no statistically significant differences between the groups. Comparing the change in visual acuity from occurrence of optic neuropathy to final visual acuity, no statistically significant differences were found between either group (P = 0.579). CONCLUSIONS: Patients treated with intravitreal therapy for radiation optic neuropathy showed no statistically significant differences related to visual acuity or optic atrophy development from patients who underwent only observation.

Systemic Rho-kinase inhibition using fasudil in mice with oxygen-induced retinopathy.

PURPOSE: To investigate the influence of the selective Rho-kinase (ROCK) inhibitor, fasudil, on the mRNA level of proinflammatory factors and the retinal vascular development in mice with oxygen-induced retinopathy (OIR). METHODS: C57BL/6J mice underwent standard protocol for OIR induction from postnatal days 7 to 12. Subsequently, they received a daily intraperitoneal injection of fasudil or sodium chloride from P12 to P16. Analyses were performed using vascular staining on retinal flat mounts, RNA expression by qPCR, and immunohistochemistry on paraffin sections. RESULTS: On retinal flat mounts, the proportion of avascular area and tuft formation did not differ between the fasudil and NaCl group. Immunohistochemical staining revealed a less intense staining with inflammatory markers after fasudil. Nevertheless, there were no differences on RNA level between the two groups. CONCLUSIONS: In conclusion, our findings support that daily systemic application of fasudil does not decrease retinal neovascularization in rodents with oxygen-induced retinopathy. The results of our study together with the controversial results on the effects of different ROCK inhibitors from the literature makes it apparent that effects of ROCK inhibition are more complex, and further studies are necessary to analyze its potential therapeutic effects.

Predictive Factors for Clinical Outcomes after Primary Descemet's Membrane Endothelial Keratoplasty for Fuchs' Endothelial Dystrophy.

PURPOSE: The purpose of this study is to identify predictors for the best-corrected visual acuity (BCVA), central corneal thickness (CCT), and the endothelial cell density (ECD) after primary Descemet's membrane endothelial keratoplasty (DMEK). METHODS: In a prospective observational study, 108 eyes with Fuchs' endothelial dystrophy underwent a primary DMEK. Preoperative data, histologic parameters from host's Descemet's membrane, and follow-up data of the first eye were analyzed in regard to BCVA, CCT, and ECD, 12 months after surgery. RESULTS: Overall, 12 months postoperative, the BCVA improved to 0.11 ± 0.11 logMAR, the CCT declined to 529 ± 42 µm, and the ECD measured 1675 ± 418 cells/mm2. A significant influence of the preoperative CCT on postoperative BCVAs and CCTs was observed (r = 0.299, p = 0.014 and r = 0.507, p < 0.001, respectively). Especially eyes with a CCT <625 µm demonstrated a better BCVA (0.05 ± 0.07 logMAR) than eyes with a CCT ≥625 µm (0.13 ± 0.11 logMAR, p = 0.002). Furthermore, the identification of eyes with an early visual restitution was possible by considering follow-up data of the first eye. A preoperative CCT ≥625 µm was also sensitive to identify eyes with a persistent corneal swelling. The anterior banded layer thickness, which was obtained histologically, correlated to the preoperative CCT and the frequency of graft detachments (r = 0.601, p = 0.023 and r = 0.652, p = 0.041, respectively). Furthermore, a graft's baseline ECD ≤2100 cells/mm2 was found to be a risk factor for an ECD deterioration under 1000 cells/mm2 (1.8% vs. 15.8%, p = 0.020). CONCLUSIONS: Simple clinical parameters, such as the preoperative CCT, the course of visual restitution of the first eye, and the graft's baseline ECD, are efficient predictors for relevant outcome parameters after DMEK and therefore may be used for stratification. Furthermore, our findings indicate that a DMEK should be performed in eyes with Fuchs' endothelial corneal dystrophy, if possible, before the CCT exceeds 625 µm to maintain good clinical results.

[Ultra-Wide Field Retinal Imaging and Angiography in the Differential Diagnosis and Therapeutic Decisions in Vascular Diseases of the Peripheral Retina]. / Ultraweitwinkel-Fundusfotografie und -angiografie in der Differenzialdiagnose und zur Therapieplanung bei peripheren vaskulären Netzhauterkrankungen.

Investigation of vascular diseases of the peripheral retina requires imaging procedures that allow a comprehensive view of the periphery, as well as reproducible pictures. In particular, ultra-wide field fluorescence angiography facilitates diagnosis, therapeutic decisions and follow-up examinations. While vasculopathies such as Coats disease and familiar exudative vitreoretinopathy are diagnosed within the first and second decade of life, patients' compliance during fundus imaging is typically reduced within this age range. Compared to the repeated imaging procedures for composite formation, ultra-wide field imaging has significantly reduced recording time. Nevertheless, current imaging systems are not able to map the entire retina in scaled proportions. Therefore, the imaging frame must be guided by patients' gaze onto the affected retinal area. Moreover, the medical photographer must be aware of the clinical setting and the region of interest. Hence, previous detailed funduscopy by trained ophthalmologists will remain indispensable.

[Multimodal Imaging of the Choroidal Melanoma, with Differential Diagnosis, Therapy (Radiation Planning) and Follow-up]. / Multimodale Bildgebung des Aderhautmelanoms mit seinen Differenzialdiagnosen, Therapie (Bestrahlungsplanung) und Verlaufskontrolle.

Imaging of intraocular tumors is multimodal, multi-purpose, and in continuous development. Therefore, imaging is indispensable for the detection, diagnosis, therapy and monitoring of intraocular tumours. A broad spectrum of imaging procedures is available for diagnostic testing and follow-up. This includes colour image acquisition, infrared imaging, autofluorescence imaging, fluorescence and indocyanine green angiography, optical coherence tomography (OCT) and sonography (US). In this article, the various investigations and their benefits are described using individual examples for the differential diagnosis of choroidal melanoma and retinal vascular tumours located in the fundus periphery.

Primary Descemet's Membrane Endothelial Keratoplasty for Fuchs Endothelial Dystrophy versus Bullous Keratopathy: Histopathology and Clinical Results.

PURPOSE: To investigate functional and anatomical results up to 12 months after Descemet's membrane endothelial keratoplasty (DMEK) for Fuchs' endothelial dystrophy (FED) versus bullous keratopathy (BK) in consideration of morphologic characteristics on host's endothelium-Descemet's membranes (EDM). METHODS: In a prospective consecutive case series, 119 eyes underwent a primary DMEK for FED or BK. Intraoperatively obtained EDM were investigated immunohistologically. Clinical and morphological parameters were compared between FED and BK. RESULTS: Overall, the 12-months best-corrected visual acuity (BCVA) was 0.14 logMAR, and 0.10 logMAR in eyes without vision-limiting comorbidities; thereby no differences were revealed between eyes with FED and BK up to 12 months postoperative (p = 0.186 and p = 0.095, respectively). Correspondingly, the mean central corneal thickness (CCT) measured 520 vs. 529 µm and the mean endothelial cell density (ECD) was 1743 vs. 1457 cells/mm2 for FED and BK, 12 months postoperative. Regarding CCT and ECD, no differences were observed between the groups (p = 0.181 and p = 0.112, respectively). The overall detachment rate was 40% (48/119). Comparing FED and BK the detachment rates did not differ, which were 41% vs. 39% and 43% vs. 35%, in pseudophakic eyes (p = 0.554 and p = 0.601, respectively). Yet, the distribution of recurring graft detachments differed between FED and BK; secondary re-detachments were more frequent in the FED group (7 cases). Regarding histologic investigations, a lower ECD was found in specimens with BK, no differences were revealed for EDM and anterior banded layer thicknesses. Immunohistologically, differences in the distribution of fibronectin and cytokeratin were observed. A rarification of matrix proteins was found in EDM complexes with FED. CONCLUSIONS: DMEK produces similar results for FED and BK. However, the postoperative course may differ with regard to the recurrence of secondary graft detachments that may be associated by histopathologic particularities.

Photochemical degradation of trypan blue.

PURPOSE: To investigate the photochemical degradation of trypan blue (TB) and to identify decomposition products. METHODS: Defined solution samples of TB and a mixture with lutein/zeaxanthin were exposed to blue light. Thermal degradation processes were ruled out using controls not subjected to irradiation. All samples were analyzed using optical microscopy, UV/Vis spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and nuclear magnetic resonance (NMR) spectrometry. Degradation kinetics were determined based on changes in absorbance; intermediates were identified by analyzing mass differences of characteristic fragment ion peaks within the fragmentation patterns, and assignments were verified by NMR. RESULTS: TB demonstrated a photochemical degradation, which can be triggered by lutein/zeaxanthin. Intermediates vary depending on the presence of lutein/zeaxanthin. The self-sensitized photodegradation of TB occurs under generation of dimethyl sulfate and presumed formation of phenol. In contrast, within the presence of lutein/zeaxanthin the decomposition of TB indicates the formation of methoxyamine and sulfonyl arin. Thermal degradation processes were not observed. CONCLUSIONS: TB demonstrated a photodegradation that may be triggered by lutein/zeaxanthin and results in the formation of cytotoxic decomposition products. Our findings contribute to understand degradation mechanisms of TB and may elucidate previous clinical and experimental observations of cellular toxicity after TB application.

Local partial depletion of CD11b+ cells and their influence on choroidal neovascularization using the CD11b-HSVTK mouse model.

PURPOSE: To assess the influence of retinal macrophages and microglia on the formation of choroidal neovascularization (CNV). Therefore, we used a transgenic mouse (CD11b-HSVTK) in which the application of ganciclovir (GCV) results in a depletion of CD11b+ cells. METHODS: We first investigated if a local depletion of CD11b+ macrophages and microglia in the retina is feasible. In a second step, the influence of CD11b+ cell depletion on CNV formation was analysed. One eye of each CD11b-HSVTK mouse was injected with GCV, and the fellow eye received sodium chloride solution (NaCl). Cell counting was performed at day 3 and 7 (one injection) or at day 14 and 21 (two injections). Choroidal neovascularization (CNV) was induced by argon laser and analysed at day 14. RESULTS: The most effective CD11b+ cell depletion was achieved 7 days after a single injection and 14 days after two injections of GCV. After two injections of GCV, we found a significant reduction of CD11b+ cells in central (52 ± 23.9 cells/mm2 ) and peripheral retina (53 ± 20.6 cells/mm2 ); compared to eyes received NaCl (216 ± 49.0 and 210 ± 50.5 cells/mm2 , p < 0.001, respectively). Regarding CNV areas, no statistical significance was found between the groups. CONCLUSION: The CD11b-HSVTK mouse is a feasible model for a local depletion of CD11b+ cells in the retina. Nevertheless, only a partial depletion of CD11b+ cells could be achieved compared to baseline data without any intravitreal injections. Our results did not reveal a significant reduction in CNV areas. In the light of previous knowledge, the potential influence of systemic immune cells on CNV formation might be more relevant than expected.

Spatial distribution of CD115+ and CD11b+ cells and their temporal activation during oxygen-induced retinopathy in mice.

PURPOSE: The model of oxygen-induced retinopathy (OIR) is widely used to analyze pathomechanisms in retinal neovascularization. Previous studies have shown that macrophages (MP) play a key role in vessel formation in OIR, the influence of microglia (MG) having been discussed. The aim of our study was to analyze the spatial and temporal distribution and activation of MP/MG expressing CD115 and CD11b during the process of neovascularization in OIR. METHODS: We used MacGreen mice expressing the green fluorescence protein (GFP) under the promoter for CD115. CD115+ cells were investigated in vivo by scanning laser ophthalmoscopy at postnatal days (P) 17 and 21 in MacGreen mice with OIR (75% oxygen from P7 to P12), and were compared to MacGreen room-air controls. In addition MP/MG were examined ex vivo using immunohistochemistry for CD11b+ detection on retinal flatmounts at P14, P17, and P21 of wild type mice with OIR. RESULTS: In-vivo imaging revealed the highest density of activated MP/MG in tuft areas at P17 of MacGreen mice with OIR. Tufts and regions with a high density of CD115+ cells were detected close to veins, rather to arteries. In peripheral, fully vascularized areas, the distribution of CD115+ cells in MacGreen mice with OIR was similar to MacGreen room-air controls. Correspondingly, immunohistochemical analyses of retinal flatmounts from wild type mice with OIR induction revealed that the number of CD11b+ cells significantly varies between vascular, avascular, and tuft areas as well as between the retinal layers. Activated CD11b+ cells were almost exclusively found in avascular areas and tufts of wild type mice with OIR induction; here, the proportion of activated cells related to the total number of CD11b+ cells remained stable over the course of time. CONCLUSIONS: Using two different approaches to monitor MP/MG cells, our findings demonstrated that MP/MG concentrate within pathologically vascularized areas during OIR. We were able to clarify that reactive changes of CD11b+ cell distribution to OIR primarily occur in the deep retinal layers. Furthermore, we found the highest proportion of activated CD11b+ cells in regions with pathologic neovascularization processes. Our findings support previous reports about activated MP/MG guiding revascularization in avascular areas and playing a key role in the formation and regression of neovascular tufts.