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Retinal detachments are considered an emergent condition warranting immediate recognition and treatment. However, not all detachments require immediate intervention. This article will differentiate the three types of retinal detachments, discuss the predisposing associations and current treatments for the different retinal detachments, and discuss retinal tears. Because many patients present directly to the emergency departments for ocular symptoms, prompt recognition and triage by emergency medical personnel can help ensure optimal visual outcome. Copyright © 2000 by Aspen Publishers, Inc. [ABSTRACT FROM AUTHOR]

Disruptions in circadian rhythms are associated with an increased risk of developing metabolic diseases. General control nonderepressible 2 (GCN2), a primary sensor of amino acid insufficiency and activator of the integrated stress response (ISR), has emerged as a conserved regulator of the circadian clock in multiple organisms. The objective of this study was to examine diurnal patterns in hepatic ISR activation in the liver and whole body rhythms in metabolism. We hypothesized that GCN2 activation cues hepatic ISR signaling over a natural 24-h feeding-fasting cycle. To address our objective, wild-type (WT) and whole body Gcn2 knockout (GCN2 KO) mice were housed in metabolic cages and provided free access to either a control or leucine-devoid diet (LeuD) for 8 days in total darkness. On the last day, blood and livers were collected at CT3 (CT = circadian time) and CT15 . In livers of WT mice, GCN2 phosphorylation followed a diurnal pattern that was guided by intracellular branched-chain amino acid concentrations ( r 2  = 0.93). Feeding LeuD to WT mice increased hepatic ISR activation at CT15 only. Diurnal oscillations in hepatic ISR signaling, the hepatic transcriptome including lipid metabolic genes, and triglyceride concentrations were substantially reduced or absent in GCN2 KO mice. Furthermore, mice lacking GCN2 were unable to maintain circadian rhythms in whole body energy expenditure, respiratory exchange ratio, and physical activity when fed LeuD. In conclusion, GCN2 activation functions to maintain diurnal ISR activation in the liver and has a vital role in the mechanisms by which nutrient stress affects whole body metabolism. NEW & NOTEWORTHY This work reveals that the eIF2 kinase GCN2 functions to support diurnal patterns in the hepatic integrated stress response during natural feeding and is necessary to maintain circadian rhythms in energy expenditure, respiratory exchange ratio, and physical activity during amino acid stress.

The alternative pathway of the complement system is implicated in the etiology of age-related macular degeneration (AMD). Complement depletion with pegcetacoplan and avacincaptad pegol are FDA-approved treatments for geographic atrophy in AMD that, while effective, have clinically observed risks of choroidal neovascular (CNV) conversion, optic neuritis, and retinal vasculitis, leaving room for other equally efficacious but safer therapeutics, including Poly Sialic acid (PSA) nanoparticle (PolySia-NP)-actuated complement factor H (CFH) alternative pathway inhibition. Our previous paper demonstrated that PolySia-NP inhibits pro-inflammatory polarization and cytokine release. Here, we extend these findings by investigating the therapeutic potential of PolySia-NP to attenuate the alternative complement pathway. First, we show that PolySia-NP binds CFH and enhances affinity to C3b. Next, we demonstrate that PolySia-NP treatment of human serum suppresses alternative pathway hemolytic activity and C3b deposition. Further, we show that treating human macrophages with PolySia-NP is non-toxic and reduces markers of complement activity. Finally, we describe PolySia-NP-treatment-induced decreases in neovascularization and inflammatory response in a laser-induced CNV mouse model of neovascular AMD. In conclusion, PolySia-NP suppresses alternative pathway complement activity in human serum, human macrophage, and mouse CNV without increasing neovascularization.

An inflammation-resolving polysialic acid-decorated PLGA nanoparticle (PolySia-NP) has been developed to treat geographic atrophy/age-related macular degeneration and other conditions caused by macrophage and complement over-activation. While PolySia-NPs have demonstrated pre-clinical efficacy, this study evaluated its systemic and intraocular safety. PolySia-NPs were evaluated in vitro for mutagenic activity using Salmonella strains and E. coli , with and without metabolic activation; cytotoxicity was evaluated based on its interference with normal mitosis. PolySia-NPs were administered intravenously in CD-1 mice and Sprague Dawley rats and assessed for survival and toxicity. Intravitreal (IVT) administration in Dutch Belted rabbits and non-human primates was assessed for ocular or systemic toxicity. In vitro results indicate that PolySia-NPs did not induce mutagenicity or cytotoxicity. Intravenous administration did not show clastogenic activity, effects on survival, or toxicity. A single intravitreal (IVT) injection and two elevated repeat IVT doses of PolySia-NPs separated by 7 days in rabbits showed no signs of systemic or ocular toxicity. A single IVT inoculation of PolySia-NPs in non-human primates demonstrated no adverse clinical or ophthalmological effects. The demonstration of systemic and ocular safety of PolySia-NPs supports its advancement into human clinical trials as a promising therapeutic approach for systemic and retinal degenerative diseases caused by chronic immune activation.

Age-related macular degeneration (AMD), a leading cause of visual loss and dysfunction worldwide, is a disease initiated by genetic polymorphisms that impair the negative regulation of complement. Proteomic investigation points to altered glycosylation and loss of Siglec-mediated glyco-immune checkpoint parainflammatory and inflammatory homeostasis as the main determinant for the vision impairing complications of macular degeneration. The effect of altered glycosylation on microglial maintained retinal para-inflammatory homeostasis and eventual recruitment and polarization of peripheral blood monocyte-derived macrophages (PBMDMs) into the retina can explain the phenotypic variability seen in this clinically heterogenous disease. Restoring glyco-immune checkpoint control with a sialic acid mimetic agonist targeting microglial/macrophage Siglecs to regain retinal para-inflammatory and inflammatory homeostasis is a promising therapeutic that could halt the progression of and improve visual function in all stages of macular degeneration.

Introduction: Intravitreal anti-vascular endothelial growth factor (VEGF) injections for exudative age-related macular degeneration (eAMD) are effective and safe but require frequent injections and have nonresponding patients. Geographic atrophy/dry AMD (gaAMD) remains an unmet medical need. New therapies are needed to address this leading cause of blindness in the increasing aged population., Areas Covered: This paper reviews the pathogenesis of macular degeneration, current and failed therapeutics, therapies undergoing clinical trials and a rationale for why certain AMD therapies may succeed or fail., Expert Opinion: VEGF-inhibitors reduce both vascular leakage and neovascularization. Experimental therapies that only address neovascularization or leakage will unlikely supplant anti-VEGF therapies. The most promising future therapies for eAMD, are those that target, more potently inhibit and have a more sustained effect on the VEGF pathway such as KSI-301, RGX-314, CLS-AX, EYEP-1901, OTX-TKI. GaAMD is a phenotype of phagocytic retinal cell loss. Inhibiting phagocytic activity of retinal microglial/macrophages at the border of geographic atrophy and reducing complement derived activators of microglial/macrophage is the most promising strategy. Complement inhibitors (Pegcetacoplan and Avacincaptad pegol) will likely obtain FDA approval but will serve to pave the way for combined complement and direct phagocytic inhibitors such as AVD-104.

Introduction: Diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) are the two complications of diabetes that cause visual loss and blindness. Laser photo-coagulation in the past was used to prevent progression of disease to these advanced stages. Advances in pathophysiologic understanding of DME and PDR have ushered the development of effective targeted therapy that given intravitreally improves vision and prevents blindness. While effective, these therapies require frequent administration and are not universally effective., Areas Covered: This purpose of this paper is to review the current pathophysiologic understanding and treatments for DME and PDR as well as the novel treatments currently being developed. The treatments will be juxtaposed to the factor in the disease cascade being targeted. The potential role of these novel treatment in the clinical armamentarium are postulated., Expert Opinion: Mono-therapy, single category targeting is the current strategy being utilized clinically. However, diabetic retinopathy needs combination therapy. Therapies that will prove successful will address multiple factors involved in the pathogenesis of diabetic retinopathy.

Introduction: The clinical development of anti-VEGF therapies for the treatment of exudative age-related macular degeneration (wet AMD) has revolutionized ophthalmology. Indeed, it has provided clinicians and patients with treatments that lessen visual loss from in a disease that once was uniformly blinding. Although blindness is yet to be eradicated from AMD, repeated intraocular anti-VEGF injections are required to preserve a patient's vision. Therefore, further advances in this field are necessary., Areas Covered: This review provides an overview of the agents that are in mid-stage phase trials for both exudative (wet AMD) and nonexudative macular degeneration (dry AMD). For wet AMD, new agents intend to enhance efficacy, develop alternative delivery such as eye drops, investigate alternate targets and construct sustained release strategies. For advanced dry AMD, the goal is to develop a strategy to slow or stop progressive loss of retinal tissue seen in geographic atrophy, the hallmark of advanced dry AMD., Expert Opinion: It is important to develop better more sensitive biomarkers, validating different approvable clinical trial endpoints and stratifying patients on their genetic polymorphisms. These developments should help to progress the already rapidly developing field of macular degeneration therapy.

Purpose: To investigate in The Standard Care versus COrticosteroid for REtinal Vein Occlusion (SCORE) Study: (1) incidences of neovascular events and retinal capillary nonperfusion (abbreviated as "nonperfusion"), and their relationship with treatment groups; (2) neovascular incidences by nonperfusion status; and (3) pertinent baseline factors for their potential risk for neovascular events., Design: Two multicenter, randomized clinical trials, 1 evaluating participants with central retinal vein occlusion (CRVO) and the other evaluating participants with branch retinal vein occlusion (BRVO)., Participants: At 36 months, data were available for 81 participants with CRVO and 128 with BRVO., Intervention: Standard care (observation or grid photocoagulation) versus 1 or 4 mg intravitreal triamcinolone., Main Outcome Measures: Neovascularization of the iris (NVI), neovascular glaucoma (NVG), disc or retinal neovascularization (NVD/NVE), preretinal or vitreous hemorrhage (PRH/VH), and nonperfusion., Results: The cumulative 36-month incidences for CRVO and BRVO eyes, respectively, were 8.5% and 2.4% for NVI or NVG; 8.8% and 7.6% for NVD/NVE or PRH/VH. There were no differences in incidences of neovascular events or risk of nonperfusion when comparing the 3 treatment groups within diseases. For CRVO at 36 months, 16.6% of eyes with ≥5.5 disc areas of nonperfusion versus 4.0% of eyes with <5.5 disc areas of nonperfusion developed NVG (P = 0.0003); for BRVO at 36 months, 14.6% versus 2.4% developed NVD/NVE (P<0.0001). Similar results were noted for most other neovascular events. Nonperfusion was the only significant baseline factor for neovascularization in BRVO, with the risk of a neovascular event increasing with greater disc areas of nonperfusion, and the highest risk noted at ≥5.5 disc areas., Conclusions: In the SCORE Study, triamcinolone treatment was not associated with lower incidences of neovascular events or nonperfusion status compared with observation or grid photocoagulation. Cumulative 36-month incidences for most neovascular events were significantly higher for nonperfused than perfused eyes. Greater baseline disc areas of nonperfusion increased the risk of neovascularization in BRVO but not CRVO eyes, possibly owing to obscuration of retinal capillary details caused by dense hemorrhage at baseline for CRVO eyes. Increased risk of neovascularization was noted below the historical threshold of 10 disc areas of nonperfusion for retinal vein occlusion., (Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate the decibel loss on the Macular threshold protocol of the Humphrey visual field as a reliable functional outcome of the intravitreal bevacizumab treatment., Methods: Thirteen patients were evaluated at baseline and on the week 6 for best corrected visual acuity, optical coherence tomography central macular thickness and decibel loss on Macular threshold protocol of the Humphrey visual field after 1.25 mg intravitreal injection of bevacizumab. The outcomes were analyzed separately and in correlation using the Wilcoxon signed ranks test., Results: The improvement of the optical coherence tomography and the Macular threshold protocol of the Humphrey visual field from baseline to week 6 were significant with p=0.032 and p=0.003, respectively. The visual acuity did not show a significant improvement. The correlation of the visual acuity and Macular threshold protocol of the Humphrey visual field was significant at baseline (p=0.041) and on week 6 (p=0.019)., Conclusion: The Macular threshold protocol of the Humphrey visual field significantly improved despite the fact that the best corrected visual acuity did not. The Macular threshold protocol of the Humphrey visual field correlated with the visual acuities significantly. The optical coherence tomography was significant to demonstrate improvement but did not correlate with best corrected visual acuity and Macular threshold protocol of the Humphrey visual field. These findings suggest that the Macular threshold protocol of the visual field may be a more reliable tool for evaluation of global macular function after intravitreal bevacizumab treatment.

The leading cause of blindness in the developed world results from several disorders that have pathologic ocular neovascularization as the common pathway leading to vision loss. These disorders include exudative age related macular degeneration (AMD), diabetic retinopathy (DR), retinopathy of prematurity (ROP), retinal vein occlusions (RVO) and ocular tumors. Because neovascularization is the common pathway to blindness in these highly prevalent conditions, the recent understanding of the cascade of angiogenesis has led to clinically available molecular therapeutics that have been proven to restore and preserve vision in patients that suffer from these blinding conditions. This article will summarize the emergence of vascular endothelial growth factor (VEGF) as a validated treatment target for and current understanding of the pathophysiology of ocular neovascularization. The article will then cover promising future strategies and therapeutic targets that are aimed at enhancing the efficacy and/or duration of effect of these clinically available anti-VEGF strategies. In particular molecules that target, VEGF, PDGF, Complement, Inflammation and Integrins that are entering or are currently in clinical trials will be reviewed.

Purpose: To assess outcomes for patients with choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) treated with verteporfin photodynamic therapy (PDT) and bevacizumab., Design: Retrospective, case series database study (registry)., Participants: We included 1196 patients with CNV due to AMD who received > or =1 combination treatment of 1.25 mg intravitreal bevacizumab within 14 days of verteporfin PDT., Methods: Retrospective analysis of baseline data with ongoing follow-up. Physicians from 45 clinical centers entered patient data at baseline and follow-up examinations, including subsequent treatments, into a secure, Web-accessed database. Snellen visual acuity (VA) was converted to logarithm of the minimum angle of resolution (logMAR) for statistical analyses., Main Outcome Measures: Change from baseline in VA and retreatment rates of any therapy after the initial combination treatment., Results: Of 1196 patients, 1073 patients had > or =6 months of follow-up. For these 1073 patients, mean baseline VA was 0.967 logMAR (approximate Snellen 20/185) and 56.3% of patients (604/1073) were treatment naïve. After their baseline combination treatment, patients received a mean of 0.6 additional verteporfin PDT retreatments and 2.0 bevacizumab retreatments over a mean follow-up period of 15.0 months. By 12 months, 82% of patients (578/701) had stable or improved vision (loss of <3 lines or a gain in VA), 36% (255/701) improved by > or =3 lines, and 17% (121/701) improved by > or =6 lines. By 12 months, patients gained approximately 1.2 lines (6 letters) of VA from baseline. Patients who were treatment naïve gained significantly more VA by month 12 (+8.4 letters) compared with those who had been previously treated (+2.4 letters; P<0.01). Most serious adverse events (26/30) were judged by investigators as not related to any study treatment, although 3 ocular events were judged related to bevacizumab alone, and 1 ocular event was judged related to both bevacizumab and PDT., Conclusions: Combination therapy with PDT and bevacizumab led to vision benefit for most patients, particularly those who were treatment naïve at baseline. The number of retreatments was lower than published reports with either treatment delivered as monotherapy. Randomized clinical trials are underway to confirm these findings.

To assess the potential visual benefit of intravitreal bevacizumab in a patient with idiopathic juxtafoveal retinal telangiectasis refractory to focal laser treatment, an intravitreal injection of bevacizumab (1.25 mg) was given. Within 1 week, visual acuity improved from 20/50 to 20/25 and optical coherence tomography demonstrated complete resolution of macular edema. There was no adverse effect. The macular edema recurred after 3 months, requiring a repeat injection of bevacizumab with subsequent resolution of macular edema. An intravitreal injection of bevacizumab may provide potential short-term visual benefit in patients with macular edema from idiopathic juxtafoveal retinal telangiectasis.

Purpose: Treatment of retinal and choroidal diseases may be influenced by overlying blood. We compared the penetration through blood of various laser wavelengths used in thermal photocoagulation, photodynamic therapy, and transpupillary thermotherapy., Methods: Laser light of wavelengths 514 nm, 568 nm, 647 nm, 689 nm, and 810 nm was directed through normal saline (control), whole blood with a hematocrit of 40%, and serial dilutions of whole blood until a steady-state reading of laser power output was obtained. Laser power output was measured with an Orion Laser Power/Energy monitor (Ophir Optronics LTD). Laser power was measured in milliwatts and expressed as a percentage of control., Results: Five hundred fourteen-nanometer and 568-nm laser wavelengths penetrated the least through all dilutions of blood tested (>60% attenuation through the highest dilution tested); 647-nm, 689-nm, and 810-nm laser wavelengths penetrated most effectively through blood but were still significantly attenuated ( approximately 46%, 49.6%, and 47.0% attenuation, respectively, at the highest dilution tested)., Conclusions: The presence of hemorrhage may have a significant effect on the delivery of laser energy to underlying structures/tissue. This may affect parameters used in thermal and nonthermal laser treatment of ocular diseases such as choroidal neovascularization.

Purpose: Rapamycin exhibits significant antitumor/antiangiogenic activity that is coupled with a decrease in vascular endothelial growth factor (VEGF) production and a reduction in the response of vascular endothelial cells to stimulation by VEGF. VEGF plays a significant role in neovascular pathologies of the eye, thus we tested the possibility of using rapamycin to inhibit retinal and choroidal neovascularization (CNV)., Methods: CNV was induced in adult mice with laser photocoagulation. Retinal neovascularization was induced using the retinopathy of prematurity (ROP) hyperoxia/hypoxia model. Experimental animals received intraperitoneal (ip) injections of rapamycin (2 mg/kg/day or 4 mg/kg/day) for 1-2 weeks. Controls were not treated or received ip injections of phosphate buffered saline (PBS). Eyes were analyzed histologically for evidence of CNV or retinal neovascularization. ROP eyes were further analyzed for changes in VEGF and VEGF receptor (Flt-1 and Flk-1) protein content following rapamycin treatment., Results: Rapamycin significantly reduced the extent of neovascularization in both the CNV and the ROP model. Immunohistochemical staining of treated and untreated ROP retina did not reveal a significant reduction in levels of VEGF protein or its receptors. Immunostaining for Flt-1 increased, while no obvious changes in Flk-1 were observed. Quantitative analysis of total protein via enzyme linked immunosorbent assay (ELISA) confirmed an increase in Flt-1 and VEGF, following drug treatment, with no effect on Flk-1., Conclusions: These results suggest rapamycin may provide an effective new treatment for ocular neovascularization.

Purpose: To study the risk of adverse events in transpupillary thermotherapy (TTT) for age-related macular degeneration by measuring how laser-induced retinal temperature increase is affected experimentally by subretinal blood, choroidal blood flow, and chorioretinal pigmentation., Methods: An ultrafine thermocouple technique was developed to measure retinal temperature increase during TTT in albino and pigmented rabbit eyes. TTT was performed with 60-second, 0.78-mm spot size, 810-nm infrared diode laser exposures with power settings ranging from 50 to 950 mW. Intraretinal and subretinal temperature increases were measured in pigmented and albino rabbits, with or without subretinal blood and choroidal blood flow., Results: Threshold power settings for visible lesions in albino and pigmented rabbits were 950 and 90 mW, respectively, corresponding to retinal temperature increases of 11.8 degrees C and 5.28 degrees C, respectively. Power settings required to produce threshold lesions in albino rabbits caused retinal temperature increases in pigmented rabbits that were five times higher than in the albino rabbits. Temperature increases in albino rabbits were 1.5 times higher with subretinal blood than without it. Choroidal blood flow generally did not affect measured retinal temperature increases., Conclusions: The results confirm prior theoretical recommendations that clinicians should consider decreasing TTT power settings in darkly pigmented eyes and proceed with caution in those with subretinal hemorrhage or pigment clumping.

Purpose: To identify risk factors for the development of choroidal neovascularization (CNV) and vision loss in the Fellow Eye Study of the Choroidal Neovascularization Prevention Trial., Methods: Retrospective review of 121 patients enrolled in a multicentered, randomized, controlled trial. Patients had neovascular age-related macular degeneration in one eye and more than 10 large drusen in the other eye. Records of patients randomly assigned to laser treatment or observation were reviewed through 4 years of follow-up. Three candidate risk factors for the development of CNV and vision loss were evaluated., Results: Eyes with hyperfluorescent drusen on fluorescein angiography at 3 minutes appeared to have a decreased risk of CNV. Patchy choroidal filling was seen in 14% of patients. Eyes with patchy choroidal perfusion showed a higher risk of developing CNV that was not statistically significant, and the increased risk was present only in treated eyes. Reticular pseudodrusen were present in only three eyes., Conclusions: Reticular pseudodrusen were rare. Late drusen fluorescence may protect against the development of CNV.

Purpose: RNA interference mediated by small interfering RNAs (siRNAs) is a powerful technology allowing the silencing of mamalian genes with great specificity and potency. The purpose of this study was to demonstrate the feasibility of RNA interference mediated by siRNA in retinal cells in vitro and in the murine retina in vivo., Methods: siRNAs specific for enhanced green fluorescent protein (EGFP) and murine and human vascular endothelial growth factor (VEGF) were designed. In vitro studies in human cell lines entailed modulation of endogenous VEGF levels through chemically induced hypoxia. Effects of siRNA treatment on these levels were measured by ELISA. In vivo studies evaluating effects of siRNA on levels of EGFP and VEGF were performed by co-injecting recombinant viruses carrying EGFP or hVEGF cDNAs along with the appropriate siRNAs subretinally in mice. Additional studies aimed at blocking production of endogenous mVEGF were performed using laser-induced choroidal neovascularization (CNV) in mice. Effects of in vivo treatments were evaluated ophthalmoscopically. Retinal/choroidal flat mounts were evaluated after perfusion with dextran-fluorescein. Alternatively, retinas were evaluated in histological sections or VEGF levels were measured in intact eyes using ELISA., Results: Successful delivery of siRNA to the subretinal space was confirmed by observing significantly reduced levels of EGFP in eyes treated with Ad.CMV.EGFP plus EGFP-directed siRNA. siRNAs directed against hVEGF effectively and specifically inhibit hypoxia-induced VEGF levels in human cell lines and after adenoviral induced hVEGF transgene expression in vivo. In addition, subretinal delivery of siRNA directed against murine Vegf significantly inhibited CNV after laser photocoagulation., Conclusions: Delivery of siRNA can be used in vitro and in vivo to target specific RNAs and to reduce the levels of the specific protein product in the targeted cells. This work suggests that RNA interference has potential for application to studies of retinal biology and for the treatment of a variety of retinal diseases, including those involving abnormal blood vessel growth.

The relationship between cardiac surgery and central retinal vein occlusion (CRVO) has been previously documented; however, in all of these cases the occlusion occurred months after the cardiac surgery. This is the first report of a patient awakening from cardiac surgery with ophthalmoscopically documented CRVO. This diagnostic case report describes a patient who developed CRVO immediately following extensive cardiac surgery including aortic valve, aortic root, and proximal aortic arch replacements, as well as coronary artery bypass grafts. Ophthalmologists and cardiac surgeons alike should be aware that CRVO is a potential complication of cardiac surgery, especially when cardiopulmonary bypass is necessary.

Objectives: To investigate the variability in fluorescein angiography interpretation for photodynamic therapy in age-related macular degeneration., Methods: Eight graders, who included two TAP-certified ophthalmologists, three other retinal specialists, two fellows in vitreoretinal diseases, and a senior fundus photograph grader, evaluated fluorescein angiograms of six patients treated according to the Treatment for ARMD With Verteporfin (TAP) protocol at a single center. Each patient's baseline angiogram was evaluated to determine whether the CNV lesion was predominantly (> or =50%) classic. For each follow-up angiogram, at 3, 6, 12, and 24 months, the grader was required to determine whether fluorescein leakage was present. Six months after the initial gradings, each reader was again presented with the baseline angiogram for each patient and once again asked to determine whether the CNV lesion was predominantly classic without knowledge of the previous grading. All gradings were performed without knowledge of the clinical course., Results: In grading initial visit and follow-up visit angiograms, the overall concordance rates were 81% and 82%, respectively. Concordance rates were not statistically different between the group as a whole when compared with the gradings of the two TAP-certified ophthalmologists. When initial visit angiograms were regraded, an intraobserver variability of 17% was noted. Overall, gradings were discordant with the majority opinion in approximately 19% of decisions., Conclusions: Considerable variability can be expected in fluorescein angiography interpretation as the results of the TAP investigation are applied to clinical practice.

Purpose: To present the clinical applications of color Doppler imaging (CDI) as an adjunctive study in the diagnosis and treatment of orbital lesions., Methods: Retrospective noncomparative case series. Medical records of 17 patients with orbital lesions who underwent orbital CDI were reviewed, and their orbital CDI results, diagnosis, and treatment were studied. The main outcome measures were detection of abnormal orbital vascular flow and presence or absence of blood flow within orbital lesions by CDI., Results: Absence of intralesional flow was associated with an orbital lesion considered benign. Tumors in which flow was present were more frequently malignant or had malignant potential. Reversal of flow in the superior ophthalmic vein was observed in patients with carotid-cavernous fistula and orbital varix., Conclusions: CDI is a useful adjunctive imaging study for evaluating the vascularity of orbital tumors. The absence or presence of intratumoral blood flow as demonstrated by CDI can help determine the nature of the orbital mass and can assist with surgical planning.

Neovascularization characterizes diabetic retinopathy and choroidal neovascularization associated with age-related macular degeneration, the most common causes of severe visual loss in the developed world. Gene transfer to the eye using adeno-associated viral (AAV) vectors is a promising new treatment for inherited and acquired ocular diseases. We used an AAV vector with rapid onset and high levels of gene expression in the retina to deliver three anti-angiogenic factors (pigment epithelium-derived factor, tissue inhibitor of metalloproteinase-3, and endostatin) to the eyes of mice in a mouse model of retinopathy of prematurity. All three vectors inhibited ischemia-induced neovascularization.

The control, over time and space, of the levels of therapeutic proteins is crucial for successful retinal gene therapy. We tested the ability of adeno-associated viral vectors (AAV) delivered intraocularly to release a secreted protein (erythropoietin (Epo) used as a marker) in the eye, either constitutively or in a pharmacologically regulated manner using the dimerizer-inducible transcriptional regulatory system. Following delivery of a constitutively expressing vector to the intravitreal or subretinal space of nude rats, Epo protein was detected in both the anterior chamber and vitreous fluids. A dual-vector system inducible by the dimerizer rapamycin and expressing Epo was administered into the subretinal space in an attempt to achieve pharmacologic control of trangene expression in the eye. Before induction with rapamycin, the intraocular Epo level was negligible. However, following a systemic administration of rapamycin, Epo was detected in the anterior chamber, peaking on day 3 and returning to baseline 2-3 weeks after withdrawal of the drug. Peak-induced Epo in the anterior chamber was proportional to the dose of rapamycin and was not detected in serum. Similar results were obtained following subretinal administration of the vectors in one nonhuman primate. The rapamycin inducible system promises to be useful for developing gene therapies for inherited retinal degeneration and ocular neovascularization.

Purpose: Vascular endothelial growth factor (VEGF) is a potent ischemia-upregulated angiogenic protein that has been implicated in diabetic retinopathy. Intravitreal VEGF injections have not previously been shown to produce preretinal neovascularization. The purpose of this study was to further characterize the angiopathic changes that occur after intravitreal injections in a nonhuman primate and determine if preretinal neovascularization develops., Design: Experimental animal study., Methods: Vascular endothelial growth factor 165 was injected into the eyes of normal cynomolgus monkeys at regular intervals. As a control, normal eyes were injected with phosphate buffered saline. Color photography and fluorescein angiography were performed at regular intervals. The retinas were incubated for adenosine diphosphatase (ADPase) activity to visualize retinal vessels. The retinas were flat-embedded and areas of potential preretinal neovascularization were identified en bloc and serially sectioned., Results: Areas of capillary nonperfusion and vessel dilation and tortuousity were seen by angiography. In serial sections, the nonperfused areas were found to be associated with endothelial cell hyperplasia in vessel lumens. Preretinal neovascularization originating only from superficial veins and venules was observed throughout peripheral retina, but was not seen in the posterior pole. Lacunae-like veins were subdivided by the process of intussusception and endothelial cell bridging. Arterioles demonstrated endothelial cell hyperplasia and microaneurysms., Conclusion: Intraocular injections of VEGF were sufficient to produce preretinal neovascularization in the nonhuman primate. Most vasculopathic structures were associated with endothelial cell hyperplasia. These results demonstrate that VEGF alone can produce many features of both nonproliferative and proliferative diabetic retinopathy including the previously undescribed development of preretinal neovascularization. This well-characterized VEGF-induced primate model of retinal neovascularization may be useful as a means of testing new treatments for retinal neovascularization.

Purpose: In tissues outside the brain, vascular endothelial growth factor-A (VEGF) causes vascular hyper-permeability by opening of inter-endothelial junctions and induction of fenestrations and vesiculo-vacuolar organelles (VVOs). In preliminary studies, we observed that in blood-retinal barrier endothelium, other cellular mechanisms may underlie increased permeability caused by VEGF. This was further investigated in material of an in vivo experimental model of VEGF-induced retinopathy., Methods: Two monkeys received 4 intravitreal injections of 0.5 microg VEGF in one eye and PBS in the other eye prior to sacrifice at day 9. One monkey received 12 injections of 1.25 microg VEGF in one eye and PBS in the other eye prior to sacrifice at day 24. As a control, an untreated eye of a fourth monkey was studied., Results: In the high-dose VEGF-injected eye, fluorescein angiography showed intense retinal micro-vascular leakage. This leakage was also demonstrated by immunohistochemistry demonstrating extravasation of endogenous fibrinogen and IgG. However, in these leaky blood vessels the number of pinocytotic vesicles (caveolae) at the endothelial luminal membrane were significantly higher and, only in the VEGF-injected eyes, these pinocytotic vesicles transported plasma IgG. By electron microscopy, no fenestrations or VVOs were found in the endothelial cells of the VEGF-injected eyes., Conclusion: We conclude that increased vascular permeability for plasma proteins induced by VEGF in blood-retinal barrier endothelium is predominantly caused by a mechanism involving active trans-endothelial transport via pinocytotic vesicles and not by formation of endothelial fenestrations or VVOs.

Objective: To determine if anti-vascular endothelial growth factor antibody and a range of dextrans with varying diffusion radii and molecular weights are permeable through experimental choroidal neovascularization (CNV)., Methods: Choroidal neovascularization was induced in 10 cynomolgus monkey retinas by means of argon laser injury. Digital fundus fluorescein angiograms were performed with fluorescein sodium, fluoresceinated IgG antibodies (anti-vascular endothelial growth factor and a control antibody), and fluoresceinated dextrans with molecular weights of 4, 20, 40, 70 and 150 kd. The 40- and 70-kd dextrans straddle the effective diffusion radius of IgG. For each reagent, early and late angiograms were performed in a standardized fashion, with follow-up images obtained to monitor residual fluorescence., Results: Perfusion of retinal vessels and choroidal vasculature was seen with all reagents. Fluorescein and 4- and 20-kd dextran leaked rapidly from the CNV within the first minute. Angiography with the use of 40-kd dextran and fluoresceinated antibody, either anti-vascular endothelial growth factor or control IgG, showed fluorescence within the CNV that increased during the first 1 to 5 hours, with mild leakage from the CNV. By 24 hours, fluorescence in the CNV was minimal, although in some cases persistent fluorescence in the surrounding tissue was evident up to 2 weeks. The 70-kd dextran showed fluorescence within the CNV and leakage in 1 of 3 eyes. The 150-kd dextran showed fluorescence within the CNV but did not demonstrate leakage., Conclusions: Fluoresceinated antibodies and dextran with smaller effective diffusion radii showed CNV perfusion and leakage. Dextrans with larger effective diffusion radii (70 kd and 150 kd) perfused into CNV but did not show leakage consistently., Clinical Relevance: Determining the permeablity of antibodies and molecules of similar size through CNV can help ascertain the feasibility of using intravenously administered antibodies against angiogenic growth factors as a future treatment for choroidal neovascularization.

Purpose: To report the clinicopathologic features of a newly recognized tumor, giant cell angiofibroma., Design: Observational case series., Main Outcome Measures: Clinical and histopathologic features of giant cell angiofibroma., Methods: Light and electron microscopy and immunohistochemistry of five cases of giant cell angiofibroma., Results: A total of five patients (4 women and 1 man) are described: two presented with a painless mass in the eyelid, two with a mass in the orbit, and one presented with a conjunctival lesion. All lesions were well demarcated with no capsule and were composed of blood vessels, a patternless spindle-shaped cell proliferation with a solid and pseudovascular appearance, and multinucleated giant cells. Both spindle-shaped and giant tumor cells were intensely positive for CD34 and vimentin., Conclusion: Giant cell angiofibroma resembles solitary fibrous tumor and giant cell fibroblastoma and should be considered in the differential diagnosis of spindle-cell tumors in the eyelid, orbit, and conjunctiva.

Objectives: To determine whether systemic hyperoxia can reverse retinal hypoxia and decrease vascular endothelial growth factor (VEGF) gene expression in ischemic nonhuman primate retina., Methods: Six eyes of 3 cynomolgus monkeys were studied. Retinal ischemia was induced via laser vein occlusion and confirmed with fluorescein angiography. Animals were randomly assigned to treatment with either 21% or 100% inhaled oxygen. Arterial PO2 was monitored while systemic acid-base status was maintained. An oxygen microelectrode on a micromanipulator was used to measure preretinal oxygen concentrations in ischemic and nonischemic retina in situ. RNA was isolated from fresh whole retinas, and VEGF messenger RNA levels were quantified with Northern blotting., Results: The preretinal PO2 in ischemic retina was less than the PO2 in nonischemic retina in animals breathing 21% oxygen (intervascular zone PO2, 14.3+/-0.53 vs 21.8+/-0.55 mm Hg; P=.002). After 8 hours of systemic hyperoxia (arterial PO2, 512+/-18 mm Hg), the preretinal PO2 in ischemic retina increased to 166.2+/-15.6 mm Hg (21.8% oxygen) and retinal VEGF messenger RNA levels were reduced by an average of 55%., Conclusions: These data demonstrate that systemic hyperoxia can lower retinal VEGF gene expression and reoxygenate ischemic adult primate retina.

Insulin-like growth factor I (IGF-I) and vascular endothelial growth factor (VEGF) levels are correlated with retinal ischemia-associated intraocular neovascularization in humans. Since VEGF is required for iris and retinal neovascularization in animal models of retinal ischemia, we tested whether IGF-I could act as an indirect angiogenic factor by increasing VEGF gene expression. IGF-I increased retinal pigment epithelial (RPE) cell VEGF mRNA in a concentration-dependent manner with an EC50 of 7 nmol/1 (53.6 ng/ml). RPE and bovine smooth muscle cells exposed to 50 nmol/l (383 ng/m1) IGF-I achieved peak VEGF mRNA expression within 2 h. IGF-I-treated RPE cells increased VEGF protein levels in conditioned media and stimulated capillary endothelial cell proliferation. Blockade of the IGF-I receptor with a neutralizing antibody abrogated the VEGF increases in RPE cells. Further, hypoxia-mediated and IGF-I-mediated increases in VEGF mRNA and protein levels were additive in RPE cells, and the hypoxia-induced VEGF increases were independent of endogenous IGF-I. VEGF promoter activity was enhanced by IGF-I in RPE cells, but VEGF transcript half-life was unaltered. In summary, the supplementation of RPE and smooth muscle cell cultures with IGF-I at 5-100 nmol/l increased VEGF mRNA and secreted protein levels. The VEGF increases in RPE cells occurred primarily through enhanced transcription of the VEGF gene and via the IGF-I receptor. Elevated IGF-I levels may promote neovascularization through increased retinal VEGF gene expression.

Enhanced ingrowth of fibrovascular tissue into alloplastic orbital implants is clinically desirable. Basic fibroblast growth factor (bFGF) is an angiogenic factor that promotes proliferation of endothelial cells. Sucralfate is known to bind bFGF and render it stable by protecting it from degradation. To test the ability of bFGF to stimulate endothelial cell proliferation, porous orbital implants coated with a sustained-release and bioactively-stabilized preparation of the angiogenic peptide bFGF were studied. Hydroxyapatite (HA) and porous polyethylene (PP) implant discs (15 x 3 mm) were coated with sustained-release polymer polyhydroxyethylmethacrylate (hydron), sucralfate (a bFGF stabilizer), hydron plus or hydron/sucralfate plus bFGF. Discs were placed in tissue culture wells plated with 50,000 endothelial cells/well. After 5 days, cells were trypsinized and counted electronically using a Coulter counter. Statistical analysis was performed using unpaired Student's t-test. Implant discs coated with hydron/sucralfate/bFGF had significantly increased endothelial cell proliferation compared to discs coated with hydron alone or hydron/sucralfate (p < 0.05). There was no significant difference in the degree of enhanced proliferation between the HA and PP implants treated with hydron/sucralfate/bFGF (p > 0.05). Minimal proliferation occurred around discs treated with hydron alone or hydron/sucralfate. Coating both HA and PP orbital implants with the sustained-release form of sucralfate/bFGF promoted endothelial cell proliferation in vitro. The enhanced proliferation with hydron/sucralfate/bFGF warrants further exploration in an in vivo model.

Purpose: The purpose of the study is to determine the effect of exogenous vascular endothelial growth factor (VEGF) on the primate retina and its vasculature., Methods: Ten eyes of five animals were studied. Physiologically relevant amounts of the 165 amino acid isoform of human recombinant VEGF were injected into the vitreous of six healthy cynomolgus monkey eyes. Inactivated human recombinant VEGF or vehicle was injected into four contralateral control subject eyes. Eyes were assessed by slit-lamp biomicroscopy, tonometry, fundus color photography, fundus fluorescein angiography, light microscopy, and immunostaining with antibodies against proliferating cell nuclear antigen and factor VIII antigen., Results: All six bioactive VEGF-injected eyes developed dilated, tortuous retinal vessels that leaked fluorescein. Eyes receiving multiple injections of VEGF developed progressively dilated and tortuous vessels, venous beading, edema, microaneurysms, intraretinal hemorrhages and capillary closure with ischemia. The severity of the retinopathy correlated with the number of VEGF injections. None of the four control eyes exhibited any abnormal retinal vascular changes. The endothelial cells of retinal blood vessels were proliferating cell nuclear antigen positive only in the bioactive VEGF-injected eyes., Conclusion: Vascular endothelial growth factor is sufficient to produce many of the vascular abnormalities common to diabetic retinopathy and other ischemic retinopathies, such as hemorrhage, edema, venous beading, capillary occlusion with ischemia, microaneurysm formation, and intraretinal vascular proliferation.

Objective: To determine whether the angiogenic peptide vascular endothelial growth factor (VEGF) is sufficient to produce iris neovascularization in a nonhuman primate (Macaca fascicularis)., Methods: Eight eyes of 4 animals were studied. The 165-amino acid isoform of human recombinant VEGF (VEGF165) was injected into the vitreous of 5 cynomolgus monkey eyes (doses ranging from 0.25-2.5 micrograms per injection). Equal amounts of inactivated human recombinant VEGF (2 eyes) or vehicle (1 eye) were injected into contralateral control eyes. Eyes were assessed by slitlamp biomicroscopy, tonometry, iris color photography, fluorescein angiography, histopathologic examination, and immunostaining with antibodies against proliferating cell nuclear antigen., Results: All 5 bioactive VEGF-injected eyes developed neovascularization with dilated and tortuous iris vessels that leaked fluorescein. None of the 3 control eyes exhibited any iris vascular changes. Inflammation was absent in both treatment groups. A dose response to VEGF was observed in the single animal that received 2.5 micrograms and 0.25 microgram in the right and left eyes, respectively. Iris vessel endothelial cells were positive for proliferating cell nuclear antigen in the bioactive VEGF-injected eyes only. Injections of 1.25 micrograms of VEGF every 3 days during a 30-day period produced advanced iris neovascularization, ectropion uvea, and neovascular glaucoma., Conclusions: Intravitreal injections of recombinant human VEGF165 in amounts comparable with those measured in eyes with active neovascularization are sufficient to produce noninflammatory iris neovascularization in a nonhuman primate. Prolonged exposure to VEGF165 can produce ectropion uveae and neovascular glaucoma.

Objective: To determine if the angiogenic peptide vascular endothelial growth factor (VEGF) is required for retinal ischemia-associated iris neovascularization in a nonhuman primate., Methods: Laser retinal vein occlusion was used to produce retinal ischemia in 16 eyes of eight animals (Macaca fascicularis). Eyes were randomized to treatment every other day with intravitreal injections of either a neutralizing anti-VEGF monoclonal antibody or a control monoclonal antibody of the same isotype. Serial iris fluorescein angiograms were assessed using a standardized grading system and masked readers. Retinal VEGF and placental growth factor expression were assessed by Northern blotting. The specificity of the antibodies was determined in capillary endothelial cell proliferation assays prior to intravitreal injection., Results: Zero of eight eyes receiving the neutralizing anti-VEGF antibodies developed iris neovascularization. Five of eight control antibody-treated eyes developed iris neovascularization. The difference was statistically significant (P = .03). Intravitreal antibody injection did not impair the ability of the ischemic retina to increase VEGF messenger RNA expression. The anti-VEGF antibodies specifically inhibited VEGF-driven capillary endothelial cell proliferation in vitro., Conclusion: These data demonstrate that VEGF is required for iris neovascularization in an adult nonhuman primate eye. The inhibition of VEGF is a new potential therapeutic strategy for the treatment of ocular neovascularization.

The phenomenon of inhibition of tumor growth by tumor mass has been studied in many experimental animal systems and has been observed in several clinical scenarios. Not until the recent discovery of angiostatin, a circulating angiogenesis inhibitor generated in the presence of a murine Lewis lung tumor, has a satisfactory mechanism been proposed to explain this phenomenon. Thus far, no other animal or human tumors are known to generate angiostatin. In this study, we utilized a mouse corneal neovascularization model to detect circulating inhibitors of angiogenesis generated by three human tumors grown in immunodeficient mice: (a) the PC-3 human prostate carcinoma; (b) the CCL188 human colon carcinoma; and (c) the UBC urinary bladder carcinoma. Mice bearing these three primary tumors demonstrated significant inhibition of angiogenesis in the cornea induced by a pellet containing basic fibroblast growth factor. Corneas of mice bearing s.c. prostate and colon carcinomas showed significant inhibition of vessel length, clock-hours of neovascularization, and vessel density. However, corneas of mice bearing s.c. bladder carcinomas demonstrated significant inhibition of vessel density only. Three colon carcinomas (clone A, CX-1, and MIP101), the MDA-MB-435S breast carcinoma, the MM-AN melanoma, and the JE-3 choriocarcinoma did not significantly inhibit corneal neovascularization.

Patients with early age-related macular degeneration (AMD) may retain good visual acuity but experience distortion and other qualitative visual changes. The purpose of the present study was to determine whether deficits of form recognition, as well as of light sensitivity, were related to retinal pigment epithelial (RPE) atrophy and/or drusen. We assessed form recognition deficits by the Amsler grid and by a perimetric test of letter recognition and sensitivity deficits by the macular threshold test of the Humphrey Field Analyzer in 59 patients with AMD and visual acuities of 20/40 or better. The number of defects on each test was compared with the area of RPE atrophy and with the area of drusen determined from fundus photographs. Multiple regression analyses based on ordinal data revealed that the number of visual field defects by each test was significantly correlated with the area of atrophy, but not with the area of drusen. There was also no significant tendency for a patient with a regional preponderance of drusen to have more impairment in the corresponding visual field. These results suggest that deficits of form recognition, as well as of sensitivity, in patients with early stages of AMD can be attributed to alteration of photoreceptor function associated with RPE atrophy, but not with drusen.

Purpose: Refractive errors for phakic eyes of patients referred with age-related macular degeneration were reviewed to determine whether some range of refractive error might be a risk factor for the neovascular form., Methods: The authors compared refractive errors of 198 patients with unilateral neovascular disease with refractive errors of 129 patients with bilateral dry disease. These groups had comparable distributions with respect to age, sex, and visual acuity of their better eyes. Student's t tests and multiple linear regression analyses were performed to assess group differences in mean refractive error. Contingency table and multiple logistic regression analyses were performed to determine odds ratios for having the neovascular form based on a stratification of refractive error., Results: By comparing better eyes of the two groups, patients with the unilateral neovascular form had an average spherical equivalent that was 1.0 diopter (D) more hyperopic than that of patients with the bilateral dry form (P < 0.001). Patients with a refractive error of +0.75 D or greater were more likely to have the neovascular form compared with patients with other refractive errors (odds ratio, 2.40; 95% confidence interval, 1.53-3.78; P < 0.001). Similar relationships between the two groups of patients were found by comparing worse eyes., Conclusion: These findings suggest that hyperopia is a risk factor for choroidal neovascularization among patients referred with age-related macular degeneration.