Systemic complement inhibition with eculizumab for geographic atrophy in age-related macular degeneration: the COMPLETE study.

PURPOSE: To evaluate the effect of eculizumab, a systemic inhibitor of complement component (C5), on the growth of geographic atrophy (GA) in patients with age-related macular degeneration (AMD). DESIGN: Prospective, double-masked, randomized clinical trial. PARTICIPANTS: Patients with GA measuring from 1.25 to 18 mm(2) based on spectral-domain optical coherence tomography imaging. METHODS: Patients were randomized 2:1 to receive intravenous eculizumab or placebo over 6 months. In the eculizumab treatment arm, the first 10 patients received a low-dose regimen of 600 mg weekly for 4 weeks followed by 900 mg every 2 weeks until week 24, and the next 10 patients received a high-dose regimen of 900 mg weekly for 4 weeks followed by 1200 mg every 2 weeks until week 24. The placebo group was infused with saline. Patients were observed off treatment for an additional 26 weeks. Both normal-luminance and low-luminance visual acuities were measured throughout the study, and the low-luminance deficits were calculated as the difference between the letter scores. MAIN OUTCOME MEASURES: Change in area of GA at 26 weeks. RESULTS: Thirty eyes of 30 patients were enrolled. Eighteen fellow eyes also met inclusion criteria and were analyzed as a secondary endpoint. For the 30 study eyes, mean square root of GA area measurements ± standard deviation at baseline were 2.55 ± 0.94 and 2.02 ± 0.74 mm in the eculizumab and placebo groups, respectively (P = 0.13). At 26 weeks, GA enlarged by a mean of 0.19 ± 0.12 and 0.18 ± 0.15 mm in the eculizumab and placebo groups, respectively (P = 0.96). At 52 weeks of follow-up, GA enlarged by a mean of 0.37 ± 0.22 mm in the eculizumab-treated eyes and by a mean of 0.37 ± 0.21 mm in the placebo group (P = 0.93, 2 sample t test). None of the eyes converted to wet AMD. No drug-related adverse events were identified. CONCLUSIONS: Systemic complement inhibition with eculizumab was well tolerated through 6 months but did not decrease the growth rate of GA significantly. However, there was a statistically significant correlation between the low-luminance deficit at baseline and the progression of GA over 6 months.

Development and initial experience with a colored perfluorocarbon liquid for intraocular tamponade in vitreoretinal surgery.

PURPOSE: To present the development and initial experience of a novel colored perfluorocarbon liquid (PFCL) in vitreoretinal surgery. METHODS: This was an experimental laboratory study and prospective human interventional study. F6H8 (Fluoron GmbH) was colored by adding 0.3 g/L blue anthraquinone dye. Subsequently, 20% colored F6H8 was prepared by mixing with perfluorooctane or perfluorodecalin (Fluoron GmbH). The novel product is not yet FDA approved for human application. In the laboratory, the colored PFCL was covered with 1) uncolored PFCL, 2) BSS, and 3) silicone oil. Cell toxicity was evaluated in L929 mouse fibroblasts using a growth inhibition assay. Porcine ex vivo eyes were evaluated after vitrectomy followed by intravitreal and subretinal colored PFCL infusion. A pilot, prospective, noncomparative interventional study was conducted in patients with retinal detachment with proliferative vitreoretinopathy (PVR). RESULTS: The density of the colored PFLC mixture was 1.664 g/cm for perfluorooctane and 1.802 g/cm for perfluorodecalin. There was no relevant cell growth inhibition with any concentration of colored PFCL tested. Experiments in pigs revealed that infusion of the colored PFCL caused neither staining of the internal limiting membrane nor intravitreal residual droplets. In the prospective study, 9 eyes (75%) underwent surgery for rhegmatogenous retinal detachment with at least grade C PVR. The colored PFCL enabled retinal break examination and detection of residual intravitreal droplets in all surgeries. There was no case of separation or leakage of the dye from the PFCL solution that could have caused unwanted staining of the vitreous or epiretinal surface. CONCLUSION: The colored PFCL enabled intraoperative maneuvers such as endolaser use. In addition, removal of the colored PFCL was easily achieved at the end of surgery.

Review of real-world evidence of dual inhibition of VEGF-A and ANG-2 with faricimab in NAMD and DME.

Management of vitreoretinal disorders (e.g., neovascular age-related macular degeneration [nAMD] and diabetic macular edema [DME]) have assumed the standard therapy of lifelong anti-VEGF injections with drugs like aflibercept, brolucizumab, ranibizumab and bevacizumab. However, the burden imposed on patients is a major deterrent for continual therapy and recovery. Faricimab, a bispecific antibody, blocking both VEGF-A and Ang-2 molecules, produces a comparable functional and anatomical results, with less injections, significantly reducing patient burden. Visual acuity, safety, adverse effects, and anatomical outcomes are discussed in the pivotal clinical trials (YOSEMITE/RHINE and TENAYA/LUCERNE), and early data from real-world studies (TRUCKEE, TAHOE, FARWIDE-DME, FARETINA and others). In YOSEMITE and RHINE, faricimab demonstrated non-inferior vision gains, better anatomical outcomes compared to aflibercept every 8 weeks. Faricimab in the personalized treatment interval (PTI), after week 96, achieved 12-week interval in 78.1% of the patients and 16-week interval in 62.3%. TENAYA and LUCERNE reported comparable best corrected visual acuity (BCVA) improvement and better anatomic outcomes during head-to-head phase, parallel to aflibercept, at its 8-week treatment schedule. Faricimab in the PTI regimen, after week 96 achieved 12-week interval in 77.8% of the patients and 16-week interval in 63.1%. Safety of faricimab has been comparable to aflibercept in these pivotal trials. Real-world data supports the data from the pivotal studies regarding the efficacy and safety profile of faricimab in heterogenous real world patient population. Moreover, in previously treated patients, it also demonstrated a faster fluid resolution, good safety profile. Considering faricimab has demonstrated anatomic and durability benefit in the treatment of nAMD and DME, additional data from ongoing extension clinical trials, AVONELLE-X and RHONE-X will help understand longer term outcomes for patients treated with faricimab as well as patients switching from aflibercept to faricimab after finishing the pivotal trials. Longer term data from the real-world studies will also continue to contribute to our understanding of long-term efficacy, safety and durability in the real world patient population.

Investigation of the retinal biocompatibility of acid violet for chromovitrectomy.

PURPOSE: The primary objective was to investigate the retinal biocompatibility of acid violet (AV) as a vital dye for chromovitrectomy. The secondary objective was to evaluate the capacity of AV to stain the anterior capsule of the lens. METHODS: An amount of 0.05 ml of 0.25 g/l and 0.5 g/l AV was injected intravitreally in the OD, while balanced salt solution (BSS) was applied in the OS for control. Clinical examination and histology with light microscopy (LM) were performed after 7 days. Retinal cell layers were evaluated for morphologic alterations and number of cells. The electroretinographic (ERG) changes were assessed at baseline and 7 days. In another part of the study, 0.1 ml of 0.25 g/l AV was injected into the anterior chamber of ex-vivo porcine eyes, and its capacity to stain the anterior capsule was determined. Cadaveric eyes were used to test the capacity of AV to stain the internal limitant membrane (ILM) during vitrectomy. RESULTS: The gross histopathologic appearance of the retina, choroids, sclera, and optic nerve was within normal limits, without any signs of severe retinal necrosis or cystic degeneration. AV caused no substantial retinal alterations in retinal layers by LM at either the lower or higher dose when compared with the control eye. The injection of AV did not induce considerable ERG alterations. The violet dye stained the anterior capsule after anterior chamber injection and the ILM, allowing a safer capsulorrhexis and vitrectomy. CONCLUSION: Acid violet may be safe for the retina at concentrations of 0.25 and 0.50 g/l after intravitreous injection, and may be used as a vital dye for staining the anterior capsule and the ILM.

Quantitative changes in retinal pigment epithelial detachments as a predictor for retreatment with anti-VEGF therapy.

PURPOSE: To determine if quantitative changes in retinal pigment epithelial detachments (PEDs) predict the need for retreatment in eyes undergoing spectral domain optical coherence tomography (SD OCT)-guided as-needed therapy with anti-vascular endothelial growth factor drugs. METHODS: Patients with vascularized PEDs undergoing SD OCT-guided treatment with anti-vascular endothelial growth factor drugs were retrospectively identified. The decision to retreat these cases was based on qualitative assessments of fluid in the macula. Spectral domain OCT images from visits in which the treatment was withheld were retrospectively analyzed. A novel algorithm was then used to measure the area and volume of PEDs at these visits. RESULTS: Fourteen eyes were identified, and retreatment was withheld at 57 visits. When the SD OCT algorithm was used to evaluate the scans from these visits, the PED volume increased at eight visits. At all of these eight visits, a treatment was needed at the next follow-up visit. For the remaining 49 visits in which the treatment was withheld, the PED volume did not increase and no treatment was needed at the next follow-up visit. CONCLUSION: Quantitation of the change in the PED volume and area may be useful in determining when to retreat eyes undergoing SD OCT-guided as-needed anti-vascular endothelial growth factor therapy.

Effect of vital dyes on retinal pigmented epithelial cell viability and apoptosis: implications for chromovitrectomy.

PURPOSE: To investigate the in vitro effect of vital dyes on toxicity and apoptosis in a human retinal pigment epithelial cell line. METHODS: ARPE-19 cells were exposed to brilliant blue (BBG), Evans Blue (EB), bromophenol blue (BroB), indocyanine green (ICG), infracyanine green (IfCG), light green (LG), fast green (FG), indigo carmine (IC) and Congo red (CR). Balanced salt solution was used as the control. Five different concentrations and 2 exposure times were tested. Cell viability was determined by the MTS (1-solution methyl thiazolyl tetrazolium) assay and apoptosis by Bax expression on Western blot. RESULTS: All dyes significantly reduced cell viability after 3 min of exposure at all concentrations (p < 0.01), except for BBG that was safe at concentrations up to 0.25 mg/ml and CR up to 0.05 mg/ml, while LG was safe at all concentrations. Toxicity was higher after 30 min of exposure. Expression of Bax was upregulated after all dye exposures, except BBG; ICG had the highest Bax expression (p < 0.01). CONCLUSIONS: Overall the safest dye was BBG followed by LG, IfCG, FG, CR, IC, BroB, EB and ICG. ICG was toxic at all concentrations and exposure times tested. Moreover, BBG was the only dye that did not induce apoptosis in ARPE-19 cells.

Staining properties of brilliant blue depending on different incubation times and solvents in humans.

PURPOSE: Intravitreous injection of vital dyes, e.g. brilliant blue (BBG), promotes better visualization of the internal limiting membrane (ILM). This paper investigates the staining properties of BBG depending on different incubation times and 2 types of solvents--5% glucose (GL) or saline solution--in a prospective study in patients. METHODS: This paper investigates various aspects of BBG in various methods. An interventional prospective study was conducted in patients to examine the binding properties of the blue dye diluted in either saline or 5% GL to epiretinal membranes (ERMs) and ILMs. Forty-nine consecutive patients older than 18 years scheduled for macular ERM, vitreomacular traction and macular hole surgeries were prospectively recruited. The primary outcomes of this study were the degree of ILM and ERM staining. The secondary outcomes of the study were the need of reinjection of BBG or any other dye, the ability of BBG to stain the vitreous, and frequency of complications. The staining of the ILM and ERM were graded as no staining, little, moderate or strong staining. RESULTS: There was no correlation between age (p = 0.32) or gender (p = 0.33) in the staining affinity of BBG to either the ILM or ERM. BBG may be an appropriate staining agent for the ILM in the majority (82%) of surgeries; however, in approximately half of the cases (45%) surgeons considered BBG not enough for ERM coloring and visualization. There is a tendency of BBG to stain the ILM better when saline solution is used compared to GL 5%; however, this was not statistically significant (p = 0.64). There was no difference in the staining efficacy of BBG to the ERMs by either solution (p = 0.70), despite the low staining affinity. CONCLUSION: BBG became the state-of-the-art dye for ILM identification. Differences in staining properties may imply that BBG should not be considered as first-line stain for ERM surgery. BBG is effective in ILM staining in over 80% of macular hole surgeries.

Biochemical analysis and decomposition products of indocyanine green in relation to solvents, dye concentrations and laser exposure.

PURPOSE: To investigate pH, ions, osmolarity and precipitation of indocyanine green (ICG), as well as the profile of ICG decomposition products (DPs) after laser exposure and the interaction with quenchers. METHODS: ICG was diluted in water, 5% glucose (GL) or balanced salt solution (BSS) to achieve concentrations of 2.5, 1, 0.25 and 0.1 mg/ml. Osmolarity, pH and precipitation were analyzed immediately and after 24 h. Precipitation analyses were done with a scanning electron microscope. Anion and iodate analyses of ICG and infracyanine green (IfCG) were performed by capillary zone electrophoresis. With regard to DPs, 0.5 mg/ml of ICG was assessed with high-performance liquid chromatography (HPLC) after 810-nm laser irradiation. DP profiles were evaluated with ICG dilution in quenchers (Trolox, histidine and DABCO) in 3 concentrations (0.1, 1 and 10 M). RESULTS: BSS promoted iso-osmotic ICG solutions of 208 mOsm (147-266) compared to GL with 177 mOsm. BSS solutions had a higher physiological pH of 7.2 compared with the GL one of 6.55. ICG precipitated more when diluted with BSS (5.95 mg); in contrast, GL showed less precipitate (3.6 mg). IfCG has no iodine derivates and other ICGs have an average 4.6% of iodate derivates. From HPLC analysis, 5 DPs were observed. The rate of DPs was higher when BSS was used (p < 0.05). Five DPs have been generated with ICG, and they may be altered with the quenchers DABCO, histidine and Trolox. CONCLUSIONS: BSS dilution induces more precipitation and DPs. ICG dilution in any solvent induces DPs. Quencher use reduces the amount of toxic DPs.

Pharmacokinetic rationale for dosing every 2 weeks versus 4 weeks with intravitreal ranibizumab, bevacizumab, and aflibercept (vascular endothelial growth factor Trap-eye).

PURPOSE: Monthly dosing with inhibitors of vascular endothelial growth factor (VEGF) results in stable or improved visual acuity in most patients with neovascular age-related macular degeneration. However, a minority of patients show little if any response to therapy with persistent or worsening macular fluid. Pharmacokinetic modeling was performed to determine if more frequent dosing with anti-VEGF drugs could be theoretically beneficial. METHODS: A mathematical model comparing the time-dependent relative binding activities of ranibizumab, bevacizumab, and aflibercept (VEGF Trap-eye; VTE) was used to determine the theoretical peak and trough binding activities when the drugs were injected every 14 days and every 28 days. The intravitreal half-lives of ranibizumab, bevacizumab, and the VTE were estimated to be 3.2, 5.6, and 4.8 days, respectively. The relative molar binding activities of ranibizumab, bevacizumab, and the VTE used in the analyses were 1, 0.05 to 0.2, and 140, respectively. The expected peak and trough binding activities for ranibizumab, bevacizumab, and VTE were calculated. Dosing every 2 weeks was performed on selected patients who had a poor response to monthly therapy. RESULTS: Dosing of a drug every 2 weeks resulted in markedly improved trough binding activity, but had little impact on the peak binding activity when calculated through Day 28. The dosing of bevacizumab every 2 weeks resulted in trough binding levels that were superior to monthly dosing with ranibizumab at a dose of 0.5 mg and potentially superior to the levels achieved when ranibizumab was dosed monthly at a dose of 2.0 mg. The VTE displayed superior binding levels for both peak and trough levels even when compared with ranibizumab doses given every 2 weeks. Two case reports demonstrate the clinical usefulness of dosing with anti-VEGF therapy every 2 weeks in eyes with VEGF-dependent macular fluid appearing to be refractory to monthly dosing. CONCLUSION: The theoretical increase in trough binding levels when anti-VEGF drugs are dosed every 2 weeks most likely explains the clinical benefit observed in patients who received biweekly injections after their poor response to monthly therapy. The short-term use of biweekly dosing may be an attractive treatment option for those eyes that show a treatment response within 2 weeks of an injection, but rebound with increased macular fluid after a month. In the future, VTE should provide higher trough levels of anti-VEGF binding activity and eliminate the need for biweekly dosing in those eyes with VEGF-mediated exudation that appear unresponsive to monthly ranibizumab or bevacizumab.

Toxicity and retinal penetration of infliximab in primates.

PURPOSE: To evaluate the retinal penetration and toxicity of two doses of intravitreal infliximab in primates. METHODS: Ten marmosets (Callithrix jacchus) were given intravitreal injection of 100 µg or 400 µg of infliximab, and balanced salt solution served as control. At baseline and after 24 hours (5 animals) and 7 days (the other 5), the eyes were examined by electroretinography. They were then killed (at 24 hours and 7 days) and assessed by light microscopy and transmission electron microscopy for toxicity and immunohistochemistry, using a biotinylated anti-human immunoglobulin G, to evaluate retinal penetration. RESULTS: There was no difference over 50% of the electroretinography b-wave between baseline and the time points studied in all animals. Light and electron microscopy, and electroretinography analysis, showed no signs of toxicity in any of the animals. Strong presence of infliximab was observed in all retinal layers 7 days after intravitreal injection at both doses (100 and 400 µg). CONCLUSION: Infliximab at doses of 100 and 400 µg seemed to cause no damage to the retina 24 hours and 7 days after its intravitreal injection, and deeply penetrated all its layers, in primates. These results encourage future perspectives for the treatment of chronic inflammatory diseases of the retina in humans.

Retinal vascular occlusion in patients with the Covid-19 virus.

BACKGROUND: The coronavirus disease (COVID-19) can cause acute respiratory distress syndrome with dyspnea, anosmia, fever, and cough. Few studies describing ocular findings have been reported. The current case series, reports the clinical findings and natural history of patients with retinal vascular occlusion after COVID-19 infection. CASE PRESENTATIONS: Patients from multiple Brazilian hospitals who had clinical and laboratory diagnoses of COVID-19 with retinal vein or arterial occlusion were analyzed retrospectively. The baseline demographics, clinical presentations of COVID-19, comorbidities, risk factors for thromboembolic events, and use of anticoagulant drugs were reviewed. The relevant clinical findings associated with the retinal vascular occlusive event, management, and outcomes were reported. Fourteen cases of retinal vascular occlusion within 3 months of the laboratory confirmed COVID-19 infection were identified. Three of which required hospitalization for COVID-19 management. Eight cases had central retinal vein occlusion, three branch retinal vein occlusion, one hemispheric retinal vein occlusion, and two central arterial occlusion. The mean patient age at presentation was 48 years; the visual acuity ranged from light perception to 20/20. Nine patients received intravitreal injections of anti-angiogenic drugs and one received ketorolac tromethamine drops for the management of secondary macular edema; four were untreated. CONCLUSIONS: COVID-19 patients may rarely have ocular manifestations of the disease. It was presented a case series of vascular occlusion events that may be related to COVID-19 infection, since these thrombotic events are actively involved in the disease pathophysiology. These cases emphasize the need for further investigation of ocular complications associated with this disease.

Natural history of drusen morphology in age-related macular degeneration using spectral domain optical coherence tomography.

PURPOSE: To characterize the natural history of drusen using spectral-domain optical coherence tomography (SD-OCT) imaging of eyes from patients with nonexudative age-related macular degeneration (AMD). DESIGN: Prospective, longitudinal, natural history study. PARTICIPANTS: We included 143 eyes of 100 patients with at least 6 months of follow-up. METHODS: Patients with drusen secondary to nonexudative AMD were scanned using the Cirrus SD-OCT instrument. Eyes were imaged using the 200 × 200 A-scan raster pattern contained within a 6 × 6 mm area. Custom software was used to quantify volumetric changes in drusen over a period of ≥ 6 months and for as long as 24 months. Drusen volume and drusen area were measured within circular regions centered at the fovea having diameters of 3 and 5 mm. The measurements were analyzed using a suitable scale transformation. For drusen volume, a cube root transformation strategy was used. MAIN OUTCOME MEASURES: Change in drusen volume and area over time. RESULTS: We analyzed 143 eyes of 100 patients with 69 eyes followed for 6 months, 106 eyes followed for 12 months, 48 eyes followed for 18 months, and 48 eyes followed for 24 months. The 3 mm circle baseline drusen volume ranged from 0.0009 to 0.7479 mm(3) or 0.10 to 0.91 mm using the cube root scale. On average, drusen volume and drusen area increased over time with the magnitude of the increase dependent on the length of follow-up (P = 0.001, 3 mm circle). In the eyes with a decrease in drusen volume, the magnitude of this decrease was dependent on the baseline drusen volume (P = 0.001, 3 mm circle) and independent of the follow-up interval. After 12 months, drusen volume increased in 48% of eyes, remained stable in 40%, and decreased in 12%. CONCLUSIONS: Imaging with SD-OCT revealed a dynamic, undulating growth pattern for drusen with a tendency for drusen to increase in volume and area over time. An appreciation of the quantitative changes in drusen volume over time using SD-OCT imaging provides a novel strategy for following normal disease progression and for identifying novel clinical trial end points to be used when investigating therapies for the treatment of nonexudative AMD. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Therapeutic monoclonal antibodies in ophthalmology.

Monoclonal antibodies (mAbs) can be used therapeutically by binding to molecular targets with high specificity. Therefore, they have excellent therapeutic applications in ophthalmology. This manuscript presents four aspects of the therapeutic use of mAbs in ophthalmology: the scientific rationale, the unique characteristics of selected mAbs, the current state-of-the-art application, and relevant therapeutic mAbs for future applications in ophthalmology. We identified in the literature various single-agent therapies that inhibit the following targets: tumor necrosis factor (TNF), epithelial growth factor receptor, vascular endothelial growth factor (VEGF) receptor, basic fibroblast growth factor receptor, platelet-derived growth factor, and cluster of differentiation antigens. The roles of all biochemical targets in ocular diseases were evaluated. Current and future mAbs against various cytokines were assessed for the treatment of ocular diseases. The medical literature showed the clinical benefits of mAbs for treating angiogenic and inflammatory ocular diseases. Two anti-VEGF mAbs, bevacizumab and ranibizumab, and three anti-TNF agents, infliximab, etanercept, and adalimumab, control ocular neovascularization and intraocular inflammation. Other mAbs such as rituximab, daclizumab, efalizumab, and alemtuzumab showed positive results in animal and early clinical studies and may represent useful adjuvant therapies for ocular lymphoma or ocular inflammation. Ranibizumab is the only FDA-approved therapy; for other mAbs the so-called off-label application remains the standard. Intravenous administration of mAbs has demonstrated acceptable toxicity profiles, while intraocular injection may decrease the chances of systemic complications and increase the amount of drug available to the retina and choroid. In conclusion, effective clinical use of mAbs in ophthalmology is more commonly seen in the field of angiogenic vitreoretinal and autoimmune inflammatory diseases. The challenge for the future is combining biologic therapies to improve the quality and duration of responses while diminishing side effects. The role of mAbs within ophthalmic treatments will be defined according to future clinical experience and the results of randomized clinical trials.

Subretinal bevacizumab detection after intravitreous injection in rabbits.

PURPOSE: To evaluate subretinal detection of bevacizumab 2 hours after intravitreous injection of 1.25 mg in rabbit eyes. METHODS: Anterior chamber paracentesis using a 30-gauge needle was performed in nine female Dutch-belted rabbits by removal of 0.05 mL of aqueous humor. Transscleral retinal detachment was performed with a modified 25-gauge infusion cannula connected to a bottle of physiologic saline solution (PSS). The animals were divided into experimental group 1, with intravitreous injection of 0.05 mL of (1.25 mg) with a 30-gauge needle (n = 6) and the control group 2, with intravitreous injection of 0.05 mL of PSS with a 30-gauge needle (n = 3). Two hours after the intravitreous bevacizumab or PSS injection, subretinal fluid was aspirated and immunoassayed to measure the level of bevacizumab. The rabbits were killed by intravenous pentobarbital injection. The eyes were enucleated and fixed in 10% formaldehyde. The pars plana site at which the transscleral cannula was introduced was analyzed by light microscopy, to exclude iatrogenic retinal tears. Eyes with accidental retinal tears were excluded. RESULTS: Subretinal bevacizumab molecules were detected in the six eyes that received an intravitreous bevacizumab injection. No subretinal bevacizumab was detected in the control eyes. Light microscopy showed no evidence of retinal tears or holes in any rabbits used for the bevacizumab detection and control group. CONCLUSIONS: Bevacizumab molecules were detected in the subretinal space after intravitreous injection of 1.25 mg of bevacizumab, possibly as the result of diffusion through the retina in a rabbit model.

Historical aspects and evolution of the application of vital dyes in vitreoretinal surgery and chromovitrectomy.

Lobeck and coworkers performed the first intravitreal application of vital dyes to visualize preretinal structures in 1932. Since then numerous investigators in the 20th century examined the use of biological stains through the endovenous, subretinal and intravitreal delivery route in order to identify vitreoretinal tissues and breaks. However, in the year 2000, a new surgical approach, recently coined chromovitrectomy, has arisen, which consists in the intraoperative application of vital dyes during vitrectomy. Initially fluorescein, and more recently indocyanine green, trypan blue, bromophenol blue, triamcinolone acetonide and patent blue have been used for the staining of preretinal membranes and tissues. Currently, many vital stains are under evaluation in animals for future clinical application during chromovitrectomy such as indigo carmine or light green. In this paper, several historical considerations in regard to the application of vital dyes in chromovitrectomy are discussed.

Current concepts of trypan blue in chromovitrectomy.

Trypan blue (TB) is a blue vital dye with fine color properties to stain the anterior lens capsule and thereby may facilitate capsulorrhexis during cataract surgery. In addition, the blue stain may assist in the visualization of various preretinal membranes and tissues during vitreoretinal surgery in a procedure also called chromovitrectomy. TB has demonstrated great binding affinity for the glial epiretinal membranes, although it remains yet to be determined in which circumstances the dye may color the vitreous and internal limiting membrane. Most studies suggest that 0.06% TB does not pose harm to the retina, but at higher concentrations further investigation is necessary. In this paper, various aspects of the application of TB for chromovitrectomy are discussed including laboratory investigations, surgical technique and clinical outcomes.

Morphologic and clinical effects of subretinal injection of indocyanine green and infracyanine green in rabbits.

PURPOSE: The aim of this study was to determine the effects of subretinal injection of indocyanine green (ICG), infracyanine (IfCG), and balanced salt solution (BSS) in rabbits. METHODS: Ten (10) animals were subjected to a subretinal injection of 0.05% ICG (279 mOsm), 0.5% IfCG (276 mOsm), and BSS (300 mOsm) used as a control. Animals were examined at 6, 12, and 24 h and 14 days following the surgical procedure by indirect binocular ophthalmoscopy, fluorescein angiography (FA), and light and transmission electron microscopy. RESULTS: The subretinal injection of ICG caused damage to all retinal layers and retinal pigment epithelium (RPE) during the entire follow-up. Subretinal injection of IfCG resulted in abnormalities of the photoreceptor outer segments (POSs) during the entire follow-up; however, abnormalities of the photoreceptor inner segments (PISs) and outer nuclear layer (ONL) were observed only 24 h and 14 days after surgery; no RPE damage was observed. FA showed that window defects were more prominent in the subretinal ICG bleb position than the IfCG-related area. BSS caused only abnormalities of the POS layer and no RPE alterations. CONCLUSIONS: Subretinal injection of 0.05% ICG results in more significant retinal damage than 0.5% IfCG. In this model, iodine-free IfCG demonstrates a safer profile than a tenfold lower concentration of ICG, which contains iodine in its composition.

Effects of subretinal injections of indocyanine green, trypan blue, and glucose in rabbit eyes.

PURPOSE: To evaluate the effects of subretinal injections of indocyanine green (ICG), trypan blue, glucose (GL), and balanced salt solution (BSS) in rabbits. DESIGN: Experimental study. PARTICIPANTS: Twenty Dutch-belted rabbits. METHODS: Ten animals underwent vitrectomy and subretinal injection of 0.02 ml of either 0.05% ICG (279 milliosmoles [mOsm]), 0.15% trypan blue (312 mOsm), 5% GL (280 mOsm), or BSS (300 mOsm), which was tested as a control. Ten additional animals underwent subretinal injection of 0.02 ml of 0.046% ICG (251 mOsm), 0.13% trypan blue (260 mOsm), 4.6% GL (253 mOsm), or BSS (300 mOsm). Animals were examined 6, 12, and 24 hours and 14 days after the procedure by fluorescein angiography and fundus evaluation; histologic studies were performed by light and transmission electron microscopy. MAIN OUTCOME MEASURES: Clinical outcome, fluorescein angiography, and histopathologic results. RESULTS: All subretinal blebs were flat 24 hours after the procedure. Fluorescein angiography showed window defects where ICG and trypan blue had been injected. Subretinal BSS and GL resulted in minimal abnormalities of the photoreceptor outer segments (POS) during follow-up. Hypo-osmolar GL caused edema in all retinal layers; pyknosis of the outer nuclear layer (ONL) was observed 24 hours after injection. Subretinal injection of trypan blue resulted in histologic abnormalities 24 hours and 14 days after surgery. Hypo-osmolar trypan blue caused edema of the POS and the photoreceptor inner segments and pyknosis of the ONL 6 and 12 hours after surgery; the retinal pigment epithelium also was affected 24 hours and 14 days after surgery. Subretinal injection of iso-osmolar and hypo-osmolar ICG caused severe damage of all retinal layers during the entire follow-up. CONCLUSIONS: Subretinal injection of 0.05% ICG results in more substantial retinal damage than that associated with the 0.15% trypan blue subretinal injection. The damage induced by hypo-osmolar solutions was more important than that caused by the iso-osmolar solutions. These findings emphasize that care must be taken regarding the solution osmolarity and that subretinal migration of these substances should be avoided during macular hole surgery.

Emerging pharmacotherapies for diabetic macular edema.

Diabetic macular edema (DME) is the most frequent cause of severe vision impairment in patients with non-proliferative diabetic retinopathy. Even though patients should achieve optimal glycemic control, normalization of blood pressure and serum lipids, as well as improvement of cardiac and renal status, these measures alone will not prevent every patient from developing visual loss caused by DME. The goal of local treatment for DME is vision improvement, usually achieved after reducing leakage on fluorescein angiography (FA) and retinal thickness on optical coherence tomography (OCT). Laser photocoagulation is still the standard treatment for clinically significant DME. However, laser photocoagulation rarely provides major visual improvement, especially in patients with diffuse DME. Thus, a therapeutic intervention that restores visual acuity impaired by DME more often remains a significant unmet medical need. This review aims to present the most important emerging drug technologies for therapy of DME at present, including corticosteroids, vascular endothelial growth factor inhibitors, protein kinase C inhibitors, small interfering RNA, hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitors and non-hormonal anti-inflammatory agents. Recent progress in this field suggests that local management of DME may change rapidly in the near future. Novel emerging drugs should enable better anatomical and functional outcomes for therapy of this sight-threatening disease.

Severe retinal thermal injury after indocyanine green-mediated photothrombosis for central serous chorioretinopathy.

PURPOSE: To report severe retinal thermal damage after indocyanine green-mediated photothrombosis (IMP) for chronic central serous chorioretinopathy (CSC). DESIGN: Interventional case report. METHODS: A 31-year-old white male underwent IMP for chronic CSC. RESULTS: During the procedure, retinal whitening was observed in the area of the treatment spot. Fluorescein angiography revealed staining of the retinal arteries in the treated area. One year later, macular retinal pigment epithelial (RPE) changes were seen, accompanied by severe loss of vision. CONCLUSIONS: IMP has been described as a relatively safe treatment option for persistent CSC. However, we herein report a case in which severe retinal damage occurred as a consequence of the treatment. We thus alert clinicians of this potential adverse event.