Eduardo B. Rodrigues

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.

The Use of Vital Dyes in Ocular Surgery

Vital dyes have advanced diagnosis and surgical technique in various specialties, including oncology, gastroenterology, and ophthalmology. In ocular surgery vital dyes are widely used in cataract and vitreoretinal surgery. Worldwide, intra-operative use of trypan blue during cataract surgery has enhanced visualization of the anterior capsule during capsulorrhexis, and patent blue has been recently licensed in Europe for cataract surgery. For chromovitrectomy, the vital dyes indocyanine green, infracyanine green, and brilliant blue stain the internal limiting membrane, and trypan blue and triamcinolone acetonide help visualize epiretinal membranes and vitreous, respectively. Intra-operative vital dyes are finding uses in corneal, glaucoma, orbit, strabismus, and conjunctival surgery. We provide a summary of current knowledge of the use of vital dyes in ocular surgery. We review the properties of dyes, techniques of application, indications, and complications in ocular surgery. Vital dyes represent an expanding area of research, and novel dyes deserve further investigation.

Chromovitrectomy: a new field in vitreoretinal surgery

Staining tissues during vitreo-retinal surgery, “chromovitrectomy”, has become a popular approach to visualize preretinal structures. Initially, Burk et al. described in 2000 the intravitreal administration of indocyanine green (ICG) to stain the internal limiting membrane (ILM) [3]. There is general agreement that ICG-assisted ILM peeling is then much facilitated, as the surgeon can easily observe the edge of the ILM rhexis thus ensuring a complete ILM removal. Consequently, trypan blue (TB) arose as the second-generation of vital dyes for chromovitrectomy [24]. Currently, triamcinolone acetonide (TA) has been added as an alternative stain for chromovitrectomy [21]. The rationale for chromovitrectomy is simple, as most preretinal structures have a semitransparent appearance. Over 90 controversial reports have been published on chromovitrectomy in the last 4 years [18]. ICG, TB, and TA are currently used for chromovitrectomy based on their familiarity for other ophthalmic applications. While ICG has been approved for intravenous application in retinal and choroidal angiography, TB has been applied for the staining of the anterior capsule during cataract surgery. Intravitreal TA injection can be applied in the treatment of several types of macular edema. Although TB and ICG demonstrated no adverse effects under those previous ophthalmic applications, their intravitreal use may pose the risk of posterior-segment toxicity. In fact, critical reassessment replaced initial excitement among vitreoretinal surgeons as the group in Munich, Germany, described worse functional outcomes after ICGassisted ILM peeling in macular hole (MH) surgery [10]. ICG staining was postulated to lead to a deeper cleavage plane in ILM dissection since their histologic analysis demonstrated Muller cell membranes adherent on the retinal ILM. Another concern on ICG-use refers to a possible higher incidence of retinal pigment epithelium (RPE) defects [18]. Although Gandorfer et al. showed severe histologic damage to the inner retina after ICG plus light exposure to wavelengths beyond 620 nm in human donor eyes [6], Grisanti et al. obtained opposite results using fresh enucleated pig eyes [9]. Further in-vivo experiments with different animal models such as rats [11], rabbits [14], and pigs [4] revealed a dose-dependent dye toxicity to various retinal cells after ICG application alone or plus light-pipe illumination. Possible toxic effects to the retinal tissue with TB have also been described in animal studies, especially in concentrations above 0.2% [24]. In addition, intravitreal TA injection may cause pseudo or infectious Presented at the Vail Vitrectomy meeting, Colorado, USA, 2004.

Inflammation in Dry Age-Related Macular Degeneration

Purpose: To summarize the current information regarding the role of immune and inflammatory response in the pathogenesis of dry age-related macular degeneration (ARMD). Methods: A Pubmed search was conducted of the period January 1999 to 2005. Relevant information in the literature on the role of inflammation in early dry ARMD was reviewed. Results: Some important evidence for inflammation in early ARMD consists in the isolation of immunoglobulins, complement proteins, cytokines and activated microglia, in retinal pigment epithelium (RPE) cells and drusen. Pivotal mechanisms in early ARMD include the accumulation of debris and proteins along the RPE surface, followed by immune-complex deposition and complement activation. In contrast, the role of other plasma enzymes such as kallikrein-kinin-bradykinin, the Hageman factor, peptides and coagulation proteins in drusen formation and ARMD has yet to be determined. Conclusion: A clear role for inflammatory mediators and cells has been established in recent years. Future studies should elucidate further mechanisms in ARMD development.

Vital dyes for chromovitrectomy.

Purpose of review The aim of this article is to present the current state-of-the-art in regard to the application of vital dyes during vitreoretinal surgery, ‘chromovitrectomy’, as well as to overview the current literature regarding the properties of dyes, techniques of application, indications, and complications in chromovitrectomy. Recent findings A large body of published research has recently addressed the toxicity profile of indocyanine green for chromovitrectomy. Experimental data demonstrate dose-dependent toxicity of indocyanine green to various retinal cells. Newer generation vital dyes for chromovitrectomy include trypan blue, patent blue, triamcinolone acetonide, infracyanine green, sodium fluorescein, bromophenol blue, fluorometholone acetate and brilliant blue. Novel instruments may enable a selective painting of preretinal tissues during chromovitrectomy. Summary This review suggests that the field of chromovitrectomy represents an expanding area of research. The first line agents for internal limiting membrane staining in chromovitrectomy are indocyanine green, infracyanine green, and brilliant blue. Patent blue, bromophenol blue and trypan blue arose as outstanding biostains for visualization of epiretinal membranes. Novel dyes available for chromovitrectomy deserve further investigation.

Effect of Needle Type and Injection Technique on Pain Level and Vitreal Reflux in Intravitreal Injection

PURPOSE To evaluate the amount of reflux and degree of pain with intravitreal injection (IVT) using 6 different types of syringes/needles and 5 techniques of scleral incision, including 3 modifications of a beveled scleral incision. METHODS This was a study conducted in 205 eyes of 205 patients. IVT of bevacizumab for retinal pharmacotherapy with 6 types of needles and 5 techniques of scleral incision. The severity of subjectively evaluated pain (0-10) and the width of the subconjunctival bleb arising from the vitreal reflux. Secondary outcomes were increase in intraocular pressure and complication rate. RESULTS The straight technique caused greater vitreal reflux than the beveled approaches, when compared individually or as a group (P < 0.01). No difference in the severity of pain was found among all 5 types of incisions (P > 0.05). There was greater reflux with 26- and 27-gauge needles in comparison to 29- and 30-gauge needles (P < 0.001); however, the width of the needle significantly affected the degree of reflux only when using the nonbeveled incision (P < 0.001). The patients injected with the 26- or 27-gauge needle experienced more pain matched to the 29- and 30-gauge needles (P < 0.001). No difference was found between the incision technique or width of subconjunctival reflux and the increase in intraocular pressure (P > 0.05). Postinjection events included transient mild uveitis, disease-related vitreous hemorrhage, foreign body sensation, conjunctival hemorrhage, and mild punctuate keratitis. CONCLUSIONS The beveled scleral incision showed benefit in performing IVTs. The 29- and 30-gauge needles caused less pain.

Mechanisms of intravitreal toxicity of indocyanine green dye: implications for chromovitrectomy.

Purpose: Indocyanine green (ICG) dye was shown to improve the visualization of preretinal tissues during chromovitrectomy. However, controversy arose regarding the safety of intravitreal ICG application, because worse functional outcomes and a higher incidence of retinal pigment epithelium (RPE) changes and visual field defects were reported. The mechanisms of ICG-related toxicity and their relevance for chromovitrectomy are reviewed. Methods: A literature search was performed from 1998 through 2005 for relevant information related to the mechanisms of intravitreal ICG toxicity. Animal and clinical data on intravitreal ICG-related toxicity were collected to clarify the mechanisms of the risk of intravitreal ICG injection. Results: Over 80 controversial in vitro, ex vivo, and in vivo animal investigations as well as clinical reports on intravitreal ICG staining were found in the literature. The main postulated mechanisms of intravitreal ICG-related toxicity were as follows: biochemical direct injury to the ganglion cells/neuroretinal cells, RPE cells, and superficial retinal vessels; apoptosis and gene expression alterations to either RPE cells or neuroretinal cells; osmolarity effect of ICG solution on the vitreoretinal interface; light-induced injury; and mechanical cleavage effect to the internal limiting membrane/inner retina. Whereas the exact mechanism of intravitreal ICG-related damage remains yet to be determined, most animal experiments proposed that ICG dye has a dose-dependent toxic effect on retinal tissue. This hypothesis was supported by clinical data, because better functional outcomes were obtained when low dye concentrations and short incubation times were reported. Conclusions: Much evidence supports that ICG dye has a dose-dependent toxic effect on the retina. Therefore, the following recommendations to minimize toxic effects on the retina are proposed: dye injection in concentrations as low as possible; avoidance of repeated ICG injections onto bare retina; dye injection far from the macular hole to prevent direct dye contact with the RPE; short incubation time of ICG in the vitreous cavity to diminish the concentration in contact with the retinal tissue; and the light pipe kept far from the retina throughout the whole surgical procedure.

Spontaneous separation of epiretinal membrane in young subjects: personal observations and review of the literature

BackgroundIdiopathic epiretinal membranes (ERM) grow on the surface of the internal limiting membrane (ILM) and are a very uncommon condition in young subjects.MethodsWe report six young subjects with ERM and describe the spontaneous separation of the membranes. The functional and anatomical recovery was assessed by Snellen visual acuity, Amsler grid and funduscopy. Selected cases were additionally assessed by optical coherence tomography (OCT).ResultsAll subjects initially claimed a sudden, unilateral, reduction in visual acuity (VA) with severe distortion at the age of 15–30 years. No ocular trauma or disease was ascertained in any case. Initial fundus examination demonstrated a gray–whitish ERM with translucent stress lines over the macula. Visual recovery occurred in all cases after resolution of the ERM. Sequential OCT demonstrated the successive peeling of an ERM accompanied by normalization of foveal thickness.ConclusionsYoung subjects should be counseled about the favorable prognosis for maintaining good vision and possible spontaneous membrane separation. Conservative observation is advocated if the visual disturbance is located temporally, as functional recovery and spontaneous membrane separation may occur. When the contracting forces of the immature ERM are stronger than its adhesions to the retina, the membrane may separate spontaneously.

Incidence of rhegmatogenous retinal detachments after intravitreal antivascular endothelial factor injections

Acta Ophthalmol. 2011: 89: 70–75

Ability of New Vital Dyes to Stain Intraocular Membranes and Tissues in Ocular Surgery

PURPOSE To evaluate the ability of novel dyes to stain lens capsule (LC), internal limiting membrane (ILM), epiretinal membrane (ERM), and vitreous. DESIGN Experimental study in animal and human donor eyes. METHODS Thirteen dyes, methyl violet, crystal violet, eosin Y, sudan black B, methylene blue, toluidine blue, light green, indigo carmine, fast green, congo red, evans blue, brilliant blue, and bromophenol blue, were injected onto the LC and ILM of enucleated porcine eyes. The vitreous was stained with 2 mL of dyes for 1 minute. Six dyes (indigo carmine, evans blue, fast green, light green, bromophenol blue, and brilliant blue) were selected for experiments in human donor eyes and freshly removed ERM. RESULTS In the porcine eyes, ILM staining with methylene blue, toluidine blue, indigo carmine, evans blue, bromophenol blue, and fast green was moderate, and methyl violet, crystal violet, brilliant blue, or sudan black resulted in strong staining. Methyl violet, crystal violet, sudan black, toluidine blue, and methylene blue caused histologic damage in porcine retinas. Vitreous examination revealed moderate staining with congo red, crystal violet, fast green, eosin Y, methylene blue, toluidine blue, brilliant blue, bromophenol blue, and methyl violet and strong staining with light green and evans blue. ERMs showed strong staining with 0.5% evans blue and moderate staining with 0.5% light green, fast green, brilliant blue, and bromophenol blue. Evaluation of donor eyes disclosed moderate staining with evans blue, light green, and bromophenol blue and strong staining with 0.5% brilliant blue. Moderate or strong staining of the vitreous occurred with most dyes. LC evaluation showed moderate staining with 0.5% evans blue, fast green, and brilliant blue, whereas 0.5% light green produced strong LC staining. CONCLUSIONS Brilliant blue shows the best ILM staining, whereas bromophenol blue, evans blue, and light green also stain ILM. Most dyes bind well to LC, vitreous, and ERM.