Intravitreal bevacizumab for treatment of choroidal neovascularization secondary to toxoplasmic retinochoroiditis: a case series

New advances in immune mechanism and treatment during ocular toxoplasmosis

Ocular toxoplasmosis (OT) is an intraocular infection caused by the parasite Toxoplasma gondii. OT is manifested as retinal choroiditis and is the most common infectious cause of posterior uveitis. Invasion of the retina by T. gondii leads to disruption of the blood-ocular barrier and promotes the migration of immune cells to the ocular tissues. Cytokines such as IFN-γ and IL-1β are effective for controlling parasite growth, but excessive inflammatory responses can cause damage to the host. In this review, we will discuss in detail the latest advances in the immunopathology and treatment of OT.

Clinical outcomes of intravitreal treatment for ocular toxoplasmosis: systematic review and meta-analysis

BACKGROUND

Ocular toxoplasmosis is the leading cause of infectious posterior uveitis worldwide, accounting for 30-50% of all cases in immunocompetent patients. Conventional treatment is associated with adverse effects and does not prevent recurrence. Intravitreal drug administration can improve disease outcomes and reduce side effects. Herein, we conducted a systematic review and meta-analysis on the efficacy of intravitreal injections for treating ocular toxoplasmosis.

METHODS

The systematic search was conducted using PubMed, SciELO, and Google Scholar with the descriptors "ocular toxoplasmosis" AND "intravitreal". We analyzed studies that met the inclusion criteria, i.e., experimental cases in patients treated intravitreally for ocular toxoplasmosis. Considering the systematic review, we focused on the number of intravitreal injections, the therapeutic drug class, and the presence of preexisting conditions. To assess the efficacy of intravitreal injections, a meta-analysis was performed using visual acuity, side effects, disease recurrence, and inflammatory responses as variables.

RESULTS

Intravitreal injection-induced side effects were rarely observed (0.49% [0.00, 1.51%] ). The use of antiparasitic and anti-inflammatory drugs afforded improved visual acuity (99.81% [98.60, 100.00%]) and marked effectiveness in treating ocular toxoplasmosis.

CONCLUSIONS

Intravitreal injections may facilitate the successful treatment of ocular toxoplasmosis. However, clinicians should carefully evaluate the presence of preexisting conditions for ocular toxoplasmosis or previous diseases, as these can impact the decision to administer intravitreal injections.

Multimodal Imaging in Ocular Toxoplasmosis

Multimodal imaging relies on combination of multiple imaging modalities to precisely delineate pathological changes in the posterior segment of the eye associated with a wide range of conditions. This combined application of fundus photography, optical coherence tomography, fundus reflectance/autofluorescence and fundus angiography (with fluorescein, indocyanine green and/or optical coherence tomography) is of great utility for assessment of patients with ocular toxoplasmosis. Multimodal imaging is helpful to characterize the typical pattern of toxoplasmic retinochoroiditis, with primary focal inflammatory involvement of the neurosensory retina, and secondary changes at the level of underlying choroid, retinal blood vessels, vitreous and even optic disc. It may also be valuable to document and follow local complications, including macular edema, vascular occlusions, and choroidal neovascularization, among others.

Pathogenesis of ocular toxoplasmosis

Ocular toxoplasmosis is a retinitis -almost always accompanied by vitritis and choroiditis- caused by intraocular infection with Toxoplasma gondii. Depending on retinal location, this condition may cause substantial vision impairment. T. gondii is an obligate intracellular protozoan parasite, with both sexual and asexual life cycles, and infection is typically contracted orally by consuming encysted bradyzoites in undercooked meat, or oocysts on unwashed garden produce or in contaminated water. Presently available anti-parasitic drugs cannot eliminate T. gondii from the body. In vitro studies using T. gondii tachyzoites, and human retinal cells and tissue have provided important insights into the pathogenesis of ocular toxoplasmosis. T. gondii may cross the vascular endothelium to access human retina by at least three routes: in leukocyte taxis; as a transmigrating tachyzoite; and after infecting endothelial cells. The parasite is capable of navigating the human neuroretina, gaining access to a range of cell populations. Retinal Müller glial cells are preferred initial host cells. T. gondii infection of the retinal pigment epithelial cells alters the secretion of growth factors and induces proliferation of adjacent uninfected epithelial cells. This increases susceptibility of the cells to parasite infection, and may be the basis of the characteristic hyperpigmented toxoplasmic retinal lesion. Infected epithelial cells also generate a vigorous immunologic response, and influence the activity of leukocytes that infiltrate the retina. A range of T. gondii genotypes are associated with human ocular toxoplasmosis, and individual immunogenetics -including polymorphisms in genes encoding innate immune receptors, human leukocyte antigens and cytokines- impacts the clinical manifestations. Research into basic pathogenic mechanisms of ocular toxoplasmosis highlights the importance of prevention and suggests new biological drug targets for established disease.

The Role of Steroids and NSAIDs in Prevention and Treatment of Postsurgical Cystoid Macular Edema

BACKGROUND

Pseudophakic cystoid macular edema (PCME) remains one of the most common visionthreatening complication of phacoemulsification cataract surgery (PCS). Pharmacological therapy is the current mainstay of both prophylaxis, and treatment of PCME in patients undergoing PCS. We aimed to review pharmacological treatment options for PCME, which primarily include topical steroids, topical nonsteroidal antiinflammatory drugs (NSAIDS), periocular and intravitreal steroids, as well as anti-vascular endothelial growth factor therapy.

METHODS

The PubMed and Web Of Science web platforms were used to find relevant studies using the following keywords: cataract surgery, phacoemulsification, cystoid macular edema, and pseudophakic cystoid macular edema. Of articles retrieved by this method, all publications in English and abstracts of non-English publications were reviewed. Other studies were also considered as a potential source of information when referenced in relevant articles. The search revealed 193 publications. Finally 82 articles dated from 1974 to 2018 were assessed as significant and analyzed.

RESULTS

Based on the current literature, we found that corticosteroids remain the mainstay of PCME prophylaxis in uncomplicated cataract surgery, while it is still unclear if NSAID can offer additional benefits. In patients at risk for PCME development, periocular subconjunctival injection of triamcinolone acetonide may prevent PCME development. For PCME treatment the authors recommend a stepwise therapy: initial topical steroids and adjuvant NSAIDs, followed by additional posterior sub-Tenon or retrobulbar corticosteroids in moderate PCME, and intravitreal corticosteroids in recalcitrant PCME. Intravitreal anti-vascular endothelial growth factor agents may be considered in patients unresponsive to steroid therapy at risk of elevated intraocular pressure, and with comorbid macular disease.

CONCLUSION

Therapy with topical corticosteroids and NSAIDs is the mainstay of PCME prophylaxis and treatment, however, periocular and intravitreal steroids should be considered in refractory cases.

Intravitreal Bevacizumab for Treatment of Bilateral Candida Chorioretinitis Complicated with Choroidal Neovascularization

Purpose: The purpose of this report is to describe a case of bilateral Candida chorioretinitis complicated with choroidal neovascularization (CNV) and effectively treated with combined intravitreal bevacizumab and amphotericin B.Results: An 83-year-old patient was diagnosed with Candida chorioretinitis in both eyes. Optical coherence tomography and fluorescein angiography revealed CNV. Treatment using combined intravitreal bevacizumab and amphotericin B was initiated followed by a 4-weekly regimen of bevacizumab, eventually resulting in the regression of the subretinal fluid and intraretinal edema.Conclusion: Our study supports the combined use of intravitreal bevacizumab and amphotericin B in the management of CNV in Candida chorioretinitis.

Intravitreal aflibercept for choroidal neovascularization associated with chorioretinitis: a pilot study

Purpose

The purpose of this study was to evaluate the potential benefits of intravitreal aflibercept injections for the treatment of choroidal neovascularization (CNV) secondary to chorioretinitis.

Methods

In this uncontrolled, prospective cohort study, 15 eyes of 14 consecutive patients affected by CNV associated with ocular toxoplasmosis were treated with intravitreal aflibercept (2 mg) pro re nata and observed over a 12-month follow-up period. The primary outcome was the change in best-corrected visual acuity (BCVA) from baseline to month 12. Secondary outcomes included change in central retinal thickness (CRT) in the foveal area on optical coherence tomography (OCT) from baseline to month 12, the number of intravitreal aflibercept injections administered, and safety.

Results

Mean (standard deviation [SD]) BCVA improved significantly from 0.36 (0.23) at baseline to 0.64 (0.3) at month 12 (P=0.0002). Mean (SD) CRT on OCT showed a reduction from 317 (74) µm at baseline to 254 (43) µm (P=0.0002) at month 12. A mean (SD) of 1.7 (0.5) injections (range, 1–2 injections) were performed during the study period. No cases of endophthalmitis, uveitis, stroke, or retinal detachment were noted. No patient demonstrated an intraocular pressure >20 mmHg at any study visit.

Conclusion

Intravitreal aflibercept showed a positive clinical effect and was well tolerated for the treatment of CNV associated with chorioretinitis. The results could be helpful for selecting a treatment for CNV secondary to chorioretinitis.

Schizophrenia and Infections: The Eyes Have It

The visual tract is prominently involved in schizophrenia, as evidenced by perceptual distortions and a type of nystagmus found in many individuals affected. Genetic explanations for these abnormalities have been suggested. This study proposes an alternate explanation based on infection. Several infectious agents thought to be associated with some cases of schizophrenia are known to cause both infection of the fetus and abnormalities of the eye. Toxoplasma gondii is examined in detail, and rubella, cytomegalovirus, varicella-zoster virus, and herpes simplex virus more briefly. Careful ophthalmic assessments, including funduscopy and direct examination of tissues for infectious agents, will clarify the role of such agents in ocular aspects of schizophrenia.

Toxocara polymerase chain reaction on ocular fluids in bilateral granulomatous chorioretinitis

To report a rare case of bilateral granulomatous chorioretinitis complicated by bilateral peripapillary choroidal neovascular membranes. This is the first reported case in Australia where intravitreal injections of anti-vascular endothelial growth factor ranibizumab were used to successfully treat choroidal neovascular membrane caused by granulomatous chorioretinitis. This is also the first reported case in Australia of Toxocara polymerase chain reaction being performed on intraocular fluids.