Efficacy of Topical Carbonic Anhydrase Inhibitors in Reducing Duration of Chronic Central Serous Chorioretinopathy

Central serous chorioretinopathy: An evidence-based treatment guideline

Central serous chorioretinopathy (CSC) is a relatively common disease that causes vision loss due to macular subretinal fluid leakage and it is often associated with reduced vision-related quality of life. In CSC, the leakage of subretinal fluid through defects in the retinal pigment epithelial layer's outer blood-retina barrier appears to occur secondary to choroidal abnormalities and dysfunction. The treatment of CSC is currently the subject of controversy, although recent data obtained from several large randomized controlled trials provide a wealth of new information that can be used to establish a treatment algorithm. Here, we provide a comprehensive overview of our current understanding regarding the pathogenesis of CSC, current therapeutic strategies, and an evidence-based treatment guideline for CSC. In acute CSC, treatment can often be deferred for up to 3-4 months after diagnosis; however, early treatment with either half-dose or half-fluence photodynamic therapy (PDT) with the photosensitive dye verteporfin may be beneficial in selected cases. In chronic CSC, half-dose or half-fluence PDT, which targets the abnormal choroid, should be considered the preferred treatment. If PDT is unavailable, chronic CSC with focal, non-central leakage on angiography may be treated using conventional laser photocoagulation. CSC with concurrent macular neovascularization should be treated with half-dose/half-fluence PDT and/or intravitreal injections of an anti-vascular endothelial growth factor compound. Given the current shortage of verteporfin and the paucity of evidence supporting the efficacy of other treatment options, future studies-ideally, well-designed randomized controlled trials-are needed in order to evaluate new treatment options for CSC.

Drug interactions of carbonic anhydrase inhibitors and activators

INTRODUCTION

Carbonic anhydrases (CAs, EC 4.2.1.1) have been established drug targets for decades, with their inhibitors and activators possessing relevant pharmacological activity and applications in various fields. At least 11 sulfonamides/sulfamates are clinically used as diuretics, antiglaucoma, antiepileptic, or antiobesity agents and one derivative, SLC-0111, is in clinical trials as antitumor/antimetastatic agent. The activators were less investigated with no clinically used agent.

AREAS COVERED

Drug interactions between CA inhibitors/activators and various other agents are reviewed in publications from the period March 2020 - January 2024.

EXPERT OPINION

Drug interactions involving these agents revealed several interesting findings. Acetazolamide plus loop diuretics is highy effective in acute decompensated heart failure, whereas ocular diseases such as X-linked retinoschisis and macular edema were treated by acetazolamide plus bevacizumab or topical NSAIDs. Potent anti-infective effects of acetazolamide and other CAIs, alone or in combination with other agents were demonstrated for the management of Neisseria gonorrhoea, vancomycin resistant enterococci, Acanthamoeba castellanii, Trichinella spiralis, and Cryptococcus neoformans infections. Topiramate, in combination with phentermine is incresingly used for the management of obesity, whereas zonisamide plus levodopa is highly effective for Parkinson's disease. Acetazolamide, methazolamide, ethoxzolamide, and SLC-0111 showed synergistic antitumor/antimetastatic action in combination with many other antitumor drugs.

Two Cases of Chronic Central Serous Chorioretinopathy Successfully Treated with Systemic Interferon Alpha

Chronic central serous chorioretinopathy (CSCR) is a sight threatening disease that can lead to legal blindness. Verteporfin photodynamic therapy is the main treatment for chronic CSCR, however, there has been a critical worldwide shortage of verteporfin. Other medical treatments have been attempted with variable efficacy. Interferons have shown efficacy in treating uveitis and associated macular edema. We report 2 cases of treatment refractory chronic CSCR successfully treated with subcutaneous injection of interferon alpha with significant anatomical and functional improvement. To our knowledge, this is the first report observing the therapeutic potential of systemic interferon alpha in the treatment of chronic CSCR. A large randomized controlled clinical trial would help to better evaluate the safety and efficacy of systemic PEG-IFNα2a in treating chronic CSCR, and further define the optimal dose, treatment interval and duration.

Topical Treatment for Retinal Degenerative Pathologies: A Systematic Review

The topical administration of medicines is the preferred route in ocular therapy, at least for the anterior segment of the eye. However, the eye's inherent functional and biological barriers all work against the active pharmaceutical ingredient (API) to efficiently reach the targeted retinal structures. The main objective of this article is to offer a systematic review of the scientific literature in recent years, focusing on the latest developments of topical treatment intended for retinal degenerative diseases. Database search returned 102 clinical studies, focused on topical treatment for age macular degeneration, macular edemas (in diabetic retinopathy, surgery related or in retinal dystrophies) or glaucoma. After the exclusion of low-powered studies and those combining vitreo-retinal surgery, 35 articles remained for analysis. Currently, the topical treatment of retinal degenerative diseases is limited by the difficulty to deliver effective drug concentrations to the posterior eye structures. However, in the case of drug classes like NSAIDs, the presence of certain molecular and metabolic features for specific representatives makes the topical administration currently feasible in several clinical contexts. For other drug classes, either a fine-tuning of the API's pharmacokinetic profile or the use of more advanced formulation strategies, such as rationally designed nanostructured drugs and vehicles, crystalline polymorphs or supramolecular complexes, could bring the much awaited breakthrough for a more predictable and controlled delivery towards the retinal structures and could eventually be employed in the future for the development of more effective ways of delivering drugs to the posterior eye, with the ultimate goal of improving their clinical efficacy.

Central serous chorioretinopathy: A review

Central serous chorioretinopathy (CSC) is the fourth most common non-surgical retinopathy associated with fluid leakage. The pathogenesis is not yet completely understood, but changes in the choroid, sclera and RPE have been described associated with venous congestion of choroidal outflow. CSC can be categorised into acute, chronic, and recurrent subtypes with recent classifications of simple and complex based on the area of RPE change seen on fundus autofluorescence. A multimodal imaging approach is helpful in the diagnosis and management of CSC and secondary complications such as type 1 neovascularisation. Although spontaneous resolution with relatively good visual outcomes is common, treatment should be considered in patients with persistent or recurrent SRF. Treatment options include laser, systemic medications, intravitreal therapy, and surgery. Of these, argon laser for focal extramacular fluid leaks and photodynamic therapy of leakage identified by indocyanine-green angiography currently have the greatest supportive evidence.

Carbonic anhydrase inhibitors in the management of macular edema: A review of the literature

Background

Macular edema (ME) is a vision-threatening condition that commonly develops as a consequence of ocular diseases, including age-related macular degeneration, retinal vaso-occlusion of the central retinal vein and its branches, diabetic retinopathy, central serous chorioretinopathy, uveitis, retinitis pigmentosa, pseudophakia, ocular trauma, and drug toxicity. The treatment of ME remains challenging, although steroids and vascular endothelial growth factor inhibitors are available. Cost-effective therapy using a noninvasive administration route is required. This study aimed at reviewing the role of carbonic anhydrase inhibitors (CAIs) in the management of ME.

Methods

A literature search was conducted using PubMed/MEDLINE and Google Scholar for studies from January 2000 to March 2022. The following keywords were used in various combinations: "macular edema", "carbonic anhydrase", "carbonic anhydrase inhibitors", "acetazolamide", "dorzolamide", and "brinzolamide".

Results

Articles with high or medium clinical relevance were selected for this review. We found that multiple studies have demonstrated the relevance and efficacy rates of CAIs in the management of ME. Most published studies focused on acetazolamide and dorzolamide, with nearly all studies reporting therapeutic responses.

Conclusions

ME is the leading cause of vision loss and requires noninvasive and cost-effective pharmacotherapy. With progress in the understanding of ME, particularly the role of carbonic anhydrase as a key driver, CAIs are the focus of research. Further optimization of the choice of CAIs and retinal bioavailability, potentially with nanoparticle formulations, is required to enable the effective management of ME. Further research is warranted to address the therapeutic effects of CAIs in different formulations.

Symptomatic idiopathic bilateral multifocal retinal pigment epithelial detachments

Purpose

To report a rare case of idiopathic bilateral serous retinal pigment epithelial detachments.

Observations

We present a case of a 43-year-old female patient with metamorphopsia with the presence of innumerable bilateral serous retinal pigment epithelial detachments. Detailed ocular and systemic clinical work-up revealed no underlying disease.

Conclusions

/Importance: Idiopathic multiple serous retinal pigment epithelial detachments are an extremely rare condition, that has been observed as an incidental clinical finding in asymptomatic patients. Multimodal imaging and detailed systemic work up are essential to rule out an underlying disease. Initial symptoms, as in our case, are uncommon and usually occur only in patients with complications such as choroidal neovascularization or hemorrhages. Therefore, regular follow ups are recommended to early detect and treat possible complications.

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Idiopathic multiple serous retinal pigment epithelial detachments (PEDs) are an extremely rare condition.

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Multimodal imaging is essential to confirm the serous nature of the PEDs and to rule out presence of an underlying disease.

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Regular follow ups are recommended to early detect and treat possible complications.