Recent trends in Glaucoma management

Abstract

Dear Friends, Welcome to this issue of IJO which has an interesting mix of articles. The article by Senthil et al., compares the treatment outcomes of different modalities of treatment in Glaucoma. Glaucoma is the second leading cause of blindness worldwide.[1] Although significant progress has been made in developing pharmacological agents and surgical procedures that can significantly enhance our ability to control intra ocular pressure (IOP), the vision loss associated with glaucoma remains a significant problem. Recent advances dwell on the options to protect or replace cells damaged by increased IOP or modulate other abnormalities explored to be associated with glaucoma. Approach toward cell-based drug delivery has shown legitimate potential as a future therapeutic option for glaucoma. Current research is targeted on retinal stem cells, Muller/glial stem cells, retinal pigment epithelial (RPE) stem cells, endothelial progenitor cells (EPCs) to regenerate the retinal neurons and neuroreceptors and to modulate the neurotrophic effect by the retinal vasculature.[2] Stem cell research offers a wide variety of approaches for the advancement of our understanding of basic mechanisms of neuro degeneration and tissue regeneration and for the discovery and development of new therapeutic strategies to prevent and restore neuronal cell loss.[3] Recent studies show that gene-replacement therapy may improve visual potential in inherited retinal disease. Gene replacement and gene knockdown strategies are now being explored in inherited glaucoma, aiming to reverse the mutation.[4,5] Neurotrophic agents are being looked at with the hope of preserving function and lifespan of ganglion cells and as an aid in maintaining vision. Unfortunately, such therapy is limited as these agents only delay cell death and do not actually cure.[6] The advent of anti-vascular endothelial growth factor (VEGF) molecules has potentiated the management of neovascular glaucoma (NVG) by effectively managing neovascularization of the iris and the angle and lowering the IOP. However, this modality needs to be supplemented with laser or surgery as the response to the drug is usually temporary.[7] Outflow of aqueous is manipulated externally or internally. External filtration is revolutionized by glaucoma drainage devices and its recent modifications and adjuncts like anti-metabolites. Internal filtration is effectively modulated by trabeculectomy, including current modifications and adjunctive. Non-penetrating surgeries have become widely popular in the recent decade. These include procedures that restore filtration through Schlemm's canal, deep sclerectomy, viscocanalostomy, or canaloplasty. Canaloplasty, a recently developed non-penetrating glaucoma surgical approach, may restore physiological outflow routes in primary open-angle glaucoma with less risk of severe postoperative complications.[8,9] Comprehensive monitoring of IOP is presumed to have a predictive value in disease progression. Current ambulatory measurement with handheld devices is variable and has not established reliable efficacy. Devices under development use sensors in intraocular-implanted devices like contact lenses or intraocular lenses, providing continuous IOP monitoring that can be transmitted to an external recording device or analyzed by a computer.[10] With a vast spectrum of surgeries including trabecular bypass devices and shunts to canal surgeries, management of glaucoma still remains a dilemma. The new modalities are worth exploring but await long-term safety and efficacy reports.[11] Adopting the paradigm of evidence-based medicine, one needs to critically evaluate the new diagnostic and therapeutic options and validate them appropriately before incorporating them into patient care. Nevertheless, evidence alone cannot be considered sufficient. Clinical experience and patients’ perspective also need to be considered. Care is to be directed not only to the patients, but also toward those undetected and inappropriately treated.[12] Renowned scientist and past President of India, Hon. A.P.J. Abdul Kalam had expressed his interest and hope toward evolving innovative and cost effective diagnostic and treatment processes for glaucoma. In one of his addresses he specifies that optic nerve regeneration is the key to partially reverse blindness from glaucoma and that future glaucoma therapy should be directed to prevent, delay or reverse decay of the retinal ganglion cells and axons. Functional genomics and proteomics are likely to play a pivotal role in early detection of glaucoma he believes. In his address, Hon. Abdul Kalam says “I request every doctor to play the role of a teacher in advising every family on eye disease prevention particularly glaucoma and methods to maintain a healthy vision. I hope you all will find time for this noble action.”[13,14] I hope as a community dedicated toward service to mankind, we will all strive to live up to the expectations of the known and the unknown.