Shantan Reddy

Age-related macular degeneration: current treatments

Purpose: Although important progress has been made in understanding age-related macular degeneration (AMD), management of the disease continues to be a challenge. AMD research has led to a widening of available treatment options and improved prognostic perspectives. This essay reviews these treatment options. Design: Interpretative essay. Methods: Literature review and interpretation. Results: Current treatments to preserve vision in patients with non-exudative AMD include antioxidant vitamins and mineral supplementations. Exudative AMD is currently most often treated monthly with anti-VEGF intravitreal injections. However, investigators are beginning to experiment with combination therapy and surgical approaches in an attempt to limit the number of treatment and reduce the financial burden on the health care system. Conclusion: By better understanding the basis and pathogenesis of AMD, newer therapies will continue to be developed that target specific pathways in patients with AMD, with the hoped for outcome of better management of the disease and improved visual acuity.

Ultra Wide Field Fluorescein Angiography Guided Targeted Retinal Photocoagulation (TRP)

We report two cases in which ultra wide field fluorescein angiography was used to direct targeted retinal photocoagulation (TRP) to areas of retinal capillary non-perfusion in an attempt to cause regression of diabetic neovascularization. By providing up to a 200 degree field of view, accurate delineation of retinal capillary non-perfusion and precise application of photocoagulation was possible. The application of TRP successfully led to the regression of the retinal neovascularization in our patients. Complications of conventional panretinal photocoagulation (PRP) such as visual field loss and macular edema may have been avoided. When TRP is used in conjunction with ultra wide field fluorescein angiography, preservation of functional retina may be possible while minimizing the amount of laser treatment that is applied to the retina.

Effect of cutting phases on flow rate in 20-, 23-, and 25-gauge vitreous cutters.

Background: Vitrectomy systems are now available with 20-, 23-, and 25-gauge vitreous cutters and are designed to be used with conventional or new generation pneumatic actuation technology. Methods: Five vitreous cutters using pneumatic actuation technology were studied. Flow rates were evaluated using porcine vitreous. A high-speed camera timed the cutting phases (open, closing, closed, and opening), and duty cycle was calculated. The cutting port surface area and internal shaft surface areas were calculated. Results: Increasing cut rate decreased the average open phase duration without affecting other cutting phases. The opening and closing phases of vitreous cutters using new generation pneumatic actuation technology were longer than those for other vitreous cutters. Flow rate was correlated to internal shaft surface area. Conclusion: In addition to confirming the importance of duty cycle at high cut rates, this study demonstrated that the transition phases should also be considered when one is evaluating the efficiency of a vitreous cutter.

Ultrawide angle angiography for the detection and management of diabetic retinopathy.

For the last 50 years, fluorescein angiography (FA) has played a pivotal role in the evaluation and management of retinal diseases including diabetes. Patterns of hyperfluorescence and hypofluorescence provide insights into the pathophysiologic processes and guide treatment. Despite recent advances in other imaging techniques, including indocyanine green angiography and optical coherence tomography, FA still plays a primary role. FA remains a vital method to assess indications and outcomes of treatment methods including laser photocoagulation, intraocular pharmacologic therapy such as steroid and antivascular endothelial growth factor (anti-VEGF) agents, and surgical intervention. The ability to capture a single image of the entire ocular fundus has been limited until recently. Standard FA using film or digital cameras typically capture an image 30 degrees across. A new fluorescein imaging technique that captures fundus images up to 200 degrees in breadth is discussed herein. Optomap fa dynamic ultrawide field angiography is a digital panoramic technique performed with the Optos P200 MA scanning laser ophthalmoscope (Optos plc, Dunfermline, UK). The ability to image the peripheral retina using Optomap fa provides a more comprehensive assessment of the extent of a retinal disease process, and

Age-related macular degeneration: experimental and emerging treatments

Purpose: This essay reviews the experimental treatments and new imaging modalities that are currently being explored by investigators to help treat patients with age-related macular degeneration (AMD). Design: Interpretative essay. Methods: Literature review and interpretation. Results: Experimental treatments to preserve vision in patients with exudative AMD include blocking vascular endothelial growth factor (VEGF), binding VEGF, and modulating the VEGF receptors. Investigators are also attempting to block signal transduction with receptor tyrosine kinase inhibitors. Experimental treatments for non-exudative AMD include agents that target inflammation, oxidative stress, and implement immune-modulation. The effectiveness of these newer pharmacologic agents has the potential to grow exponentially when used in combination with new and improved imaging modalities that can help identify disease earlier and follow treatment response more precisely. Conclusion: With a better understanding, at the genetic and molecular level, of AMD and the development of superior imaging modalities, investigators are able to offer treatment options that may offer unprecedented visual gains while reducing the need for repetitive treatments.

Ultra-wide-field and autofluorescence imaging of choroidal dystrophies.

The authors retrospectively identified 2 cases of gyrate atrophy, 3 cases of choroideremia, and 1 case of the carrier state of choroideremia who underwent ultra-wide-field fundus photography and fluorescein angiography. The findings were studied and compared to standard fundus photography and fluorescein angiography. Gyrate atrophy demonstrated a diffuse confluent extent of chorioretinal atrophy extending from the anterior to the posterior pole to the periphery. Choroideremia demonstrated a patchy irregular pattern of chorioretinal atrophy extending from the posterior pole to the periphery. Peripheral reticular degeneration without chorioretinal atrophy was appreciated in the carrier state. Ultra-wide-field imaging of these choroidal dystrophies demonstrated distinctive patterns that may aid in their identification and diagnosis.

Nasal Retinoschisis Associated with Glaucoma.

The authors describe a case of nasal and macular retinoschisis in a patient with open angle glaucoma. A 75 year-old female with optic nerve head damage secondary to chronic open angle glaucoma developed macular schisis and a separate area of retinoschisis nasal to her optic disk. There were no other identifiable causes for her retinoschisis. Glaucoma related structural defects offer a plausible explanation for multiple cavities of retinoschisis in favor of multiple occult congenital pits of the optic nerve head.

Vitreous Web after Pars Plana Vitrectomy and Bevacizumab with Fluid-Air Exchange

Background: Intravitreal bevacizumab may result in intraocular inflammation of infectious and non-infectious etiology. Appropriate recognition of a sterile process can circumvent unnecessary treatment for endophthalmitis. Design: Observational case report. Methods: A marked web-like inflammatory response within the vitreous following intraoperative intravitreal bevacizumab is described in a patient with pre-proliferative diabetic retinopathy, macular edema, and epiretinal membrane who underwent pars plana vitrectomy, membrane peel, endolaser, and fluid-air exchange. Wide-field fundus photography captured the full extent of this reaction. Results: On post-operative day one, the patient presented with vitreous opacities in the form of a web of multiple white strands inferior to an air bubble, with minimal anterior or vitreous cell. At one week, the inflammatory reaction had completely resolved. Conclusion: Existing reports of intraocular inflammation following intravitreal bevacizumab range from uveitis to infectious endophthalmitis. With wide-field fundus imaging, we report an acute, marked web-like inflammatory response following intraoperative intravitreal bevacizumab that resolved spontaneously.