RESUMEN
Cataracts are a leading cause of preventable blindness globally. Although care varies between developing and industrialized countries, surgery is the single effective approach to treating cataracts. From the earliest documented primitive cataract removals to today's advanced techniques, cataract surgery has evolved dramatically. As surgical techniques have developed, so have approaches to surgical pain management. With current cataract surgical procedures and advanced technology, anesthesia and intraoperative pain management have shifted to topical/intracameral anesthetics, with or without low-dose systemic analgesia and anxiolysis. Despite this, pain and discomfort persist in some patients and are underappreciated in modern cataract surgery. Although pain management has progressed, opioids remain a mainstay intraoperatively and, to a lesser extent, postoperatively. This article discusses the evolution of pain management in cataract surgery, particularly the use of opioids and the associated risks as well as how ophthalmology can have a positive impact on the opioid crisis.
Asunto(s)
Catarata , Oftalmología , Analgésicos Opioides/uso terapéutico , Anestesia Local/métodos , Anestésicos Locales/uso terapéutico , Catarata/complicaciones , Humanos , Dolor , Manejo del Dolor/efectos adversos , Dolor Postoperatorio/tratamiento farmacológicoRESUMEN
Purpose: Corneal collagen crosslinking (CXL) through an intact epithelium (epi-on) at high irradiance could potentially improve patient comfort, visual recovery, and clinical workflow compared to conventional epi-off CXL. However, intact epithelium limits stromal delivery of the oxygen, photosensitizer, and ultraviolet-A (UV-A) radiation needed to drive CXL. This ex vivo study evaluated three different epi-on CXL protocols compared to positive and negative controls, specifically focusing on the impact of supplemental oxygen. Endpoints included stromal oxygen levels, stiffness of crosslinked tissue, and acute flattening of whole eyes.Materials & Methods: Ex vivo porcine eyes were held in a custom environmental chamber. Intrastromal oxygen levels were continuously measured before, during, and after UV illumination by a fiberoptic probe inserted into a laser-cut flap. Accelerated, high irradiance, epi-on CXL protocols using riboflavin formulated with benzalkonium chloride (BAC) were studied, with and without supplemental oxygen. These were compared to an alternate, low irradiance, epi-on protocol using riboflavin formulated with sodium iodide. Both negative (no CXL) and positive (epi-off modified Dresden protocol) controls were performed. Post-CXL elastic modulus was measured using extensiometry and anterior tangential curvature was measured using a Scheimpflug tomographer.Results: Protocols including supplemental oxygen resulted in an approximately 5-fold increase in stromal oxygen levels prior to CXL. During epi-on, high-irradiance UV-A delivery under hyperoxic conditions, an aerobic state was maintained. Conversely, under normoxic conditions, stromal oxygen rapidly depleted to 0-5% for all other protocols. The combination of supplemental oxygen, BAC formulation, and high-irradiance UV-A resulted in the largest biomechanical changes and most pronounced flattening effects of the three epi-on protocols.Conclusions: Ex vivo analysis of stromal oxygen levels, corneal stiffness, and acute anterior curvature change indicates that simultaneous optimization of the oxygen environment, riboflavin formulation, and UV-A protocol can significantly increase the effects of corneal collagen crosslinking.
Asunto(s)
Colágeno/farmacología , Sustancia Propia/metabolismo , Reactivos de Enlaces Cruzados/farmacología , Queratocono/metabolismo , Oxígeno/metabolismo , Fotoquimioterapia/métodos , Riboflavina/farmacología , Animales , Sustancia Propia/diagnóstico por imagen , Topografía de la Córnea , Modelos Animales de Enfermedad , Queratocono/diagnóstico , Queratocono/tratamiento farmacológico , Fármacos Fotosensibilizantes/farmacología , Porcinos , Rayos UltravioletaRESUMEN
PURPOSE: To develop and evaluate a calibrated force gauge designed to simulate the effect of patient-induced manipulation of the eye with resultant elevation of intraocular pressure (IOP) and use the device to determine the stability of cataract incisions. SETTING: Three private practice study sites. DESIGN: Clinical trials. METHODS: A calibrated force gauge was developed to apply controlled and quantifiable amounts of force to the eye. In study 1, the calibrated force gauge was used to evaluate the change in IOP during application of 1 oz of external force in a group of healthy volunteers. In studies 2 and 3, the calibrated force gauge was used to assess wound leakage of clear corneal incisions that were subjected to stromal hydration or sutures, respectively. RESULTS: In study 1, with the application of 1.00 oz of external force, the mean IOP rose from a baseline of 17.49 mm Hg to 43.44 mm Hg. In study 2 (stromal hydration) using up to 1.00 oz of force, the leak rate was 67% for the main incision. The overall leak rate for study 3 (sutures) using up to 1.00 oz of force was 23.8%. No adverse events or serious adverse events occurred during these studies. CONCLUSIONS: Study 1 confirmed that 1.00 oz of force is a realistic approximation of the amount of force a patient's eye may experience during rubbing. After clear corneal cataract surgery, the application of 1.00 oz of force to the ocular surface for approximately 2 to 3 seconds may simulate the propensity for postoperative wound leak resulting from patient manipulation.