Operation for central serous chorioretinopathy
Low Fluence Photodynamic Therapy (PDT)
Low Fluence Photodynamic Therapy (PDT)
La Central serous chorioretinopathy is a pathology characterized by lifting of the sensorineural retina at the level of the macula, the most central part of the retina. Retinal lift is due to a phenomenon of exudation from the vessels of the choroid and to the next passage of fluid from the choroid to the subretinal space through the epithelium retinal pigment.
Central serous chorioretinopathy located in the stress one of the main risk factors. It seems in fact that the excessive production of adrenalina e norepinephrine, which occurs in conditions of excessive and prolonged stress, contributes to generate exudation in the choroid and to weaken the firm bond normally existing between the cells of the retinal pigment epithelium, which in this way is no longer able to act as a barrier and prevent the passage of fluid from the choroid to the subretinal space.
The accumulation of fluid under the macula causes the photoreceptors to rise and causes a visual impairment of an entity proportional to the amount of accumulated fluid. Over time, the separation of photoreceptors from the retinal pigment epithelium becomes detrimental to the survival of the photoreceptors themselves which, in the absence of spontaneous remission or treatment, can undergo atrophy and cell death, with irreversible damage to central vision.
Currently, the reference therapy for acute and chronic central serous chorioretinopathy is photodynamic therapy (PDT, from the English Photodynami Therapy) low fluence with verteroporphyrin, able to strengthen the bonds between the cells of the retinal pigment epithelium, restoring the structural integrity of the retina.
Photodynamic therapy involves the injection of a dose of verteporphyrin of about 3mg / m2 through an infusion lasting about 8-10 minutes. At the end of the infusion, wait about 2 minutes to allow the verteporphyrin to bind to the areas of the retina affected by altered permeability. Subsequently, a non-thermal red laser is aimed at these areas, which activates the verteporphyrin triggering a repair mechanism of intravasal and intercellular damage.
The PDT is able to promote the reabsorption of edema and reaccollection of the sensorineural retina retinal pigment epithelium in almost all patients treated, already 3-4 weeks after treatment.
The mechanism of action of verteroporphyrin is not completely known, but its use allows the restoration of the anatomical continuity of the treated tissue and the repair of the "leaks" which in the pathological process allow the trans-epithelial migration of fluids from the choroid to the subretinal space.
PDT must be performed in highly specialized centers since therapeutic success strictly depends on the perfect combination of the different parameters involved: intensity of the laser radiation, intravenous dilution of verteporphyrin, diameter of the laser spot, identification of the specific retinal area to be treated.
