Drug injections replace laser sclerotherapy with retinopathy
Diabetes, as a disease of our civilization, is rapidly spreading throughout society, affecting in particular the eye and the retina. For middle-aged individuals, diabetic retinopathy is the most common cause of blindness and of severe vision loss. 50% of people affected with abnormal vascular growth on the retina, the so-called proliferative retinopathy, which is typical for diabetes, will suffer from a severe loss of vision within five years. With the introduction of laser sclerotherapy of the retina, significant progress has been made on the slowing of the progression of the disease, with now only five percent of the patients losing their eyesight. However, this therapy has drastic side effects such as loss of large parts of the visual field, a limited ability to see in twilight or an edema forming in the center of the retina causing a loss of the ability to read.
The successful treatment of macular disease in diabetes with drugs that are directly injected into the affected eye, led to the conclusion that the same substances could also be effective against more severe forms of ocular disease, the proliferative retinopathy. In November 2015, the first relevant study was published in the US. The result: After two years, the group of patients treated with injections had a better vision and a well-functioning visual field, were less affected by a rare macular edema and had a much lower need for surgery.
As Ms. Schmidt-Erfurth stated: "After 40 years of laser sclerotherapy, we have set a new milestone for a more effective and at the same time substantially gentler treatment of one of the most common threats to eyesight, diabetic retinal disease. This is a very substantial step forward for patients who, for many decades, have already been restricted in their lifestyle due to their chronic disease. For the field of ophthalmology, this means that the last bastion of laser sclerotherapy has fallen. New guidelines and recommendations for the treatment of the thousands of diabetic patients need to be established."
Digital OCT angiography
The visualization of blood vessels in the ocular fundus is an essential basic examination for the diagnosis and monitoring of a number of diseases that are leading causes of significant visual impairment in Austria - such as age-related macular degeneration (AMD), diabetic retinopathy or vascular occlusions. Until recently the classic angiography by means of contrast-methods was the only way to visualize these blood vessels.
For the first time, the new digital "OCT angiography" allows, by means of digital analysis, the study of blood vessels in the fundus oculi. As explained by Andreas Pollreisz of the Medical University of Vienna: "Contrary to the classic angiography method, digital angiography only takes a few seconds. And there is no need to administer a dyeing agent, which can case nausea and vomiting in certain patients. "
With this new contactless and painless method, it only takes a few seconds to make several images of the retina using a special laser light, which is non-hazardous to the eye. The system compares the sequential shots at each specific location, and calculates a map of perfused vessels by measuring the movement of the erythrocytes. In addition to the vascular imaging, the process also takes images of the different layers of the entire retina. "For the first time this allows assigning the corresponding retinal layers to the individual vascular structures. Within seconds, we obtain a three-dimensional reconstruction of the entire vascular structures of the ocular fundus" adds Pollreisz.
Measuring the visual acuity - even in the brain
Up until now, during conventional retinal examinations it was not taken into account that the retina is already virtually a part of the brain. In order to investigate the processing visual impressions in the corresponding areas of the brain, retina patients were enrolled in a collaborative project of the Department of Ophthalmology and the Center for Medical Physics and Biomedical Engineering at the Medical University of Vienna and examined via functional magnetic resonance imaging. The patients were given visual stimuli in the form of moving patterns; at the same time the brain activity was measured by the local oxygen consumption. It was established that for a defined region of the retina, a corresponding area of the visual center could be assigned to it. In the case of a retinal disease, if the function of a particular retinal region were impaired, one would expect a reduced activity in the presentation of visual stimuli in the corresponding area of the visual cortex. This has been found to be true with most patients.
"However, in some patients that have been affected by retinal diseases for many years, it seems that neighboring, relatively healthy retinal areas partially take over the function of the impaired areas, which results in a change in the presentation of the corresponding retinal visual center" explains Markus Ritter of the Department of Ophthalmology and Optometry of the Medical University of Vienna. "This leads us to think that this system is not rigid, but adaptable to a certain extent. And it seems to be able to partially compensate for malfunctions in the retina. This discovery allows us to better understand the changes in visual acuity of patients with retinal diseases and will lead to new therapeutic approaches."