Medical Minutes by John Schieszer
New Artificial Iris Helping Improve Vision
The first stand-alone prosthetic iris is now helping improving vision for adults and children. The surgically implanted device is being to treat adults and children whose iris (the coloured part of the eye around the pupil) is completely missing or damaged due to a congenital condition called aniridia or other damage to the eye.
“Patients with iris defects may experience severe vision problems, as well as dissatisfaction with the appearance of their eye,” said Dr. Malvina Eydelman, who is with the U.S. Food and Drug Administration (FDA). Dr. Eydelman said the approval of the first artificial iris provides a novel method to treat iris defects that reduces sensitivity to bright light and glare.
Congenital aniridia is a rare genetic disorder in which the iris is completely or partially absent. The iris controls the amount of light entering the eye. Individuals with aniridia have sensitivity to light and other severe vision problems. In addition to congenital aniridia, the CustomFlex Artificial Iris is indicated to treat iris defects due to other reasons or conditions, such as albinism, traumatic injury or surgical removal due to melanoma.
The CustomFlex Artificial Iris is made of thin, foldable medical-grade silicone and is custom-sized and coloured for each individual patient. A surgeon makes a small incision, inserts the device under the incision, unfolds it and smooths out the edges using surgical instruments. The prosthetic iris is held in place by the anatomical structures of the eye or, if needed, by sutures.
The safety and effectiveness of the CustomFlex Artificial Iris was demonstrated primarily in a non-randomised clinical trial of 389 adult and paediatric patients with aniridia or other iris defects. The study found low rates of adverse events associated with the device or the surgical procedure. It is hoped that this will now helping scores of individuals who in the past had few or no options.
Combating High Blood Pressure with Surgery instead of Daily Pills
An operation that targets the nerves connected to the kidney has been found to significantly reduce blood pressure in patients with hypertension, according to a clinical trial led in the UK by Queen Mary University of London and Barts Health NHS Trust.
If the findings are confirmed in more extensive clinical trials, the surgery could offer hope to patients with high blood pressure who do not respond to drugs, and are at increased risk of cardiovascular diseases, including stroke and heart attack. The international clinical trial, carried out from 2017 to 2018 at St Bartholomew’s Hospital in the UK by the NIHR Barts Biomedical Research Centre, tested a one-hour operation called renal denervation. It uses ultrasound energy to disrupt the nerves between the kidneys and the brain that carry signals for controlling blood pressure.
For the current study, 146 patients in the United States, France, Germany, the Netherlands, Belgium and the United Kingdom were randomised to receive either renal denervation or a “sham procedure” (the surgical equivalent of a placebo). Patients also remained off blood pressure medications for two months unless specified blood pressure levels were exceeded.
After two months, the renal denervation group experienced an 8.5 mm Hg reduction in blood pressure, which was a 6.3 mm Hg greater reduction compared with the sham group. More than 66 per cent of subjects treated with renal denervation demonstrated a 5 mm Hg or greater reduction in blood pressure, compared with 33 per cent in the sham group. No major adverse events were reported in either group, and the blood pressure lowering effect of renal denervation was consistent across sex and ethnicity.
“These results leave us clinicians in no doubt that this ultrasound-based therapy works to improve blood pressure control, at least in the short term. Further larger trials will be needed to confirm the efficacy and safety of the technology, but we hope that they could lead to renal denervation therapy being offered as an alternative to lifelong medications for hypertension,” said UK principal investigator Dr. Melvin Lobo from Queen Mary University of London and Barts Health NHS Trust.
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at firstname.lastname@example.org.