To treat certain diseases of the eye, the injection unfortunately remains unavoidable; but a new type of needle could make the procedure more tolerable.
For part of the population, the mere sight of a syringe can trigger real panic, even in the context of a vulgar vaccination. But even for those without belenophobia, some needles tend to send chills down your spine. One thinks, for example, of the terrifying trocars used during certain biopsies, or those used to perform intravitreal injections – that is to say straight into the eye.
In addition to being not very reassuring, this procedure is unfortunately not without risk. The eye is a very delicate structure; when several layers are perforated in this way, it literally opens the door to a whole host of complications such as infections or even tumors.
But these injections remain essential to treat certain pathologies, in particular the famous age-related macular degeneration (AMD). Most often, you even have to try several times, which further increases the risk. Researchers are therefore trying to develop techniques that could make it possible to perform these intravitreal injections with a minimum of complications, and while limiting the inconvenience for the patient as much as possible.
An ultra-thin and persistent needle
And this is what a team of mostly South Korean researchers has just proposed in work spotted by ScienceAlert with a new kind of microneedle. For starters, it’s exceptionally thin compared to a standard needle. This keeps damage to the incredibly delicate tissues that make up the eye to a minimum.
The other major difference is that it is not designed to be removed! Indeed, unlike a standard needle, this one is designed to remain housed in the eye. It then gradually delivers the substance there over an extended period of time. The blunt end is covered with a swelling hydrogel to seal the orifice.
This approach has several advantages. Initially, this avoids leaving a gaping hole at the injection site, which significantly reduces the risk of infection. In addition, this persistent needle also allows the patient to avoid having to undergo several consecutive injections. This is a significant bonus in terms of comfort, in addition to massively reducing the risk of infection.
In addition, since these needles are extremely thin and do not require pressing on them to inject, they are also significantly more precise than these standard needles.
A biodegradable body and hydrogel cap
And once the treatment is over, the patient simply won’t have to worry about that needle anymore; no need to return to the practitioner to have this therapeutic splinter removed from the eye. Instead, it will disappear spontaneously since it can be completely degraded by the immune system.
On paper, this technology therefore has many advantages over current intravitreal injections. The researchers therefore wanted to test them in real conditions, first on pig eyes, then directly on live animals.
And during these tests, the needle remained quite wisely in place for an entire week. The hydrogel seal had consolidated by then, and the team found no signs of inflammation, leakage or infection. Furthermore, the injected test substance appears to have behaved exactly as expected. “These data indicate that the material at the needle tip dispersed well in the vitreous body and retina.”, explain the researchers.
It is therefore a very interesting approach which has many advantages on paper. And it’s not just intravitreal injections. Because when we go through the list of characteristics, we notice that this approach could be useful in other clinical contexts. Many diseases that require recurrent injections could eventually be treated with such a system.
But in the current state of things, we will still have to wait. To begin with, it will already be necessary to go beyond pig tests and verify that this approach works as well in humans. And if this eventuality occurs, it will still be necessary conduct a long clinical trial to confirm its therapeutic interest. Finally, it will be necessary to qualify these conclusions by drawing up a list of side effects and contraindications. Suffice to say that it is not tomorrow that your ophthalmologist will offer you a procedure of this type, but there is reason to be enthusiastic.
The text of the study is available here.