Not only does the procedure seem unpleasant, but other things could go wrong. Endophthalmitis, for example, is a bacterial infection caused by germs entering the hole where the needle was inserted.
Repeated injections can also harm the eye tissue. Worse, tumor cells may float through the newly formed hole and spread to other parts of the body.
With these considerations in mind, an international team of researchers has developed a new, potentially better system for delivering drugs to the eye that avoids these complications.
"This novel improvement in drug delivery treatment can avoid problems associated with using needles to treat serious eye diseases," said Ali Khademhosseini, director of the Terasaki Institute for Biomedical Innovation.
The new procedure has done well in preclinical studies, but it still includes eye needles, which gives us nightmares.
Intravitreal Injection is the medical term for injecting a medication into the vitreous humor of the eye (a jelly-like fluid that fills the eyeball). It is used to treat a variety of diseases such as age-related macular degeneration (AMD) and diabetic eye disease.
Instead of relying on several infection-risking injections between treatments, the researchers developed an ultrathin microneedle that stays in the eye and biodegrades over time.
Currently, the treatment consists of multiple injections of an anti-VEGF drug into the jelly-like substance in the eye.
The microneedle has a hydrogel 'plug' that seals the created hole and gradually releases the drug-coated in it while inside the eye.
The researchers, who were mostly from South Korean institutions, put the new system to the test in a variety of ways.
First, the team injected microneedles into the eyes of excised pigs. This demonstrated that the hole was closed after the injection and that the drug (in this case, a purple dye) spread through the eye as expected.
The team then proceeded to insert the microneedle into live pigs. The team discovered no leakage or inflammation at the site, and the needle tip was still securely lodged in place seven days later.
As is typical with these types of experiments, there's a long way to go before you're injected with a biodegradable self-plugging microneedle at your neighborhood optometrist. Longer studies in animal models will be required to ensure safety, and clinical trials will be required to confirm if the design is also safe in humans.
For the time being, however, this is an exciting discovery that may provide a slightly less horrible solution to a very horrible problem.
