Intravitreal injection of drugs is now the standard of care for treatment of many forms of diabetic macular edema and “wet” macular degeneration. The results after injection can be amazing, yet every time I inject a patient, I am acutely aware that there is a small risk of developing endophthalmitis with the injection – 1/1000 per injection. And as is often the case, the organisms causing infection with intravitreal injections often lead to loss of vision. It’s a small risk, but a very real one. I wish there were some way to deliver the drugs without having to inject them into the vitreous.
So, I was excited to read of the study by Patel et al from the Georgia Institute of Technology that was published in the July 2012 issue of Ophthalmology and Visual Science. They describe using a 750 micron needle to inject drugs into the suprachoroidal space (SCS) of rabbit eyes. This technique delivers drugs to the chorioretinal area, through the sclera, and avoids entering the vitreous cavity. Presumably, the risk of endophthalmitis would be greatly reduced, if not eliminated, with this technique.
The study showed that drug concentrations after such injections were higher in the posterior segment of the eye than the anterior segment, and that they stayed around longer than with intravitreal injections.
Of course, the efficacy of this technique would need to be proven in humans, and I look forward such studies. I’m thrilled that such work is being done as it could help reduce the main concern of intravitreal injection, endophthalmitis.
If you are Medscape member, you can read more about the study here. Microneedle Developed for Back-of-the-Eye Injections