Clinical outcomes of nonpenetrating subretinal tissue plasminogen activator injection through a focal internal limiting membrane window for severe submacular hemorrhage

The back of the eye contains a delicate layer of tissue called the retina, which acts like the film in a camera, capturing the light that allows us to see. At the very center of this layer lies the macula, a tiny spot responsible for sharp, detailed vision. When blood leaks into the space just beneath this critical area, it creates a submacular hemorrhage. This event is often devastating because the blood clots, separates the light-sensing cells from their nutrient supply, and releases toxic substances that can permanently damage vision. For decades, surgeons have tried to clear this blood, often using a fine needle to inject a clot-dissolving medication directly under the retina. However, this traditional approach carries a risk: the needle must pierce the fragile retinal tissue, and even a tiny mistake can tear the retina or create a hole, potentially causing more harm than the blood itself.

A team of surgeons at China Medical University Hospital recently tested a gentler way to deliver this life-saving medication. Instead of forcing a needle through the retina, they created a small, temporary window in the protective membrane that sits on top of the retina. Through this opening, they slid a needle flat against the surface of the eye tissue and pushed the medication sideways, allowing it to flow underneath the blood without ever puncturing the deeper layers. They applied this technique to thirteen eyes suffering from severe bleeding caused by various conditions, including age-related macular degeneration, trauma, and even a rare blood disorder. The results showed that this non-piercing method successfully cleared the blood and improved vision in nearly every case, with no instances of the needle causing new tears or holes in the retina.

The study focused on patients who had severe bleeding that threatened their central vision. In some cases, the blood was so thick it had lifted the retina away from the back of the eye, a condition known as hemorrhagic retinal detachment. In others, the bleeding was linked to systemic illnesses, such as a severe form of leukemia that left the patient with dangerously low blood cell counts. The surgeons performed a standard vitrectomy, a procedure to remove the gel that fills the eye, and then carefully stained the inner surface of the retina to make it visible. Instead of peeling away the entire protective membrane, they removed only a tiny patch, just large enough to serve as an entry point. They then lowered a needle so thin it is measured in forty-one gauge units until it rested flat against the exposed tissue. By injecting the medication tangentially, or sideways, they created a bubble of fluid that lifted the blood away from the sensitive center of the eye.

Over the course of six months, the researchers tracked the vision of the twelve patients who survived the follow-up period. The improvement was significant. At the start of the study, the average patient could barely see shapes or count fingers at a short distance. By the sixth month, the average vision had improved enough that many patients could read standard text or recognize faces. Every single eye that completed the six-month checkup showed a measurable gain in vision, with most seeing at least a moderate improvement and several seeing a dramatic recovery. The thickness of the retina, which was swollen and thickened by the blood at the beginning, returned to a much more normal state within the first month after surgery. Even in the most difficult cases, such as a woman with a blood disorder whose platelet count was critically low, the surgery proceeded without complications, and her vision improved before she sadly passed away from her underlying illness.

Safety was a primary concern, given that the eye is a fragile organ and the patients were already in poor health. The surgeons looked for any signs that the new technique might have caused damage, such as a hole in the retina, a new detachment, or an infection. In all thirteen eyes treated, there were no such procedure-related complications. The only instance of bleeding returning was in an elderly patient whose original blood vessel ruptured again due to the underlying disease, not because of the injection technique. The study did not find a clear link between how quickly the surgery was performed after the bleeding started and the final visual outcome, though the researchers noted that their group was too small to draw a firm conclusion on timing. They also observed that the technique worked well across different causes of bleeding, from trauma to age-related disease, suggesting the method is robust enough to handle varied and severe presentations.

This work builds upon earlier technical reports that suggested removing a small piece of the inner membrane could make subretinal injections safer. While previous studies had tested this idea in animals or in limited groups of patients with a single disease, this series provided a broader look at how the method performs in real-world, complex scenarios. The surgeons demonstrated that it is possible to deliver medication under the retina without piercing the tissue, a maneuver that avoids the mechanical risks associated with traditional needles. Although the number of patients was small, the consistency of the results across such a diverse group of severe cases offers strong evidence that this approach is feasible. The findings suggest that for eyes that are too fragile for standard needle insertion, a non-penetrating window offers a viable path to restoring sight, provided that larger studies can confirm these early successes.