In a medical first, surgeons have used a robot to operate inside the human eye , greatly improving the accuracy of a delicate surgery to remove fine membrane growth on the retina . Such growth distorts vision and, if left unchecked, can lead to blindness in the affected eye.

In the trial, at a hospital in the United Kingdom, surgeons performed the membrane-removal surgery on 12 patients; six of those patients underwent the traditional procedure, and six underwent the new robotic technique. Those patients in the robot group experienced significantly fewer hemorrhages and less damage to the retina , the findings showed.

The technique is “a vision of eye surgery in the future,” Dr. Robert E. MacLaren, a professor of ophthalmology at the University of Oxford in the United Kingdom, who led the study team and performed some of the surgeries, said in a statement. MacLaren presented the results today (May 8) at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO), happening this week in Baltimore.

Membrane growth on the retina results in a condition called epiretinal membrane, a common cause of visual impairment . The retina is the thin layer at the back of the eye that converts light waves into nerve impulses that the brain then interprets as images.

An epiretinal membrane can form because of eye trauma or conditions such as diabetes, but more commonly it is associated with natural changes in the vitreous, the gel-like substance that fills the eye and helps it maintain a round shape. As people age, the vitreous slowly shrinks and pulls away from the retinal surface, sometimes tearing it.

Faced with the need for such precision, de Smet and his Dutch-based group developed a robotic system over the course of about 10 years. Robot-assisted surgery is now commonplace, particularly for the removal of cancerous tumors and diseased tissues, as in the case of hysterectomies and prostatectomies. But it has never been tried on the human eye, given the finer precision needed, the researchers said.

MacLaren’s team first used the system on a human, a 70-year-old priest from Oxford, England, in September 2016. Upon the success of that surgery, MacLaren’s team conducted a study on 11 more patients in a randomized clinical trial, hoping to measure the robotic system’s accuracy compared to the human hand.

The robot acts like a mechanical hand with seven independent motors that can make movements as precise as 1 micron. The robot operates inside the eye through a single hole less than 1 millimeter in diameter and goes in and out of the eye through this same hole during various steps of the procedure. But the surgeon is in control, using a joystick and touch screen to maneuver the robot hand while monitoring movements through the operating microscope, MacLaren explained.

“The robotic technology is very exciting, and the ability to operate under the retina safely will represent a huge advance in developing genetic and stem cell treatments for retinal disease,” MacLaren told Live Science.

The surgical system was developed by Preceyes BV, a Dutch medical robotics firm established at the University of Eindhoven by de Smet and others.