This study is testing a new medicine called tonabersat for people with a condition called diabetic macular edema (DME). DME is an eye problem that can happen to people with diabetes, causing fluid to build up in a part of the eye called the macula, which is important for seeing fine details. The study compares tonabersat with a placebo (a sugar pill with no medicine) to see if it can help reduce the thickness of the central area of the retina, which is the back part of the eye that helps us see clearly.

Tonabersat is a pill taken by mouth that blocks something called Connexin43 hemichannels, which may help with DME. The study lasts for 6 months, and researchers will also look at kidney health markers.

• The study is for adults with type 1 or type 2 diabetes with good eyesight.
• Participants should not have had recent major eye surgery or other treatments for DME.
• Participants should not have serious kidney problems or need dialysis.