This is an interesting report of a potential negative consequence of prescribing the GLP-1 agonist drug semaglutide for those with diabetes, on their risk of NAION (nonarteritic ischemic optic neuropathy), a cause of blindness. Compared to those prescribed other drugs for diabetes, those who received semaglutide had a greater risk of NAION after 3 years (6.7% versus 0.8%).
 
Basically, the authors sound a warning that the drug may increase risk of this condition, while pointing out that more work is required to confirm any association. It is noteworthy that the group prescribed semaglutide was older than the other group, but the authors suggest the risk was not related to baseline differences. 
 
The authors point out that the retrospective nature of the research design does not permit causality to be determined, and are careful to add various caveats to their findings, including the data being generated in a tertiary setting, and the possibility of bias in those prescribed this particular drug class (for instance, the drug may have been more likely to have been used in those with more serious disease).  They call for a larger study with well described optic neuropathy diagnostic criteria to assess whether there is a casual link between eye disease and semaglutide use.