Medications such as Ozempic, Wegovy, and Mounjaro—which contain the active ingredients semaglutide and tirzepatide—have revolutionized the management of diabetes and obesity globally. These drugs, classified as GLP-1 agonists, work by mimicking the hormone GLP-1, thereby reducing appetite and food cravings while simultaneously aiding in blood sugar control. However, recent studies have raised concerns regarding a potential increased risk of serious eye conditions and vision loss in patients using these medications.
Two significant studies published recently indicate that individuals taking GLP-1 medications may have a slightly elevated risk of developing serious eye conditions, particularly non-arteritic anterior ischaemic optic neuropathy (NAION). This rare condition, often referred to as an "eye stroke," occurs when blood flow to the optic nerve is abruptly diminished or blocked, leading to sudden vision loss.
Unlike other eye disorders that progress gradually, NAION results in a rapid, painless loss of vision, typically noticed upon waking. While the exact cause of NAION is still uncertain and no effective treatments currently exist, it is important to note that individuals with diabetes are at a heightened risk of developing this condition.
A study conducted in 2024 revealed alarming statistics: participants prescribed semaglutide for diabetes exhibited a fourfold increased likelihood of developing NAION, while those using it for weight loss faced an almost eightfold risk. In June, the European Medicines Agency acknowledged NAION as a very rare side effect of semaglutide, estimating a risk of one in 10,000, and mandated that product labels reflect this potential risk.
The recent studies reviewed medical records of between 159,000 and 185,000 individuals with type 2 diabetes over a two-year period. One study found that the risk of developing NAION among patients taking semaglutide or tirzepatide was more modest than previously reported, with 0.04% of those on these medications developing NAION compared to 0.02% in the control group. Additionally, there was an observed increase in other optic nerve disorders, although the specifics of these conditions remain unclear due to the coding used in medical records.
Conversely, the second study found no increased risk of NAION among GLP-1 drug users but did note a minor increase in the incidence of diabetic retinopathy. This condition arises when elevated blood sugar levels damage the small blood vessels in the retina, potentially leading to vision loss. Interestingly, the study indicated that patients on GLP-1 medications experienced fewer sight-threatening complications from diabetic retinopathy and required less invasive treatment compared to those on alternative diabetes medications.
While NAION poses a serious risk, it is crucial to weigh this against the numerous benefits of GLP-1 medications in managing diabetes, addressing obesity, and potentially reducing heart attack risks. Patients should engage in informed discussions with their healthcare providers to understand their individual risk levels, especially if they have multiple risk factors for NAION, such as sleep apnoea, high blood pressure, or existing diabetes.
Additionally, individuals with anatomical features such as crowded optic nerve heads should consider this risk before commencing GLP-1 medications. Regular eye examinations with an optometrist or ophthalmologist are essential for monitoring eye health, particularly for those on GLP-1 drugs.
Emerging research suggests that maintaining good heart health may mitigate the risks associated with NAION. Effective management of conditions such as high blood pressure, diabetes, and cholesterol is vital, as these factors can compromise the small blood vessels supporting the optic nerve. Studies indicate that patients with heart conditions who adhere to their medication regimens have a lower risk of developing NAION.
Healthcare providers should prioritize discussions about NAION risks when prescribing GLP-1 medications and collaborate with eye care specialists to monitor patients for diabetic eye disease. Clear communication regarding the need for immediate medical attention in the case of sudden vision loss is vital, alongside the importance of routine eye examinations.
In conclusion, while there are potential risks associated with GLP-1 medications, ongoing research is necessary to fully comprehend their impact on eye health. A five-year clinical trial is currently underway to examine the long-term effects of semaglutide on diabetic eye disease, which will provide further insights into these ocular risks.
