Ophthalmologists point to growing evidence that drugs to promote weight loss and improve blood sugar control may be linked to the initial worsening of diabetic retinopathy.
Medical experts have urged caution about the potential eye risks associated with GLP-1 receptor agonists, a class of drugs increasingly used to treat obesity and type 2 diabetes.
Drugs such as semaglutide (marketed as Ozempic and Wegovy) and tirzepatide (Mounjaro) have gained worldwide attention for their effectiveness in improving blood sugar control and aiding weight loss.
Their use in India is expected to grow after the key patent for semaglutide expires on March 20, potentially paving the way for more affordable versions. While this could expand access, doctors warned it could also lead to uncontrolled or inappropriate use.
Emerging concerns
Ophthalmologists point to growing evidence that these drugs may be associated with the initial worsening of diabetic retinopathy and, in rare cases, non-arteritic ischemic optic neuropathy (NAION) — often described as an “eye stroke” that can cause sudden, painless vision loss.
Experts said that the rapid reduction in blood sugar produced by these therapies can temporarily affect blood flow to the retina and optic nerve in some patients.
Evidence and risk factors
Although long-term data are still developing, global agencies such as the World Health Organization and the European Medicines Agency have recognized NAION as a rare potential adverse effect.
The risk appears higher in individuals with preexisting diabetic retinopathy, hypertension, sleep apnea, or certain optic nerve characteristics, although the overall incidence remains low.
Call for careful use
Rohit Shetty, director of Narayana Nethralaya, said the benefits of these drugs must be balanced with careful clinical judgment.
“These drugs are effective when used correctly, but their increasing use means we need to be more vigilant in identifying patients at higher risk of complications,” he said.
He emphasized the need for a detailed pretreatment evaluation. “Assessment of both systemic and ocular health—particularly the presence of diabetic retinopathy or vascular risk factors—helps stratify patients and select the most appropriate therapy,” he said.
He added that high-risk patients may need closer monitoring, including baseline and regular retinal examinations. “In some cases, closer monitoring or even re-evaluation of therapy may be needed, especially during the early phase when blood sugar levels are changing rapidly,” he said.
The need for integrated care
GV Divakar, former president of the Bangalore Ophthalmic Society and consultant at Divakars Specialty Hospital, said GLP-1 receptor agonists are associated with rare but serious eye complications.
“These include non-arteritic anterior ischemic optic neuropathy, which can result in permanent vision loss, as well as progression of diabetic retinopathy,” he said, emphasizing the need for regular eye exams and follow-up.
“Collaboration between endocrinologists and ophthalmologists is key to minimizing risks while ensuring that patients benefit from these therapies. A broader approach is expected, patients should not self-medicate. Treatment should only be done under proper medical supervision,” he said.
Rajesh R., Consultant – Vitreo-Retina and Ophthalmic Oncology at Sankara Eye Hospital, said that while these drugs are effective, awareness of the potential risks is essential.
“Rapid improvement in blood glucose can sometimes lead to a temporary worsening of diabetic retinopathy. This is not unique to these drugs and can occur with any form of intensive glucose control,” he explained.
The most vulnerable
Patients with long-standing uncontrolled diabetes or advanced retinopathy are particularly vulnerable. Some visual disturbances reported during treatment may be related to fluctuations in blood sugar rather than a direct effect of the drugs, he said.
Dr. Rajesh also pointed out that isolated reports of vision loss related to the optic nerve are still under investigation. “Currently there is insufficient evidence to establish a clear causal relationship and further research is needed,” he said.
Published – 01 April 2026 22:13 IST
