Cataract Surgery Linked to Increased Risk of Worsening Diabetic Retinopathy

Cataract surgery was associated with an increased risk of worsening diabetic retinopathy in adults with type 2 diabetes, according to a retrospective analysis.

After propensity score matching, cataract surgery was linked to increased 1-year risks of proliferative diabetic retinopathy (PDR) without complications, vitreous hemorrhage, and a composite outcome (including PDR, vitreous hemorrhage, and tractional retinal detachment or combined tractional and rhegmatogenous retinal detachment) in both right and left eyes, respectively:

• PDR without complications: HR 1.45 (95% CI 1.09-1.92) and HR 1.58 (95% CI 1.17-2.13)
• Vitreous hemorrhage: HR 1.92 (95% CI 1.13-3.25) and HR 2.12 (95% CI 1.23-3.66)
• Composite outcome: HR 1.49 (95% CI 1.13-1.96) and HR 1.60 (95% CI 1.21-2.13)

A sensitivity analysis of those who had type 2 diabetes for at least 5 years showed that cataract surgery was tied to increased 1-year risks of PDR without complications (HR 1.52, 95% CI 1.06-2.19), vitreous hemorrhage (HR 2.50, 95% CI 1.20-5.20), and the composite outcome (HR 1.75, 95% CI 1.22-2.51) in operated eyes, reported Ahmed Sallam, MD, PhD, of the University of Arkansas for Medical Sciences in Little Rock, and colleagues in Ophthalmology.

There was no significant difference in the risk for tractional retinal detachment or combined tractional and rhegmatogenous retinal detachment in all analyses (all P>0.05).

“PDR may lead to severe and irreversible vision loss, with earlier detection and treatment generally leading to better long-term outcomes,” Sallam told MedPage Today. “Identifying this risk factor for progression may allow for increased index of suspicion at follow-up postoperatively and lead to earlier diagnosis and treatment.”

He added that while the overall risk of PDR in the study patients was low, “cataracts and diabetic retinopathy are amongst the most common conditions encountered in daily practice. Considering the very large and expanding at-risk population, this difference is clinically meaningful.”

However, “despite the noted increased risk, cataract surgery provides substantial visual and quality-of-life benefits for patients with diabetes,” Sallam said. “The key is not to avoid surgery but to be vigilant about diabetic retinopathy progression in the postoperative period.”

Diabetes doubles the risk for cataracts and is a risk factor for complications due to cataract surgery. Older strategies for cataract surgery, such as intracapsular cataract extraction and conventional extracapsular cataract extraction, were linked to an increased risk of PDR.

However, “evidence about modern phacoemulsification has been scarce and conflicting,” co-author Asad Loya, MD, of Baylor College of Medicine in Houston, told MedPage Today. “Some small studies suggested no significant increased risk, while others hinted at an elevated risk of diabetic retinopathy worsening.”

What might explain the higher risk? Loya said cataract surgery creates a temporary pro-inflammatory state in the eye, which could accelerate diabetic retinopathy. In addition, “postoperative alterations in vascular endothelial growth factor, hepatocyte growth factor, and decreased pigment epithelium-derived factor may promote angiogenesis,” he noted.

Ninel (Nell) Gregori, MD, of the University of Miami Miller School of Medicine, said that previous studies exploring the possibility of worsening diabetic retinopathy after modern phacoemulsification cataract surgery were small and inconsistent, while the new research relies on a large dataset.

The findings, she told MedPage Today, “highlight the need for patient education and close follow-up. Typically, we follow diabetic patients more frequently with regular dilated fundus examinations after cataract surgery.”

Paolo Antonio S. Silva, MD, of Harvard Medical School in Boston, noted that preoperative assessment of diabetic retinopathy is important, “but cataracts may obscure severity.”

Silva told MedPage Today that “optimizing diabetes control, considering anti-VEGF therapy for high-risk patients, and close follow-up can help reduce risk.”

For this study, Sallam and colleagues used data from the TriNetX research network from June 2004 to June 2024, a period when phacoemulsification was the main cataract surgery method in the country, and compared adults with type 2 diabetes and non-proliferative diabetic retinopathy who underwent routine cataract surgery versus those who did not receive cataract surgery.

They included 7,178 patients in the right-eye analysis and 7,232 patients in the left-eye analysis. Mean age was 67.2 in the surgery group and 67.8 in the control group. The majority of both groups were women and white.

A limitation to the study was that TriNetX lacks visual acuity data, which the researchers could not account for while matching.

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