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A study of 80,106 matched eyes in the American Academy of Ophthalmology IRIS Registry found a small association between cataract surgery and conversion from dry to neovascular AMD. The association was strongest during the first year and declined over time; the observational study cannot show that surgery caused the progression.
A national registry study found that people with dry age-related macular degeneration (AMD) had a modestly higher rate of conversion to neovascular AMD after cataract surgery than matched patients who did not have surgery. The association was strongest in the first year and declined over time, but the observational findings do not establish that surgery caused the progression.
Researchers analyzed records for patients aged 55 or older with early or intermediate dry AMD who had a natural lens at the start of the study. After matching, the comparison included 40,053 eyes in each group, one group with cataract surgery and one without. The data came from the American Academy of Ophthalmology’s IRIS Registry and covered January 2016 through December 2022.
Across follow-up, cataract surgery was associated with a 22% higher hazard of conversion to neovascular AMD (hazard ratio 1.22; 95% confidence interval 1.16 to 1.30). A time-based analysis found a stronger association in the first year after surgery, with a hazard ratio of 2.5, followed by a steady decline. The association was no longer statistically significant after four years.
At six years, cumulative conversion was 17.7% among eyes that had surgery and 15.2% among those that did not, an absolute difference of 2.5 percentage points. The reported association was weaker for eyes with intermediate-stage AMD. The analysis measured an association in registry data; it cannot establish the reason for the difference or show that the procedure itself caused AMD to progress.
Follow-Up After Cataract Surgery
The findings matter to people weighing the benefits of cataract surgery while living with dry AMD. Cataracts can impair vision, and the report notes that surgery can improve vision even in patients who have AMD. The registry results add a small potential risk to conversations about timing and follow-up, while providing no basis to treat the association as proof that surgery accelerates the disease.
For clinicians and patients, the early concentration of the association supports attention to AMD assessment around surgery and regular monitoring afterward. Neovascular AMD has treatments, and early detection can inform care. Emily Y. Chew of the National Eye Institute and co-authors wrote in an invited commentary that vigilant follow-up is important because patients with AMD may already face a high risk of progression, and surgery may allow a clearer view of the retina for diagnosis.
Why the Registry Study Matters
About 80% of people with AMD have the dry, or non-neovascular, form, which is associated with gradual vision loss. Whether cataract surgery affects the chance of progression to late AMD has remained uncertain. Earlier research has produced mixed findings: some large population studies conducted more than 20 years ago reported higher risks, while smaller cross-sectional studies found no association. A systematic review reported a correlation, with a stronger risk in studies with longer follow-up.
The study authors, led by Grayson Armstrong, MD, MPH, of Massachusetts Eye and Ear, said differences in study design, sample size, follow-up, statistical methods and changes in cataract surgery techniques may help explain those conflicting results. Their IRIS Registry analysis used propensity matching to compare eyes with similar measured characteristics, but matching cannot account for every difference between patients or determine what caused an outcome.
“This [observational] finding does not establish a causal relationship between CS and nvAMD conversion.”
— Grayson Armstrong, MD, MPH, and colleagues, reporting in Ophthalmology
Cause of Early Conversions
The registry study cannot determine whether cataract surgery biologically contributed to conversion, whether patients who had surgery differed in ways the analysis could not capture, or whether closer examinations after surgery led to more cases being detected. The authors said some vision loss attributed to cataracts before surgery could have reflected existing or incipient neovascular AMD, with postoperative surveillance revealing it.
The invited commentary likewise said increased surveillance could help explain the small association and that progression may occur coincidentally in people already at risk. The study reports a weaker association for intermediate-stage AMD, but it does not settle why that pattern appeared. The findings also do not establish how the association applies to an individual patient.
Counseling and Ongoing Monitoring
The report supports discussing the potential for AMD progression when patients with dry AMD consider cataract surgery, alongside the possible vision benefit. Armstrong and colleagues said each patient should be considered individually. Chew called for regular, potentially more frequent follow-up after surgery to monitor AMD and support good visual outcomes.
The registry analysis describes outcomes through six years, but it does not identify a specific follow-up schedule or establish that surgery caused the observed difference. Further research would need to clarify how disease severity, examination frequency and other patient factors contribute to the early association. For now, the next step described by the researchers and commentator is careful evaluation and continued clinical monitoring.
Key Questions
Does cataract surgery cause dry AMD to become neovascular AMD?
The registry study found an association, but it cannot establish that surgery caused conversion. The researchers said increased postoperative monitoring or AMD already developing before surgery could help explain the findings.
How large was the difference in the study?
At six years, cumulative conversion was 17.7% in the surgery group and 15.2% in the matched group without surgery, an absolute difference of 2.5 percentage points. The overall hazard ratio was 1.22.
When was the association strongest?
The association was strongest during the first year after surgery and declined over time. It was no longer statistically significant after four years.
What did the commentary recommend?
Emily Y. Chew and colleagues emphasized vigilant follow-up after surgery. They said regular monitoring can help manage AMD and that removing a cataract can sometimes improve the view needed for diagnosis.
Source: rss
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