It’s been suggested that pseudophakic eyes may experience greater retinal damage from intense near-ultraviolet light sources than crystalline lenses, resulting in an increased risk of age-related macular degeneration (AMD). Blue light-filtering intraocular lenses (BF-IOLs) have been hypothesized to offer photoprotective benefits and are often used in an attempt to prevent retinal damage in cataract patients post-surgery. However, when researchers tested this theory in a recent study, they found that BF-IOLs offer no tangible benefit over non-filtering IOLs in reducing patient risk for AMD development.
This Taiwanese cohort study included 186,591 patients who had bilateral cataract surgery between 2008 and 2013 and were followed for up to 10 years. Of these patients, 11.3% had BF-IOL implants, while the remaining 88.7% had conventional IOL implants. The researchers used a statistical tool called propensity score matching (PSM) to balance the baseline characteristics between the two groups.
The incidence rate of AMD after cataract surgery was 11.59 per 1,000 person-years. After PSM, there was no significant difference in AMD incidence rates between patients with BF-IOLs and those with non-filtering IOLs. “The incidence rate of non-exudative AMD and exudative AMD (per 1,000 person-years) was 9.95 and 1.22 for the BF-IOL group, and 11.13 and 1.44 for the non-BF-IOL group, respectively,” the researchers wrote.
However, before PSM, the AMD incidence in the BF-IOL group was significantly lower than in the non-BF-IOL group. The researchers explained, “Patients in the BF-IOL group tended to be younger, with a higher income, more non-manual workers, more patients from urban and suburban areas and fewer chronic diseases. Patients with longer life expectancy and higher income were willing to pay extra money to implant premium IOLs, such as the BF-IOL, and because the patients were younger, the incidence of AMD was also lower.” Once baseline characteristics were adjusted between the groups, the lack of evidence supporting the photoprotective benefits of BF-IOLs became clear.
So, why are BF-IOLs still being recommended to patients as though they offer an additional layer of protection? The study authors argue it’s because there’s not enough evidence to say whether they confer a benefit or not. A study investigating ophthalmologists’ clinical practice patterns found that, “although about 70% of respondents consider that there is little evidence in the protective effect of BF-IOLs on macular health, the most frequent reason for prescribing these lenses was a general safety measure against blue light.”
If you and your cataract surgery patient want to take the extra precaution to preserve ocular health and vision, implanting BF-IOLs over non-BF-IOLs won’t hurt, but this research doesn’t suggest it’ll help, either.
Lee JS, Li PR, Hou CH, et al. Effect of blue light-filtering intraocular lenses on age-related macular degeneration: a nationwide cohort study with 10-year follow-up. Am J Ophthalmol. 2021. [Epub ahead of print].