Blue-blocking Intraocular Lenses: Myth or Reality?

The Beaver Dam and Blue Mountain eye studies correlated late AMD with cataract surgery, but the Age-Related Eye Disease Study and recent Swiss, Chinese, and German studies found that pseudophakia was not a major risk factor for AMD.1,4,8,9 If a correlation does exist between cataract surgery and AMD, it is probably attributable to shared risk factors and/or the effects of intraocular surgery.1,10 Acute retinal phototoxicity experiments on cell cultures and experimental animals have been used to advocate blue-blocking IOLs, but AMD is a chronic process whereas photic retinopathy occurs only when brilliant light exposure acutely overwhelms retinal defenses.3 Acute phototoxicity can injure the retina but it cannot simulate AMD, just as sun gazing can scar the fovea but it cannot simulate a lifetime of normal environmental light exposure.1 Age-related decreases in crystalline lens transmittance and pupil area progressively reduce retinal illumination in an older adult's eyes.1,4 The transmittance spectra of crystalline lenses of different ages and current IOLs can be multiplied wavelength by wavelength with sensitivity spectra to estimate their relative effects on photoprotection and photoreception.1,4 For example, 65-year-old and 75-year-old pseudophakes with 20-diopter blue-blocking IOLs have the same protection against acute retinal phototoxicity (equivalent ocular age) as 28-year-old and 34-year-old phakic adults, respectively.