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G.R. Jackson, R.J. Olson; Effect of Blue–Blocking IOLs on Scotopic Sensitivity . Invest. Ophthalmol. Vis. Sci. 2005;46(13):806.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: This study is the first to examine whether blue blocking IOLs have a detrimental effect on rod–mediated vision. Scotopic sensitivity was measured in pseudophakic patients at multiple wavelengths to determine whether tinted IOLs reduce scotopic sensitivity relative to UV–blocking IOLs. Methods: The sample included 8 pseudophakic, normal subjects (mean 72 yrs old) and 3 pseudophakic, mild ARMD patients (mean 76 yrs old). The transmission curves of a 20 D Alcon Natural blue–blocking IOL (trial lens) and a UV–blocking IOL (control lens) were replicated in trial lenses. Each patient's scotopic visual field was measured twice, once with each trial lens. The order of the trial lenses were counterbalanced across subjects. Scotopic sensitivity was measured using a modified Humphrey Field Analyzer. Subjects were dark adapted for 40 minutes. Scotopic sensitivity was measured at the following wavelengths: 410 nm, 450 nm, 500 nm, and 560 nm. The stimulus was a 1.8 degree diameter circular test spot. Test locations were at 7 degrees eccentricity on each visual axis with an additional point at 18 degrees in the peripheral nasal field for the ARMD subjects. Results: The mean impairment for the trial lens compared to the control lens for the normal group was 65% at 410 nm (P=0.003), 27% at 450 nm (P=0.016), 2% at 500 nm, and 4% at 560 nm. The ARMD group was 55% at 410 nm, 44% at 450 nm, 4% at 500 nm, and 2% at 560 nm. Impairment was even greater peripherally in the ARMD group; 66% at 410 nm, 54% at 450 nm, 26% at 500 nm, and 21% at 560 nm. Conclusions: This study indicates that blocking blue light leads to measurable impairments in scotopic sensitivity. As expected, scotopic sensitivity impairment decreased with increasing wavelength. Interestingly, the deficits were larger in the periphery than in the macula. The findings suggest that blue–blocking IOLs may impair night vision. We are proceeding with a randomized, prospective study of scotopic vision in individuals implanted with the Alcon Natural IOL. Further studies addressing the effects of blue blocking IOLs on mobility and driving at night are warranted.
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