NOV 10, 2015
The authors of this randomized trial wade into the controversy over blue-blocking IOLs and circadian rhythm and found that neither cataract surgery nor IOL type have a significant impact on circadian photoentrainment or sleep quality.
The authors randomized 76 patients (76 eyes) in a single center to receive either blue-blocking (SN60WF) or neutral (ZCB00) IOLs, which transmit approximately 80% or 95% at 480nm, respectively. The primary outcome was post-illumination pupil response (PIPR) as a measure of the activation of intrinsic photosensitive ganglion cells by blue light. Secondary outcomes were actigraphy, salivary melatonin and subjective sleep quality.
At 3 weeks postop, the authors found a 24% increase in blue light PIPR (P<0.001) and an increase in nightly peak melatonin concentration (P=0.037). However, these changes failed to correspond with any significant differences in actigraphy parameters or subjective sleep quality. Additionally, there were no significant differences in any of the endpoints between the two IOL groups, which the authors attribute to the relatively small 15% difference in blue light transmission between blue-blocking and neutral IOLs.
While their data failed to show an adverse effect on sleep quality, the authors acknowledge that there may be long-term effects outside the scope of this study.