Effects of ultraviolet and blue-light filtering on sleep: a meta-analysis of controlled trials and studies on cataract patients.

Purpose: Two types of intraocular lenses (IOLs), namely ultraviolet-filtering IOL (UVF-IOL) and blue-light-filtering IOL (BF-IOL), are used to replace the aging lens in cataract patients. This provides a clinical scenario to investigate the BF and UVF effects on circadian rhythm. We revisited this topic and conducted an updated meta-analysis investigating the effects of UVF-IOL and BF-IOL on sleep quality.

Methods: A literature search was conducted using the PubMed, Embase, and Cochrane Library databases, and finally, four randomized controlled trials, one nonrandomized controlled study, and two cohort studies were included in this meta-analysis.

Results: The fixed-effect model revealed a significantly larger sleep quality improvement in the UVF-IOL group than in the BF-IOL group (standard mean difference [SMD] = 0.10, 95% confidence interval [CI]: 0.00-0.21) at 3-8 weeks but not 7-12 months after IOL implantation (SMD = 0.03, 95% CI: -0.08 to 0.13). The random effects model revealed no difference between groups at 3-8 weeks (SMD = 0.16, 95% CI: -0.07 to 0.39) and 7-12 months (SMD = 0.03, 95% CI: -0.08 to 0.13) after IOL implantation.

Conclusions: Our study found some weak evidence supporting that UVF-IOL implantation demonstrated a greater improvement in subjective sleep quality than the BF-IOL implantation only in a shorter period but not in a longer period. More trials should be conducted before further recommendations. Nevertheless, our study provides some insights into the effects of short wavelength electromagnetic radiation on the circadian rhythm. PROSPERO registration number: CRD42019128832.