Cataract surgery is a medical procedure performed to remove the cloudy lens from the eye and replace it with an artificial lens, known as an intraocular lens, to restore clear vision.
Baglioni, C., Battagliese, G., Feige, B., et al. (2011). Insomnia as a predictor of depression: A meta-analytic evaluation. Sleep Medicine Reviews, 15(4), 237-245.