For how we live.
Cataract surgery was tied to 29% lower dementia risk in a strong cohort. But the largest hearing-aid trial found no overall effect on cognition. The signal is real; the proof that fixing senses prevents dementia is not.
Serious contact-lens eye infections are uncommon in absolute terms, but overnight wear is the single largest modifiable risk factor. The rare cases can scar the cornea and cost vision.
The trials that made eye vitamins a standard recommendation enrolled only people who already had substantial disease. In AREDS2, neither omega-3 nor lutein beat placebo on the primary endpoint.
Eye strain is close to universal among heavy device users, and it is temporary. The evidence that screen time causes myopia is real but weak, and every study of it measured screen time by questionnaire.
Cochrane's living review of 104 trials rates high-dose atropine and orthokeratology moderate certainty. The low-dose atropine most widely used sits at very low certainty, and two Western trials disagree.
Reviews put patient satisfaction around 95 percent. FDA-collaborative studies also found that a large minority reported new glare, halos or dry eyes afterward — two true findings that must be held together.
A cluster-randomised trial in Guangzhou cut three-year myopia incidence by 9.1 percentage points with 40 extra minutes outdoors a day. The eye's underlying growth barely changed.