I'm curious about how to diagnose cataract symptoms.

Depending on the location, severity, and extent of the cataract opacity, various degrees of vision impairment can occur.

If there is partial clouding, monocular diplopia (seeing double images with one eye) may occur, and if sclerosis (hardening) of the lens nucleus (the central part of the lens) increases the refractive index of the lens, it can lead to myopia, making nearby objects appear clearer than before. If, as you age, presbyopia causes difficulty seeing, but suddenly you can see well again, it should not be thought of as your eyes improving, but rather as a symptom caused by cataracts. Is there an easy way to self-diagnose this?