Alcohol
Alcohol has many serious disadvantages over health. Alcohol can lead to cataracts by damaging the protein required to build a lens. The free radicals formed after the breakdown of ethanol may trigger cataract formation. Alcohol also alters the calcium levels required by the eye lens which can, in turn, give rise to cataract. After cataract surgeries, the doctors advise patients to quit alcohol entirely for a week in order to obtain better results.