Hypertension can also cause cataract which is similar to the age related cataract. Hypertension combined with diabetes greatly increases the chances for cataract formation. The reason for cataract formation is usually swelling of the lens. If the blood pressure is kept under control, then it decreases the cataract formation.

Studies have shown that smokers are at a much greater risk of developing cataract than others. The degree of cataract is also proportional to the amount or frequency of smoking. The exact reason why smokers develop cataract is not clear but the correlation between the two has been established. No conclusive result has been obtained to show if the cessation of smoking decreases the chances for cataract. 

Exposure to cosmic rays, infra red radiations and even microwave radiation can lead to cataract formation. A study has shown that people who are exposed to ionizing radiations as part of their profession, like airline pilots, are three times more susceptible to cataract than others.

Sometimes eye surgery itself (other than cataract operation) can lead to cataract. One reason for this is that during surgery, sometimes when the lens comes in contact with laser or metal surgical instrument, it can lead to lens damage. Another reason for this is that after the eye surgery there will be an alteration or difference in the movement of eye fluid. But chances of cataract development after an eye surgery is usually very low and even if cataract develops, the development will be very slow. Retinal and glaucoma surgeries are the common causes.

Congenital cataracts are the type of cataract that are present from birth. This occurs due to malformation or abnormal formation of the lens while the baby is in womb. These can be caused by number of factors including genetic. Mostly, these cataracts do not worsen with time. But sometimes they can result in marked decrease in vision. In such cases, infants undergo cataract surgery to allow them to see normally and clearly as they age. Mostly these type of cataracts are not known to cause any significant decrease in vision. In fact, they can usually be left in the eye without any problem.

Prolonged use of certain types of medication can cause cataract. The most common form of medication that causes cataract are steroids. Steroids called corticosteroids are common cataract causing agents. A number of diseases and illness are treated with steroids. For example, asthma and rheumatoid arthritis require long term steroid treatment. Steroid related cataracts are mostly posterior subcapsular type of cataracts. Long term use of some eye medication like pilocarpine can also cause cataract formation.

Sometimes as a result of severe eye injury, cataracts can develop. Such cataracts are called traumatic cataracts. This form of cataract occurs especially when foreign objects enter or pierce the eye. Severe lens damage and some blunt injury which results in temporary collapsing of eyes can also cause traumatic cataracts.

This is the most common cause for cataract. As people age they will develop some degree of cataract. The exact reason for this in correlation is ambiguous. With increase in age, people are at a greater risk. 75% of people above 70 years of age have cataract complications. Most of the cases will require a cataract surgery, which is a simple procedure to restore vision. The common age related cataracts include nuclear sclerosis and cortical spoke cataracts.