Partial or total clouding of the lens due to various causes is called cataract. Cataracts mainly manifest as loss of vision and blurred vision, but in clinical practice vision is not the only criterion to diagnose cataracts.
The front of the eye, which we can see as the so-called black eye, is called the cornea, and after the cornea, the iris and pupil are visible, and through the pupil, the subsequent lens is visible. Hanging from the ciliary body by the suspensory ligament of the lens, it is located at the front of the eye and consists of the lens capsule, cortex and nucleus. Its role is similar to that of a camera lens, helping to focus accurately so that we can see objects near and far clearly. If the lens becomes cloudy, it is a cataract. There are many causes of lens clouding, including: age, ultraviolet light, malnutrition, metabolic diseases such as diabetes, drugs, poisoning, other diseases of the eye such as uveitis, retinitis pigmentosa, retinal detachment, advanced glaucoma, intraocular tumors, low eye pressure, high myopia, and genetic and congenital factors. One of the most common causes is age. As we age, the lens undergoes natural aging and causes lens clouding.
There are many classifications of cataracts: (1) congenital, senile, traumatic, concurrent, metabolic, drug and toxic cataracts by etiology; (2) congenital and acquired cataracts by onset; (3) punctate, coronal and nuclear cataracts by lens clouding pattern; (4) cortical, nuclear and subcapsular cataracts by lens clouding site; (5) primary cataracts by degree of lens clouding. (5) The degree of lens clouding is divided into primary, immature, mature and premature cataracts.
In summary, cataract is a clouding of the lens and treatment is mostly surgical.