What Is Cataract?

Cataract is a disease in which the eye’s clear lens becomes clouded. Like a window that is frosted or fogged with steam, cataract also causes blurred vision. There are false beliefs about cataracts, but it should be said that a cataract:

• is not a film on the eye

• is not due to excessive use of the eye

• is different from cancer

• does not spread from one eye to the other

• does not cause reversible blindness

The most common symptoms of cataracts include:

• Blurred vision that is painless

• Light sensitivity

• Frequent changes in eyeglasses prescription

• Doubled vision in single eye

• Need for brighter light for reading

• Increasing difficulty with vision at night

• Fading or yellowing of colors


 Normal Vision Cataracts may cause blurred and cloudy vision


The amount and shape of the clouding of the lens is different. If the clouding of the lens is not near the central portion of the lens, you may not be aware of the presence of cataracts.

What Causes Cataracts?

most common cause of cataracts is aging. Other causes include:

• A family history of cataracts

• Health problems such as diabetes

• Previous eye injuries

• Long-term use of corticosteroid medications

• Long-term exposure to sunlight

• Previous eye surgery

How Is a Cataract Diagnosed?

A comprehensive eye examination done by an ophthalmologist can determine the presence and severity of cataracts, as well as any other problems that may cause low vision or visual discomfort. Other eye disorders in addition to cataracts, especially retinal detachment or optic nerve disorders may cause reduced vision. If low vision is caused by these problems, it will not be corrected after cataract surgery. And if these eye problems are severe, even cataract surgery may not improve visual problems. An ophthalmologist can determine whether your low vision is because of these problems or cataracts.

How Fast Do a Cataract Develop?

The rate of cataract development varies among people, and may even differ between the two eyes. Often, cataracts, which are caused by aging, develop gradually over few years. Other cataracts, especially in young people or in patients with diabetes, may quickly cause low vision over several months. Therefore, accurate prediction of the rate of cataract development is not feasible. How to treat cataracts The only way to treat cataracts is surgery. However, if the symptoms of cataracts are mild, a new prescription for your eyeglasses may temporarily resolve your vision problems. There is no medicine, no nutrition, exercise or lighting equipment that can cure or prevent cataracts. Avoiding sun exposure may help prevent or slow down the progression of cataracts. Sunglasses that absorb ultraviolet light or eyeglasses with an ultraviolet coating can protect your eyes.

When Should an Individual Undergo a Cataract Surgery?

If an individual undergoes a cataract and resultant blurred vision that makes it difficult to do his/her daily activities, it is time to consider cataract surgery. The idea that cataracts need to be "ripe" before it can be removed is not correct. When a cataract develops, the lens of the eye becomes thick and cloudy. Light can not easily pass through it, and then causes blurred vision. If your vision is too blurred to do your activities, cataract surgery can be done to improve your vision. You should consider these items: Is your vision good enough to do your job without any inconvenience? Can you drive safely? Can you read or watch TV comfortably? Can you do your daily activities such as cooking, shopping, doing chores, and taking your medications without difficulty? Based on your vision problems, you and your ophthalmologist can decide together whether cataract surgery is needed or not.

Patients’ Expectations Before Cataract Surgery

Each year, more than tens of millions cataract surgeries are performed in developed countries, of which about 95% of these surgeries have no post-operative complications. In Iran more than 100,000 cataract surgeries per year are performed using various surgical procedures.

In cataract surgery, which is usually carried out under local anesthetics, the cloudy lens is removed from the eye through a surgical incision. In most cases, the natural lens is replaced with a permanent intraocular lens (IOL) implant. The intraocular lens stays in your eyes forever and does not get corrupted. The ophthalmologist performs cataract surgery with ophthalmic surgical microscopes and modern technology. An intraocular lens implantation, which is performed by a surgeon, not only will not cause more post-operative complications, but also will make the patient's vision sharper after surgery, and will not require thick and heavy glasses that cause many problems.

In about one-fifth of patients who undergo cataract surgery, the natural capsule that holds the intraocular lens, becomes cloudy after surgery, and a laser surgery to open this cloudy capsule is needed to improve the patient’s vision again.

After cataract surgery, you can do all your daily activities except for heavy ones. You should use the drops prescribed by your surgeon correctly and at the right time. Several post-operative visits are required to control your eye condition. Cataract surgery is a very successful surgery. In more than 90% of cases, vision is improved unless there is a problem in the cornea, retina or optic nerve. It is important to note that complications may occur during or after surgery, which may reduce vision.


Cataracts are common cause of vision loss, especially in the elderly, but can be cured. An ophthalmologist can tell you whether your loss of vision is due to cataracts or other causes. It also helps you decide on surgery.