Cataract: what is it, types, symptoms, surgery, is it curable?


What is cataract?

Ocular cataract is a disease in which the lens, the natural lens of the eyes, loses its transparency and begins to become opaque. It can cause partial or total loss of vision (blindness), in addition to making vision blurred or blurred, decreasing night vision and causing photophobia (hypersensitivity to light).

This condition develops slowly, often going unnoticed before causing any more serious symptoms. Before evolving, wearing glasses can help to cope with the disease, but when it becomes more serious, cataract surgery is necessary.

According to the World Health Organization (WHO), cataracts are responsible for 47.8% of all cases of blindness in the world. Among people over 65, almost half suffer from the problem. Thus, the most common cause for the onset of the disease is aging.

Understand what the lens is

The lens is the natural lens of the human eye . It is a biconvex and transparent lens, whose main function is to focus the rays of light that enter the retina (tissue at the back of the eye responsible for “capturing” images).

The light focused by the lens travels to the retina and there initiates a series of chemical reactions that, in turn, trigger electrical reactions that are sent to the optic nerve and interpreted by the brain.
In a healthy eye, light passes through the transparent lens towards the retina. When this lens starts to become cloudy and opaque, that is, when it starts to show the symptoms of cataracts, the image interpreted by the brain starts to be out of focus, the colors lose their shades and the vision is blurred.

How does a cataract form?

Basically, the lens is composed of water and proteins that, together, help to allow light to pass through the lens clearly. However, over the years, there are some changes in this structure, thus favoring the appearance of cataracts.

When part of these proteins accumulate with each other, opaque layers are created on the lens, which causes the lens to thicken and lose its transparency. In situations of very large accumulation, the first signs of the disease begin to appear.

Types of cataracts

In general, the types of cataracts can be divided into three categories: congenital, in which the child is born with the disease or starts to present in the first months of life; acquired, which concerns aging and other diseases; and spatial, which refers to the region of the affected lens.

Congenital cataract

Also known as infantile cataracts, congenital cataracts appear at birth or develop during the first six months of life. It can affect one eye (unilateral congenital cataract) or both at the same time (bilateral congenital cataract).

Congenital cataracts often happen because of infections during the first three months of pregnancy and are the main responsible for cases of childhood blindness, having an incidence of 0.4% or 1 case for every 250 births worldwide.

Acquired cataract

Senile cataract

Also known as age cataracts , it develops after age 65, with a slow progression and usually in both eyes. If the elderly person has diabetes , the cataract may progress more quickly and become more severe, requiring urgent surgery.

Diabetic cataract

It arises as a result of diabetes and develops more quickly compared to all other types of cataracts.

Cataracts caused by medications

It is a type of cataract that can happen after long-term use of corticosteroids.

Traumatic cataract

Traumatic cataracts are those caused by bruising or perforation injuries. This condition usually only affects the eye affected by the trauma, and can arise regardless of age. In addition, it can develop very quickly if, on impact, the lenticular capsule is damaged. Otherwise, the disease can take months or even years to evolve.

Incipient cataract

The incipient cataract, also known as phacosclerosis , is a terminology used to describe an early stage of the disease, when there is a degree of turbidity of the lens, without significant loss of vision.

Depending on the degree of opacification of the lens, the name may vary from incipient cataracts, to mature or hyper-mature.

In the case of incipient cataracts, there is no need for surgery. The ophthalmologist will make the decision of when to operate according to the evolution of the disease and the clouding of the lens.

Space Cataract

Subcapsular cataract

Subcapsular cataracts can be divided into two types:

  • Posterior subcapsular cataract: it is the turbidity of the part of the lens located further down the eye.
  • Anterior subcapsular cataract: it is the turbidity of the part of the lens located in front of the eye.

Nuclear cataract

Nuclear cataracts are characterized by the turbidity of the lens nuclei. As with senile cataracts, nuclear is more frequent in elderly people, enhancing the increase in the density of the lens, which can cause myopia .

Cortical cataract

Cortical cataracts are more common in people with diabetes, being very similar to nuclear, in that they cause the lens cortex to become opaque.


There are several factors that contribute to the onset of cataracts. Are they:

  • Ultraviolet radiation from the sun and other sources;
  • Diabetes;
  • Hypertension;
  • Obesity;
  • Smoking;
  • Prolonged use of corticosteroids;
  • Use of statins to reduce cholesterol;
  • Inflammation of the eye;
  • Eye injury;
  • Vitrectomy (removal of the vitreous gel) in people over 50;
  • Hormone replacement therapy;
  • Alcohol abuse;
  • High myopia index;
  • Family history;
  • Frequent exposure to X-rays;
  • Disease inside the eye, such as glaucoma, retinitis pigmentosa or retinal detachment;
  • Eczema.

Congenital cataract

Unlike acquired cataracts, congenital cataracts are associated with infections, allergic reactions and genetic diseases. Between them:

  • Down’s syndrome;
  • Hallermann-Streiff syndrome;
  • Lowe’s syndrome;
  • Cockayne syndrome;
  • Trisomy 13-15;
  • Galactosemia;
  • Marfan syndrome;
  • Hypoglycemia;
  • Alport’s syndrome;
  • Myotonic dystrophy;
  • Fabry disease;
  • Hypoparathyroidism;
  • Conradi syndrome;
  • Pigmentary incontinence;
  • Toxoplasmosis;
  • Rubella;
  • Cytomegalovirus;
  • Herpes simplex;
  • Syphilis;
  • Varicella;
  • Aniridia;
  • Congenital glaucoma;
  • Exposure to corticosteroids.

Cataract Symptoms

Cataract development is usually slow and gradual. It usually takes years to diagnose cataracts because of severe symptoms.

The most common signs of the disease are:

  • Blurry or out of focus vision;
  • Sensitivity to colors and reduced contrast;
  • Difficulty driving at night because of the headlights;
  • Increased sensitivity to light (photophobia);
  • Double vision in one eye;
  • Frequent change of glasses;
  • Difficulty performing day-to-day activities due to vision problems.

Risk factors

Some factors can contribute to the appearance of cataracts. Are they:

  • Age;
  • Diabetes;
  • Alcoholism;
  • Obesity;
  • Smoking;
  • Exposure to ultraviolet rays;
  • Exposure to X-rays;
  • Previous eye injury or inflammation;
  • Hypertension;
  • Prolonged use of corticosteroids.


The diagnosis of cataracts is usually made by an ophthalmologist , although it can also be made by an optometrist.

In congenital cataracts, the diagnosis becomes more difficult because it is a child or baby. One way to recognize infantile cataracts is to look at the baby’s eyes for white spots or lack of reflection in the pupil.

In Brazil, it is mandatory, in all maternities in the country, to carry out the eye test (or red reflex test) in newborns, which helps in the recognition of the disease in the first days of life.

In adults, the doctor will analyze the patient’s history and may request some tests, which include:

Visual acuity test

Also known as “eye exam” , the visual acuity test measures the degree of the eye’s ability to detect the shape and contour of objects, that is, the sharpness with which the eye observes. Through this test, the doctor can determine if there is any loss of vision in the eyes.

In it the patient is placed in front of about six meters away from a graph containing letters, numbers or shapes, which gradually decrease in size. Then, the patient must say out loud what he sees, with each eye being examined separately.

Examination of slit lamp

A slit lamp is a device that allows the doctor to see details inside the human eye. A thin, intense beam of light is focused into the patient’s eye. With the aid of a microscope, the doctor analyzes the physical aspects of the eye to determine if there are any irregularities.

Examination of the slit lamp is to find out if there are problems with the frontal structures of the eye, which include the cornea, iris, eyelid, sclera, conjunctiva and lens.

Retinal mapping

In this examination, done separately in each eye, a special eye drop is used to dilate the pupil. The doctor, with the aid of an ophthalmoscope, analyzes the back of the eye and the lens for signs that may indicate a cataract.

Can a cataract be cured? What is the treatment?

Cataracts are a curable disease that can be reversed through a surgical procedure. However, the condition often does not cause major problems to the patient, and in these cases, surgery becomes unnecessary.

At first, as long as the symptoms are mild, the use of reading glasses or sun glasses, in addition to the correct use of the reading light can help to alleviate the symptoms.

In the case of congenital cataracts, treatment should be carried out as soon as possible. If the cataract is partial, that is, if it does not reach the whole eye and still does not present risks of seriously compromising vision, the use of mydriatic eye drops, occlusion and special glasses to improve vision are an alternative.

Cataract in the eyes: when to operate

Cataracts commonly do not harm the eyes. Therefore, surgery will only be necessary if the problem interferes with daily activities or disrupts the patient’s quality of life. In addition, the doctor may order the procedure if the disease is preventing the diagnosis or treatment of other eye damage, such as diabetic retinopathy.

How is cataract surgery done?

There are some types of cataract surgery, which vary according to the method used. Basically, they all involve the removal of the opaque and faulty lens, the same being replaced by a new artificial transparent lens.

However, in patients who have other eye problems, the use of the artificial lens is not possible. In these cases, after cataract removal, vision can be corrected through glasses or contact lenses.

In congenital cataracts, the recommendation for surgery differs in the following aspects:

  • If the cataract affects only one eye, surgery is necessary, as amblyopia (very large difference in degrees between the eyes), makes it difficult for the brain to form images, which can complicate the child’s cognitive development;
  • If the cataract affects both eyes, the doctor usually waits until the child is six years old to have the surgery, to allow time for the eye to reach the correct proportion for the insertion of the intraocular implant.

Currently, cataract surgery is considered to be quite safe and effective, although it presents the risk of infection and bleeding, in addition to increasing the chances of retinal detachment.

How long does it take for the vision to return to normal?

The time for the vision to return to normal will depend on the intensity of the inflammation of the eye after surgery. Inflammation manifests itself at different levels in patients, depending on the degree to which the cataract and cornea were found before the surgical procedure.

In addition, diabetes and other changes can interfere with recovery. It is very common that the vision is blurred in the first days of the postoperative. When there is little or no inflammation, vision tends to recover quickly.

Is there a risk that the cataract will return after surgery?

There is no chance that the cataract will affect the operated eye again. What can happen, in very rare cases, is that the prosthesis undergoes fibrosis that can make it opaque, impairing vision depending on its intensity.


When left untreated, the disease can cause total loss of vision (blindness). However, as the cataract tends to develop slowly, it is very likely that the patient will correct the problem before it occurs, through clinical or surgical treatment.

How to prevent cataracts?

Some measures can be useful in order to prevent the development of the disease:

Protect your eyes from the sun

The use of hats, caps and especially sunglasses with UV protection help to ensure eye health. This is because the sun emits ultraviolet radiation, which can be harmful to the eyes.

It is also good to avoid exposing yourself to the sun at times when it is strongest, that is, between 11 am and 3 pm.

Protect eyes from screens

Although there are no scientific studies relating exposure to screens with cataracts, being restrained and careful when using computers, cell phones and television is important. This is because the screens also emit radiation, although it is much smaller than that emitted by the sun.

Some tips to protect your eyes from the radiation emitted by the screens are:

  • Sit at least 30cm away from the computer or television;
  • Adjust the brightness and contrast settings, seeking to minimize the strain on the view;
  • Use the 20-5-20 method. In it, every 20 minutes, you should look at an object away from the screen, at least 5m away, focusing your vision on it for approximately 20 seconds. That way, the view is not flawed.

Avoid smoking and drinking

Smoking hinders the body’s recovery due to the release of free radicals, which damage cells and increase the chances of cataract development.

In addition, avoiding consuming more than one dose of alcoholic beverages a day is an interesting measure. Alcohol modifies the interaction of eye proteins, impairing calcium stability in the lens, which increases the risk of damage to the ocular membrane.

Eat leafy and dark vegetables

Dark vegetables and leaves are rich in antioxidants, which help prevent eye diseases such as cataracts. Substances such as lutein and zeaxanthin (found naturally in the retina and lens) are proven to be effective in combating cataracts, as they absorb light and ultraviolet rays.

If you choose supplements, it is recommended to consume more than 6mg of lutein and zeaxanthin. However, there are good natural sources of antioxidants, such as:

  • Cabbage leaves;
  • Spinach;
  • Kale;
  • Turnip;
  • Taraxacum;
  • Mustard leaf;
  • Beetroot;
  • Red chicory;
  • Pumpkin.

Consume more vitamin C

The most famous of the antioxidants is present in many foods. It is recommended to avoid supplements and obtain the substance from natural sources, such as:

  • Cantaloupe;
  • Cauliflower;
  • Grape;
  • Lychee;
  • Pumpkin;
  • Broccoli;
  • Guava;
  • Pepper;
  • Orange;
  • Strawberry.

Consume more vitamin E

Like vitamin C and vegetables, vitamin E is also a well-known source and antioxidants. Some foods that are rich in vitamin E are:

  • Spinach;
  • Almond;
  • Sunflower seed;
  • Wheat germ;
  • Peanut butter;
  • Kale;
  • Avocado;
  • Mango;
  • Hazelnut;
  • Chard.

Exercise regularly

Cataracts are directly related to diabetes. So, as obesity increases the risk of getting the disease, regular physical exercise is recommended. In addition, studies indicate that the greater the intensity of exercise, the greater the health benefits, including disease prevention.

Common questions

Does cataract always affect both eyes?

No. The cataract can be bilateral, when it affects both eyes, or unilateral, when it affects only one.

Should both eyes be operated simultaneously?

No. Because the recovery from the surgery is slow and gradual, it is customary to perform the surgery on one eye at a time. In many cases, it is even necessary to use an eye patch during post-surgery as a precaution.

Is cataract surgery fast?

The cataract operation lasts about 30 minutes and is painless. Recovery, however, requires more time. Depending on the size of the inflammation left after surgery, it may take days or weeks for a complete recovery. In addition, the operation is complex and microscopic, which means that the procedure cannot be considered simple.

Do I need to wear glasses after surgery?

It depends on the type of implant that is used. If the implanted lens is multifocal, it may be that it is no longer necessary to wear glasses, except in cases of tired eyes, in which the problem is present in the lens contraction muscles and not in the lens itself. But it all depends on the characteristics of the patient and the implanted lens.