What Is Cataract?


The term cataract comes from the Greek word katarraktes (down rushing; waterfall) because earlier it was thought that the cataract was a congealed fluid from the brain that had flowed in front of the lens.

Our eye is like a camera. The lens focuses the light rays coming through the pupil onto the retina or back side of the eye. The different parts of the retina collect this light and send a massage to our brain then we can see.

For perfect vision the lens should be clear, so that light can pass through it and reach the retina. When the lens becomes cloudy or opaque, light can not pass through it and vision becomes dim or blurred. A cloudy lens is called cataract.


  • Sensitive to Sunlight (Photophobia).
  • Cloudy, fuzzy, foggy, or filmy vision.
  • Difficulty in seeing at night or in dim light.
  • Monocular diplopia.
  • Problems seeing shapes against a background or the difference between shades of colors.
  • Seeing Rainbow halos around lights.

Causes and risk factor of Cataract:

  • With age.
  • Diabetes.
  • Glaucoma.
  • Eye infection (Uveitis).
  • Family history of cataract.
  • Eye Injury.
  • Infection.
  • Congenital or by birth.
  • Exposure to ultraviolet light (Sunlight).
  • Long-term use of corticosteroids (taken by mouth for skin or any other systemic diseases).
  • Radiation exposure (X-ray technicians, airline pilots have a higher risk of developing cataract than non-pilots and that the cause may be exposure to cosmic radiation.).
  • Smoking
  • Surgery for another eye problem.
  • Using long term anti-glaucoma eye drop like Pilocarpine.

Classification of cataracts according to time of occurrence:

(A) Congenital and developmental Cataracts (less than 1% of all cataracts):

These occur due to some disturbance in the normal growth of the lens. When the disturbance occurs before birth, the child is born with a congenital cataract. Developmental cataract may occur from infancy to discrimination. There are many congenital cataracts. They are either hereditary or acquired through the placenta

1. Hereditary Congenital Cataracts: Familial forms of congenital cataracts may be autosomal dominant, autosomal recessive, sporadic, or X-linked.

2. Cataract from Transplacental Infection in the First Trimester of Pregnancy:

Incidence of congenital cataract is due to virus infection contracted by the mother during the first trimester of pregnancy.

  • Rubella.
  • Mumps.
  • Hepatitis.
  • Toxoplasmosis.

The most frequent cause of congenital cataract is a rubella infection contracted by the mother, which also produces other developmental anomalies like hearing loss. This infection occurred during the fifth to eighth week of pregnancy, the phase in which the lens develops. Because the protective lens capsule has not yet been formed at this time, viruses can invade and opacify the lens tissue.

(B) Acquired Cataract (over 99% of all cataracts):

1. Senile cataract (over 90% of all cataracts) – This type of cataract occurs with age.
2. Traumatic cataract.
3. Cataract with systemic disease like diabetes or any other systemic diseases.
4. Secondary and complicated cataracts due to night blindness (retinitis pigmentosa), inflammation in the eye (Uveitis).
5. Toxic cataract-Corticosteroid (taken by mouth for skin or any other systemic diseases).
6. Postoperative cataracts due to any intraocular surgery like vitrectomy and retinal surgery.

Treatment: In early stage of cataract following things may help temporarily.

  • Better eyeglasses (Frequently changes spectacle power).
  • Better lighting.
  • Magnifying lenses.
  • Sunglasses.

If with spectacle vision gets worse, may need cataract surgery.

Is there any medication to remove cataract?

There is no medication to remove cataract, only option is cataract surgery to achieve a good visual result.

If I do not go for cataract surgery, what complication may occur?

A cataract that goes on to an advanced stage (called a hypermature cataract) can begin to leak into other parts of the eye. This may cause severe pain is called Secondary Glaucoma. If this type of thing occurs then after cataract surgery also vision may not improve.

When should I go for cataract surgery?

When a cataract has been diagnosed, consider how your vision affects your quality of life and ability to do the things, you ordinarily do. Without a cataract interferees with work, driving, computer work, reading or day to day work, there is no urgent need to remove it. There is no harm in waiting if you keep regular appointments with your eye doctor to evaluate how the cataract is progressing.

Will the operation be successful?

Cataract surgery is now performed as a microsurgical technique under an operating microscope. Modern techniques, microsurgical instruments and specially trained surgeons have made it possible to successfully perform cataract surgery without any serious complications in 98% of all patients.

Therefore it is important that the patient under goes a thorough preoperative eye examination to exclude any ocular disorders, as well as the cataract, that may worsen visual acuity and compromise the success of the cataract operation. Such disorders include uncontrolled glaucoma, uveitis, macular degeneration, retinal detachment, atrophy of the optic nerve, and amblyopia (lazy eye).

How much time it takes to perform a cataract surgery?

The procedure takes only 15-20 minutes.

Duration of hospitalization:

Now a day's no need to stay in hospital, after the surgery immediately can go home. Even medical insurance company also recommended this as a day care procedure.

Is it painful surgery?

You will not feel any pain because cataract surgery is performed under anesthesia. There are two type of anesthesia one is Local anesthesia and second is General anesthesia. Now a day, most of the cataract surgery is performed under local anesthesia.

Local anesthesia: (Retrobulbar injection, Peribulbar injection, or topical anesthesia): Here one small injection is given lower portion of the eye is called Retrobulbar or peribulbar.

Now a day topical anesthesia is very popular, because the procedure of cataract surgery takes only 15-20 minutes. So, long term anesthesia is not required for that. Here before surgery only one drop needs to instill in the eye that is enough for cataract surgery. This type of anesthesia is recommended for patients who are very smart and not nervous.

General anesthesia: This is recommended for patients who are extremely nervous, deaf, or mentally retarded or children. It is also indicated for patients with Parkinson's disease or rheumatism, who are unable to lie still without pain.

Surgical techniques to remove cataract:

Several techniques are used for removing cataracts. Latest technique is phacoemulsification. In this method a tiny instrument is inserted through a very small incision. The instrument uses ultrasound vibration to break the cataract into fine pieces, which are nicely suctioned out. Then an intra ocular lens (IOL) is inserted into the eye. No stitches are required to close the incision.

Is it necessary to implant IOL during surgery?

In 95-98% of all cataract extracts, an intraocular lens (IOL) is implanted in place of the natural lens (Posterior chamber lens). An eye with an artificial lens is called Pseudophakia. If surgery is performed without intra ocular lens then you have to use + 10D spectacle to see clearly. Without spectacle you can`t do day to day activity and second thing is heavy weight of spectacle that is very disgusting. So during surgery IOL is necessary.

Types of Intra Ocular Lens:

Monofocal IOLs: This type of lens can be implanted either for distance or near. Here patient can select wherever he wants distance vision clear or near vision clear without spectacle. If someone has so much near work and he wants to do near work without spectacle then it is possible in this type of lens. But most of the people want distance vision clear without spectacle, surgeon also want same.

Multifocal IOLs: These allow you to see at distance and near clearly. So Spectacle is not required. But one disadvantage of this type of lens is glare problem. So much perfectionist people should not go for this type of lens. This type of lens is work for housewife who has less visual demand.

Can I get 20/20 or 6/6 vision without spectacle after cataract surgery?

Pre-operative check can give an idea for 20/20 or 6/6. It depends on several conditions like:

  • Corneal curvature of the eye (Horizontal and vertical), if both meridian different more than 0.75D in keratometry then after surgery spectacle is required (Today Alcon toric IOL is available for this solution but it is very expensive).
  • If eye ball length (axial length) is very high or very less then spectacle is necessary after surgery. Eye ball length is measured by A-Scan machine. Normal eye ball length is 23-24 mm.
  • Image form in the retina. For good visual exit retina should be healthy and diseases free like diabetic retinopathy, age-related macular degeneration or any other retinal diseases.
  • If prior cataract vision was good then after surgery also chances to get same vision.
  • 90% visual exit depends on proper IOL power calculation. IOL power calculation should be done by expert technician, optometrist or doctor.
  • Last important thing is surgeon should be skilled and qualified.

Once cataract surgery done, Can I develop cataract again?

No there is no chance to develop cataract once surgery is done. But posterior capsule of the lens where lens in implanted becomes thick with time is called Posterior capsular opacification (PCO) or secondary cataract. Once PCO is developed then need to go for YAG (yttrium-aluminum-garnet) laser. This is maximum two minutes opd procedure. With laser beam the thickened capsule is to cut. So it is painless procedure.


  • The best prevention involves controlling diseases that increase the risk of a cataract.
  • Wearing sunglasses when you are outside during the day can reduce the amount of ultraviolet (UV) light your eyes are exposed to. Some sunglasses do not filter out the harmful UV. An optician should be able to tell you which sunglasses filter out the most UV.
  • For patients who smoke cigarettes, quitting will decrease the risk of cataract.
  • Eat green leafy vegetable.
  • Some studies suggest people with diabetes are at risk for developing a cataract. So, control blood sugar.
  • Should not take oral steroids for long time for any systemic disease.
  • Some eye care practitioners believe that eating a lot of salt may increase the risk of cataract.