Cataract is clouding of the lens which affects vision. It is the most common eye disease amongst elderly people and is a major cause of visual impairment and blindness worldwide. In India, 3.8 million cataract cases add per year to the already existing backlog of cataract cases. Cataract procedure is the most common surgical procedure performed in the population aged over 60.
To understand about cataract we need to understand about the functions of the eye and implications of cataract on it.
The normal eye works like a camera. The light from an object passes through the transparent cornea, through the pupil and through the transparent lens and focuses on the retina. The retina (the light sensitive layer at the back of the eye) then transmits this image to the brain through the optic nerve and that is how we see.
The normal human crystalline lens is clear and transparent like glass. Whenever this lens becomes cloudy or develops opacity it is called a cataract. This blocks the light rays from passing through the lens and a blurry image is formed. The patient feels as if he or she is looking through a frosted/fogged glass. This blurring keeps increasing and eventually all vision is blocked when a cataract becomes mature.
Cataract development is a part of the normal ageing process. It is said that if you live long enough, everyone is going to have cataract.
In India, we generally see cataracts in 50s and 60s. But it can present earlier if there is a strong family history of early cataract. Other causes of early cataracts are diabetes, any kind of eye injury, use of certain medications, infection or inflammation of the eye, radiation exposure etc. Rarely cataract can be seen in children as a congenital defect or developmental anomaly.
The most common symptom of cataract is progressive, painless blurring of vision in one or both the eyes. Many people notice that objects look yellow, hazy or distorted. They may see double or multiple images. Also there can be increased glare, haloes from oncoming lights and night driving may become tricky. Others notice improvement in near vision or frequent change in their glass prescription.
A lot of people claim that homeopathic medicines or some drops delay/prevent formation of cataract. However, till date there is no conclusive documented medical evidence suggesting that cataract can be prevented or cured. Some reports suggest that decreasing exposure to ultraviolet light by using sunglasses, good nutrition with antioxidants delay cataract formation. The only known treatment for cataract is surgery.
In older days, we had to wait for Cataract Surgery till one lost all vision due to mature or ripe cataract. This was due to limitation of surgical procedures and their success rate. Big incision (9mm to 12 mm) was made to remove cataract and stitches were applied to close it. Postoperatively there were lots of restrictions, recovery was slow, stitches caused problems like discomfort, astigmatism, infections etc. Before the intraocular lenses came in practice, patients had to wear thick glasses and quality of vision was not that great.
Last 2-3 decades have seen many breakthrough changes in Cataract Surgery. Now we break the cataract by ultrasonic sound waves with a probe vibrating at 40,000 cycles per second and liquefy it and suck it out through a very small incision (1.8mm to 2.2 mm) Foldable intraocular lenses are then put through that same incision. This does not require sutures or patching after surgery. Now we dont give injections also, as surgery can be done after putting only numbing drops except in certain situations like very hard or complicated cases, Parkinsonism patient with tremors, dementia, children or extremely anxious, uncooperative patients. The recovery is much faster with patient returning to normal activities in a matter of days. Hence Cataract Surgery is done whenever it interferes with your vision and daily activities and not when it becomes ripe. It has success rate of 95 to 99 %.
There is no concept of mature or ripe cataract nowadays for considering cataract surgery. Modern day cataract surgery is done by advanced techniques and very good quality of lens implants are available which restore sight to as near to normal as possible.
Therefore, whenever a cataract starts interfering with the patients routine activities at work or leisure it is time to consider cataract surgery, of course after consultation with an ophthalmologist.
If left untreated for a long time, the cataract may become overripe and burst giving rise to raised eye pressure, redness and swelling of eyes resulting in permanent vision loss. Sometimes we have to remove a cataract for cosmetic purposes to restore a black pupil even if there is no visual gain.
The medical team will do a detailed eye examination to check the type of cataract, eye pressures, retina etc. to rule out any other eye problem. A Scan or Intraocular lens power calculation test will be done to know what power lens should be implanted after cataract removal. You will also be given a list of routine investigation mandatory for undergoing any kind of surgery. If you have any hypertension, diabetes etc. it needs to be controlled by your physician. Kindly inform your doctor if you are on any kind of blood thinning medication so that it can be stopped in consultation with your physician prior to surgery.
If everything is alright you can fix the date and also collect the list of pre and post operative instructions from the counter. Your doctor/ophthalmic technician will inform you about the different options of lenses and you can choose the category depending upon your preference and budget.
Cataract surgery by laser is a misnomer. Phacoemulsification technique by many is known as laser. There are different methods for removing cataract:
The most popular and safe technique today is Phacoemulsification. Here, a small entry is made into the eye. The lens is situated inside a thin membranous bag. In the front portion of the membrane a hole is made. The cataract is broken into pieces, emulsified and sucked out. Foldable intraocular lenses can be put inside the eye where they get unfolded. Since it is a very small and specifically created incision, stitches are not required. A small incision ensures stitch-less surgery, faster recovery, less discomfort, less astigmatism and faster return to normal life. During the surgery we use state of art machines and medications which protect the corneal endothelium. We may need to use some protective solution inside the eye for best outcome in certain cases.
10 -15 years back, extra capsular technique was popular but nowadays it is opted for only if Phacoemulsification can not be done safely due to extremely hard cataracts, poor corneas or some other contraindication. It requires a bigger incision and therefore takes a longer time to heal. There are more chances of getting higher numbers and is not very comfortable due to more sutures.
Cataract surgery is generally done under local anesthesia. Patient is awake during surgery but does not feel the pain. Some very apprehensive patients or children need general anesthesia.
The intraocular lens is a small acrylic or silicon lens resembling the normal lens. After removing the cataract, it is replaced by an intraocular lens. Once placed inside they do not require any care/cleaning etc. from you. There are different kind of lenses available today like monofocal, multifocal, foldable/non-foldable, aspheric etc. owing to major technological advances – you can make a decision after discussing with your doctor or eye care provider.
Foldable lenses are made of special acrylic or silicone material and can be folded by special injectors. They require a very tiny incision for insertion in the eye and no stitches. This helps in faster healing, less astigmatism and better quality of vision.
Aspheric lenses are aberration free lenses which were introduced few years back. Their surface is modified and they are technologically more advanced to decrease aberration (distortion) of image. They improve image quality; give better contrast and depth perception and excellent night vision compared to traditional foldable lenses
We shall try to reduce your dependence on glasses for distance as much as possible, that you can perform most of your routine activities without them. Still some fine tuning of distance vision may be required for activities requiring very sharp vision like watching TV or driving etc. For near vision, you will require reading glasses as you were using before the surgery. Sometimes the number can be adjusted depending on your lifestyle and specific requirement.
People who do not wish to wear glasses after surgery and require a good vision for intermediate and near distance for their daily activities can opt for multifocal intraocular lenses. Your doctor can discuss with you the suitability of these lenses depending on your lifestyle, visual requirement, personality and presence of any other ocular disease. Also the cost involved is higher because of the exacting and advanced technology required these lenses.
In spite of the best care and precautions, like any other surgical procedure in the human body, there is a possibility of minor to major complication.
Some minor complications like slight drooping of the eyelid, swelling around the eye, corneal haze, reflection or slight distortion from lens implant, delayed healing, corneal edema are temporary and recover with time and medication. The chances of a serious complication like infection, severe inflammation, retinal detachment, nucleus drop, hemorrhage are negligible.
In a majority of cases these complications can be treated successfully or may resolve on their own with a good final restoration of vision. Since all the complications cannot be listed, the above list is not exhaustive.
Cataract surgery is a highly successful procedure (95-98% success rate) technically. However, the final visual outcome also depends on the condition of the eye i.e. cornea, retina, optic nerve, any pre-existing disease, amblyopia (lazy eye) etc.
Sometimes it may be difficult to diagnose these abnormalities before the surgery due to cataract and we can know about it only after the operation. No surgeon in the world can perform a surgery with guaranteed results. However, almost all the patients regain good vision following a cataract surgery.
Till now, Phacoemulsification is the ultimate method of choice for cataract surgery. Recently, Famtolaser has been used for Cataract Surgeries; it can make incisions to correct astigmatism, open the capsule and softens the cataract, but has to be used in conjunction with Phacoemulsification to complete the procedure. It is a two step procedure now, may be in future, it can develop into exciting technology and the increased cost can be justified in terms of visual benefit.
We have the best Centurion Vision System for Cataract Surgery by Phacoemulsification. We also have "The lens star" for calculating IOL power (which number lens to put in the patient so that the glass number can be reduced) and Specular microscope (to check health of cornea) for preoperative work up. Hence, we have one of the best Cataract suites for surgery.
The natural lens in cataract surgery replaced by an artificial lens made of acrylic or silicone material. There are many types of lenses available nowadays.
Monofocal Lenses : Can correct the vision problem due to cataract but reading glasses are required.
Monofocal Aspheric lenses : The quality of vision offered by them is better due to their superior technology. The dim light vision, the contrast & sharpness is better appreciated.
Toric Lenses : Can correct cylindrical power.
Multifocal Lenses : Are specialized lenses which help in treating the cataract and also getting rid of reading glasses. The dependence on any kind of glasses is reduced by almost 95-98 per cent.
Patients opting for multifocal lenses do not require glasses for watching TV, reading newspaper, computer work or any kind of routine activities.
Prelex stands for presbyopic lens exchange which is an age related condition. It uses eye surgery with lens implantation to get rid of glasses in patients above the age of 45.
After the age of 40, in addition to the distance number (plus, minus, cylindrical) one also gets near number for reading. In this case, LASIK cannot get rid of both distance & near numbers.
In these cases, the number removal is done by exchanging the natural lens with specialised lenses. Since this removes the natural lens, the patient will never develop cataract & will not require additional surgery for that later in life.