A cataract is clouding or opacity of the lens inside the eye.
It is useful to learn about how the eye works in order to understand what a cataract is.
Inside the eye, behind the colored part (the iris) with a black hole in the middle (the pupil), is the lens. In a normal eye, this lens is clear. It helps focus light rays on to the back of the eye (the retina), which sends messages to the brain allowing us to see. When cataract develops, the lens becomes cloudy and prevents the light rays from passing through.
Cataracts usually form slowly over years causing a gradual blurring of vision, which eventually is not correctable by glasses. In some people the vision can deteriorate relatively quickly. Developing cataract can also cause glare, difficulty with night-time driving and multiple images in one eye which can affect the quality of the vision.
No. But often they develop in both eyes either at the same time or one after the other with a gap between
Yes. Most cataracts are age-related, but other examples include congenital (present at birth), drug induced (steroids), and traumatic (injury to the eye).
Yes. Cataract is more common in people who have certain diseases such as diabetes.
Most forms of cataract develop in later adult life. This is called age-related cataract, and can occur at any time after the age of 40. The normal process of ageing causes the lens to gradually become cloudy. Not all people who develop cataract require treatment.
Yes, but this is rare.
At first, you might not be aware that cataract is developing and, initially, it may not cause problems with your vision. Generally, as cataract develops over time, you start to experience blurring of vision. In most cases, eyes with a cataract look normal but, if the cataract is advanced, your pupil may no longer look black and can look cloudy or white.
You may need to get new prescription glasses more frequently when the cataract is developing. Eventually, when your cataract worsens, stronger glasses may no longer improve your sight and you might have difficulty seeing things even with your glasses on.
In many cases, cataract is harmless and may be left in your eye. It is usually safe not to have surgery if you feel that you do not have a problem with your vision. When the cataract progresses to the point that it is interfering with daily activities or lifestyle, even when using up-to-date glasses, then cataract surgery may be the next step. Modern surgery is highly successful for the majority of patients but, as with all surgery, there are risks. Cataract surgery is performed when you have a problem with your vision and you want to do something about it.
There is no known method of preventing cataract.
It is common for cataract to develop more quickly in one eye than in the other. The timing of an operation is agreed after discussion between you and the cataract team.
Usually, your more seriously affected eye is operated on first. Sometimes it is advisable to have your second eye operated on even if it causes you few vision symptoms, to balance the spectacle prescription so that your eyes can be used comfortably together.
Yes. Special tests are required to determine the strength of lens implant which is inserted into the eye. These are usually done prior to the operation day and may be done at your first clinic attendance or a few weeks before surgery.
You may also have tests for your general health, such as blood tests and an electrocardiogram (ECG).
An experienced eye surgeon will carry out your operation . Your eye is never removed and replaced when operations are carried out.
The commonest form of cataract surgery is performed by surgeons using a small incision (wound) and a process called "phacoemulsification", often shortened to "phaco". This technique uses ultrasound to soften the lens, which is then broken up and flushed out using fine instruments and special fluids. A clear artificial lens (intraocular lens implant or IOL), made of a plastic-like material, is placed inside the eye. The back membrane of the lens (capsule) is left behind and this holds the artificial lens in place.
The wound is very small and most patients do not require stitches, although very fine stitches are sometimes needed to close the wound safely. This can occasionally cause some temporary post-operative irritation. Depending on the type of stitch used, these may need to be removed.
New technology is being developed using a femtosecond laser to automate key parts of the procedure. However, the surgeon still needs to operate using phacoemulsification to complete the surgery at present.
The operation is performed while you are lying down on your back. Your face is partially covered by a sterile sheet. If you have difficulty lying flat or are claustrophobic, we will do our best to make sure that you are comfortable before the operation starts, but please tell the nurses during your pre-operative assessment.
During the operation, the surgeon uses a microscope and the bright light from the microscope and the covering sheet mean that you do not see the operation or the detail of the instruments but you may see moving shapes.
Usually you will be awake during the operation and will be aware of a bright light, and often pretty coloured lights and shadows. You may feel the surgeon's hands resting gently on your cheek or forehead.
A lot of fluid is used during the operation. Sometimes, excess fluid may escape under the sheet and run down the side of your face, into your ear or on your neck, which can be uncomfortable.
You might hear conversations during the operation. These could be about the operation or about other subjects. Please do not join in as it is important that you remain still during the procedure.
Most operations for cataract are performed under local anaesthetic, in which you are awake but your eye is numb. This is usually given by eye drops or an injection around your eye. A small number of patients require sedation or even a general anaesthetic, where you are asleep.
Cataract surgery is performed on a day-care basis. This means you are admitted to hospital, have your operation and are discharged home all in the same day. You could spend several hours in hospital from arrival to discharge.
Standard monofocal lenses
Your lens, which helps you focus, is removed during the operation and is replaced with an artificial lens, the intraocular lens implant. There is a choice of different strengths (powers) of lenses which, just like different strengths of glasses lenses, affect how clearly you see when looking into the distance or when looking at near things such as reading a book.
During your initial assessment, the cataract team will discuss with you whether you want to have better focus for close vision or for distance vision. Most people choose to aim for good distance vision after the operation. If you choose this option, you will usually need reading glasses and you may still need glasses for fine focusing in the distance.
Multifocal lenses are lenses that aim to correct vision for both near and distance. However, the quality and biocompatibility of standard monofocal and multifocal is the same. Multifocal lenses do not work for all patients and may cause some visual quality problems.
Increasing redness, pain, blurring of vision or yellow/green discharge
This can indicate a serious infection or inflammation.
This may indicate macular oedema (water logging of the central part of the retina).
This can be due to a recurrence of post-operative inflammation inside the eye.
The eye drops help reduce the risk of infection and inflammation after surgery and may be necessary for one to two months.
You are advised to be careful when washing: do not directly splash water into your face in the shower or immerse your head in the bath for one week after surgery, but a clean face cloth can safely be used.
No, but you can develop a thickening or clouding of the posterior capsule membrane behind your new lens implant in the months or years following your surgery, which occurs in approximately one in 10 cataract surgery patients. This is called posterior capsular opacification and causes blurring of vision.
This can be treated as an outpatient with a laser procedure, known as YAG laser capsulotomy. This involves one outpatient visit. It is usually very effective, painless and quick, but can very occasionally cause complications such as retinal detachment or waterlogging of the central part of the retina. The risks of YAG laser treatment are smaller than the risks of the original cataract procedure and will be detailed at your consultation.
Glasses or contact lenses are worn when the focusing power of the eye does not give a clear picture. In other words, there is a refractive error. Excimer laser refractive surgery can reduce refractive errors by changing the shape of the cornea and thus its focusing power. A similar effect can sometimes be achieved by lens surgery.
If you have a refractive error, such as nearsightedness (myopia), farsightedness (hyperopia), astigmatism or presbyopia, refractive surgery is a method for correcting or improving your vision. There are various surgical procedures for correcting or adjusting your eye's focusing ability by reshaping the cornea, or clear, round dome at the front of your eye. Other procedures involve implanting a lens inside your eye. The most widely performed type of refractive surgery is LASIK (laser-assisted in situ keratomileusis), where a laser is used to reshape the cornea.
LASIK (laser in situ keratomileusis) is an outpatient surgical procedure used to treat nearsightedness, farsightedness, and astigmatism. LASIK cannot reverse presbyopia, the age-related loss of close-up focusing power, which mainly affects near vision. With LASIK, the ophthalmologist uses a laser to reshape the cornea, which is located at the front of the eye. This improves the way the eye focuses light rays onto the retina, at the back of the eye, allowing for better vision.
Suitable for treatment
Unsuitable for treatment
Patients will be carefully assessed prior to listing for surgery to ensure that they are suitable. This will include a detailed history, refraction, wavefront aberrometry, keratometry (measuring the curvature of the cornea), corneal thickness assessment, slit lamp examination and dilated fundoscopy. Prospective patients should not wear hard contact lenses for four weeks or soft contact lenses for two weeks prior to this assessment.
With LASIK, an ophthalmologist creates a thin flap in the cornea using either a blade or a laser. The surgeon fold backs the flap and precisely removes a very specific amount of corneal tissue under the flap using an excimer laser. The flap is then laid back into its original position where it heals in place.
These are day-case procedures done under local anesthetic, carried out in specialist centres. LASIK can be a unilateral or bilateral procedure. Following the procedure, patients are prescribed a course of prophylactic antibiotics, will be asked not to drive home and will have been advised to wear sunglasses until the (normal) mild photobhobia resolves. Recovery can take between days and a few weeks, depending on which procedure is done and whether both eyes were done or not.
It is important for anyone considering LASIK to have realistic expectations. LASIK allows many people to perform most of their everyday tasks without wearing corrective lenses. However, those hoping to achieve perfect vision and become completely free of the need to wear eyeglasses or contact lenses run the risk of being disappointed. Everyone develops the need to wear reading glasses in their 40s or 50s due to presbyopia.
Glaucoma is caused by a number of different eye diseases that in most cases produce increased pressure within the eye. This elevated pressure is caused by a backup of fluid in the eye. Over time, it causes damage to the optic nerve.
Optic nerve is the part of the eye that carries visual information to the brain. It is made up of over one million nerve cells, and while each cell is several inches long, it is extremely thin -- about one twenty-thousandth of an inch in diameter. When the pressure in the eye builds, the nerve cells become compressed, causing them to become damaged and to eventually die. The death of these cells results in permanent visual loss. Early diagnosis and treatment of glaucoma can help prevent this from happening.
Everyone should be concerned about glaucoma and its effects. It is important for each of us, from infants to senior citizens, to have our eyes checked regularly, because early detection and treatment of glaucoma are the only way to prevent vision impairment and blindness.
While glaucoma can develop in younger patients, it occurs more frequently as we get older.
Glaucoma appears to `run´ in families. The tendency for developing glaucoma may be inherited. However, just because someone in your family has glaucoma does not mean that you will necessarily develop the disease.
High IOP is the most important risk factor for glaucomatous damage.
African-Americans have a greater tendency for developing primary open-angle glaucoma than do people of other races.
With open-angle glaucoma, there are no warning signs or obvious symptoms in the early stages. As the disease progresses, blind spots develop in your peripheral (side) vision.
Most people with open-angle glaucoma do not notice any change in their vision until the damage is quite severe. This is why glaucoma is called the "silent thief of sight." Having regular eye exams can help your ophthalmologist find this disease before you lose vision.
People at risk for angle-closure glaucoma usually show no symptoms before an attack. Some early symptoms of an attack may include blurred vision, halos, mild headaches or eye pain. People with these symptoms should be checked by their ophthalmologist as soon as possible. An attack of angle-closure glaucoma includes the following:
People with "normal tension glaucoma" have eye pressure that is within normal ranges, but show signs of glaucoma, such as blind spots in their field of vision and optic nerve damage.
Some people have no signs of damage but have higher than normal eye pressure (called ocular hypertension). These patients are considered "glaucoma suspects" and have a higher risk of eventually developing glaucoma. They should be carefully monitored by an ophthalmologist.
Variety of diagnostic tools that aid in determining whether or not you have glaucoma -- even before you have any symptoms.
Glaucoma can be treated with eye drops, pills, laser surgery, eye operations, or a combination of methods. The whole purpose of treatment is to prevent further loss of vision. This is imperative as loss of vision due to glaucoma is irreversible. Keeping the IOP under control is the key to preventing loss of vision from glaucoma.
Diabetes can harm your eyes. The excessive amount of glucose circulating in the blood stream can damage the small blood vessels in your retina, the back part of your eye. This is called diabetic retinopathy. It affects up to 80% of all patients who have had diabetes for 10 years or more. The longer a person has diabetes, the higher his or her chances of developing diabetic retinopathy. Diabetes also increases your risk of having glaucoma, cataracts, and other eye problems.
The retina is the layer of tissue at the back of the inner eye. It changes light and images that enter the eye into nerve signals that are sent to the brain which enables us to "see" things. Often, there are no symptoms until the damage to the eyes is severe.
Symptoms may include blurred vision and slow vision loss over time, floaters, shadows or missing areas of vision, and/or trouble seeing at night.
Blocked blood vessels or vessels that are larger in certain spots, small amounts of bleeding and fluid leaking from the vessels, and/or abnormal growth of new, fragile vessels are signs that an eye doctor looks for during a diabetic eye exam. Regular diabetic eye exams are vitally important to the continued health of your eyes, as well as your continued ability to see.
During this test, your doctor will inject a dye into your arm, allowing them to track how the blood flows in your eye. They'll take pictures of the dye circulating inside of your eye to determine which vessels are blocked, leaking, or broken.
An optical coherence tomography (OCT) exam is an imaging test that uses light waves to produce images of the retina. These images allow your doctor to determine your retina's thickness. OCT exams help determine how much fluid, if any, has accumulated in the retina.
Treatment options are limited for people who have early diabetic retinopathy. Your doctor may want to perform regular eye exams to monitor eye health in case treatment becomes necessary. An endocrinologist can help to slow the progression of retinopathy by helping you optimally manage your diabetes.
In advanced diabetic retinopathy, the treatment depends on type and severity of retinopathy.
Pediatric ophthalmology is a subspecialty of medicine and surgery whose physicians are trained to perform all aspects of medical care for children's eyes and visual systems.
Children may not complain if they do not see out of one or both eyes. Sometimes the only clue may be poor performance in School, as well viewing the blackboard at a very close distance. Hence all children need an eye exam at the time of starting Schooling.
Of the eye problems in children, the most important are refractive errors, squint and amblyopia.
Refractive error or the need for glasses is the single most important cause of vision impairment in children. This may lead to permanent deficiency in vision if not detected and treated early.
Squint, also known as cross eyes, is the condition where the eyes do not work together. Treatment includes glasses, eye exercises or eye muscle surgery.
Lazy eye or amblyopia is the term for poor vision in one or both eyes. It can result from refractive error, squint or several other causes. This needs to be identified and treated at an early age to recover vision.
Infants born prematurely are at risk for developing Retinopathy of pre-maturity (ROP) which may lead to permanent blindness. Sankara Nethralaya has been in the forefront in India in the treatment of this disorder.
Cataract (opacification of the lens) can occur in children. This may be present since birth or result from injury. The treatment involves surgical procedures but very often treatment of lazy eye.
There are several causes of double vision and squint in adults as well. These are managed by exercise, special glasses, and eye muscle surgery when required.
Poor performance in School
Viewing objects at a very close distance
Family history of eye problems or wearing glasses
Babies have poor vision at birth but can see faces at close range, even in the newborn nursery. At about six weeks a baby's eyes should follow objects, and by four months should work together. Over the first year or two, vision develops rapidly. A two-year-old usually sees around 20/30, nearly the same as an adult.
Parents should be aware of signals of poor vision. If one eye turns or crosses, that eye may not see as well as the other eye. If the child is uninterested in faces or age-appropriate toys, or if the eyes rove around or jiggle (nystagmus), poor vision should be suspected. Other signs to watch for are tilting the head and squinting. Babies and toddlers compensate for poor vision rather than complain about it.
Should a baby need glasses, the prescription can be determined accurately by dilating the pupil and analyzing the light reflected through the pupil from the back of the eye. Prescriptions for glasses can be measured in even the youngest and most uncooperative children by using a special instrument called a retinoscope to ana lyze light reflected through the pupil from the back of the eye.
Obstruction of the tear duct will cause tearing or watering of the eye because the tears cannot drain properly. Symptoms of a blocked tear duct include eyelashes that are stuck together by mucus or an accumulation of tears in one or both eyes. The tears trapped within the duct may become infected, causing a painful swelling in the inner corner of the eyelid. In infants the membrane that causes the obstruction will usually open by six months of age. If this does not occur, your physician will often recommend treatment to open the blockage.
Initial treatment involves massaging the area over the affected tear sac (located under the skin between the eye and nose) to force the tears and mucus from the sac, hopefully pushing open the membrane causing the obstruction. In infants, this massage requires the active involvement of the parent, as it must occur frequently. Massage is generally continued until the tearing resolves. Antibiotic drops or ointments may also be prescribed by the physician in the event of infection. If the obstruction is still present, it may be necessary to open the tear duct by probing and irrigation. This is most commonly performed between six months and one year of age. The probing is done by passing a thin probe down the tear drainage system in an attempt to open the blockage. There is minimal pain associated with this procedure. After the probing, there may be some brief blood staining of the tears or a slight nosebleed. Antibiotic drops may be prescribed. This procedure is 90-95% effective after the first treatment. Unfortunately, blockages may recur in spite of probing. If the tearing persists, then a small tube may be placed down the duct to keep the tear draining system open. The tubes are tiny and generally imperceptible, and usually remain in place for six to twelve months to prevent the obstruction from recurring.
Amblyopia is poor vision in an eye that did not develop normal sight during early childhood. It is sometimes called " lazy eye" . When one eye develops good vision while the other does not, the eye with poorer vision is called amblyopic.
Children learn to suppress double vision so effectively that the deviating eye gradually loses vision.
Strabismus refers to misaligned eyes. If the eyes turn inward (crossed), it is called esotropia. If the eyes turn outward (wall-eyed), it is called exotropia. One eye can be higher than the other, which is called hypertropia (for the higher eye) or hypotropia (for the lower eye). Strabismus can be subtle, (occurring occasionally), or c onstant. It can affect one eye only or shift between the eyes.
There are many medical conditions that are associated with strabismus. Strabismus usually begins in infancy or childhood, but many adults develop strabismus often due to trauma or brain tumors. Some toddlers have accommodative esotropia. Their eyes cross because they need glasses for farsightedness. Most cases of strabismus do not have a well-understood cause. It seems to develop because the eye muscles are uncoordinated and do not move the eyes together.
When young children develop strabismus, they typically have mild symptoms of strabismus. They may hold their heads to one side if they can use their eyes together in that position. Or, they may close or cover one eye when it deviates. Often, the child's brain learns to ignore or suppress the vision in the deviated eye. Adults, on the other hand, have more symptoms when they develop strabismus. They have double vision (see a second image) and may lose depth perception. Studies show school children with significant strabismus have self-image problems.
Strabismus is often treated by surgically adjusting the tension on the eye muscles. The goal of surgery is to straighten the eyes and allow them to move normally so that they will use the eyes together. Surgery is very successful at improving the condition, though a few patients (15-20%) will require additional surgery.
Fact 1: More than 20% of the people have some refractory error.
Fact 2: 70% of population doesent knows that they are suffering from Eye related problems.
Fact 3: Presbyopia- Lack of focus of near objects starts by the age of 38-40 years and 100% of the people with presbyopia need corrective glasses.
Fact 4: Cataract – By the age of 55-60 more than 50% of the population will develop some form of Cataract.
Fact 5: 5% of the people over the age of 40 have chances of developing Glaucoma and the Glaucoma is the silent thief of vision and is symptom less and most of the people with Glaucoma don't know that they have it.
Fact 6: 25% of the people in Urban areas suffer from Diabetes and have high chances of developing irreversible Diabetic Retinopathy.
Fact 7: All Children need to have a eye examination before going to school and once every year.
A qualified Ophthalmologist is the only person authorised to perform a eye examination.
A typical eye testing would take 30-60 mins.
The following tests would be done routinely by the Ophthalmologist
Visual Acuity Screening
Distance, Near and Colour Vision Testing.
Dilatation and a Detailed Fundus Examination.
Intra Ocular Pressure Measurement.
More than 90% of Urban Indians use the computer. With more and more use of Computers, computer related eye problems are on the rise. If you get headache or Eye strain at the end of the day after using the computer for long hours, or if you have difficulty in focussing distant objects, you may be suffering from Computer Vision Syndrome or CVS.
Computer vision syndrome is a serious problem for the millions of Indians who spend hours in front of a computer every day. Aside from the physical discomfort you may experience from symptoms, computer vision syndrome can have a lasting effect on your vision. There are several preventive steps that you should take if you frequently use a computer.
98% of professionals in urban India show sympoms of CVS.
16 new patients are treated each month by Ophthalmologists.
40 million Indians surf the net and 180 million use cell phones every day.
90% of urban Indians use computers over 4 hours a day.
Neck pain and Body pains.
Inability to focus.
Redness of the Eyes.
CVS is caused by our eyes and brain reacting differently to characters on the screen than they do to printed characters. Characters ( Pixels) on a computer screen lack the contrast or well-defined edges that printed characters have. Because the color intensity of digital characters diminishes around the edges, it is difficult for eyes to remain focused. Having to continually refocus on digital text fatigues the eyes and can lead to burning or tired eyes.
Demand 1: Very fast and jumpy movements from one eye position to another- between document screen and key board. This puts a lot of strain on the six muscles holding the Eye.
Demand 2 : Focussing for too long, too close and too often. This puts strain on the ciliary muscle which controls focussing of the eye and the ciliary muscle is made to work harder.
Demand 3 : Reduced Blinking rate, leads to dry, itchy , red and burning eyes.
1) The monitor should be between 16-30 inches away from your eyes. Adjust the height of the monitor too. The top of the monitor should be 10-20 degrees below eye level and the screen should be 4-8 inches lower. Tilt up the screen slightly as if you are reading a book or a magazine.
2) Occupational or Computer Eye Glasses with Anti reflection coatings helps.
3) Windows and light sources should be on the side of the monitor.
4) Blink rapidly atleast 10 times a minute.
5) Feet should be firmly on the ground, hips , knees and arms should be straight at right angles . Neck should not tilt beyond 0-15 Degrees.
Contact Lenses are a good cosmetic option for refractory errors. If you are wearing Contact Lenses for the first time, please keep in mind that Contact Lenses should always be bought from a qualified eye care practitioner, preferrably a Eye Doctor. Please do remember that Contact Lenses are classified Medical Devices.
Always handle the lenses gently. Shake the lens case a bit before you take out the Lenses. Place the lens on the tip of your index finger , which should be clean and dry. With the fingers and thumb of your other hand, simultaneously pull up on your upper eyelid and down on your lower eyelid.Then place the lenses over the cornea or on the white of the eye.Once the lens is in position , look in various directions so that the lens settles down.
Many people have doubts in finding out if the Lens is inside out. A simplest way is to place the lens on your index finger. If the lens forms a perfect cup , its normal, if it forms a distorted cup, it may be inside out
Wash your hands with Soap and water before wearing Lenses . Its very important that you do not have long nails when you are wearing lenses. These might damage the contact lenses or can also damage the cornea of your eye while you are removing the Lenses
Wash your hands with soap and water before you remove your lenses.To remove soft contact lenses, look upward or sideways while you pull down on your lower eyelid. With a finger, gently maneuver the lens onto the white of your eye. There, you can very gently pinch the lens together with your index finger and thumb and lift it off the eye. Until you master contact lens removal, you might consider keeping your fingernails clipped to avoid accidentally scratching and damaging your eye.
Rigid contact lenses can be removed by holding out the palm of your hand, bending over, and then opening your eye wide. With one finger of your other hand, pull on the skin of your eye's outside corner straight out toward your ear with your eye wide open. Then blink. The contact lens should pop right out and into your open palm
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