In the blink of an eye
M. VEERASAMY
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Create awareness and prevent eye injuries.
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VISION is very important for our daily activities. Yet many people suffer different kinds of visual disorders or eye diseases. Some can be cured either by medicine or by surgical correction. Ignorance, self-medication, lack of knowledge are the causes that lead to blindness.
Preventable
Some types of blindness can be prevented. Corneal blindness is one such. For healthy vision, the cornea and the lens should be transparent. Light rays pass through the cornea and the lens and focus on the retina.
Sometimes the cornea loses its transparency and becomes opaque either due to disease or injury. So now the light rays cannot enter the eye. The person becomes blind even though all other parts of the eyes are normal. Statistics show that corneal blindness is more prevalent among children. Most injuries happen when no adult is present and many are the result of everyday activities. Defective vision due to short sight or long sight can be corrected by wearing spectacles, contact lenses or by LASIK. Cataract can also be cured by surgery.
Transplant
But corneal blindness depends on transplant from a donor eye also known as keratoplasty. The affected opaque cornea Corneal blindness due to accidents can be prevented by simple safety measures and relevant health education in schools. For example children should be taught the dangers of playing with objects like pencils, needles and stones.
Injuries to the eyes are the result of such games. Often parents resort to self-medication and proper treatment is not given in time. If the cornea is affected, an ulcer develops and blindness is the result.
In schools, students should handle chemicals in the laboratory with care and all containers should be labelled to prevent injury.
During the festive season, injuries result from improper use of fireworks. Carelessness in handling crackers can lead to permanent damage. Children must use fireworks only under adult supervision.
Prevention is better than cure and by implementing safety measures and by creating awareness on these issues we can prevent many eye injuries.
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DR. J. AGARWAL
The intraocular lens has revolutionised cataract surgery. A look at how it came about.
PHOTO: A. ROY CHOWDHURY
Clear Vision: Cataract surgery is now successful.
THE saga of the Intraocular lens began 200 years ago. An Intraocular lens or IOL is an artificial lens inserted inside the eye once the cataract is removed.
Cataract occurs when the lens of the eye becomes opaque. The normal lens allows light to reach the retina. When it becomes opaque, the light does not reach the retina and we are unable to see clearly.
Modern medical advances have made cataract surgery very successful. New surgical techniques and the Intraocular lenses can restore excellent vision in 97 per cent of the cases. In the 1960's Dr. Charles Kelman from the U.S. pioneered a technique called Phacoemulsification in which cataracts were removed through a three mm incision, as against the earlier 12 mm incision in which the whole cataract was removed. In 1998, Dr. Amar Agarwal from India started a technique called PHAKONIT in which cataracts could be removed through a one mm opening.
Artificial lens
Once the cataract is removed, the eye cannot focus, as there is no lens. So an artificial lens has to be used to focus the object onto the retina. This can be a spectacle, contact lens or an Intraocular lens. Spectacles are very heavy and not comfortable. Further, if the glasses are removed the person cannot see. Another problem is that everything is magnified and the side view is very poor. The second alternative is to use a contact lens. This is an artificial lens placed on the eye. The disadvantage again is that once removed the person cannot see. Also they have to be put on and removed.
The best method is to give the patient an Intraocular lens. This is an artificial lens placed in the eye during surgery and will remain in place till the end of life. In 1764, an Italian ophthalmologist called Tadini working at Warsaw, Poland, played around with the idea of inserting small glass pieces into the eye after cataract surgery. He did not carry out his idea, but it was passed on to Casaamata, an Italian ophthalmologist, working in Dresden. To him goes the credit of implanting the first intraocular lens made of glass in 1795. This was disastrous as the glass was too heavy and sank into the interior of the eye.
First time
After World War II, many pilots had pieces of plastic from the windshields of their bombers embedded in their eyes. These pieces were inert and did not cause any reaction. One visionary British doctor, Dr. Harold Ridley, wondered if these pieces could be shaped like a lens and inserted into the eye after cataract surgery. Thus on November 24,1949, Sir Harold Ridley implanted the first Intraocular lens in a 45-year-old woman.
The International Council of Ophthalmology honoured Sir Harold Ridley posthumously for this marvellous discovery in June 1994. Though Dr. Ripley did have a fair amount of success, he also had failures that disheartened him. This was mainly because his lenses were bulky and heavy.
With sophistication of instruments, came phacoemulsification by Kelman. Although phacoemulsification required a three mm opening, the incision had to be enlarged to five or six mm to implant the IOL. To avoid increasing the incision size, foldable IOLs were created. The new foldable IOL's became popular in the 1990's. The latest technique in cataract extraction is Phakonit in which the cataract is removed through a one mm incision. The problem with this technique was to find an IOL, which would pass through such a small incision. Then on October 2, 2001 the first Phakonit Rollable IOL using a special lens of five mm optic size was implanted.
Advantages
The advantage was that it was a very thin lens, which became pliable when put in water and could then be rolled and inserted into the eye. Inside the eye, the lens opened gradually. The advantage was that the incision was so very small. Now there are accommodating or multifocal IOL's with which patients can use for both distance and near vision.
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DR. C. SENTHIL NATHAN
Dropping eyelids can cause a variety of problems. But it can be cured.
THE eyelids are the first line of defence for the eyes. Normally, the lids are placed at about 4-4.5mm above the centre of pupil with the eyelashes pointing away from eyes. There are various conditions in which the position of the lids is altered leading to serious consequences.
One patient complained of an inability to open both eyes fully. He had to tilt his head upwards to see clearly and was thus unable to work for more than a few hours at a stretch. His facial appearance seemed abnormal. After an examination by an Oculoplastic Consultant, he was diagnosed with ptosis, in which the eyelid is at an abnormally low position and can occur either at birth (congenital) or develop later in life (acquired).
Early correction
Congenital ptosis is the result of maldevelopment of the muscle, which lifts the eyelid (Levator Palpebrae Superioris). Thus the upper lid covers the eye either partially or completely. If not corrected early, the development of the eye is hampered and can lead to permanent decrease in vision (Amblyopia or Lazy Eye Syndrome). Also the child's psychological development is affected due to the cosmetic blemish caused by a drooping lid.
Acquired ptosis can occur due to various reasons, the commonest being other eye surgeries. Here the ptosis occurs due to stretching and weakening of the fibres of the muscle either due to surgery or as a result of ageing.
Ptosis can also be the first sign of an underlying systemic disease like "Myasthenia Gravis." Here the individual develops drooping lids following physical exertion or when he is tired. A detailed examination and laboratory investigations can uncover the underlying disease, which can be easily corrected by medication.
It can also be the first sign of serious conditions like brain tumour, aneurysm and apical lung cancer due to damage to the nervous pathway, which supplies the levator muscle. This underscores the importance of prompt ophthalmic examination in patients who develop sudden onset of Ptosis.
Congenital ptosis needs to be managed early if it is severe, as the visual development would be affected if not treated at the appropriate time. Surgery usually is the treatment of choice and a variety of surgeries are available to lift the eyelid.
Ptosis in the elderly can also be corrected by surgery, which would help them to see more clearly and also decrease the strain on the forehead muscles. Ptosis occurring as a result of other systemic causes usually resolve once the underlying condition is treated.
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