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• Out Patient Section.
  
  WESTEND EYE HOSPITAL
  High Court Junction
  Banerji Road,
  Cochin
  Kerala, India.
   

• Surgical Wing & OP Section:
  
  WESTEND EYE HOSPITAL
  Near Vimalalayam,
  Kacheripady, Chittoor Road
  Cochin 18, Kerala, India.
  
  Phones:
  High Court Jn: (0484) 235 4452
  Kacheripady: (0484) 329 3051
  Mobile : (91) 94467 07272
  e-mail : davisa@sify.com

SHORT SIGHT & ITS TREATMENT

Dr. Davis J. Akkara &
Dr. Ethamma Davis
Westend Eye Hospital.
Cochin 31

Short sight or "Myopia" is ability to see near objects clearly and disability to see far objects clearly. There are different reasons for short sight. Most common reason is hereditary. Short sight tends to appear in child hood or during adolescence. It is important to check the vision of children around the age of five and around the age of twelve.

During adolescence, the power of glasses changes along with the change of height and voice. The change stabilises at about 20 years of age. This power usually remains with out much of change up to the age of forty. It is not possible to treat myopia with medicines or special food.

Spectacles

Spectacles are the oldest method of treating short sight. It is probably the easiest way to over come short sight. It is not with out disadvantages or dangers. To many, wearing spectacles is a stigma. Others find it difficult to wear them. If involved in an accident, the glasses can break and pierce the eyeball and cause complications. Of course, chances are very remote.

Fitting right lenses on a suitable frame for a person needs a lot of knowledge of refraction. Spectacles, when fitted under the direct supervision of a doctor, will get you the perfect match.


Contact Lenses

Contact Lenses are another way of treating short sight. Small plastic lenses are fitted over the cornea in between the eyelids by the myopic person. These lenses are only 10 mm to 14 mm in diameter. These lenses cannot be easily seen by another person. The natural look of the person is preserved with contact lenses. The contact lenses have to be worn in the morning and removed in the evening. The lenses have to be cleaned and stored in a special solution. There are some extended wear contact lenses available, which are intended to be worn for a week continuously. But these lenses have so much of complications that they are not recommended anymore.

The contact lenses are difficult to be handled by an elderly person. These lenses if not cleaned properly, will collect dirt and cause infection to the cornea. Corneal infections can cause reduced vision. Allergy is another common cause of irritation for contact lens wearers. Generally it is well tolerated by young individuals who care for their good looks.

Mainly there are four types of contact lenses available:

1. Soft.

2. Semi-soft (Rigid Gas-permeable Lenses).

3. Coloured Contact Lenses.

4. Disposable Contact Lenses.

Soft lenses are very thin and bends like a plastic paper. They are very comfortable to wear and patients get used to the lenses in no time. Unlike the semi-soft lenses they do not fall off the eyes very easily. But being very thin, they tend to tear if not handled carefully. The average life of soft contact lens is about two years.

Semi soft lenses {rigid gas-permeable lenses (RGP)} are thicker and as the name suggests, are rigid. They are not as comfortable to wear as the soft lenses. These lenses tend to fly off the eyes in windy weather. The life of a semi-soft contact lens is longer than that of a soft lens.

Coloured contact lenses are soft lenses available with different powers and colours. When worn the eyes become blue, green, brown, red, etc. depending on the colour of the lens. They are expensive but are great to give special effects on to the eye.

Disposable contact lenses are the most hygienic contact lenses to use. These lenses are replaced every month with new lenses so that there is hardly any dirt build up on the lens. By the time dirt starts building up they are disposed off and are replaced with fresh pair of contact lenses. These lenses are ideal for people who don't have enough time to clean their contact lenses.

Radial cuts are made
in the yellow region on the cornea

Diagramatic representation
of RK in progress
with a diamond knife.

Radial Keratotomy is a simple surgical procedure, which can treat powers up to - 5.00 Diopters (points). It is not as sophisticated as Laser treatment but is very much cheaper and gives good results for myopia up to - 5.00 dioptors. After the advent of Laser treatment (Lasik), the number of surgeons performing RK has reduced.

Excimer Laser

Excimer Laser treatment is the latest method of treating short sight. Both the eyes are treated at the same sitting to avoid gross difference of power between the two eyes. Very rarely one eye is treated at a time. A week's rest is advisable after LASIK laser treatment and a month after PRK.

There are two types of treatment available:

1. PRK or surface treatment.
2. LASIK (laser treatment under the partial thickness corneal flap).

PRK and LASIK are done under topical (eye drops and not injection) anesthesia. The procedures are not at all painful.

In PRK, the laser is applied directly on the surface of the cornea after removing the epithelium (skin of the cornea).

The laser reshapes the cornea into a lens of required power. The skin of the cornea grows back in about 4 to 7 days after treatment. Till the skin of the cornea grows back, the patient will have irritation of the eyes and will find it difficult to open the eyes. The visual recovery will start only after the skin grows back. Patient will have to apply medicines for 3 to 6 months after PRK. PRK has an upper limit of minus 9.00 Diopters (points) for treatment. PRK is cheaper than Lasik treatment.

In LASIK treatment a computer-controlled kerotome (Blade) cuts the cornea to raise a 60 to 80-micron (1 micron = 1/1000 mm.) corneal flap. Laser is applied under the flap.

Corneal flap replaced after Laser treatment under the flap.

The corneal flap is replaced after the procedure. Here the skin of the cornea is not removed and so the patient's discomfort is minimal. The visual recovery is rapid and the patient is able to regain near normal vision on the very next day. Medicines have to be applied for a month following LASIK Laser treatment.

The major draw back of Laser treatment is that it is not possible to guarantee a 100% cure for every body. Some people may have - 0.5 or -1.0 Diopter residual power. But for a person who was wearing - 10.0 or -15.0 Diopter glasses prior to laser treatment, these small residual powers are not significant. Being a surgical procedure, LASIK also has it own risks like all other surgical procedures.