CATARACT



What is cataract?

The haziness of clear transparent lens in the eye is known as cataract. The cause for this is still unknown. However some causes are: 

  Old age : Most important factor. However it may develop in any age. 

  Hereditary. 

  Diseases during pregnancy such as German measles. 

  Traumatic cataract: Cataract due to injury. 

  Eye diseases such as iritis. 

  Medicines as steroids. 

  Systemic diseases like diabetes. 

  Long term exposure to sunlight. 











Cataract as seen by Slit Lamp



Symptoms of Cataract 

Common complaints of cataract patients are: 

Painless blurring of vision.

Glare and reduction of vision in bright light.

Frequent change in eye glass power.

Double vision in one eye,

Fading of colors.
 


Treatment

Only treatment available for it is operation. No medicines can remove cataract or slow the progress of its growth. No one can predict how fast a cataract will grow. 


When to operate

In earlier days, because of higher complications associated with cataract surgery and poor quality of vision by thick glasses required after surgery, the surgery was delayed till patient had very poor vision ( Less than 20/200 ) by almost mature cataract. Now with improved methods - the surgical risks have gone down, Intraocular Lenses give good vision - we find no reason to wait for maturity, affecting the life style of a person. Only indication for surgery now days is difficulty in managing the work. It is only you to decide whether blurred vision is preventing you to do the things you like to do. For some even slight visual interference may be bothersome needing early surgery while others may be happy with marked visual loss due to cataract.


Lens Induced Glaucoma

When Cataract matures there may be swelling of lens tissue blocking the drainage angles leading to sudden rise of the pressure in the eye ( Lens induced glaucoma).
There is severe pain and the features are similar to acute congestive glaucoma.
Immediate reduction of eye pressure followed by immediate cataract surgery may save the eye. However it involves higher surgical risk.


Methods

In the beginning whole lens was removed and thick glasses were given to replace it. The wound was left open and patient was not allowed to move at all till the wound healed on its own.

With the development of stitches mobility of patient was increased and he was allowed to move on same day with some restrictions. These stitches were thick and caused irritation and so needed removal.


Operating Microscope

  Microsurgery: with the advent of microscope it was possible to do surgery under magnification. This gives better light combined with magnification and better overall view of eye making the surgeon’s job easier. Surgery under the microscope is called microsurgery. Finer sutures were also invented giving lesser post-operative irritation to the patient and stitches need not be removed. Now a days most of eye surgeries are done under microscope.

Extracapsular cataract surgery : In this we break the cataract and remove anterior layer and inside of cataract leaving behind a thin layer of lens, posterior capsule.This layer is supposed to protect the retinal complications and gives support for Intraocular implantation. Here the incision size is about 12 mm and it need stitches to close the wound.

Larger incision with stitches in extracapsular cataract surgery 




  Intra ocular lens (IOL) : These are powered lenses made to be inserted in the eye. These are permanent lenses and are usually not removed. Lens power is calculated by a machine called biometer. This reduces the lens power required in the specks after cataract surgery. It makes person life easier as :


  • heavy glasses are replaced by light weight glasses.
  • thick glasses caused magnification effect making walking difficult for many.
  • as the power in thick glass is only in center the side vision is also affected making smaller visual field.














                
          Intraocular Lens

  Yag laser: The posterior  layer of cataract may get thickened with time and again decrease the vision. This layer is cut by yag laser,  which is a safe procedure. This does not involve hospitalization and there are no postoperative restrictions. Whole cataract cannot be removed by the laser.

  Phacoemulsification: (known as phaco surgery) - in this procedure by aid of a machine using ultrasonic energy we cut, break and suck out the cataract from the small opening of 3.00MM. Normally this surgery does not involves stitches and have following advantages:
  • less healing time and so early recovery.
  • less irritation - which may happen otherwise due to stitches.
  • lesser postoperative complication.
  • early and better visual recovery which is some what affected by the stitches in extracapsular surgery – Stitches may cause higher degree of astigmatism.

Small Incision of Phacoemulsification



Normal IOL is 5.5 mm in size and so we have to increase the opening to 5.2mm in these cases.

  Foldable IOL : These lenses give full advantage of phaco surgery. These lenses are made of special material so IOL is flexible and can be folded . Thus we need not enlarge the incision and whole surgery can be done by 3.00mm cut. Now we have variety of IOL.


  Laser Surgery : Nucleus can also be broken and sucked out by different machine using laser. But it still needs surgery as phacoemulsification. Further its use is limited to soft cataracts only. This procedure is still not an established technique.





Foldable IOL




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