Question

Explain briefly what excimer lasers are and the reason why they are used in photorefractive keratectomy, in which the front of the cornea is sculpted to correct nearsightedness.

-Why is the argon ion laser not a good choice for this operation?

-Why is the reverse true for laser surgical procedures performed on the retina?

Answer 1

I have referred some sources and my text books to answer these questions. Let me know if you have any doubt.

In simple words, an excimer laser is a type of UV laser which uses noble gases as a medium. Here the amplification occurs in excited dimers. These are usually fabricated with stainless steel, Teflon etc.

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There are many reasons why these are used in photorefractive keratectomy. In fact these are also used in LASIK surgery procedure.. The excimer laseralters the refractive state of the eye by removing tissue from the anterior cornea

1) does not generate heat in the cornea

2) No need to remove the entire corneal thickness

3) Less than 10% of cornea is affected with these lasers

4) This is usually pain free

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Argon ion lasers usually produce so much heat if used without halogen medium and in unskilled hands, it can cause serious burns. The laser intensity is so high that it may tear into a blood vessel or may puncture it.

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In retinal operation, Argon laser is useful because it can help in preventing retinal detachment. It occurs when any fluid passes through a retinal tear, it can result in the retina breaking away from the surrounding tissue.

The laser induces heat energy in the retina and can be precisely focused and adjusted from simply stimulating the retina to reduce swelling and to prevent a retinal tear leading to a retinal detachment. use of excimer laser can cause retinal tear which can then be prevented using argon lasers.