LASIK (Laser assisted in situ keratomileusis) is useful in treatment of
Correct Answer: All of the above
Description: Ans. d (All of the above) (Ref. Khurana's ophthalmology, 2nd ed., p 77; Parson's 20th/pg. 76)EXCIMER LASER IN SITU KERATOMILEUSIS (LASER)# Principle:- Myopia is corrected with preservation of Bowman's layer.- A superficial corneal flap (approx. 160 pm) is created with a microkeratome.- The keratome is withdrawn, the flap is reflected, and the exposed underlying corneal stroma is ablated with an excimer laser to correct the myopia.- Then the flap is repositioned on the corneal bed and fixed in place by force of its own adhesion.# Indication:- Severe myopia (up to 10-12 diopters).- Photoablation:* Excimer laser produces photoablation.* It produces UV light of very short wavelength, which breaks chemical bonds of biologic materials, converting them into small molecules that diffuse away.- Photorefractive keratectomy:* LASIK for correcting refractive errors and* LASIK for phototherapeutic keratectomy for corneal disease like "band-shaped" keratopathy.# LASIK is superior to photorefractive keratectomy in that it:- Less painful procedure* As LASIK does not expose raw corneal surface at the end of surgery it is less painful.- Can be repeated by lifting the flap created if further refinement is necessary- Gives a faster visual rehabilitation- Has less myopic regression- Causes less scarring than photorefractive keratectomy- Can Rx higher myopia* It can also treat a higher myopia, causes less scarring and has less myopic regression. However, because a flap needed to be created, it has a higher potential risk.* Involves the use of microtome* Is contraindicated in patients with thin cornea# Side effects of LASIK:- Reduced corneal sensation- Inaccurate biometry if the patient requires cataract surgery in later life- Tear film abnormality- Erroneously high intraocular pressure with applanation tonometer.
Category:
Ophthalmology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now