The excimer laser used in photorefractive keratectomy (PRK) and LASIK operates at which wavelength?
- A 1064 nm infrared, produced by a Nd:YAG crystal
- B 193 nm ultraviolet, produced by an argon fluoride gas ✓
- C 1053 nm infrared, produced by a femtosecond solid-state source
- D 308 nm ultraviolet, produced by an excimer dye mixture
Correct answer: B. 193 nm ultraviolet, produced by an argon fluoride gas
Explanation
Corneal refractive surgery uses an argon fluoride excimer laser emitting at 193 nm in the far ultraviolet. At this wavelength photon energy breaks molecular bonds directly (photoablation) with negligible thermal spread, giving submicron precision. The femtosecond lasers used for flaps and lenticules operate in the infrared around 1053 nm and work by photodisruption, not photoablation. The Nd:YAG 1064 nm laser is used for capsulotomy and iridotomy, never for stromal ablation.
Reference: Khurana, Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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