Selective laser trabeculoplasty (SLT) uses which laser and targets which cells in the trabecular meshwork?

• A Nd:YAG laser, Q-switched (532 nm) targeting melanin-containing trabecular cells selectively ✓
• B Argon laser (514 nm) targeting all trabecular cells
• C Diode laser (810 nm) targeting Schlemm's canal endothelium
• D Excimer laser (193 nm) ablating the trabecular meshwork

Explanation

SLT uses a frequency-doubled, Q-switched Nd:YAG laser at 532 nm (green wavelength). The nanosecond pulse duration is selectively absorbed by melanin-containing (pigmented) trabecular meshwork cells without damaging adjacent non-pigmented cells or causing coagulative burns — hence 'selective.' This contrasts with argon laser trabeculoplasty (ALT), which uses 514 nm (argon) and causes thermal burns to all trabecular cells. SLT can be repeated, whereas repeat ALT is limited by scarring.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.