Selective laser trabeculoplasty (SLT) differs from argon laser trabeculoplasty (ALT) in that SLT:

• A Uses an argon laser to thermally coagulate trabecular meshwork openings, permanently improving outflow
• B Requires administration of topical corticosteroids for 4 weeks post-procedure due to high thermal energy
• C Acts on the ciliary body to reduce aqueous production rather than increasing trabecular outflow
• D Uses a 532 nm Nd:YAG frequency-doubled laser targeting melanin in trabecular cells without thermal coagulation of adjacent non-pigmented cells, making it repeatable ✓

Explanation

SLT uses a Q-switched frequency-doubled Nd:YAG laser (532 nm, nanosecond pulse) that selectively targets melanin-containing trabecular cells (selective photothermolysis) without causing structural damage to adjacent non-pigmented tissue. The IOP-lowering mechanism involves macrophage recruitment, cytokine-mediated trabecular remodelling, and improved outflow facility. Because SLT causes minimal collateral damage, it can be repeated (unlike ALT which causes scarring). ALT causes coagulative thermal damage making re-treatment less effective.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.