The selective laser trabeculoplasty (SLT) mechanism differs from argon laser trabeculoplasty (ALT) in that SLT:

• A Uses UV wavelength to photocoagulate the trabecular meshwork, creating scar tissue that contracts and opens Schlemm's canal
• B Selectively targets melanin-containing trabecular meshwork cells using a Q-switched Nd:YAG 532 nm laser with minimal collateral damage, allowing retreatment ✓
• C Creates permanent structural changes in the trabecular meshwork similar to ALT but with higher energy
• D Targets the uveoscleral outflow pathway exclusively

Explanation

SLT uses a frequency-doubled Q-switched Nd:YAG laser at 532 nm with a very short pulse duration (3 nanoseconds), which selectively targets melanin-containing cells in the trabecular meshwork (pigmented TM cells) via selective photothermolysis, without causing thermal coagulative damage to adjacent non-pigmented cells or collagen. This selective action stimulates macrophage-mediated TM remodeling and improves outflow without the coagulative scarring of ALT, allowing the procedure to be safely repeated. ALT causes irreversible coagulation damage limiting retreatment.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.