Selective laser trabeculoplasty (SLT) lowers IOP by a mechanism that differs from argon laser trabeculoplasty (ALT) in that SLT:
- A Creates thermal coagulation spots on the trabecular meshwork to improve outflow
- B Ablates the pigmented trabecular meshwork to create new drainage channels
- C Selectively targets melanin-containing trabecular meshwork cells using short-pulsed 532 nm Q-switched Nd:YAG laser without coagulative thermal damage to adjacent tissue ✓
- D Reduces ciliary body aqueous secretion via thermal neuromodulation
Explanation
SLT uses a Q-switched, frequency-doubled 532 nm Nd:YAG laser with nanosecond pulse duration. The short pulse duration confines energy to melanin-containing trabecular meshwork cells (selective photothermolysis) without thermal coagulation of adjacent non-pigmented cells or collagen. The proposed mechanisms include macrophage recruitment, cytokine release, and biological remodeling of the trabecular meshwork. Because SLT does not cause coagulative damage, it can be safely repeated, unlike ALT which creates permanent thermal burns limiting retreatment. Both ultimately improve trabecular (conventional) outflow.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.