Could adverse effects and complications of selective laser trabeculoplasty be decreased by low-power laser therapy?

Abstract

Selective laser trabeculoplasty (SLT) has been used for treatment of primary open-angle glaucoma, ocular hypertension, pigmenter and pseudoexfoliative glaucoma being considered a low-risk procedure. Therefore, transitory and permanent adverse effects have been reported, including corneal changes, subclinical edema, and reduction in endothelial cells and in central corneal thickness. Despite rarer, serious corneal complications after SLT can be permanent and lead to visual impairment, central corneal haze, opacity and narrowing. The mechanism involves increase of vasoactive and chemotactic cytokines causing inflammatory infiltrate, destruction of stromal collagen by fibroblasts and increase of matrix metalloproteinases type 2, which impair reepithelization. SLT also increases free radical production and reduces antioxidant enzymes, resulting in endothelium damages. Low-power laser therapy (LPLT) has been used in regenerative medicine based on its biostimulatory and anti-inflammatory effects. Biostimulation occurs through the interaction of laser photons with cytochrome C oxidase enzyme, which activates intracellular biochemical cascades causing synthesis of a number of molecules related to anti-inflammatory, regenerative effects, pain relief and reduction in edema. It has been showed that LPLT reduces gene expression related to pro-inflammatory cytokines and matrix metalloproteinases, and it increases expression of growth factors related to its proliferative and healing actions. Although radiations emitted by low-power lasers are considered safe and able to induce therapeutic effects, researches based on experimental models for glaucoma could bring important data if LPLT could be an alternative approach to improve acceptation for patients undergoing SLT.

Evaluation of selective laser trabeculoplasty effectiveness in cases with pseudoexfoliation glaucoma and ocular hypertension

“…Laser may affect the corneal function by causing an increase in the production of inflammatory cytokines, matrix metalloproteinases, and free oxygen radicals in tissues. [3,8,23] Therefore, the effects of SLT on CCT and ECC were also examined in the literature. [6,[24][25][26] Kanagaratnam and Ong determined a transient increase in CCT and a transient decrease in ECC at 20th min after adjuvant 180° SLT in OAG patients.…”

Eficacia, seguridad y eficiencia de dispositivos de drenaje subconjuntival con aproximación ab-interno para cirugía del glaucoma primario de ángulo abierto

“…Los principales efectos secundarios asociados a la trabeculoplastia láser incluyen cambios corneales, edema corneal subclínico y reducción de las células endoteliales y del grosor de la córnea central. A pesar de ser más raras, las complicaciones graves de la córnea pueden ser permanentes y dar lugar a una deficiencia visual, opacidad y estrechamiento de la córnea central 10 .…”

Expression profile analysis to identify potential gene changes induced by dexamethasone in the trabecular meshwork

“…It is boldly speculated that the TRP pathway may be involved in the remodelling of the ECM of the TM to mediate the occurrence of SIG. When laser trabeculoplasty is used to treat POAG, the cytokine TNF increases the protein levels of matrix MMP-3 and MMP-9, and the increase in MMP-3 plays a crucial role in the success of the treatment [34] . Therefore, we need further experiments to verify the roles of these pathways, which will help elucidate the mechanism of SIG.…”