Use SLT to slow RNFL thinning

Glaucoma treatment usually gets framed around one number — intraocular pressure. Lower the pressure, slow the damage. But the thing patients actually lose is tissue and function, not a pressure reading. That is why a small ARVO 2026 study got attention: after selective laser trabeculoplasty, eyes that had been showing measurable OCT progression looked much more stable on retinal nerve fiber layer tracking. ### What exactly changed? At the ARVO meeting in Denver, Raeesah Ahsan from Wills Eye presented a retrospective analysis of 25 eyes from 21 people with open-angle glaucoma. The group looked at longitudinal OCT measurements before and after SLT. Before laser, several structural markers were steadily worsening — especially average, superior, and inferior RNFL thickness. After SLT, the rates of change for all evaluated OCT parameters were no longer significantly different from zero, and the slowdown was significant for average RNFL, superior RNFL, and cup-to-disc ratio. (ophthalmologymanagement.com) ### Why is RNFL thinning such a big deal? RNFL is basically the axon layer of retinal ganglion cells. In glaucoma, that layer thins as nerve tissue is lost. OCT gives clinicians a way to track that loss earlier and more quantitatively than waiting for a patient to notice symptoms. The 2026 AAO Preferred Practice Pattern update also leans harder on structural imaging — including circumpapillary RNFL and macular ganglion cell thinning — when classifying and following glaucoma suspects. (ophthalmologymanagement.com) ### Isn’t SLT already standard? Pretty much, yes — at least as a mainstream first-line option. SLT has already earned its place because it lowers IOP without the adherence problems of daily drops. The LiGHT trial pushed that shift years ago, and its longer follow-up kept supporting SLT-first care as clinically effective. The new wrinkle here is not “SLT lowers pressure” — everybody already knows that. The wrinkle is that OCT structure may stabilize more than expected after the laser. (reviewofoptometry.com) ### So is this just an IOP story? Not entirely. The presentation described the pressure reduction after SLT as modest but statistically significant. That matters because the structural signal looked larger than a simple “pressure went down a bit” story would neatly explain. The article covering the presentation did not give the exact post-SLT IOP delta, so you should be careful not to overclaim mechanism. But the clinical takeaway is fair — if OCT slope flattens after SLT, that may be worth noticing even when the pressure drop looks unremarkable. (ophthalmologymanagement.com) ### How strong is this evidence? Promising, but early. This was a retrospective study, not a randomized trial, and it only included 25 eyes. That means selection effects, regression to the mean, imaging variability, and treatment changes around the same time could all muddy the picture. Older data have also been less clean. A 2022 ARVO abstract following SLT out to 5 years found that many eyes still progressed on visual field and inferior RNFL despite pressure control, and about half needed later intervention. (ophthalmologymanagement.com) ### What should residents and clinicians do with it? Use it as a reason to watch OCT trends more deliberately after SLT, not as proof that laser has a separate neuroprotective effect. If a patient’s RNFL slope had been drifting down and then stabilizes after laser, that is clinically meaningful even if the pressure story looks only modestly improved. But scan quality, segmentation error, and normal aging still matter — OCT can mislead if you read the color map instead of the full context. (iovs.arvojournals.org) ### Does this change the early-laser debate? It nudges it. The case for early SLT used to be convenience, adherence, cost-effectiveness, and pressure control. Add even a tentative structural benefit on OCT, and the argument gets easier — especially in patients where you are deciding between escalating drops and intervening earlier. But this still needs prospective confirmation with larger cohorts and clearer adjustment for IOP and medication changes. (reviewofoptometry.com) ### Bottom line? The interesting part is not that SLT worked. It is that the tissue trend may have slowed in a way clinicians can actually see on OCT. If that holds up, success after SLT will be judged a little less by tonometry alone — and a little more by whether the nerve stops quietly disappearing. (ophthalmologymanagement.com)