Selective laser trabeculoplasty (SLT) never ceases to amaze me. Just last week, I read about an interesting prospective trial that found that SLT can be safely and efficaciously performed without a gonioscopic lens.1 For more tips and tricks on getting the most out of the procedure, read Dr. Ahmad Aref’s article below on what’s new with SLT.
—Nathan M. Radcliffe, MD
1. Geffen N, Ofir S, Belkin A, et al. Transscleral selective laser trabeculoplasty without a gonioscopy lens. J Glaucoma. doi:10.1097/IJG.0000000000000464.
For more than a decade, selective laser trabeculoplasty (SLT) has been a well-accepted treatment for primary open-angle glaucoma (POAG), pigmentary glaucoma, and pseudoexfoliative glaucoma. Yet, studies published in the past 1 to 3 years point to several new indications for SLT as well as other exciting developments in this procedure.
According to these studies, SLT may also be an effective treatment for normal-tension glaucoma (NTG), primary angle-closure glaucoma (PACG), and steroid-induced glaucoma (SIG). In addition, several studies suggest SLT retreatment benefits, while others question the need for anti-inflammatory drugs after the surgery.
Below is a look at these intriguing studies.
PRIMARY ANGLE-CLOSURE GLAUCOMA
To perform SLT, visualization of the trabecular meshwork is required. In patients with PACG, the iris occludes the trabecular meshwork, which would seem to rule out SLT. However, the iris often occludes less than the entire 360° of the trabecular meshwork, leaving some sectors visible and amenable to SLT treatment.
Two recent studies have shown that treating those visible areas with SLT can significantly reduce intraocular pressure (IOP). A 2015 study showed that eyes with PACG responded to SLT at 6 months,1 and another study published in 2016 found that the safety and efficacy of SLT for PACG was equivalent to that for POAG.2
These results are exciting because, although PACG is not the most common type of glaucoma, it can be difficult to treat. SLT provides an alternative to incisional surgery for patients with PACG in whom IOP is high despite medical treatment. My patients’ responses have mirrored these study findings.
Because IOP likely fluctuates to a greater degree in patients with NTG, it is often difficult to determine whether SLT may be a beneficial treatment modality. However, two studies published in 2015 found that SLT lowered IOP by 15% and medication use by 27% at 1 year,3 and results were still evident at 2 years in this patient population.4
These results are encouraging because we do not know how the IOP of a patient with NTG varies throughout the day or overnight. Even if the response to SLT is moderate, treatment is providing a beneficial effect at all times.
Steroids often increase the trabecular meshwork’s resistance to aqueous outflow from the eye, which, in turn, may raise IOP. When patients need steroid therapy, we must be prepared to manage their pressure.
A 2016 retrospective study looked at eyes with well-controlled uveitis in which a fluocinolone acetonide intravitreal implant induced glaucoma.5 Researchers found that SLT was safe and effective in these patients, reducing IOP through the study’s 1-year termination.SLT succeeds by targeting the trabecular meshwork, the same structure negatively affected by the steroids.
Many surgeons have repeated SLT. The practice is accepted as safe, primarily because SLT leaves no scarring. Anecdotally, we have seen positive outcomes, but, until very recently, we did not have the study data. Now, three studies show that repeat SLT treatment is effective in lowering IOP from baseline and is just as effective as initial treatment in some cases, with treatment effects lasting up to 24 months.6-8
Our reflex is to start patients on medication after laser treatment, but there has always been question about the benefit of anti-inflammatory eye drops following SLT. Two recent studies show that no postoperative treatment is just as effective as steroids and NSAIDs for patient comfort, appearance of anterior chamber cells, and IOP.9,10 SLT is a low-risk procedure, and it is acceptable to not treat patients with any postoperative medication.
I have stopped ordering anti-inflammatories after SLT in most cases. With studies that back up the clinical use of SLT for additional types of glaucoma, I have expanded my range of candidates as well. These are exciting developments in a treatment area that has long remained largely unchanged.
1. Narayanaswamy A, Leung CK, Istiantoro DV, et al. Efficacy of selective laser trabeculoplasty in primary angle-closure glaucoma: a randomized clinical trial. JAMA Ophthalmol. 2015;133(2):206-212.
2. Ali Aljasim L, Owaidhah O, Edward DP. Selective laser trabeculoplasty in primary angle-closure glaucoma after laser peripheral iridotomy: a case-control study. J Glaucoma. 2016;25(3):e253-e258.
3. Lee JW, Ho WL, Chan JC, Lai JS. Efficacy of selective laser trabeculoplasty for normal tension glaucoma: 1 year results. BMC Ophthalmol. 2015;15:1.
4. Lee JW, Shum JJ, Chan JC, Lai JS. Two-year clinical results after selective laser trabeculoplasty for normal tension glaucoma. Medicine (Baltimore). 2015;94(24):e984.
5. Maleki A, Swan RT, Lasave AF, Ma L, Foster CS. Selective laser trabeculoplasty in controlled uveitis with steroid-induced glaucoma. Ophthalmology. 2016;123(12):2630-2632.
6. Francis BA, Loewen N, Hong B, et al. Repeatability of selective laser trabeculoplasty for open-angle glaucoma. BMC Ophthalmol. 2016;16:128.
7. Khouri AS, Lari HB, Berezina TL, Maltzman B, Fechtner RD. Long term efficacy of repeat selective laser trabeculoplasty. J Ophthalmic Vis Res. 2014;9(4):444-448.
8. Polat J, Grantham L, Mitchell K, Realini T. Repeatability of selective laser trabeculoplasty. Br J Ophthalmol. 2016;100(10):1437-1441.
9. De Keyser M, De Belder M, De Groot V. Randomized prospective study of the use of anti-inflammatory drops after selective laser trabeculoplasty. J Glaucoma. 2017;26(2):e22-e29.
10. Jinapriya D, D’Souza M, Hollands H. Anti-inflammatory therapy after selective laser trabeculoplasty: a randomized, double-masked, placebo-controlled clinical trial. Ophthalmology. 2014;121(12):2356-2361.