Laser in Glaucoma and Ocular Hypertension (LiGHT) trial aiming to investigate the efficacy and duration of effect of repeat SLT in medication naive POAG and OHT eyes. One hundred and fifteen eyes of 90 subjects had undergone two SLTs during the initial 18 months of the LiGHT trial. After the first SLT, 34 were considered as early failure (second SLT two months after the first one) and 81 as later failure (second SLT more than two months after). Mean IOP was 24.5 ± 6.6 mmHg before the first SLT and 19.1 ± 3.9 mmHg two months after (-5.3 mmHg; - 21.6%). Mean IOP was 21.0 ± 4.2 mmHg before the second SLT and 16.3 ± 3.3 mmHg two months after (-4.6 mmHg; -21.9%), without significant difference between the early and later groups.
To compare the duration of effect after the first and second SLT, a clinical definition of success was used rather than a numerical definition: IOP below target IOP (defined by the clinician) without medications, further laser procedure or glaucoma surgery. The authors demonstrated an equivalent or longer duration of effect after the second SLT compared to the first SLT. Only 38/115 eyes (33%) that underwent a second SLT needed a medical treatment in the 18 months after the second SLT. No adverse events were reported.
The findings of this study are interesting for clinical practice. SLT is frequently used as a first-line treatment in OHT and OAG subjects. When the efficacy is not enough or when the IOP subsequently goes up, the choice between performing a second laser procedure or starting a medical treatment is debated. To date, few studies have been performed and most of them have been retrospective with a small number of patients, and therefore did not fully answer the question. However, the LiGHT trial supports the use of a second SLT when an initial SLT is not enough to reach the target IOP or when the IOP further goes up. One limitation of this study is that the authors did not use a numerical criterion to define the success, and thus it could be difficult to precisely quantify and compare the mid- and long-terms effect after the first and second SLT.
The LiGHT trial supports the use of a second SLT when an initial SLT is not enough to reach the target IOP or when the IOP further goes up