Repeat-selective laser trabeculoplasty (SLT) administered during the LIGHT Trial lowered intraocular pressure (IOP) in eyes with IOP increases during 1.5 years after the initial SLT application. The decrease lasted longer than the initial lowering.
Dr. Gazzard reported that the mean IOP was higher before the initial SLT compared with the repeat-SLT (24.5 versis 21.0 mm Hg, p < 0.001).
“We did not allow the patients to return to the baseline IOPs before we re-intervened, to mirror normal clinical practice,” he pointed out.
At that important two-month time point, the absolute IOP reduction was greater after the initial SLT, that is 5.3 versus 4.6 mm Hg (p = 0.02).
Dr. Gazzard also explained that if the two-month IOP adjusted for the starting IOP immediately before laser treatment was used, there was a greater adjusted effect after the repeat-SLT.
“The adjusted difference between the primary laser and the repeat laser showed that the latter seemed to be producing a greater proportional effect,” he said.
The adjusted mean difference was -1.1 mm Hg (P = 0.001).
The results also showed that the targeted IOP after the repeat-SLT was maintained better than the IOP after the initial SLT.
A comparison of the early failures with the later failures who were not included in the Repeated-SLT subgroup was undertaken to determine a bias.
Thirty-four eyes were retreated at two months because they had not achieved the target IOP and compared with 81 eyes that failed after two months. There was no difference in effect in the early versus later failures; the mean difference in the IOP reduction was 0.3 mmHg, Dr. Gazzard explained.
“The early failures tended to more often have moderate to more severe POAG, and, therefore, the IOP target was more stringent,” he said.
Dr. Gazzard concluded that repeat-SLT successfully reduced IOP in eyes that failed within 1.5 years of the start of the LIGHT Trial.
“The adjusted absolute IOP reduction, controlling for the pre-treatment IOP, seemed to be greater than after the first laser treatment,” he said. “The IOP lowering in these eyes seemed to last longer after repeat-SLT. The response did not seem to be linked to the time of the first failure.”
Gus Gazzard, FRCOpthMA, MBBCHIR, MD
E: [email protected]
Dr. Gazzard is supported by a grant from the National Institute for Health Research-Health Technology Assessment. He reports that he has no financial interest in any ophthalmic products, company, or related stocks.