This prospective, double-blind, randomized, placebo-controlled trial compared the effect of apraclonidine and diclofenac on IOP changes after selective laser trabeculoplasty (SLT).
Researchers randomized 60 eyes (35 patients) undergoing 360° SLT to 1 of 3 groups:
- apraclonidine pre-SLT, placebo post-SLT
- placebo pre-SLT, diclofenac post-SLT
- placebo before and after SLT
All 3 groups received 1 drop an hour before SLT and 1 drop 4 times daily for 5 days after the procedure. Eyes were examined for anterior chamber reaction and IOP at day 0 and 1, weeks 1, 4 to 6 and months 4 to 6. Patients were also instructed to check IOP with a home-monitoring device at 1, 2 and 3 hours post-SLT followed by every 3 hours until 24 hours.
None of the eyes in the apraclonidine group experienced an IOP spike (≥5 mm Hg) compared with 63% and 45% of the of the diclofenac and placebo groups, respectively. The average change in IOP during the first 24 hours was -2.4 mm Hg in the apraclonidine group compared with 4.5 mm Hg and 4.1 mm Hg in the diclofenac and placebo groups, respectively (P<0.0001 for apraclonidine vs. other groups). However, mean IOP reduction at 6 months was similar among the 3 groups (range 4.4–5.8 mm Hg).
The diclofenac group had a significant decrease in anterior chamber reaction at day 1, but not at any other time point. All 3 groups had similar rates of post-laser discomfort. Peak IOP typically occurred at 1 hour post-treatment. Higher baseline IOP correlated with higher risk of IOP spike but short-term IOP spikes did not correlated with long-term efficacy.
The study population was entirely white—mostly of Nordic origin—limiting the applicability of the findings to patients of other races. The study does not comment on whether bilateral, same-day SLT could have led to a crossover effect for patients with eyes randomized to different groups. The sample size may have been too small to detect slight differences in long-term IOP.
This study illustrates the effectiveness of the alpha agonist apraclonidine for reducing the risk of same-day IOP spikes after SLT, without having a negative effect on long-term IOP reduction. Diclofenac may be unnecessary for post-SLT management because it did not significantly affect long-term IOP or patient comfort; this cohort was small, however. Peak IOP typically occurred at 1 hour post-laser, indicating that an IOP check at 1 hour will likely catch most IOP spikes following SLT.