This prospective, double-blind, randomized, placebo-controlled trial compared the effect of apraclonidine and diclofenac on IOP changes after selective laser trabeculoplasty (SLT).
Study design
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.
Outcomes
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.
Limitations
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.
Clinical significance
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.