Effect of prior cataract surgery on the long-term outcome of selective laser trabeculoplasty

OBJECTIVE To determine if pseudophakia affects selective laser trabeculoplasty (SLT) intraocular pressure (IOP) lowering effect. METHODS A retrospective chart review was performed on 94 eyes of 75 consecutive patients who underwent SLT as primary treatment for ocular hypertension and primary open-angle glaucoma between 2002 and 2005 and completed at least 30 months follow up. Patients were excluded if they required additional glaucoma medications, laser, or ocular surgery during the follow-up period. Patients were categorized as phakics or pseudophakics. Independent-samples t-test was performed to compare the mean percentage of IOP reduction at 3, 6, 12, 18, and 30 months after SLT between the phakic and pseudophakic groups. RESULTS Seventy-six phakic and 18 pseudophakic eyes were included. IOP reduction in phakic group was 27.4% (2 week), 29.8% (3 months), 27.7% (9 months), 27.4% at (12 months) and 27.3% at (30 months). In pseudophakic patients, the mean IOP reduction was 19.8% (2 weeks), 26.5% (3 months), 23.2% (9 months), 22.5% (12 months), and 25.9% (30 months). An independent-sample t-test compared the percentage of IOP reduction between the phakic and pseudophakic groups and revealed higher percentage of IOP reduction in the phakic group at 2 weeks by 7.6% (P = 0.01). P value for difference was 0.34 (3 months), 0.25 (6 months), 0.18 (9 months), 0.12 (12 months), 0.36 (18 months), and 0.7 (30 months) after SLT. CONCLUSIONS SLT response was delayed in pseudophakic compared to phakic patients, while the long-term effectiveness of SLT is the same in both groups.