Abstract
Purpose: :
To determine if Central Corneal Thickness (CCT) has an impact on Intraocular pressure (IOP) lowering effect of Selective Laser Trabeculoplasty (SLT) as primary treatment for patients with Ocular Hypertension (OHT) and Primary Open Angle Glaucoma (POAG).
Methods: :
A retrospective, chart review of consecutive patients, who underwent SLT as primary treatment for OHT and POAG, between 2002 and 2005, and completed at least 30 months follow up was performed. Patients were excluded if they required additional glaucoma medications, laser, or ocular surgery during the follow up period.Partial correlation analysis was performed to correlate the CCT to the percentage of IOP reduction at 3, 6, 12, 18 and 30 months after SLT controlling for baseline IOP. Independent samples t test was performed to compare mean percentage of IOP reduction in eyes with CCT < 555 microns versus mean percentage of IOP reduction in eyes with CCT ≥ 555 microns.
Results: :
80 eyes of 47 patients were identified (32 with OHT and 48 with POAG). The CCT was 564.3 +/- 37.1 microns (range, 453-646 microns). The baseline IOP was 23.8 +/- 3.1 mmHg (range, 14-30 mmHg). The partial correlation coefficient value between the CCT and percentage of IOP reduction following SLT at 3 month was - 0.167 (p = 0.145), at 9 month was -0.252 (p=0.06), at 18 month was -0.173 (p=0.128), and at 30 month was -0.301(p=0.007). Independent samples t test showed that the mean percentage of IOP reduction in eyes with thinner corneas (CCT< 555 microns) was 6.3% greater than the percentage of IOP reduction in thicker corneas (CCT≥ 555 microns) at 30 months post SLT (p= 0.03)
Conclusions: :
In patients with POAG and OHT, we found no significant correlation between CCT and the percentage of IOP reduction following SLT at 3, 9 and 18 months, while at 30 months we found a moderate inverse correlation between CCT and percentage of IOP reduction. Percentage of IOP reduction at 30 months following SLT was significantly greater in eyes with thinner corneas (CCT < 555 microns). These findings indicate that patients treated with SLT as primary therapy who had thinner corneas, demonstrated better IOP control at 30 months.
Keywords: laser • anterior chamber • outflow: trabecular meshwork