Intraocular Pressure Changes Post Selective Laser Trabeculoplasty in the Contralateral Untreated Eyes of Nigerian Patients With Primary Open Angle Glaucoma

Abstract

Background: Glaucoma is the commonest cause of irreversible blindness in Nigeria and raised intraocular pressure (IOP) is the only modifiable risk factor. Selective laser trabeculoplasty (SLT), one of the treatment modalities, has been reported to have a cross-over effect on the fellow untreated eyes.
Objectives: To determine the IOP lowering effect of SLT on the contralateral untreated eyes in patients with primary open angle glaucoma.
Methods: This was a retrospective chart review of patients who underwent SLT at Guinness Eye Centre, Lagos from June 2011 – June 2012. Information on bio-data, diagnosis and modality of treatment were retrieved. Excluded were patients who had glaucoma surgery or needed additional medications. Each patient had SLT in one eye either as primary or adjunctive treatment. IOPs were measured post-operatively in both treated and untreated eyes at various time points using the Goldmann applanation tonometer. Data was analysed using paired and unpaired two-tailed t-test for comparison of means with level of significance set at p<0.05.
Results: Forty eyes of twenty subjects were included. 60% (12) were males and 40% (8) were females. The mean age was 48.9 ± 17.0 years (range, 23 – 74 years). Reduction in IOP from baseline was found in both the treated and the fellow untreated eyes at the various time points. Mean IOP reduction was maximal at 3 months; 8mmHg or 26% (p=0.024) in the treated eyes and 7mmHg or 25.9% (p=0.097) in the untreated eyes. Mean IOP reduction from baseline were 1.3 ± 5.9mmHg or 6.3% (P=.624) in the treated eyes and 2.9 ± 7.5 mmHg or 9.7% (P=.418) in the untreated eyes at 6months.
Conclusion: This study shows that there is a sustained IOP reduction in the fellow untreated eyes following SLT in patients with POAG. In view of the retrospective nature of the study, small sample size, non-randomization and lack of control definite conclusions cannot be drawn from the findings.

Keywords: Intraocular pressure, Selective laser trabeculoplasty, Primary open angle glaucoma