Background: Normal tension glaucoma (NTG) is commonly treated with anti-glaucoma medications. Recently, selective laser trabeculoplasty (SLT) has been demonstrated to lower the intraocular pressure (IOP) and medication use in NTG. The purpose of this study was to investigate the efficacy of a single session of SLT for NTG at 1 year.
Methods: This prospective cohort study recruited NTG patients taking anti-glaucoma medication. Potential subjects were excluded if they had had previous glaucoma surgery or laser and also if intraocular surgery or additional SLT procedures were performed after the first treatment. All subjects underwent a 1-month washout. A 30% IOP reduction was set as the target IOP. A single session of SLT was performed to 360 degrees of the trabecular meshwork. At 1-month after SLT, medication was resumed to achieve the target IOP. The IOP was measured every 3 months, and the number of medications was recorded at 3, 6, and 12 months. Only the right eye was used for statistical analysis.
Results: In 41 right eyes, the mean pre-study IOP was 14.3 ± 3.4 mmHg while on 1.5 ± 0.8 eye drops. The post-washout IOP was 16.2 ± 2.2 mmHg. A mean of 191.1 ± 26.3 SLT shots at 1.0 ± 0.07 mJ were applied. There was significant IOP reduction at all time intervals following SLT when compared to the post-washout IOP (P < 0.0001). The number of medications was significantly reduced at all time intervals following SLT when compared to the pre-study level (P < 0.0001). At 12 months, the mean IOP was 12.2 ± 2.2 mmHg while on 1.1 ± 0.9 eye drops.
Conclusions: A single session of SLT for NTG achieved an additional 15% IOP reduction while using 27% less medication at 1 year compared to pre-study levels.
Trial registration: The Clinical Trials Register of the University of Hong Kong HKCTR1847 The European Clinical Trials Database 2014-003305-15 (August 11, 2014) ( https://www.clinicaltrialsregister.eu/ctr-search/search?query=2014-003305-15 ).