Selective Laser Trabeculoplasty (SLT) vs Timolol Trial

Irreversible blindness caused by glaucoma can be prevented by reducing intraocular pressure through daily eye drops, eye surgery, or laser treatment. Currently timolol eye drops are the most affordable and commonly available treatments to reduce intraocular pressure. However, they come with problems, as many people struggle to take them regularly or access new bottles, for example due to cost or distance to the nearest provider.

We wanted to test whether using a laser therapy commonly used in Europe and North America, Selective Laser Trabeculoplasty (SLT), as a treatment in Tanzania would be superior to timolol drops.

Conducting a randomised controlled trial in Tanzania, we enrolled 201 patients with open-angle glaucoma who were assigned to either receive 0·5% timolol eye drops twice daily or SLT.

We found that SLT successfully reduced eye pressure to normal levels (up to 18 or 21mmHg) in significantly more patients after one year (61% of eyes) compared to the standard treatment of timolol eye drops (31% of eyes).

The study also considered the affordability of SLT, finding that in spite of the initial cost of the laser equipment, for hospitals dealing with high volumes of glaucoma patients the treatment could be offered at a similar price as the annual supply of eye drops.

The results indicate that glaucoma can be treated more successfully with a one-off or occasionally repeated outpatient laser treatment to reduce eye pressure at least for one year, compared to the most commonly used eye drops in lower income regions.

Publications

Selective laser trabeculoplasty versus 0·5% timolol eye drops for the treatment of glaucoma in Tanzania: a randomised controlled trial. Philippin, Heiko et al. The Lancet Global Health, Volume 9, Issue 11, e1589 – e1599. https://doi.org/10.1016/S2214-109X(21)00348-X

Differentiating stages of functional vision loss from glaucoma using the Disc Damage Likelihood Scale and cup:disc ratio. Philippin H, Matayan EN, Knoll KM, Macha E, Mbishi S, Makupa A, et al. British Journal of Ophthalmology. 2024;108:349–56. https://doi.org/ 10.1136/bjo-2022-321643

Acknowledgements

We would like to thank our partners in this research, the Kilimanjaro Christian Medical Centre, and Seeing is Believing Innovation Fund and Christian Blind Mission for funding.