Key messages
• Laser trabeculoplasty may work better than topical medication (eye drops) in slowing down the progression of open-angle glaucoma (rate of visual field loss i.e. vision loss at the edges of vision) and may be similar to modern eye drops in controlling eye pressure at a lower cost. It is not associated with any serious unwanted effects, particularly for the newer types of trabeculoplasty, such as selective laser trabeculoplasty.
• Laser trabeculoplasty appears to work less well than trabeculectomy (surgery for glaucoma).
What is open-angle glaucoma?
Glaucoma is an eye disease where the nerve that connects the eye to the brain (optic nerve) is damaged. Usually, this happens because the pressure inside the eye (intraocular pressure) is too high, probably because the drainage channels in the eye have become blocked.
How is open-angle glaucoma treated?
The aim of treatment for glaucoma is to reduce the pressure in the eye to protect the optic nerve from more damage. Reducing the pressure in the eye can be done by eye drops, laser treatment, or surgery. Laser trabeculoplasty involves opening up the blocked drainage channels in the eye.
What did we want to find out?
The aim of this Cochrane Review is to find out how well laser trabeculoplasty works as a treatment for open-angle glaucoma.
What did we do?
This review compared laser treatment (laser trabeculoplasty) with topical medication (eye drops) and surgery (trabeculectomy). Cochrane researchers collected and analysed all relevant studies to answer this question.
What did we find?
Cochrane researchers found 40 studies. These studies were mainly from Europe and the USA.
The results were as follows:
• Different studies found different effects on eye pressure when comparing laser trabeculoplasty with eye drops. Older studies were more likely to show a benefit of laser trabeculoplasty which may be because the eye drops in these older studies did not work as well as modern eye drops (low-certainty evidence). Three studies showed a benefit of trabeculoplasty over eye drops for avoiding visual field progression at 24 months (argon) and 48 months (selective) (moderate-certainty evidence, downgraded for risk bias).
• Harmful effects were more common in the laser trabeculoplasty group and included more cases where the iris was stuck to the edge of the drainage mechanism inside the eye (peripheral anterior synaechiae) but this was seen only with older types of laser (argon) trabeculoplasty (low-certainty evidence).
• People receiving laser trabeculoplasty may be more likely to have pressure in the eye that is too high compared with people who had surgery (trabeculectomy) (low-certainty evidence).
• Surgery (trabeculectomy) may increase the risk of cataract compared with laser (very low-certainty evidence).
• A number of studies compared different types of laser (argon, selective, diode, excimer, pattern scanning, titanium-sapphire, and micropulse) but with inconclusive results.
What are the limitations of the evidence?
Some of the studies were not masked and were not large enough to provide a reliable answer to the question. There have been changes over time in both laser and eye drops which meant that, for some outcomes, there were different effects in different studies.
How up-to-date is this evidence?
Cochrane Review authors searched for studies that had been published up to 28 October 2021.