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Benefits and risks

Benefits and risks

When NICE looked at the evidence, it decided that there was enough evidence to show that it is safe enough and works well enough for use in the NHS. The 8 studies that NICE looked at involved a total of 3,096 patients.

Generally, they showed the following benefits:

  • lower pressure in the eye, up to 5 years after the procedure

  • less use of medication for glaucoma

  • successful procedure in nearly all patients.

The studies showed that a small number of people had problems after the procedure, and some of these were serious. The risks included:

  • significantly worse vision after the procedure in 1 patient and decreased vision in 7 eyes

  • increased pressure in the eye in up to 50% of patients in 1 of the studies

  • bleeding in the eye in about 2% of patients

  • damage or changes to structures in the eye in about 2% of patients

  • dry eye in about 2% of patients

  • the stent not in the correct place in 2 to 18% of patients

  • the stent becoming blocked in 4 to 15% of patients

  • some people needing a second procedure to reposition the stent or to insert a replacement stent.

If you want to know more about the studies, see the guidance. Ask your health professional to explain anything you don't understand.

  • Information Standard