Why cataract surgery alone can lower pressure
The natural crystalline lens gets thicker with age. Replacing it with a thin artificial lens deepens the front of the eye and opens the drainage angle. Studies consistently show a 2–4 mmHg reduction in intraocular pressure in open-angle glaucoma, and much larger falls (often 10 mmHg or more) in narrow- and closed-angle eyes. For some patients this is enough on its own to control the glaucoma.
When to combine cataract surgery with a glaucoma procedure
Combined surgery is worth considering when any of these apply:
- You need two or more glaucoma drops to control pressure
- You struggle with drop side effects (stinging, red eye, allergy)
- You forget or find it hard to instil drops reliably
- You already have some visual field damage from glaucoma
- Pressure is not at target despite drops
- You have pseudoexfoliation, pigmentary or narrow-angle glaucoma
The glaucoma options that combine with cataract surgery
iStent inject W / Hydrus microstent (MIGS)
Tiny titanium or nitinol stents placed into the eye's natural drainage channel through the cataract incision. Add 5 minutes to surgery. Around 65–70% of patients are on fewer drops at 2 years; roughly half are off drops entirely. Very safe profile.
PRESERFLO MicroShunt
A soft implant that creates a new drainage pathway from the front of the eye to a reservoir under the conjunctiva. Bigger pressure drops than MIGS; used for moderate to advanced glaucoma. More follow-up needed in the early weeks. More on PRESERFLO.
Trabeculectomy
The traditional gold-standard glaucoma operation. Reserved for advanced glaucoma or where very low target pressures are needed. Combined cataract-trabeculectomy remains an important option. More on trabeculectomy.
Lens choice with glaucoma
Multifocal and trifocal lenses split light and reduce contrast — a compromise most glaucoma patients should avoid because the disease already reduces contrast and peripheral vision. A high-quality monofocal or, in selected mild cases, an EDOF lens is usually the best choice.
Frequently asked questions
Can cataract surgery help glaucoma?
Yes — cataract surgery on its own typically lowers intraocular pressure by 2–4 mmHg in open-angle glaucoma and often much more in angle-closure. That is why many patients with mild glaucoma find their pressure improves after routine cataract surgery, without any additional glaucoma procedure.
What is combined cataract and glaucoma surgery?
It is a single operation that removes the cataract and adds a glaucoma procedure — usually a minimally invasive glaucoma surgery (MIGS) device such as an iStent inject W, Hydrus microstent, or a PRESERFLO MicroShunt. One recovery, one visit list.
Who should have combined surgery rather than cataract alone?
Patients with moderate glaucoma on two or more drops, patients with tolerability problems from drops, and patients with early visual field damage where more aggressive pressure lowering is desirable. Patients with well-controlled mild glaucoma on one drop can often just have cataract surgery.
What is MIGS?
Minimally invasive glaucoma surgery — a family of tiny devices implanted through the same incision as cataract surgery to improve the eye's natural fluid drainage. iStent inject W and Hydrus are the most commonly used in the UK. They add about 5 minutes to the operation and rarely cause the complications of traditional glaucoma surgery.
Will I still need my glaucoma drops afterwards?
Often you can reduce drops after combined surgery — about half of patients are off drops entirely at 12 months after cataract + MIGS. More advanced procedures such as PRESERFLO or trabeculectomy have a higher chance of drop-free control but with more intensive follow-up.
Is combined surgery riskier than cataract alone?
MIGS combined with cataract surgery has a safety profile very close to cataract surgery alone. Larger procedures (PRESERFLO, trabeculectomy) carry more risk and are chosen only when the glaucoma justifies it. The trade-off is discussed in detail before you decide.
Combined cataract and glaucoma assessment
A single consultation covering your cataract, your glaucoma control, and whether combined surgery is the right next step.