Cataract surgery with an epiretinal membrane: which operation first?

How do a cataract and a membrane affect vision differently?

A cataract clouds the eye's natural lens. An epiretinal membrane is a thin sheet of tissue on the surface of the macula, the central part of the retina used for reading and recognising faces. It can contract and pull the retina out of shape.

Both can reduce clarity. Distortion — such as straight lines looking bent or letters seeming crowded — is particularly relevant to the membrane. Symptoms alone cannot reliably separate the two, and a good result on the letter chart does not capture every difficulty with reading or using both eyes together.

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The useful question is what you want to do more comfortably: read, drive, recognise faces or work with fine detail. Tell your surgeon about distortion as well as blur. If the membrane is mild and symptoms are acceptable, observation rather than membrane surgery may remain a reasonable choice.

What does the OCT scan add?

OCT produces a cross-sectional picture of the macula. It can show the membrane, retinal thickening, changes to the normal central dip and the arrangement of the retinal layers. Your surgeon considers these findings alongside your symptoms and visual acuity.

More marked changes to the retinal layers can limit the result, even if surgery successfully removes the membrane. The scan cannot predict your final vision exactly. A thickness number by itself is not a universal trigger for surgery; changes over time and their effect on your life also matter.

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These are separate example scans, not before-and-after images of one eye. A baseline OCT also helps distinguish pre-existing retinal changes from new swelling after an operation.

What are the three surgical options?

The main trade-off is between treating one problem and reassessing, or treating both during one operation. The following describes common reasons for each approach, rather than rules that apply to every eye.

If neither problem is currently troublesome enough to justify surgery, monitoring can also be appropriate. Having both diagnoses does not automatically mean you need both operations.

When might cataract surgery come first?

Cataract surgery first is often worth considering when the lens opacity seems to explain most of the difficulty and the membrane has limited effects on daily life. Removing the cloudy lens lets you and your surgeon assess the useful vision with the membrane still present.

A large UK study found that eyes with an epiretinal membrane often improved after cataract surgery alone, although the average improvement was smaller than in eyes without a membrane. More recent follow-up of mostly mild membranes also supports cataract surgery as a useful option in selected eyes. Those findings should not be applied to every advanced or worsening membrane.

If the clearer vision meets your needs, membrane surgery may not be necessary at that stage. If troublesome distortion remains, a second discussion can focus on whether peeling the membrane is likely to add worthwhile benefit. Cataract surgery should not be presented as a treatment for the membrane itself.

When might membrane surgery come first?

Membrane surgery first can make sense when distortion or retinal change is the main concern and the lens is still relatively clear. It avoids removing a natural lens before there is a clear reason to do so, which can matter particularly in a younger person who still has useful natural focusing ability.

The operation usually involves vitrectomy — removing the vitreous gel — and peeling the membrane from the retinal surface. A natural lens commonly becomes more cataractous after vitrectomy, so the possibility of later cataract surgery belongs in the original plan.

Treating the retina first can also allow its recovery to be assessed before final cataract planning. However, a worsening cataract can obscure that improvement. Cataract surgery after vitrectomy has its own planning considerations.

See what membrane surgery involves. This video shows Dr Simon Chen performing vitrectomy and membrane peeling. It contains actual surgical footage.

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When is a combined operation reasonable?

A combined cataract and retinal operation is reasonable when both conditions warrant treatment. The cloudy lens is replaced with a lens implant, and vitrectomy with membrane peeling treats the retinal traction in the same session. This can avoid a separate planned cataract operation after vitrectomy.

There is no convincing basis for telling every patient that combined surgery is always better, or that staging is always safer. Comparative studies generally report improvement with both strategies. A large retrospective UK comparison found broadly similar visual outcomes with combined surgery and membrane surgery followed later by cataract surgery. The groups were not randomly assigned, so this does not prove the approaches are equivalent or determine the best sequence for you.

Practical factors matter too: arranging transport, time away from work, anaesthesia and help at home. These should be weighed alongside the condition of the eye. The broader guide to cataract and retinal surgery together or separately explains the shared practical considerations.

How long should you wait between operations?

There is no single correct interval. If surgery is staged, the second operation is planned around recovery, inflammation, the OCT findings, the remaining symptoms and the clarity of the lens. It may be weeks or months; a study's scheduled interval is not a timetable for every patient.

After cataract-first surgery, reassessment asks how much difficulty remains because of the membrane. After membrane-first surgery, reassessment asks how the macula is recovering and whether the cataract is now holding vision back. Worsening distortion or vision should prompt an earlier review rather than simply waiting for a pre-booked date.

Which lens implant is suitable when the macula has a membrane?

Lens choice should protect the quality of the vision your retina can provide. A monofocal lens is often a practical starting point. You still choose a focusing target, such as distance vision with reading glasses; the membrane does not remove the need for that discussion.

A toric lens may help when there is suitable regular corneal astigmatism. It corrects the eye's optical focusing error, not the wrinkling of the retina. The guide to toric lens implants explains that distinction.

Multifocal and extended-depth-of-focus lenses need particular care when macular function is reduced. Their optical trade-offs differ. A small study of one non-diffractive extended-depth-of-focus lens reported useful results in selected patients whose membrane was also treated surgically. It did not prove that this lens class is suitable for every membrane or better than a monofocal lens.

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Discuss the expected contrast, night-time visual symptoms, residual distortion and likely need for glasses. Accurate measurements matter, but neither a premium lens nor a precise lens-power calculation can guarantee normal vision from an abnormal macula.

How much improvement should you expect, and what are the risks?

Separate the goals of sharper vision and straighter vision. Cataract removal can improve the image entering the eye; membrane peeling aims to release retinal traction. Some distortion may remain after either sequence, and improvements after membrane surgery can continue over months, sometimes up to a year. The retina may not return to its original structure or function.

Macular swelling is one issue to discuss. In a large retrospective UK study of cataract surgery alone, cystoid macular oedema was recorded in about 8.6% of eyes with a membrane, compared with about 1.4% of eyes without one. These are study averages, not a prediction for your eye, and risks vary with other conditions and the operation planned.

Other risks include infection, bleeding, pressure changes, retinal tears or detachment, an unexpected focusing result and occasionally further surgery. Your surgeon should explain the risks relevant to your eye and how the follow-up and treatment plan address them.

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Ask whether air or gas will be left in the eye. If so, do not fly or travel to high altitude until your surgeon confirms the bubble has fully gone. You must not receive nitrous oxide ("laughing gas" or "gas and air") while the bubble remains. Tell any doctor, dentist or ambulance clinician treating you that you have a bubble in your eye. Follow your surgeon’s instructions about positioning and other activities.

What should you ask at your appointment?

Useful questions bring the decision back to your own eye:

• Which problem is contributing most to my difficulties, and what supports that judgement?
• What benefit should I expect from the first operation, and what is likely to remain?
• Why do you recommend this sequence for me, and what would change the plan?
• What lens target is realistic, and what glasses am I likely to need?
• When will you reassess the macula, and what symptoms should bring review forward?

When should you seek urgent help?

Seek urgent eye assessment for sudden loss or marked worsening of vision, a curtain or shadow, new flashes, or a sudden increase in floaters. These symptoms can indicate a retinal tear or detachment and should not be attributed to a longstanding membrane without assessment.

After surgery, increasing pain, increasing redness, discharge or worsening vision also need urgent advice. Contact your surgeon or their after-hours service straight away. If you cannot reach them, seek urgent medical care through an emergency department. Do not wait for the next routine appointment.