Author: Dr Val Phua
Estimated reading time: 11–13 minutes
Why Do Straight Lines Look Bent or Wavy?
An epiretinal membrane is a thin layer of fibrocellular tissue that develops on the inner surface of the retina.
When it forms over the macula—the central part of the retina responsible for detailed vision—the membrane may contract and wrinkle the underlying retinal tissue. This can cause:
- Blurred central vision
- Straight lines appearing bent or wavy
- Words looking crowded or distorted
- Objects appearing larger or smaller
- Difficulty reading or recognising faces
- Double or overlapping images from one eye
An epiretinal membrane is also called a:
- Macular pucker
- Cellophane maculopathy
- Preretinal macular fibrosis
Many epiretinal membranes are mild and remain stable without treatment. Surgery may be considered when visual distortion or blur begins interfering with reading, driving, work or other daily activities.
What Is the Macula?
At its centre is the macula, which provides the sharp vision needed for:
- Reading
- Recognising faces
- Driving
- Seeing colours
- Performing detailed tasks
The retina is a thin layer of light-sensitive nerve tissue lining the back of the eye.
The very centre of the macula is called the fovea. This area provides the finest vision.
An epiretinal membrane grows on the surface of the macula rather than inside the lens or at the front of the eye. It may pull tangentially across the retinal surface, changing the arrangement of the retinal cells and distorting the image sent to the brain.
What Is an Epiretinal Membrane?
An epiretinal membrane is a semi-transparent sheet of cells and fibrous tissue that forms along the inner surface of the retina.
The membrane contains cells that can migrate, multiply and produce collagen. As the membrane matures, it may contract.
This contraction can:
- Wrinkle the macula
- Thicken the central retina
- Displace retinal tissue
- Distort the normal foveal contour
- Create traction on the retinal surface
A mild membrane may be visible only on optical coherence tomography and cause no noticeable symptoms. A stronger or more contracted membrane may significantly distort central vision.
Is an Epiretinal Membrane a Type of Scar Tissue?
It is often described to patients as a thin layer of scar tissue.
This is a useful explanation, although an epiretinal membrane is more accurately a fibrocellular membrane made from several cell types that have grown across the retinal surface.
Unlike a scar on the skin, the membrane may contract across delicate retinal tissue and alter the way the macula processes visual information.
What Symptoms Can an Epiretinal Membrane Cause?
Blurred Central Vision
The eye may remain able to see large letters while struggling with fine detail.
Patients may notice:
- Difficulty reading small print
- Reduced clarity when looking at faces
- Difficulty threading a needle
- Reduced detail when using a computer
- A difference in clarity between the two eyes
Blur usually develops gradually and is painless.
Wavy or Bent Lines
The characteristic symptom is metamorphopsia, meaning visual distortion.
Straight objects may appear:
- Wavy
- Bent
- Curved
- Broken
- Misaligned
Patients may first notice this when looking at:
- Door frames
- Window grilles
- Lines of text
- Floor tiles
- Telephone poles
- Spreadsheet rows or columns
Distortion is often easier to detect by covering the better eye and testing each eye separately.
Words May Look Crowded or Incomplete
Retinal contraction may cause letters to appear:
- Compressed
- Overlapping
- Unevenly spaced
- Missing in places
Reading speed may decrease even when conventional visual-acuity testing remains relatively good.
This is why eye-chart vision alone does not always reflect how much an epiretinal membrane affects daily life.
Objects May Appear Larger or Smaller
An affected eye may perceive objects as being a different size from the fellow eye.
These symptoms are called:
- Micropsia: objects appear smaller
- Macropsia: objects appear larger
- Aniseikonia: the two eyes perceive images at different sizes
A difference in image size can interfere with binocular vision and depth perception.
Double or Overlapping Vision
Some patients experience double, ghosted or overlapping images from the affected eye.
This is known as monocular diplopia and may remain present even when the other eye is covered.
It may result from retinal distortion rather than an eye-alignment problem.
Reduced Contrast and Reading Endurance
Patients may also notice:
- Colours appearing less vivid
- Reduced contrast
- Poorer vision in dim lighting
- Increased difficulty reading for long periods
- Eye strain when using both eyes together
These symptoms may be functionally important even when the measured visual acuity has changed only slightly.
Can an Epiretinal Membrane Cause Complete Blindness?
An isolated epiretinal membrane usually affects detailed central vision rather than peripheral vision.
Severe membranes can cause substantial central blur and distortion, but complete blindness from an uncomplicated epiretinal membrane is unusual.
The prognosis may be different when the membrane is associated with another retinal condition, such as:
- Retinal detachment
- Diabetic retinopathy
- Retinal vein occlusion
- Uveitis
- Significant macular damage
What Causes an Epiretinal Membrane?
Age-Related Vitreous Separation
The most common form is an idiopathic epiretinal membrane, meaning there is no specific underlying eye disease apart from age-related vitreous change.
The vitreous is the clear gel filling the eye.
As we age, it gradually becomes more liquefied and separates from the retina. This is known as a posterior vitreous detachment, or PVD.
During this process, tiny changes may occur at the retinal surface. Cells can then migrate and form a membrane over the macula.
Most people who develop a PVD do not develop a significant epiretinal membrane, but PVD is the most common association.
Secondary Epiretinal Membranes
An epiretinal membrane may also develop after or in association with:
- A retinal tear
- Retinal-detachment surgery
- Diabetic retinopathy
- Retinal vein occlusion
- Inflammation inside the eye
- Eye trauma
- Previous retinal laser
- Cataract or other eye surgery
- Retinal vascular disease
These are known as secondary epiretinal membranes.
Visual recovery after surgery may depend partly on how much damage the underlying retinal condition has already caused. Idiopathic membranes generally have a more favourable prognosis than membranes associated with retinal detachment or significant vascular disease.
Who Is More Likely to Develop an Epiretinal Membrane?
Risk increases with:
- Increasing age
- Posterior vitreous detachment
- Previous retinal tear or detachment
- Previous retinal surgery
- Retinal vascular disease
- Diabetes
- Uveitis
- Eye trauma
Epiretinal membranes may affect both eyes, although they are often more advanced in one eye than the other. The ASRS notes that approximately 10%–20% of affected patients have membranes in both eyes.
Is an Epiretinal Membrane the Same as a Cataract?
No.
A cataract is clouding of the natural lens near the front of the eye.
An epiretinal membrane is tissue growing across the macula at the back of the eye.
Both may cause blur, but distortion is more suggestive of macular disease.
Cataract symptoms commonly include:
- Generalised blur
- Glare
- Halos
- Poor night vision
- Faded colours
- Frequent changes in spectacle power
Epiretinal membrane symptoms commonly include:
- Bent or wavy lines
- Crowded letters
- Image-size differences
- Central visual distortion
- Vision that remains distorted despite glasses
Some patients have both a cataract and an epiretinal membrane. OCT helps determine how much the macula may be limiting vision.
Is an Epiretinal Membrane the Same as Macular Degeneration?
No.
Age-related macular degeneration involves drusen, retinal pigment epithelial damage, retinal atrophy or abnormal leaking blood vessels.
An epiretinal membrane is a sheet of tissue on the retinal surface that mechanically wrinkles or pulls the macula.
Both may cause blur and distortion, but their causes and treatments are different. A dilated examination and OCT usually distinguish between them.
Is It the Same as Vitreomacular Traction?
No, although the conditions are related.
Epiretinal Membrane
A membrane grows across the surface of the macula and exerts tangential traction.
Vitreomacular Traction
The vitreous remains attached to the macula and pulls forwards on it.
Some eyes have both an epiretinal membrane and vitreomacular traction.
OCT is important for identifying the type and direction of traction.
Is It the Same as a Macular Hole?
No.
A macular hole is an actual opening through the central retinal tissue.
An epiretinal membrane wrinkles the retinal surface without necessarily creating a hole.
Severe traction can occasionally be associated with a lamellar or full-thickness macular hole, but this is not the usual progression for most membranes.
How Is an Epiretinal Membrane Diagnosed?
Visual-Acuity Testing
Vision is measured in each eye.
However, a patient may have meaningful distortion despite relatively good visual acuity. The impact on reading, depth perception and binocular vision should therefore also be considered.
Amsler Grid
An Amsler grid is a square pattern of straight lines with a central dot.
It may help document distortion.
To use it:
- Wear your reading glasses.
- View the grid in good light.
- Cover one eye without pressing on it.
- Look directly at the central dot.
- Notice whether any lines appear wavy, broken, crowded or missing.
- Repeat with the other eye.
An Amsler grid can help monitor known macular disease but does not replace an examination or OCT.
Dilated Retinal Examination
Dilating drops enlarge the pupil so that the ophthalmologist can examine the macula and the peripheral retina.
A membrane may appear as:
- A transparent cellophane-like sheen
- Fine retinal wrinkles
- Distortion of retinal blood vessels
- A thicker, more opaque layer in advanced disease
The examination also checks for underlying retinal tears, vascular disease, inflammation or previous retinal damage.
Optical Coherence Tomography
Optical coherence tomography, or OCT, is the most important imaging test for an epiretinal membrane.
OCT uses light waves to produce detailed cross-sectional images of the retina.
It can demonstrate:
- The epiretinal membrane
- Retinal thickening
- Loss of the normal foveal depression
- Retinal folds
- Cysts or swelling
- Vitreomacular traction
- Lamellar or full-thickness macular holes
- The integrity of the photoreceptor layers
OCT is painless, quick and useful for comparing the membrane over time.
Does OCT Severity Determine Whether Surgery Is Needed?
Not by itself.
Some membranes look prominent on OCT but cause few symptoms. Others produce severe distortion despite relatively modest thickening.
The decision should consider:
- Visual acuity
- Degree of distortion
- Reading ability
- Binocular symptoms
- Progression
- OCT findings
- Condition of the fellow eye
- Patient’s occupational and lifestyle needs
- Surgical risks
The scan should be interpreted together with the patient’s actual visual experience.
Are Other Tests Needed?
Selected patients may undergo:
- Retinal photography
- OCT angiography
- Fluorescein angiography
- Metamorphopsia testing
- Tests of contrast sensitivity
- Measurement of image-size differences
Angiography may be helpful when diabetes, vein occlusion, inflammation or another vascular cause is suspected. It is not required for every uncomplicated idiopathic membrane.
Does Every Epiretinal Membrane Need Treatment?
No.
Most epiretinal membranes cause either no symptoms or only mild changes and can be monitored safely.
Observation may be appropriate when:
- Vision remains good
- Distortion is mild
- Daily activities are not affected
- OCT findings are stable
- The patient is comfortable with the current vision
- Surgical risks outweigh the likely benefit
There are no eye drops, exercises, medications or nutritional supplements proven to remove an epiretinal membrane.
Can an Epiretinal Membrane Disappear by Itself?
Spontaneous separation can occur but is uncommon.
It is more likely when the membrane is relatively thin or when changes in the vitreous release traction from the retinal surface.
Most membranes that are being observed remain present. Some stay stable, while others slowly become more contracted.
How Often Should It Be Monitored?
The follow-up interval depends on:
- Symptoms
- Visual acuity
- OCT severity
- Evidence of progression
- Cause of the membrane
- Condition of the other eye
A mild, stable membrane may be reviewed every six to twelve months. Earlier review may be advised when the membrane is newly diagnosed, symptomatic or showing progression.
Patients should return sooner if they notice:
- Increasing distortion
- Worsening reading ability
- A new central blur
- A new difference between the eyes
- Sudden flashes, floaters or a visual-field shadow
When Should Surgery Be Considered?
Surgery may be considered when the membrane causes:
- Distortion interfering with reading
- Difficulty recognising faces
- Reduced driving confidence
- Impaired occupational tasks
- Troublesome image-size difference
- Double or overlapping vision
- Progressive visual decline
- Increasing retinal traction on OCT
The decision is not based on a single visual-acuity threshold.
A patient with 6/9 or 6/12 vision may still be significantly affected by distortion, while another patient with poorer measured vision may be comfortable and prefer observation.
Current AAO guidance recognises that vitrectomy generally improves visual acuity and metamorphopsia in appropriately selected symptomatic patients.
Is Epiretinal Membrane Surgery an Emergency?
Usually not.
Unlike retinal detachment, an uncomplicated epiretinal membrane normally progresses slowly.
Patients usually have time to:
- Monitor symptoms
- Compare OCT scans
- Consider the expected benefits
- Discuss the risks
- Decide whether daily function justifies surgery
Earlier surgery may be considered when distortion is progressing or when OCT shows increasing traction and disruption of important retinal layers.
What Happens During Epiretinal Membrane Surgery?
The operation is called a pars plana vitrectomy with epiretinal membrane peeling.
It is performed by a vitreoretinal surgeon.
Step 1: Anaesthesia
The operation is usually performed using local anaesthesia with sedation, although general anaesthesia may be used in selected patients.
Step 2: Vitrectomy
Very small instruments are inserted through the white part of the eye.
The surgeon removes the vitreous gel to gain safe access to the surface of the retina.
The vitreous is replaced naturally by fluid produced within the eye after surgery.
Step 3: Membrane Peeling
The epiretinal membrane is carefully lifted and peeled from the macula using microscopic forceps.
Removing the membrane releases tangential traction and allows the retina to relax gradually.
Step 4: Internal Limiting Membrane Peeling
The surgeon may also remove the internal limiting membrane, or ILM—the extremely thin innermost layer of the retina.
The ILM may act as a scaffold on which another epiretinal membrane could grow.
Research suggests that ILM peeling lowers the risk of recurrent epiretinal membrane, although it has not consistently produced better visual acuity than peeling the epiretinal membrane alone.
Step 5: Completing the Operation
The eye is generally left filled with clear fluid.
A gas bubble is not routinely required for a straightforward epiretinal membrane peel, although gas may be used if another condition—such as a retinal tear or macular hole—is treated at the same time.
How Long Does Surgery Take?
The duration varies according to:
- Membrane complexity
- Whether ILM peeling is performed
- Lens status
- Presence of a cataract
- Associated retinal conditions
- Whether additional laser or repair is needed
An uncomplicated procedure is commonly completed as day surgery.
Is the Operation Painful?
The eye is anaesthetised during surgery.
Patients may feel pressure, movement or bright lights rather than sharp pain.
Afterwards, mild discomfort, grittiness or aching is common. Severe or increasing pain is not expected and requires prompt review.
Will I Need Face-Down Positioning?
Usually not after an uncomplicated epiretinal membrane peel.
Positioning may be required if a gas bubble is inserted to treat another retinal problem.
When gas is used:
- Air travel is prohibited.
- Significant altitude changes must be avoided.
- Scuba diving is prohibited.
- Nitrous oxide anaesthesia must not be used.
- The surgeon’s positioning instructions must be followed.
What Should I Expect After Surgery?
The eye may initially be:
- Red
- Watery
- Gritty
- Mildly swollen
- Blurred
- Sensitive to light
Vision is often worse immediately after surgery because of:
- Dilating drops
- Ocular inflammation
- Corneal surface disturbance
- Temporary retinal swelling
- Air or gas inside the eye
- The time required for the macula to relax
Prescription antibiotic and anti-inflammatory drops are commonly used during recovery.
How Quickly Will Vision Improve?
Visual recovery is gradual.
Many patients notice improvement over the first several weeks to three months. Continued improvement may occur for six to twelve months as the retinal architecture remodels and the brain adapts to the reduced distortion.
The OCT may improve before the patient notices the full functional benefit.
Will the Distortion Completely Disappear?
Not always.
Surgery usually reduces distortion, but some waviness may remain.
The likelihood of complete recovery depends on:
- Duration of the membrane
- Degree of preoperative distortion
- Severity of retinal contraction
- Integrity of the photoreceptor layers
- Associated retinal disease
- Preoperative vision
- Age and healing response
The purpose of surgery is to improve vision and reduce distortion—not to guarantee that the retina will return to a completely normal shape.
How Successful Is Epiretinal Membrane Surgery?
Most appropriately selected patients experience improved visual acuity, less distortion or both after surgery. Long-term studies have found that visual gains can remain sustained for years.
The amount of improvement varies.
A patient with relatively healthy retinal layers and significant mechanical distortion may improve substantially. An eye with longstanding photoreceptor damage, macular ischaemia, previous detachment or severe diabetic disease may have more limited recovery.
Visual improvement should therefore be discussed in terms of probability rather than certainty.
What Are the Risks of Surgery?
Potential complications include:
- Cataract progression
- Retinal tear
- Retinal detachment
- Infection inside the eye
- Bleeding
- Raised or reduced eye pressure
- Macular swelling
- Recurrent membrane
- Damage to the retina
- Reduced vision
Serious complications are uncommon but can be sight-threatening.
ASRS patient guidance cites retinal detachment in approximately 1 in 100 patients and infection in approximately 1 in 2,000 following vitrectomy for epiretinal membrane, although individual risk varies according to the eye and procedure.
Will Vitrectomy Cause a Cataract?
Vitrectomy commonly accelerates cataract progression in an eye that still has its natural lens, particularly in older adults.
A mild pre-existing cataract may become visually significant during the months or years after retinal surgery.
Patients who have already undergone cataract surgery do not face this particular complication.
Should Cataract and Epiretinal Membrane Surgery Be Combined?
They can sometimes be performed together.
Combined cataract surgery and vitrectomy may be considered when:
- A visually significant cataract is already present.
- The cataract is expected to limit postoperative vision.
- Avoiding a second operation is desirable.
- The retinal surgeon and cataract surgeon consider the combined approach appropriate.
Advantages may include:
- One anaesthetic
- One main recovery period
- Avoiding rapid cataract progression after vitrectomy
- Earlier clearing of both lens and retinal causes of blur
Possible disadvantages include:
- More postoperative inflammation
- Less predictable refractive results
- Difficulty determining how much blur came from each condition
- A more complex combined procedure
A 2024 systematic review found broadly comparable postoperative visual acuity between combined phacovitrectomy and cataract surgery performed separately, although combined surgery showed greater variability in refractive prediction.
Can Cataract Surgery Be Performed First?
Yes.
When the cataract appears to be the main cause of blur and the epiretinal membrane is mild, cataract surgery alone may be reasonable.
The patient should understand that:
- Cataract surgery may improve clarity and glare.
- Existing retinal distortion may remain.
- Final vision may still be limited by the epiretinal membrane.
- Macular swelling may occur after cataract surgery.
- Future membrane-peeling surgery may still be required.
Recent observational evidence suggests that cataract surgery can provide useful visual improvement in selected eyes with mild, stable epiretinal membranes, although OCT monitoring remains advisable.
Can the Membrane Grow Back?
Yes, but clinically significant recurrence is uncommon.
Residual cells may grow along the retinal surface and form another membrane.
Peeling the internal limiting membrane appears to reduce recurrence and the likelihood of repeat surgery. Many recurrent membranes remain mild and do not require another operation.
Can Glasses Correct an Epiretinal Membrane?
Glasses may improve vision when an uncorrected spectacle prescription or cataract is also present.
They cannot remove retinal wrinkling or fully correct metamorphopsia.
If straight lines remain wavy despite the best spectacle correction, the remaining problem is likely retinal rather than refractive.
Can Eye Drops or Supplements Treat It?
No eye drop, vitamin, supplement, exercise or dietary treatment has been shown to dissolve or peel an epiretinal membrane.
Artificial tears may help coincidental dry-eye symptoms but will not alter the membrane itself.
Can Laser Treat an Epiretinal Membrane?
No.
Retinal laser does not remove the membrane and could damage the central retina if applied to the macula.
The only established treatment for a visually significant epiretinal membrane is surgical peeling through vitrectomy.
What Should I Avoid After Surgery?
Follow the surgeon’s specific instructions.
Temporary restrictions may include:
- Avoiding eye rubbing
- Avoiding swimming
- Avoiding dusty or contaminated environments
- Avoiding heavy lifting or strenuous activity
- Avoiding driving until vision is safe
- Using an eye shield during sleep
- Keeping water and soap out of the eye
- Using prescribed drops exactly as directed
Restrictions differ according to whether gas, laser or another retinal procedure was performed.
When Can I Drive Again?
Do not drive while:
- Vision remains significantly blurred
- Depth perception is impaired
- Dilating drops are active
- A gas bubble obstructs vision
- You do not meet the legal driving standard
- Your surgeon has not cleared you
Even when the operated eye improves, binocular visual adaptation may take time.
Warning Signs After Surgery
Contact your surgeon promptly if you experience:
- Increasing eye pain
- Worsening redness
- Sudden or progressive reduction in vision
- Marked light sensitivity
- Thick discharge
- Nausea or headache with eye pain
- New flashes
- A sudden increase in floaters
- A curtain or shadow
These symptoms may indicate infection, raised eye pressure, a retinal tear or retinal detachment rather than ordinary postoperative healing.
Frequently Asked Questions
Is an epiretinal membrane dangerous?
Most are not dangerous and can be monitored.
They become clinically important when they cause meaningful distortion, visual decline or traction affecting the macula.
Does it always get worse?
No.
Many remain stable for years. Some progress, while a small number may partially or completely release spontaneously.
Should surgery be done before the vision becomes very poor?
The decision depends on symptoms and function rather than waiting for severe visual loss.
Surgery may be reasonable when distortion meaningfully affects daily activities, even if eye-chart vision remains moderately good.
Can waiting too long reduce the result?
Longstanding severe traction may produce irreversible changes within the retinal layers. However, a mildly symptomatic stable membrane does not automatically require early surgery.
OCT findings, symptom progression and functional impact should guide timing.
Can surgery make vision worse?
Yes, although this is uncommon.
Any intraocular surgery carries risks, including retinal detachment, infection, bleeding and retinal damage. The expected benefit should outweigh these risks before surgery is recommended.
Why is my vision still wavy after successful surgery?
The retinal tissue may take months to relax, and permanent microscopic changes may remain after longstanding traction.
Improvement can continue gradually for up to a year.
Why does my OCT still look thick after surgery?
Retinal thickness does not always return completely to normal.
Functional improvement may occur even when the macula remains thicker than the unaffected eye.
Can an epiretinal membrane affect both eyes?
Yes.
Both eyes should be examined, but the severity and need for treatment may differ.
Can it return after surgery?
Recurrence can occur, but most recurrent membranes are mild. ILM peeling reduces the recurrence risk.
Will I need a gas bubble?
Not usually for an uncomplicated epiretinal membrane peel.
Gas may be used when another retinal condition is treated during the same operation.
Can I fly after surgery?
Flying is generally permitted once the eye is stable if no gas bubble is present.
If gas was inserted, flying and high-altitude travel are prohibited until the surgeon confirms that the bubble is completely gone.
The Bottom Line
An epiretinal membrane is a thin sheet of tissue that grows across the surface of the macula.
It may contract and cause:
- Blurred central vision
- Bent or wavy lines
- Crowded words
- Image-size differences
- Double or overlapping images
Many membranes are mild and can be safely monitored with visual testing, dilated examination and OCT.
Surgery is considered when distortion or reduced vision interferes meaningfully with daily life. The operation involves vitrectomy and delicate peeling of the membrane, often together with the internal limiting membrane.
Most appropriately selected patients experience improved clarity, reduced distortion or both. Recovery is gradual and may continue for several months, although vision may not return completely to normal when the retina has been distorted for a long time or another retinal disease is present.
The decision to operate should be based not only on the eye-chart result, but on how the distortion affects the patient’s actual vision and quality of life.
References
- American Academy of Ophthalmology. Idiopathic Epiretinal Membrane and Vitreomacular Traction Preferred Practice Pattern. 2025.
- National Eye Institute. Macular Pucker. Updated December 2024.
- American Society of Retina Specialists. Epiretinal Membranes.
- American Society of Retina Specialists. Vitrectomy.
- Steinkerchner MS, et al. Long-Term Visual Outcomes in Patients With Idiopathic Epiretinal Membranes After Surgery. 2024.
- Drummond SC, et al. Long-Term Outcomes of Vitrectomy for Idiopathic Epiretinal Membrane. 2024.
- Mihalache A, et al. Pars Plana Vitrectomy With or Without Internal Limiting Membrane Peeling for Epiretinal Membrane: Systematic Review and Meta-analysis. 2024.
- El-Ali O, et al. Postoperative Outcomes of Combined Phacovitrectomy for Epiretinal Membrane and Cataract Versus Standalone Cataract Surgery. 2024–2025.
