Distorted shape, rather than only reduced sharpness
Metamorphopsia describes objects or straight lines appearing distorted. An epiretinal membrane can contract on the retinal surface and cause this symptom; other macular disorders can produce distortion too. The symptom does not identify a single disease. [1]
A macular hole and AMD are examples of other conditions that can affect central vision. New distortion should be assessed rather than diagnosed from a distorted grid or a simulator match. [2]
Describe the geometry
Bent, stretched, compressed and blurred are different descriptions.
Check the cause
A symptom label is not a retinal diagnosis.
Measure more than acuity
Daily reading and distortion may deserve separate discussion.
Terms in this guide
- Epiretinal membrane
- A membrane on the retinal surface that can exert traction.
- Metamorphopsia
- Perceived distortion of shape.
One condition. Different experiences.
These original illustrations show different wave shapes and central blur. They are not standardized M-CHARTS or an Amsler test.
Original VisualSim schematic illustrations, informed by the cited clinical descriptions. These are not study figures, patient recordings or validated severity levels. Clinical basis: source 1. Artwork: © VisualSim; see image provenance.
Retinal structure and perceived shape
An epiretinal membrane can exert traction and wrinkle the macular surface. OCT helps show the structure. The degree of distortion in daily life is not captured by a single screen image or by sharpness alone. [1]
In a prospective study of people undergoing epiretinal membrane surgery, researchers measured reading performance as well as acuity and distortion. This illustrates why it is useful to explain the tasks affected, rather than reporting only the size of letters you can read. [3]
What can look similar?
Blur
A fuzzy edge and a bent edge are different descriptions, though both can occur together.
Double vision
Two images are different from a single image whose shape is distorted. Describe both if present.
Migraine aura
An evolving, reversible episode may have a different origin from a new persistent central distortion. Assessment considers the time course.
Similar-looking symptoms can have different causes. A matching picture cannot establish a diagnosis.
What an assessment may involve
An eye examination and retinal imaging can help identify the cause. The clinician may assess visual acuity and distortion and ask about one-eye versus two-eye symptoms. A screen-generated grid is not a substitute for the test or instructions your clinic provides. [1]
- Describe shape and locationWhich lines bend, and where in the scene does that happen?
- Explain the practical effectInclude reading, faces and the difference between eyes.
- Discuss cause and monitoringAsk which changes need prompt reassessment.
What may help—and what is still being studied
Management depends on the cause and functional impact. Some epiretinal membranes can be monitored; surgery may be discussed for significant progression or symptoms. Results vary and a straighter-looking illustration cannot predict an operation’s outcome. [1]
Other causes, such as a macular hole or active wet AMD, have different management. That is why a new distortion should not simply be labelled “macular pucker” without examination. [2]
What this can mean for daily life
Bring a task example
Describe letters crowding, a bowed door frame or a pattern that looks irregular. These concrete examples can be more useful than “my vision is bad.”
Use clinical monitoring advice
If your clinician recommends a monitoring chart, use their instructions and contact plan. This simulator is for communication, not monitoring.
Bring a clearer description to your appointment
Choose the questions you want to discuss. These choices stay in this page’s memory.
Research, with the context left in
The studies below examine distortion and functional vision in specific epiretinal-membrane populations. They do not validate this wave effect as a clinical measurement.
What the evidence supports
Metamorphopsia is a symptom, not a single diagnosis. Retinal structure, visual acuity, reading and perceived distortion answer different questions. Epiretinal-membrane evidence is useful but should not be generalized to AMD, macular holes or other causes. New persistent distortion needs assessment; a simulator or uncalibrated grid cannot determine the cause, measure severity or predict surgery.
How we select and interpret researchAAO: Idiopathic Epiretinal Membrane and Vitreomacular Traction Preferred Practice Pattern
Assessment considers symptoms, function and retinal imaging. Monitoring or intervention depends on the individual clinical picture, rather than a slider amount or the appearance of a single distorted line.
Limits and applicability: Guidance for ERM and VMT, not a universal guideline for every cause of metamorphopsia. The absence of trials for a particular situation does not establish that surgery is ineffective.
How to read this evidence: A stronger clinical framework for ERM/VMT than an isolated treatment anecdote; recommendations still combine evidence and specialist judgement.
Yusuf et al.: Surgery for idiopathic epiretinal membrane
For mild symptoms, immediate surgery did not show a clear visual-acuity advantage over watchful waiting with deferred surgery when indicated. The review distinguishes this question from disabling ERM, where routine surgical practice rests substantially on nonrandomized evidence.
Limits and applicability: Small sample, imprecision, possible bias, inconsistent cataract management and no quality-of-life outcome. Search through May 2020; not evidence that all ERM should be observed or that every cause of distortion behaves alike.
How to read this evidence: The review authors judged evidence for immediate versus deferred surgery in mild disease to be uncertain; a small trial cannot settle all clinical situations.
Kinoshita et al.: Daily-life metamorphopsia after ERM surgery and correlation with M-CHARTS
Changes in a clinical M-CHARTS measure related to reports of daily-life distortion after surgery. Test repeatability mattered when deciding whether an observed change was meaningful.
Limits and applicability: Selected unilateral ERM population, questionnaires and a calibrated clinical instrument. The relationship does not validate a web wave slider or transfer its cutoff to screen pixels.
How to read this evidence: Directly relevant to measuring distortion and patient-reported change, but not a randomized estimate of surgical benefit.
Evaluation of pre- and post-surgery reading ability in patients with epiretinal membrane
Reading acuity and critical print size improved in some eyes whose letter-chart acuity changed little. Horizontal and vertical distortion scores did not behave identically. Functional assessment can add information beyond a single acuity score.
Limits and applicability: Small selected surgical sample, no untreated comparison and Japanese reading materials. Results do not promise recovery of reading speed or correction of every type of distortion.
How to read this evidence: Useful evidence that reading and acuity can differ; an uncontrolled surgical cohort cannot establish an individual treatment effect.
Mehraban Far et al.: Internal limiting membrane peeling in idiopathic ERM surgery
Adding internal limiting membrane peeling reduced ERM recurrence in the available trials without a clear visual-acuity advantage. Anatomical and functional outcomes are not interchangeable.
Limits and applicability: Specific comparison of two surgical approaches, modest sample sizes and follow-up. It should not become a recommendation that one technique always improves subjective distortion or suits every eye.
How to read this evidence: Randomized comparative evidence helps distinguish surgical technique outcomes; it does not establish whether an individual needs surgery.
Questions researchers still need to answer
- Which underlying condition is causing the distortion, and what evidence applies to that cause?
- Should reading, binocular symptoms and distortion be measured separately from visual acuity?
- What are the reasons to monitor versus intervene, and which outcomes are realistically expected?
- Does a study report patient-noticeable benefit or only a change in OCT anatomy?
These are editorial interpretations, not formal GRADE ratings or independent clinical review. A large sample, recent date or well-known publisher does not make every claim certain.
Trusted places to go next
Selected clinical references, research and support organizations. Each link explains who it is for.
ASRS: epiretinal membranes
Clinical explanation with accessible and translated fact sheets.
ASRS: macular hole
A different possible cause of central visual change.
RNIB: epiretinal membrane
Patient information and practical support.
Reading and distortion study
Why reading performance can add information beyond acuity.
Organizations & ways to connect
Selected charities, professional organizations and communities, with their scope and region. Official pages checked 24 October 2026. Community discussions are peer support; each external service has its own privacy and moderation rules.
Foundation of the American Society of Retina Specialists
Retina-specialist patient fact sheets, large-print and translated materials, a patient podcast and a specialist directory. Clinical education; not a peer-support group.
Macular Society
A helpline, local groups, telephone befriending, counselling, accessible information and research funding. Peer support shares lived experience and does not replace clinical assessment.
Connections listed by the organization.
Macular Disease Foundation Australia
Condition information, a national helpline, research and practical support. Eye Connect is for AMD and diabetes-related eye disease; people with other macular conditions can ask the helpline about suitable services.
Connections listed by the organization.
RNIB
Accessible condition information, practical and emotional support, assistive technology and routes to community connection. Broader sight-loss support rather than a condition-specific medical service.
Connections listed by the organization.
Retina International
A route to national retinal-disease groups, patient education, advocacy and research participation information. Member services vary by country; this is a global directory rather than a claim that every local group has been reviewed.
Connections listed by the organization.
Questions you may still have
Does wavy vision always mean AMD?
No. Several macular conditions can cause distortion. The cause needs assessment.
Is the simulator an Amsler test?
No. Pixel size, display settings and viewing distance are not calibrated here.
Will treatment make every line straight again?
Results vary by cause and individual findings. Ask what improvement is realistic for your situation. [1]
Sources, image credits and review status
Compiled by VisualSim from clinical references and published research. Sources checked 24 October 2026. Independent clinical review has not been recorded; no named clinical reviewer or clinical validation is claimed. Research evidence and its limitations are linked below.
- American Society of Retina Specialists. Epiretinal membranes. Clinical information; sources checked 24 October 2026.
- American Society of Retina Specialists. Macular hole. Clinical information; sources checked 24 October 2026.
- Evaluation of pre- and post-surgery reading ability in patients with epiretinal membrane: a prospective observational study (2020). Clinical information; sources checked 24 October 2026.
- Changes in metamorphopsia in daily life after successful epiretinal membrane surgery and correlation with M-CHARTS score (2015). Clinical information; sources checked 24 October 2026.
- AAO: Idiopathic Epiretinal Membrane and Vitreomacular Traction Preferred Practice Pattern (2025). Specialist clinical practice guideline informed by literature searches and evidence review
- Yusuf et al.: Surgery for idiopathic epiretinal membrane (2021). Cochrane systematic review; one eligible randomized trial of 53 eyes with mild symptomatic ERM
- Kinoshita et al.: Daily-life metamorphopsia after ERM surgery and correlation with M-CHARTS (2015). Clinical outcomes study of 65 operated eyes, with a separate 56-eye repeatability assessment
- Mehraban Far et al.: Internal limiting membrane peeling in idiopathic ERM surgery (2021). Systematic review of seven randomized trials, 387 eyes
The simulator helps people communicate an experience. It cannot diagnose a condition, measure a visual field, or establish that someone is safe to drive.