Disease Description (Causes and Symptoms)
- Definition: A thin fibrous membrane (epiretinal membrane; ERM) forms on the surface of the macula (central retina), pulling on or distorting the retina and causing reduced central vision and distortion of objects (metamorphopsia).
- Causes/Pathophysiology: Glial cells, fibroblasts, RPE cells, and other cells proliferate and fuse on the retinal surface through microscopic defects that develop after posterior vitreous detachment or in the internal limiting membrane, forming a membrane. Contraction of the membrane can distort the macular structure (retinal folds or wrinkling), and, rarely, a macular hole may occur concurrently. Idiopathic cases are common, and the incidence is higher in older adults. It may develop secondarily after retinal detachment surgery, laser photocoagulation, intraocular inflammation, retinal vascular disease, trauma, and other conditions. Bilateral involvement has been reported in approximately 10% of cases.
- Main symptoms: Reduced central visual acuity, distortion of objects (objects appearing bent or warped), objects appearing smaller or larger than they are (micropsia or macropsia), and difficulty reading due to central distortion. Progression is usually slow.
Treatment Methods
- Diagnosis: Fundus examination together with optical coherence tomography (OCT) is the standard diagnostic method for epiretinal membrane. It is used to assess the thin membrane on the retinal surface and the degree of distortion of the retinal layers. If necessary, visual acuity testing, the Amsler grid test, fluorescein angiography, and other tests may be performed.
- Conservative management (mild symptoms): If central visual acuity is relatively preserved and symptoms are mild or stable, regular observation (OCT and visual acuity follow-up) is recommended. Patients may be advised to check the degree of distortion at home using an Amsler grid.
- Surgical treatment: If symptoms interfere with daily life or vision worsens, vitrectomy and epiretinal membrane peeling (often including ILM peeling) are performed. Surgery may partially improve distortion and restore some vision; however, complete recovery may be difficult when the membrane has been present for a long time.
- When accompanied by a macular hole: Surgery with gas tamponade and posturing may be necessary (in some cases, a face-down position is recommended for approximately 2 weeks), and the success rate and complications vary depending on the condition of the lesion.
- Medication/non-surgical treatment: There is currently no established standard drug treatment that completely removes ERM itself.
- Precautions and complications before and after procedures: Possible issues include progression of cataracts after surgery (especially in older adults), retinal tears/detachment, infection (endophthalmitis), bleeding, uncertainty regarding visual improvement, and recurrence. If gas is injected after surgery, lifestyle precautions are necessary, including avoiding air travel while gas remains in the eye.
Checklist Before an Outpatient Visit (Including Preparation and Sample Questions)
- Items to prepare/bring:
- A list of currently used medications, including eye drops
- A history of previous ophthalmic surgeries and procedures (vitreous surgery, laser treatment, trauma, etc.)
- Previous visual acuity test results, if available, and previous OCT or fundus photographs, if available
- Symptom record: when symptoms began, the pattern of progression (gradual/sudden), whether one or both eyes are affected, the degree of distortion (e.g., how much text appears bent), and difficulties in daily life
- Amsler grid results (photographs or records from home testing)
- Key information to report to the healthcare provider during the visit:
- When the decrease in vision began and how quickly it has progressed
- Whether distortion (warping) is present and its severity
- Whether pain, eye redness, flashes of light (photopsia), or floaters (vitreous symptoms) are present
- Systemic diseases (diabetes, hypertension, etc.) and whether anticoagulants are being taken
General Sample Questions to Ask the Doctor
- How might this condition affect my vision? What is the prognosis?
- What are the criteria for recommending surgery? Do I need surgery now, or can I be observed?
- What are the main risks and complications of surgery (vitrectomy + membrane removal)? How likely are they to occur?
- When and to what extent can I expect my vision to recover after surgery?
- What are the long-term risks of not having surgery (e.g., macular hole, permanent vision loss)?
Examples of Condition-Specific Questions
- Based on the distortion of the retinal layers or retinal thickness seen on my OCT, does this meet the criteria for surgery? (Doctor: Ask to review the OCT images together.)
- My current symptoms are mild. If I choose observation, how often should I visit and undergo testing? (e.g., OCT every 3 months)
(Note: For daily management, periodic self-testing with an Amsler grid, visiting a hospital immediately if changes in vision occur, and, if gas is injected during surgery, avoiding air travel and following instructions regarding the face-down position are recommended.)