General Overview
- Epiretinal membrane (ERM) is a fibrocellular membrane over the internal limiting membrane (ILM) due to myofibroblast proliferation and metaplasia.
- Historical terms: macular pucker, cellophane maculopathy.
- Prevalence: 34.1% (Beaver Dam Eye Study via OCT) vs. 7-11% (clinical exam/fundus photos).
- Primary (idiopathic) ERM: linked to posterior vitreous detachment (PVD).
- Secondary ERM risk factors: uveitis, retinal vascular disease, intraocular tumors, trauma, retinal tear/detachment.
Indications and Symptoms
- Surgery recommended when visual function decreases (similar to cataract surgery).
- Symptoms: micropsia, macropsia, decreased vision, metamorphopsia (key symptom often tested).
Surgical Techniques
- Standard technique: vitrectomy with membrane peel.
- Variations: vitrectomy gauge (23 vs. 27 gauge, no significant outcome difference), staining dyes (Brilliant Blue FCF, indocyanine green [ICG]), ILM peeling.
- ICG: rare retinal toxicity risk (mostly animal models, less conclusive in humans).
- ILM peeling reduces ERM recurrence but recurrences are often mild/nonvisually significant (PEELING trial).
- ILM peeling downsides: delays visual acuity recovery, may increase microscotomas (via microperimetry), causes retinal displacement (centrifugal foveal traction).
- Novel tools: microserrated ILM forceps preferred over conventional (fewer deep retinal grasps, better ILM grasp success).
Visual Outcomes
- Long-term visual acuity predictors: ellipsoid zone integrity, external limiting membrane presence (5-9 year follow-up data).
- Extent of ectopic inner foveal layers (EIFL) preop correlates with visual outcomes—may guide symptom-independent surgery.
- No significant outcome difference between sequential vs. concurrent ERM and cataract surgery.
Complications
- Endophthalmitis rate: <1% (small gauge vitrectomy), but possibly higher in ERM surgery (0.44% Korea cohort vs. 0.15% overall vitrectomies).
- Possible reason: fluid-filled eyes (vs. gas tamponade in other retinal surgeries).
OCT and Imaging Biomarkers
- Preop OCT: disorganized retinal inner layers (DRIL) linked to intraoperative hemorrhage, worse visual outcomes, delayed recovery.
- EIFL: less lasting correlation with visual acuity than DRIL.
- Postop OCT: retinal nerve fiber layer (RNFL) thickening associated with faster visual recovery.
- Foveal herniation severity (retinal protrusion above ERM) impacts baseline/final visual acuity, but improvements still occur.
- Deep learning models: predict postop OCT anatomy from preop OCT with high accuracy.
Intraoperative OCT (IOCT)
- Assesses real-time retinal changes (e.g., full/partial thickness distortions, subretinal fluid).
- No correlation between macular stretching and final visual acuity (but affects central macular thickness).
- Peeling under perfluorocarbon bubble: fewer ERM grabs, less neurofiber layer disassociation, comparable visual outcomes.
ERM and Retinal Detachment
- Post-rhegmatogenous retinal detachment ERM risk factors: older age, worse baseline VA, macula-off detachments.
- Scleral buckle: 22% ERM formation (nonvisually significant).
- Silicone oil tamponade: 12% ERM formation (risk factors: oil duration, age, diabetes, photocoagulation extent).
Novel Approaches
- Autologous platelet concentrate: no significant benefit in ERM surgery.
- Dexamethasone implant (Ozurdex): reduces macular thickness at 1 month, effect gone by 3 months.
- Robot-assisted surgery: longer operative time, fewer forceps movements.
Cataract Surgery and Lens Selection
- Combined phacoemulsification + ERM repair vs. sequential: comparable outcomes (visual acuity, CME, recurrence).
- Advanced monofocal IOL (e.g., Eyhance): no reduction in distance vision/contrast sensitivity, improved intermediate vision—needs more research.
* The TECNIS Eyhance™ IOL is a monofocal intraocular lens (IOL) designed to extend depth of focus, offering improved vision at both distance and intermediate ranges compared to standard monofocal lenses, while also potentially reducing visual disturbances like halos and glare.
Unique ERM Profiles
- Uveitis-associated ERM: 4% prevalence; posterior/intermediate uveitis most linked, anterior uveitis protective; 60.5% improve post-surgery.
- Pediatric ERM: diffuse central ERM shows greater visual improvement than localized foveal ERM.
Key Takeaways
- OCT advances (preop, intraop, postop) enhance ERM management and outcome prediction.
- Ongoing research: ILM peeling necessity, optimal surgical timing, novel techniques (e.g., robotics).