A disciform scar is a dense, disc-shaped patch of fibrous tissue that replaces the delicate layers of the central retina, almost always as the end stage of wet (neovascular) age-related macular degeneration. Once it forms, the scar permanently destroys the sharp central vision people rely on for reading, recognizing faces, and driving. In histopathologic studies, scars thicker than about 200 micrometers retained photoreceptor cells over only roughly a quarter of their surface, which helps explain why useful central vision rarely survives the scarring process.1PubMed. Age-related macular degeneration histopathologic studies. The 1992 Lorenz E. Zimmerman Lecture The word “disciform” simply refers to the round, disc-like shape the scar takes when viewed through the pupil or on imaging, and the condition has been recognized by that name since the early twentieth century.
How a Disciform Scar Forms
The process begins with abnormal blood vessels growing from the choroid (the vascular layer beneath the retina) into the retinal space. These new vessels are fragile and leaky, spilling blood, fluid, and protein under and into the retina. The body treats this as a wound and mounts a healing response. If the leaking vessels are not shut down quickly enough, that healing response overshoots, producing scar tissue instead of restoring normal anatomy. The scar typically incorporates remnants of the retinal pigment epithelium (RPE), fibrous and vascular tissue, and deposits from the damaged membrane beneath the RPE known as Bruch’s membrane.2PubMed Central. Ageing and degeneration in the macular region: a clinico-pathological study
In a large series of disciform scars examined under the microscope, about three-quarters were vascularized, meaning they still contained blood vessel networks woven through the fibrous tissue, while about a quarter were purely fibrous with no remaining blood vessels.3Molecular Vision. Histopathology of age-related macular degeneration The scars varied in architecture. Some sat entirely beneath the RPE, some had a single layer of scar tissue above the RPE (subretinal), and nearly half had two distinct layers of scar, one above and one below the RPE. In the overwhelming majority of vascularized scars, the abnormal vessels originated from the choroid rather than from the retinal circulation itself.4Molecular Vision. Histopathology of age-related macular degeneration
The Molecular Machinery Behind Scarring
Several interlocking molecular pathways drive the transition from leaky new vessels to irreversible scar. The best-studied involves transforming growth factor-beta (TGF-β), a signaling molecule the body uses widely in wound repair. In mouse models, TGF-β1 and TGF-β2 levels surged within days of the injury that triggers subretinal fibrosis, peaking at roughly five- to sixfold above normal for their messenger RNA and more than tenfold for the active proteins themselves.5PubMed Central. Transforming growth factor-β neutralizing antibodies inhibit subretinal fibrosis in a mouse model When researchers blocked TGF-β with neutralizing antibodies in those mice, the area of subretinal fibrosis shrank by about 65%.6PubMed Central. Transforming growth factor-β neutralizing antibodies inhibit subretinal fibrosis in a mouse model
TGF-β does not act alone. The Notch signaling pathway, which normally helps regulate cell fate, feeds into the same fibrotic cascade. When Müller cells, the major support cells of the retina, are exposed to Notch signaling molecules or TGF-β1, they ramp up production of TGF-β1 themselves, creating a self-reinforcing loop.7PubMed Central. Targeting the Notch and TGF-β signaling pathways to prevent retinal fibrosis in vitro and in vivo Meanwhile, parts of the complement system, the innate immune cascade best known for fighting infection, also stoke the fire. The complement fragment C5a pushes RPE cells to behave more like scar-producing cells through a process called epithelial-to-mesenchymal transition, increasing their production of fibronectin and other structural proteins while boosting their output of VEGF and additional TGF-β.8PubMed Central. Complement activation contributes to subretinal fibrosis through the induction of epithelial-to-mesenchymal transition (EMT) in retinal pigment epithelial cells
A further twist involves immune cells. Macrophages recruited to the site of injury can transform directly into myofibroblasts, the contractile, collagen-secreting cells that are the workhorses of scar formation. This macrophage-to-myofibroblast transition has been documented in human macular fibrosis tissue, suggesting it is not just a laboratory curiosity but a real contributor to the scars patients end up with.9PubMed Central. Macrophage to myofibroblast transition contributes to subretinal fibrosis secondary to neovascular age-related macular degeneration
How Common Is Scarring Despite Treatment
Anti-VEGF injections, now the standard of care for wet AMD, are excellent at shutting down leaky new vessels and preserving vision in the short term. But they do not directly prevent fibrosis. A ten-year follow-up study found that fibrosis was present in only about 2% of eyes at the start of anti-VEGF treatment, yet by ten years the cumulative incidence had climbed to nearly 63%. Half the eyes in the cohort showed signs of fibrosis by roughly eight years.10American Journal of Ophthalmology. Ten-Year Incidence of Fibrosis and Risk Factors for Its Development in Neovascular Age-Related Macular Degeneration In other words, even with consistent anti-VEGF therapy, the majority of eyes with wet AMD will develop some degree of scarring over the long haul.
Several risk factors predicted which eyes were more likely to scar. Greater fluctuations in central retinal thickness over the course of treatment, the occurrence of bleeding under the macula at any point, and a higher cumulative number of injections all independently raised the risk. On the protective side, starting treatment when vision was still relatively good (better than about 20/100) was associated with a lower chance of fibrosis.11American Journal of Ophthalmology. Ten-Year Incidence of Fibrosis and Risk Factors for Its Development in Neovascular Age-Related Macular Degeneration The injection count finding is probably not causal in the way it sounds; eyes needing more injections tend to be more severely affected to begin with, so the extra treatment reflects disease severity rather than causing the scarring.
Wet AMD is not the only cause of disciform scarring. Myopic choroidal neovascularization, which affects some people with high myopia, can follow a similar path. In one series of 54 such eyes treated with anti-VEGF, subretinal fibrosis developed in about 40%.12PubMed. Risk factors for subretinal fibrosis after anti-VEGF treatment of myopic choroidal neovascularisation
Genetic Vulnerability
There are hints that some people may be genetically predisposed to developing fibrosis. The complement factor H gene variant known as CFH Y402H, one of the strongest known genetic risk factors for AMD itself, has been linked to poorer responses to anti-VEGF treatment. Because patients who respond poorly to anti-VEGF are the same ones who tend to develop fibrosis, researchers have proposed this genotype as a possible risk marker for scarring, although direct proof is still lacking.13eBioMedicine. Molecular mechanisms of macular fibrosis secondary to neovascular age-related macular degeneration The connection makes biological sense given complement’s role in driving RPE cells toward a scar-producing state, as described above.
What the Scar Looks Like on Imaging
Clinicians identify disciform scars using a combination of examination and imaging. On standard optical coherence tomography (OCT), the scar appears as a bright, hyperreflective mass replacing the normal layered architecture of the retina. A newer form of OCT called polarization-sensitive OCT can specifically detect subretinal fibrosis by measuring how the tissue changes the polarization of light, an approach that takes advantage of the fact that organized collagen fibers alter polarization in a way normal retinal tissue does not.14PubMed Central. Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography
OCT angiography, which maps blood flow without injecting dye, reveals the vascular skeleton hiding within many scars. One study found three distinct vessel patterns inside subretinal fibrosis: a “pruned vascular tree” (present in about 53% of eyes), “tangled networks” (about 29%), and “vascular loops” (about 51%, often overlapping with the other patterns). Most scars also contained large areas devoid of blood flow, appearing as dark voids surrounded by a halo of reduced signal.15Retina. Optical Coherence Tomography Angiography Features of Subretinal Fibrosis in Age-Related Macular Degeneration These vascular remnants matter clinically: they can reactivate, leaking again and requiring retreatment even years after the scar appeared stable.
Not all disciform scars look identical on OCT, and the differences can reflect the type of abnormal vessel network that caused them. Scars arising from vessels that grew beneath the RPE tend to be associated with thicker underlying choroids, while scars from vessels that broke through above the RPE more often show disorganized inner retinal layers.16Cureus. Optical Coherence Tomography Characteristics for Scars in Type 1 (Polypoidal Choroidal Vasculopathy (PCV)) and Type 2 (Classical) Macular Neovascularization (MNV) in Age-Related Macular Degeneration (AMD)
Why Anti-VEGF Alone Cannot Prevent Scarring
Anti-VEGF drugs target the growth and leakiness of abnormal blood vessels, which is the opening act of the disease. But fibrosis is driven by a separate, overlapping set of signals. TGF-β, complement activation, and the macrophage-to-myofibroblast switch all proceed through pathways that anti-VEGF drugs were never designed to block. Once those pro-fibrotic cascades are running, removing the VEGF signal does not shut them down. This is why even eyes under excellent anti-VEGF control can still quietly develop scar tissue over years.
The practical implication for patients is that early treatment matters enormously. Starting anti-VEGF injections while the abnormal vessels are still small and vision is still good limits the amount of leakage, bleeding, and inflammation that kicks off the fibrotic cascade. The ten-year data showing that better baseline vision is protective reinforces this point.17American Journal of Ophthalmology. Ten-Year Incidence of Fibrosis and Risk Factors for Its Development in Neovascular Age-Related Macular Degeneration Every month of delay between the appearance of symptoms (distortion, blurring, dark spots in the center of vision) and the first injection is a month in which the pro-fibrotic machinery gains momentum.
Experimental Anti-Fibrosis Therapies
Because no approved treatment can reverse or reliably prevent disciform scarring, researchers are pursuing several strategies that target the fibrotic process itself rather than just the blood vessels.
TGF-β inhibition remains the most obvious target given its central role. The mouse experiments showing a 65% reduction in subretinal fibrosis with TGF-β-neutralizing antibodies are a proof of concept, but translating that to human eyes is tricky. TGF-β does many things throughout the body, including suppressing immune activity and regulating wound healing in other tissues, so blocking it broadly could have unwanted consequences. Researchers are trying to develop approaches that confine TGF-β inhibition to the eye itself.
Another approach targets fibroblast growth factor 2 (FGF2), which promotes both abnormal vessel growth and scar formation. An aptamer called RBM-007, a short synthetic molecule designed to bind and neutralize FGF2, reduced subretinal fibrosis in a rat model of laser-induced choroidal neovascularization. Animals given two or three intravitreal injections of RBM-007 showed fibrosis covering about 40% of the lesion area, compared with roughly 67% in untreated controls.18Molecular Therapy – Nucleic Acids. Anti-Angiogenic and Anti-Scarring Dual Action of an Anti-Fibroblast Growth Factor 2 Aptamer in Animal Models of Retinal Disease The dual action against both vessels and fibrosis is appealing because it could, in theory, replace anti-VEGF drugs and add anti-scarring protection in a single injection.
Complement pathway inhibitors are also being investigated, driven by the evidence that C5a pushes RPE cells toward scar-producing behavior.19PubMed Central. Complement activation contributes to subretinal fibrosis through the induction of epithelial-to-mesenchymal transition (EMT) in retinal pigment epithelial cells Several complement-targeting drugs are already in clinical trials for geographic atrophy, the other advanced form of AMD, and there is interest in testing whether they can also reduce fibrosis in wet AMD.
Surgical Attempts at Scar Removal
Before anti-VEGF injections existed, the only option for many patients with established disciform scars was surgery. Early attempts at physically excising the scar from beneath the retina were technically possible but disappointing. In one small series, disciform scars were surgically removed from three patients; vision improved minimally in one and worsened in the other two.20PubMed. Submacular scar excision in age-related macular degeneration The problem is that the scar is intimately fused with the RPE and Bruch’s membrane, so removing it strips away the very cells the retina needs to survive.
A more ambitious variation combined scar excision with transplantation of RPE cells. One patient who received an autologous RPE graft (a pedicle of her own tissue rotated into the scarred area) improved from counting fingers to roughly 20/400 over 14 months. A second patient, who received donor RPE cells, saw the graft become encapsulated without improving vision.21Ophthalmic Surgery, Lasers and Imaging Retina. A Technique for Retinal Pigment Epithelium Transplantation for Age-Related Macular Degeneration Secondary to Extensive Subfoveal Scarring These approaches never became mainstream. Modern stem-cell-derived RPE patches are being studied in early trials, but their role in eyes with established disciform scars remains uncertain.
Living with a Disciform Scar
Once a disciform scar is established, the central scotoma, that blank or dark spot in the center of vision, is permanent. But peripheral vision remains intact, and many people adapt better than they initially expect. The retina surrounding the scar still functions, and the brain can learn to use a “preferred retinal locus” just outside the scarred area as a substitute fixation point. In a study of 20 patients with AMD-related central scotomas and very poor acuity (averaging about 20/475), researchers were able to train patients to use eccentric viewing with the help of a scanning laser ophthalmoscope. Their preferred fixation point was often located to one side of the lesion, a position that is natural but not ideal for reading, since text flows horizontally.22PubMed. Patients with AMD and a large absolute central scotoma can be trained successfully to use eccentric viewing, as demonstrated in a scanning laser ophthalmoscope
Low-vision rehabilitation makes a measurable difference. A review of 61 patients with macular scars who received low-vision aids, primarily high-powered magnifying lenses, found that patients with dry (atrophic) scars achieved similar reading print sizes to those with exudative (wet) scars but needed significantly less powerful lenses to get there.23PubMed. Visual results with low-vision aids in age-related macular degeneration The practical message is that a referral for low-vision services should not wait until the patient has “given up.” People with disciform scars can regain the ability to read, manage medications, and navigate their surroundings with the right combination of optical aids, training in eccentric viewing, and environmental adjustments like task lighting and high-contrast labeling.
The Physical Dimensions of a Disciform Scar
For a structure that causes so much functional devastation, a disciform scar is physically small. In a large pathology series, the average scar measured about 3.7 mm across and less than half a millimeter thick.24Molecular Vision. Histopathology of age-related macular degeneration To put that in perspective, the macula itself is only about 5.5 mm in diameter, and the fovea, the pinpoint center responsible for the sharpest vision, spans less than 2 mm. So a typical disciform scar easily engulfs the fovea and much of the surrounding macula. As scars grow larger and thicker, RPE and photoreceptor damage becomes progressively more complete, leaving fewer cells capable of any light detection over the scarred zone.25PubMed. Age-related macular degeneration histopathologic studies. The 1992 Lorenz E. Zimmerman Lecture A tear of the RPE and the deposit layer beneath it was present in about 7% of eyes with disciform scars, representing a particularly severe subtype.26Molecular Vision. Histopathology of age-related macular degeneration
Why Retinal Scars Differ from Scars Elsewhere in the Body
A scar on your skin is cosmetically unpleasant but functionally tolerable. The retina does not have that luxury. Skin can lose a patch of specialized cells and still do its job of covering and protecting, but the retina’s job is to convert light into electrical signals with extreme spatial precision. Scar tissue has none of that capacity. It is opaque to light, it displaces the photoreceptors that do the actual sensing, and it disrupts the nutrient supply from the choroid that remaining cells need. Furthermore, retinal tissue does not regenerate in the way that skin epithelium does. Once photoreceptors are lost in the scarred zone, no new ones grow to replace them.
The immune environment also differs. Severe or prolonged retinal injury can summon circulating immune cells that drive chronic inflammation and abnormal wound healing, producing fibrosis rather than the orderly tissue repair seen in most skin wounds.27PubMed Central. Immune Cells in Subretinal Wound Healing and Fibrosis The eye is an immune-privileged site, which usually protects it from excessive inflammation, but when that privilege breaks down under the pressure of neovascular disease, the resulting scarring is especially destructive because there is no regenerative fallback.