The Biology of Your Eye: How MFC Works
At a Glance
Multifocal Choroiditis (MFC) is an immune-mediated eye disease where the immune system mistakenly blocks tiny blood vessels behind the retina. This cuts off vital nutrients to the eye, causing inflammation and vision changes that are typically treated with corticosteroids.
To understand Multifocal Choroiditis (MFC), it helps to think of the eye as a layered camera. While most people focus on the “film” (the retina), MFC is actually a disease of the “power supply” behind the film—a dense network of tiny blood vessels called the choriocapillaris [1].
The Biological Mechanism: Choriocapillaritis
MFC is biologically classified as an inflammatory choriocapillaropathy [1]. This means your immune system mistakenly attacks and causes inflammatory occlusion (blockage) of those vital tiny blood vessels [1].
When these vessels are blocked, the layers above them—specifically the Retinal Pigment Epithelium (RPE) (the support cells) and the light-sensing photoreceptors—lose their nutrient supply and become damaged [2]. On specialized eye scans, doctors can often see this inflammation physically pushing through and disrupting the delicate layers of your retina [3].
Why It Is “Immune-Mediated”
Doctors call MFC an immune-mediated condition because the damage is caused by your own immune system rather than an external infection [4]. We know this because the inflammation typically improves when treated with medications that quiet the immune system, such as corticosteroids [5].
What MFC is NOT: Differential Diagnosis
Because many eye diseases cause “white dots” on the retina, your doctor must rule out other conditions to ensure you have the right treatment plan.
- POHS (Presumed Ocular Histoplasmosis Syndrome): POHS is generally not an active inflammatory disease and typically lacks vitritis (inflammation in the eye gel), whereas MFC often has active inflammation in the gel [6].
- Tuberculosis (TB): TB is an infection that can perfectly mimic MFC. Doctors must rule it out because treating TB with only steroids can be dangerous [7].
- MEWDS (Multiple Evanescent White Dot Syndrome): MEWDS is usually a one-time event that resolves on its own without permanent scarring. MFC is chronic and can cause permanent scars [4].
By identifying MFC as a chronic blockage of the blood supply, your medical team can focus on keeping the immune system quiet enough to protect your sight [8].
Common questions in this guide
What causes Multifocal Choroiditis (MFC)?
How is MFC different from POHS or MEWDS?
Why does my doctor need to rule out Tuberculosis before treating MFC?
What will an OCT scan show if I have MFC?
How do doctors treat the inflammation in MFC?
Questions to Ask Your Doctor
Curated prompts to bring to your next appointment.
- 1.Has my testing ruled out infectious causes like Tuberculosis or Sarcoidosis, which can look similar to MFC?
- 2.Do my imaging results show 'vitritis' or other signs of active inflammation in the vitreous gel?
- 3.Does my OCT scan show the 'finger-like projections' that are typical of active choriocapillaritis?
- 4.Are my lesions localized to the inner choroid, or is this a 'full-thickness' inflammatory process?
- 5.If my condition is MEWDS, why do we think it has progressed to or overlaps with MFC?
Questions For You
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References
References (8)
- 1
Non-Infectious Choroiditis Subdivided into Its Diverse Pathophysiological Sub-Groups Is the Best-Known and Most Appropriate Nomenclature to Date for the Reclassification and Diagnosis of Former White Dot Entities.
Herbort CP, Silpa-Archa S, Papasavvas I, et al.
Diagnostics (Basel, Switzerland) 2026; (16(11)) doi:10.3390/diagnostics16111735.
PMID: 42279602 - 2
Differences in epiretinal macrophage-like cells and associated retinochoroidal changes between multifocal choroiditis and punctate inner choroidopathy observed using widefield optical coherence tomography angiography.
Yang R, Zhang X, Li M, Wen F
Photodiagnosis and photodynamic therapy 2026; (57()):105325 doi:10.1016/j.pdpdt.2025.105325.
PMID: 41429400 - 3
FOVEAL OUTER RETINAL HYPERREFLECTIVITY: A NOVEL OPTICAL COHERENCE TOMOGRAPHY FINDING IN IDIOPATHIC MULTIFOCAL CHOROIDITIS.
Dolz-Marco R, Kalevar A, McDonald HR, et al.
Retinal cases & brief reports 2021; (15(6)):651-656 doi:10.1097/ICB.0000000000000878.
PMID: 31274847 - 4
The multimodal imaging features and outcomes of multifocal choroiditis/punctate inner choroidopathy lesion with multiple evanescent white dot syndrome-like features: a retrospective study.
Chen C, Cheng Y, Zhang Z, et al.
BMC ophthalmology 2024; (24(1)):3 doi:10.1186/s12886-023-03277-6.
PMID: 38166867 - 5
Multifocal Choroiditis with Retinal Vasculitis, Optic Neuropathy, and Keratoconus in a Young Saudi Male.
Dhafiri Y, Al Rubaie K, Kirat O, et al.
Middle East African journal of ophthalmology 2017; (24(2)):109-112 doi:10.4103/meajo.MEAJO_331_16.
PMID: 28936058 - 6
Presumed Tuberculous uveitis: clinical features and management.
Gargouri S, Kaibi I, Zone I, et al.
La Tunisie medicale 2019; (97(1)):106-112.
PMID: 31535701 - 7
Presumed Tubercular Multifocal Choroiditis.
Soheilian M, Azadi P
Journal of ophthalmic & vision research 2024; (19(4)):512-518 doi:10.18502/jovr.v19i4.11199.
PMID: 39917450 - 8
The use of optical coherence tomography angiography in comparing choriocapillaris recovery between two treatment strategies for multifocal choroiditis: a pilot clinical trial.
Agarwal A, Abhaypal K, Aggarwal K, et al.
Journal of ophthalmic inflammation and infection 2022; (12(1)):12 doi:10.1186/s12348-022-00291-5.
PMID: 35275320
This page explains the biology of Multifocal Choroiditis (MFC) for educational purposes. It does not replace professional medical advice from an ophthalmologist or retina specialist.
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