Eagleview Eye Clinic

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DISCIFORM SCAR

Disciform scar is the final scar stage of wet AMD or other causes of choroidal neovascularization (CNV). It’s basically the eye’s “healing” response after a bleed under the macula, but the scar damages central vision.

What it is

  • Definition: A gray-white, disc-shaped fibrous scar under the retina in the macular area
  • Size: Usually 1-5 mm wide, right where you need sharp vision
  • Tissue: Made of fibrous tissue, blood vessels, and pigment after a CNV membrane closes off

How it forms

  1. CNV develops: Abnormal blood vessels from the choroid break through Bruch’s membrane into the subretinal space
  2. Leakage and bleeding: Those vessels are fragile. They leak fluid and blood under the macula
  3. Inflammation + scarring: Your body tries to heal the bleed. Fibroblasts lay down collagen and the CNV becomes fibrotic
  4. RPE disruption: Retinal pigment epithelium clumps or dies, leaving pigment changes around the scar
  5. End stage: Active leakage stops, but the scar remains. This whole process takes weeks to months

Main causes

  • Wet age-related macular degeneration: Most common cause. Seen in patients 60+
  • Pathologic myopia: Can also end in a disciform scar, but in younger myopes it’s often called a Fuchs spot
  • Ocular histoplasmosis: POHS can cause CNV and scarring
  • Trauma or inflammation: Any CNV that bleeds can end this way if untreated

Appearance on exam

  • Color: Gray-white to yellow-white central lesion
  • Shape: Round or oval, “disc” like
  • Surrounding changes: Pigment clumps, atrophy, or lipid deposits at the edges
  • Size: Correlates with how bad vision loss is. Larger = worse

Symptoms

  • Central vision loss: Permanent blur or blank spot in the middle of vision
  • Distortion first: Before scar forms, patients report wavy lines from fluid. After scarring, it’s replaced by a fixed blind spot
  • Peripheral vision stays: You won’t go completely blind. Side vision is normal
  • Contrast loss: Reading and faces are hard even if acuity isn’t terrible

Diagnosis

  • Dilated fundus exam: Doctor sees the pale elevated scar
  • OCT scan: Shows hyperreflective subretinal material, loss of outer retinal layers, RPE disruption
  • Fluorescein angiography: Early CNV leaks. Late disciform scar stains but doesn’t leak because vessels are closed
  • History: Patient usually describes sudden vision drop months earlier from a bleed

Treatment

  • No reversing the scar: Once formed, the tissue is fibrotic and vision doesn’t return
  • Goal is prevention: Anti-VEGF injections like Avastin, Eylea, Vabysmo treat active wet AMD before it scars
  • Too late if scarred: Injections don’t help a mature disciform scar
  • Low vision rehab: Magnifiers, better lighting, eccentric viewing training to use peripheral retina

Disciform scar vs Fuchs spot
Feature Disciform scar Fuchs spot
Main cause Wet AMD Myopic CNV
Age 60+ usually 30s-50s
Color Gray-white fibrous Dark pigmented
Eye shape Normal axial length Long, >26.5 mm
Bilaterality Second eye at risk in 4-7 years Second eye at risk in 30-35%
Prognosis

  • Vision: Usually 6/60 or worse if the scar is subfoveal. If it’s off center, vision may be 6/12 to 6/24
  • Stability: Scar doesn’t grow, but geographic atrophy can develop around it
  • Other eye: High risk of wet AMD in fellow eye. Regular monitoring with Amsler grid and OCT is key

Bottom line: A disciform scar is the “tombstone” of wet AMD. Modern anti-VEGF therapy has made them much less common because we can shut down CNV before it bleeds and scars. That’s why sudden distortion or vision drop needs an urgent retina check.

ICG ANGIOGRAPHY

ICG angiography = Indocyanine Green Angiography. It’s an imaging test that maps blood flow in the choroid, the blood-vessel layer under your retina.

What it is

  • Dye test: A green dye called indocyanine green is injected into your arm vein
  • Infrared camera: Special camera uses near-infrared light at 790-805 nm to see the dye through the retinal pigment
  • Shows choroid: Unlike fluorescein angiography which shows retinal vessels, ICG goes deeper and highlights choroidal circulation

Why doctors order it

  • See through blood/pigment: ICG light penetrates melanin, fluid, and thin blood. Useful when fluorescein images are blocked
  • Diagnose specific conditions:
    • Choroidal neovascularization (CNV): Especially “occult” CNV hidden under the retina in AMD
    • Polypoidal choroidal vasculopathy (PCV): Branching vessels with polyp-like aneurysms, common in African/Asian patients
    • Central serous chorioretinopathy (CSCR): Shows choroidal hyperpermeability areas
    • Lacquer cracks: Checks if CNV is growing through the cracks
    • Inflammatory diseases: Vogt-Koyanagi-Harada, choroiditis, to see active lesions
    • Tumors: Choroidal melanoma vs nevus

How the test works

  • Prep: Pupils dilated. You’ll sign consent and get an IV line
  • Injection: 25 mg ICG dye injected into arm. It binds to plasma proteins and stays inside blood vessels
  • Imaging phases:
    • Early 0-1 min: Choroidal arteries and choriocapillaris fill
    • Mid 5-15 min: Venous phase and leakage patterns show
    • Late 20-30 min: Staining or “washout” patterns. Polyps stay bright late
  • Time: Takes 20-30 minutes total

ICG vs Fluorescein angiography
Feature ICG Fluorescein
Light used Near-infrared 790-805 nm Blue light 490 nm
What it shows Choroidal vessels Retinal vessels
Dye leakage Minimal. Stays in vessels Leaks easily from damaged vessels
See through blood Yes No
Best for PCV, CSCR, occult CNV, choroidal tumors Diabetic retinopathy, vein occlusion, macular edema
Safety & side effects

  • Very safe: Severe reaction rate is about 0.05%, much lower than fluorescein
  • Common effects: Temporary green discoloration of skin, green urine for 1 day
  • Mild reactions: Nausea in 1-2%, sneezing, itching
  • Contraindications: Iodine allergy because ICG contains iodine. Also avoid in liver disease and pregnancy unless essential
  • No kidney issues: Unlike CT contrast, ICG isn’t nephrotoxic

What to expect after

  • Vision: Not blurred by the dye itself, but dilation makes you light sensitive for 4-6 hours
  • Drive: Bring someone. You can’t drive until dilation wears off
  • Results: Retina specialist reads images same day and decides on treatment like anti-VEGF or photodynamic therapy

Bottom line: If fluorescein angiography shows the retinal circulation, ICG shows the “basement” blood supply under it. It’s the go-to test when doctors suspect PCV, CSCR, or hidden CNV, especially in highly pigmented eyes.

ICG ANGIOGRAPHY

ICG angiography = Indocyanine Green Angiography. It’s an imaging test that maps blood flow in the choroid, the blood-vessel layer under your retina.

What it is

  • Dye test: A green dye called indocyanine green is injected into your arm vein
  • Infrared camera: Special camera uses near-infrared light at 790-805 nm to see the dye through the retinal pigment
  • Shows choroid: Unlike fluorescein angiography which shows retinal vessels, ICG goes deeper and highlights choroidal circulation

Why doctors order it

  • See through blood/pigment: ICG light penetrates melanin, fluid, and thin blood. Useful when fluorescein images are blocked
  • Diagnose specific conditions:
    • Choroidal neovascularization (CNV): Especially “occult” CNV hidden under the retina in AMD
    • Polypoidal choroidal vasculopathy (PCV): Branching vessels with polyp-like aneurysms, common in African/Asian patients
    • Central serous chorioretinopathy (CSCR): Shows choroidal hyperpermeability areas
    • Lacquer cracks: Checks if CNV is growing through the cracks
    • Inflammatory diseases: Vogt-Koyanagi-Harada, choroiditis, to see active lesions
    • Tumors: Choroidal melanoma vs nevus

How the test works

  • Prep: Pupils dilated. You’ll sign consent and get an IV line
  • Injection: 25 mg ICG dye injected into arm. It binds to plasma proteins and stays inside blood vessels
  • Imaging phases:
    • Early 0-1 min: Choroidal arteries and choriocapillaris fill
    • Mid 5-15 min: Venous phase and leakage patterns show
    • Late 20-30 min: Staining or “washout” patterns. Polyps stay bright late
  • Time: Takes 20-30 minutes total

ICG vs Fluorescein angiography
Feature ICG Fluorescein
Light used Near-infrared 790-805 nm Blue light 490 nm
What it shows Choroidal vessels Retinal vessels
Dye leakage Minimal. Stays in vessels Leaks easily from damaged vessels
See through blood Yes No
Best for PCV, CSCR, occult CNV, choroidal tumors Diabetic retinopathy, vein occlusion, macular edema
Safety & side effects

  • Very safe: Severe reaction rate is about 0.05%, much lower than fluorescein
  • Common effects: Temporary green discoloration of skin, green urine for 1 day
  • Mild reactions: Nausea in 1-2%, sneezing, itching
  • Contraindications: Iodine allergy because ICG contains iodine. Also avoid in liver disease and pregnancy unless essential
  • No kidney issues: Unlike CT contrast, ICG isn’t nephrotoxic

What to expect after

  • Vision: Not blurred by the dye itself, but dilation makes you light sensitive for 4-6 hours
  • Drive: Bring someone. You can’t drive until dilation wears off
  • Results: Retina specialist reads images same day and decides on treatment like anti-VEGF or photodynamic therapy

Bottom line: If fluorescein angiography shows the retinal circulation, ICG shows the “basement” blood supply under it. It’s the go-to test when doctors suspect PCV, CSCR, or hidden CNV, especially in highly pigmented eyes.