Retinal Vascular Diseases


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Retinal Vascular Diseases


NONPROLIFERATIVE DIABETIC RETINOPATHY


Sasha Hubschman, MD and Jayanth Sridhar, MD



  • Hyperglycemia results in endothelial damage in retinal capillaries, leading to vascular remodeling, leakage, and occlusion.
  • Twenty-three percent of people with type 1 diabetes mellitus develop diabetic retinopathy (DR) after 5 years, 80% after 15 years. Up to 21% of patients with type 2 diabetes mellitus already have retinopathy at time of initial diagnosis of diabetes.
  • Intense glycemic control is associated with reduced progression to severe nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).


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Figure 2-1. NPDR with intraretinal hemorrhages (short arrow) and exudates (long arrow).


Signs and Symptoms


Blurred vision, usually due to presence of macular edema (see the Diabetic Macular Edema section) or, less commonly, from macular ischemia


Exam Findings



Testing



Differential Diagnosis


Branch or central retinal vein occlusion (CRVO), ocular ischemic syndrome, hypertensive retinopathy, radiation retinopathy


Management




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Figure 2-2. FA can demonstrate microaneurysms (arrows) in NPDR.



  • Pregnancy poses higher risk of developing worsening retinopathy and patient should be examined during first trimester and followed closely until 1 year post-partum. Vitreous surgery, intravitreal corticosteroids, and laser therapy are safe during pregnancy. No randomized controlled trials to prove safety of anti-VEGF during pregnancy and is therefore generally avoided.


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Figure 2-3. OCTA of the superficial plexus (6 × 6 mm) reveals areas of non-perfusion (long arrows) as well as microaneurysmal changes (short arrow).



  • Mild and moderate NPDR: generally not treated unless DME is present
  • Severe or very severe NPDR and patients with higher risk of progressing to PDR: May consider anti-VEGF therapy to reduce retinopathy severity and rate of progression even in absence of DME. Panretinal photocoagulation may also be considered, particularly if there is heightened concern for non-compliance with recommended follow-up.


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Figure 2-4. PDR with NVD (arrow) and elsewhere (arrowheads).


PROLIFERATIVE DIABETIC RETINOPATHY


Michael J. Venincasa, MD and Jayanth Sridhar, MD



  • PDR is the leading cause of vision loss in working-age Americans.
  • Prevalence ↑ with duration of diabetes mellitus. Other risk factors include hypertension, smoking, nephropathy, dyslipidemia, and pregnancy.
  • Pathophysiology: diabetic microvascular changes → retinal ischemia → increased angiogenic growth factors → secondary neovascularization (Figure 2-4) → complications (eg, vitreous hemorrhage [VH], tractional retinal detachment [TRD])

Signs and Symptoms


Many are initially asymptomatic; blurred vision, floaters, shadows, pain if intraocular pressure (IOP) is elevated


Exam Findings



  • Stages of PDR

    • Early: neovascularization is present, but does not meet high-risk criteria
    • High-risk: (1) neovascularization of the optic disc (NVD) ≥ 1/3 to 1/2 disc area, or (2) NVD and vitreous or preretinal hemorrhage, or (3) neovascularization elsewhere (NVE) ≥ 1/2 disc area and VH or preretinal hemorrhage
    • Severe: posterior fundus obscured by VH or preretinal hemorrhage or macula center detached

  • Macular edema can be present at any stage of PDR and should be addressed concomitantly (see the Diabetic Macular Edema section)

Testing



Differential Diagnosis


Radiation retinopathy, branch retinal vein occlusion (BRVO)/CRVO, macular telangiectasia, retinal vasculitis, sarcoidosis, ocular ischemic syndrome, sickle cell retinopathy



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Figure 2-5. PDR complicated by (A) TRD confirmed with subretinal fluid (*) visible in the macula on (B) OCT.


Management



DIABETIC MACULAR EDEMA


Jordan D. Deaner, MD and Carl D. Regillo, MD



  • Common manifestation of DR that reduces central vision and is the leading cause of vision loss in developed world
  • Etiology: Chronic hyperglycemia leads to breakdown in the blood-retinal barrier (maintained by pericytes and endothelial cell tight junctions) and increased vasopermeability (mediated by VEGF).

Signs and Symptoms


Decreased vision, metamorphopsia


Exam Findings



  • Slit lamp biomicroscopy: thickening (edema) of macula with or without cystoid changes centrally, microaneurysms, and lipid exudation
  • Clinically significant macular edema (CSME) as defined by Early Treatment Diabetic Retinopathy Study (ETDRS; Figure 2-6)3

    • Retinal thickening within 500 μm of center of the fovea
    • Hard exudate with adjacent retinal thickening at or within 500 μm of center of the macula
    • Retinal thickening 1 disc area or larger, any part of which is within 1 disc diameter of center of macula

Testing



  • OCT: shows retinal thickening typically with cystic change and subretinal fluid when severe (Figure 2-7)

    • Allows quantification of degree and location (central vs non-central) of edema
    • Reveals associated vitreoretinal interface abnormalities, such as epiretinal membrane (ERM) or vitreomacular traction (VMT)
    • Useful for monitoring response to therapy


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Figure 2-6. Color fundus photograph demonstrating CSME, hard exudates (black *), and retinal hemorrhages (white *) in severe NPDR.




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Figure 2-7. OCT shows mild cystic macular edema (white *) and hard exudates (black *) in the central macula of a patient with DME and moderate NPDR.




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Figure 2-8. Intravenous FA demonstrating numerous microaneurysms and late macular leakage (*) in a patient with severe NPDR and DME.



Differential Diagnosis


Post-operative cystoid macular edema (Irvine-Gass syndrome), cystoid macular edema from medications (epinephrine, E2-prostaglandins, nicotinic acid), retinal vein occlusion (RVO), choroidal neovascularization, hypertensive retinopathy, ocular ischemic syndrome, radiation retinopathy, retinal arterial macroaneurysm; uveitis



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Figure 2-9. OCT angiography showing enlargement of the foveal avascular zone and focal loss of the deep vascular plexus (*) in a patient with DME.


Management



  • Asymptomatic patients with mild and/or non–center-involving macular edema may initially be observed.
  • Intravitreal anti-VEGF agents are first-line therapy for center-involving (CI) DME.

  • Corticosteroids (intravitreal triamcinolone, dexamethasone implant, fluocinolone implant) are generally considered to be second-line therapy for CI DME

    • Longer-lasting than anti-VEGF agents: up to 3 to 4 months for intravitreal triamcinolone and dexamethasone implant; 2 to 3 years for fluocinolone implant
    • Often used when there is inadequate response to anti-VEGF agents or as an alternative to ongoing, frequent anti-VEGF injections
    • Side effects: IOP elevation and cataract progression

  • Focal macular laser photocoagulation: proven in ETDRS3 to decrease risk of vision loss in eyes with CSME, but inferior to anti-VEGF or corticosteroids (DRCR Network Protocol I5) as far as improving vision in eyes with CI DME

    • May be considered for non-CI DME that has not completely responded to intravitreal pharmacotherapy

  • PPV and membrane peeling may be considered if vitreomacular interface abnormalities are contributing to macular edema, particularly if response to medical treatment is suboptimal.


COTTON WOOL SPOTS


Ashley Khalili, MD and David Y. Rhee, MD



  • Represent focal areas of nerve fiber layer ischemia and thrombosis of the precapillary arteriole, resulting in swelling of ganglion cell axons due to interrupted axoplasmic flow (Figure 2-10)
  • Histopathology: hallmark finding of cytoid bodies within the CWS, which are eosinophilic segments of ganglion cell axons that are dilated due to interrupted axoplasmic flow and accumulation of intracellular material


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Figure 2-10. A patient with inferior BRVO occlusion with a sectoral area of CWS on color fundus photography.


Signs and Symptoms


Often asymptomatic unless there is foveal involvement, occasionally scotoma or vague description of blurred vision, systemic symptoms of an underlying etiology may be present


Exam Findings


Focal white or yellow-white, slightly elevated and fluffy lesions in the superficial retina, usually smaller than 1/3 disc areas in diameter and most commonly in the posterior pole; usually disappear within 4 to 12 weeks, but may last longer in diabetes.



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Figure 2-11. CWS. OCT of the CWS with localized retinal nerve fiber layer thickening.

Nov 28, 2021 | Posted by in OPHTHALMOLOGY | Comments Off on Retinal Vascular Diseases
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