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Ocular System

Cystoid macular edema (CME)

Type of macular edema characterized by the formation of radially oriented multiple cyst-like spaces within the neurosensory retina.

Macular edema characterized by the formation of radially oriented multiple cyst-like spaces within the neurosensory retina.

  • Macular edema: Swelling/thickening of neurosensory retina within the macular region, resulting from fluid collection within/below the retina
  • M/C cause of decreased vision postoperatively in uneventful cataract surgery

Aetiology

CME is the common pathologic sequel of the retina and occurs in a variety of pathological conditions such as intraocular inflammation, central or branch retinal vein occlusion, diabetic retinopathy and most commonly following cataract extraction.

  • Inflammatory disorders: intraocular surgery, uveitic syndromes, laser procedures
    • Irvin-Gass syndrome: Cystoid macular edema (CME) following cataract surgery
  • Retinal vascular disease (M/C causes): diabetic retinopathy, retinal vein occlusion, hypertensive retinopathy
  • Choroidal vascular disease: choroidal neovascularization
  • Tractional maculopathies: epiretinal membrane, vitreomacular traction syndromes
  • Drug reactions: epinephrine, prostaglandin analogs, nicotinic acid, tamoxifen, glitazones
  • Inherited retinal dystrophies: retinitis pigmentosa
  • Retinal detachment: exudative, rhegmatogenous
  • Intraocular tumors: choroidal melanoma
  • Optic nerve head abnormalities: diabetic/hypertensive papillopathy, neuroretinitis, optic nerve pits/colobomas
  • Idiopathic

Pathophysiology

Caused by a break caused cystic accumulation of intraretinal fluid in the outer plexiform and inner nuclear layers of the retina as a result of the breakdown of the blood–retinal barrier

Pathophysiologic mechanisms of cystoid macular edema | BRB: Blood-retinal barrier; RPE: Retinal pigment epithelium. Blue dots: Disrupted basement membranes. | Chung, Y. R., Kim, Y. H., Lee, S. Y., Byeon, H. E., & Lee, K. (2019). Insights into the pathogenesis of cystoid macular edema: leukostasis and related cytokines. International journal of ophthalmology, 12(7), 1202–1208. https://doi.org/10.18240/ijo.2019.07.23

Diagnosis

Fluorescein angiography (FA):

  • Flower petal pattern (d/t accumulation of dye in outer plexiform layer at fovea)
Fluorescein angiography, right eye. The recirculation phase of the angiogram demonstrates a classic “petalloid” appearance consistent with cystoid macular edema. | Cho, H., & Madu, A. (2009). Etiology and treatment of the inflammatory causes of cystoid macular edema. Journal of inflammation research, 2, 37–43. https://doi.org/10.2147/jir.s5706

Optical coherence tomography (OCT):

Optical coherence tomography shows intraretinal cystic spaces consistent with cystoid macular edema. | Cho, H., & Madu, A. (2009). Etiology and treatment of the inflammatory causes of cystoid macular edema. Journal of inflammation research, 2, 37–43. https://doi.org/10.2147/jir.s5706

Management

Anti-inflammatory agents:

Mainstay treatment of postoperative and uveitic CME
  • Topical corticosteroids:
    • Difluprednate
    • Loteprednol etabonate
    • Prednisolone acetate
    • Rimexolone
  • Topical NSAIDs:
    • Ketorolac
    • Diclofenac
    • Nepafenac
    • Bromfenac

Posterior sub-Tenon steroid injections:

Resistant cases of postoperative CME and most cases of uveitic CME

Systemic corticosteroids:

Reserved for bilateral CME complicating noninfectious uveitis

Intravitreal steroids:

  • Intravitreal triamcinolone acetonide (IVTA)
  • Dexamethasone intravitreal drug delivery system (DDS)

Vitrectomy:

Selected cases with chronic inflammatory CME

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