Macular Diseases


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Macular Diseases


NON-EXUDATIVE (DRY) AGE-RELATED MACULAR DEGENERATION


Jordan D. Deaner, MD and Allen C. Ho, MD, FACS



  • Constitutes 85% to 90% of age-related macular degeneration (AMD). Drusen are the hallmark lesions, however retinal pigment epithelial (RPE) hyperpigmentation and atrophy may also be present.
  • Oxidative stress is the suspected disease mechanism, resulting in photoreceptor toxicity, lipofuscin accumulation in RPE, drusen formation, and choriocapillaris atrophy.

Risk Factors



  • Modifiable risk factors: smoking tobacco, hypertension, diet, physical activity, cardiovascular disease, hypercholesterolemia, obesity, and UV protection
  • Non-modifiable risk factors: age (risk increases > 3-fold in those > 75 years old), genetic susceptibility (eg, complement factor H, ARMS2), female gender, Caucasian race, hyperopia, family history, light color irides

Signs and Symptoms


Decreased vision, metamorphopsia, micropsia, central scotoma


Exam Findings



Staging of AMD as Defined by the Age-Related Eye Disease Study



  • Early AMD: many small drusen or few (< 10) intermediate drusen; risk of progression to advanced AMD is 1.3% over the 5-year period in the Age-Related Eye Disease Study (AREDS)
  • Intermediate AMD: 10 or more intermediate drusen, a single large druse; risk of progression to advanced AMD is 18%
  • Advanced AMD: presence of either geographic atrophy (GA) or choroidal neovascularization (CNV)


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Figure 1-1. Dry AMD. (A) Color fundus photograph demonstrating areas of well-defined GA (white *) associated with many medium and large (black *) drusen. The choroidal vessels are well visualized in the areas of atrophy. (B) Infrared fundus image and OCT show areas of well demarcated GA (*).


Testing



Differential Diagnosis


Adult-onset foveomacular vitelliform dystrophy, Best disease, pattern dystrophy, central serous retinopathy, drug induced maculopathy (chloroquine, hydroxychloroquine)


Management



WET AGE-RELATED MACULAR DEGENERATION


Priya Sharma Vakharia, MD and Chirag P. Shah, MD, MPH



  • CNV typically develops in eyes with pre-existing dry AMD, which can lead to permanent visual impairment if not treated.
  • Associated with older age, family history, genetics, and smoking; may also be associated with obesity and cardiovascular disease

Signs and Symptoms


Metamorphopsia, decreased vision, or scotoma


Exam Findings


Subretinal and/or intraretinal fluid, subretinal and/or intraretinal hemorrhage, gray membrane, lipid exudates, fibrovascular pigment epithelial detachment, associated with pre-existing drusen, atrophy, and retinal pigment epithelium changes (Figures 1-2A, 1-3A, and 1-3C)



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Figure 1-2. (A) Fundus photo demonstrating intraretinal and subretinal hemorrhage (arrow), associated with wet AMD. (B) FA with a well-defined hyperfluorescent lesion typical of classic CNV.




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Figure 1-3. (A) Fundus photo demonstrating hemorrhage, fluid, and exudate, characteristic of wet AMD. (B) Corresponding OCT shows subretinal hemorrhage (white arrowhead), subretinal fluid (red arrowhead), and RPE detachment (white arrow). After 1 year of monthly anti-VEGF treatments, fundus photo (C) demonstrates resolution of hemorrhage and OCT (D) shows resolution of subretinal fluid and hemorrhage as well as a more compact retinal pigment epithelium detachment (white arrow).


Testing



  • OCT: reveals presence of a CNV complex with intraretinal or subretinal fluid (Figures 1-3B and 1-3D)
  • FA: Shows early hyperfluorescence and late leakage in the area of the CNV (Figure 1-2B). This can be associated with a classic or occult appearance.
  • Indocyanine green angiography: Ancillary test to visualize the CNV complex, particularly helpful for occult CNV, polypoidal lesions, or when hemorrhage is present. Visualization is enhanced because indocyanine green is highly protein-bound and a longer wavelength is used.
  • OCT angiography: noninvasive method of angiography which can reveal the CNV

Differential Diagnosis


Central serous chorioretinopathy, polypoidal choroidal vasculopathy, myopic CNV, idiopathic CNV, pattern dystrophy, vitelliform dystrophy, ocular histoplasmosis syndrome, angioid streaks and associated CNV, macular telangiectasia, chorioretinitis


Management



EPIRETINAL MEMBRANE (MACULAR PUCKER)


Sundeep K. Kasi, MD



  • Growth of fibrocellular tissue on surface of retina causing disruption and wrinkling of macular contour
  • Most frequently age-related and due in part to vitreous detachment, but must look for retinal tears, prior ocular surgery, and history of vein occlusion, inflammation or trauma
  • Affects 2% of patients > 50 years old and 20% of patients > 75 years old. Ten to twenty percent bilateral but often asymmetric.

Signs and Symptoms


Decreased vision, distortion, metamorphopsia, and/or macropsia


Exam Findings


Reflective sheen over macula with effacement of foveal light reflex, retinal striae and thickening with membranous tissue in more advanced cases (Figure 1-4A)


Testing



  • Amsler grid: distortion of lines with waviness, slanting, or bending
  • OCT: reflective material on superficial retina with wrinkling or flattening of macular contour, retinal thickening, cystoid or schisis changes (Figure 1-4B)
  • FA: can show hyperfluorescence indicating leakage from edema due to the traction exerted on retinal vessels

Differential Diagnosis


Macular edema, vitreomacular traction (VMT), lamellar macular hole


Management



  • No treatment indicated when patient is asymptomatic, but continued semi-annual or annual monitoring is advised to detect progression
  • PPV with membrane peeling; internal limiting membrane (ILM) peeling is optional and studies have shown mixed results in terms of effect on vision and recurrence rate. It is particularly effective for patients with significant metamorphopsia.


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Figure 1-4. (A) Fundus photograph of a right eye with retinal striae due to an ERM. (B) OCT of a left eye with irregular macular contour, thickening, subfoveal ellipsoid zone disruption (arrowhead), and hyperreflective signal on inner surface (arrows) consistent with an ERM.


FULL-THICKNESS MACULAR HOLE


M. Ali Khan, MD



  • Foveal defect involving all neural retinal layers, spanning from ILM to RPE
  • Most cases are idiopathic (due to abnormal vitreo-foveal traction); secondary causes include trauma and pathologic myopia
  • Prevalence: Ranges from 0.2 to 3.3 in 1000. Risk factors: female gender and older age (sixth decade of life or greater).
  • Classification systems

    • Gass classification (exam-based, not imaging based): Stage 1 (impending hole), Stage 2 (small, < 400 µm defect), Stage 3 (large, > 400 µm defect), Stage 4 (full defect with associated complete posterior vitreous detachment)
    • International Vitreomacular Traction Study Group (IVTS)9 classification (spectral domain-OCT [SD-OCT] based system). Full-thickness macular hole are classified by the following:

      • Size based on minimum hole diameter: small (≤ 250 um), medium (> 250 but ≤ 400 um), or large (> 400 um)
      • Status of vitreous: with or without VMT

Signs and Symptoms


Decreased central vision, metamorphopsia, and/or a central blind spot (scotoma); vision: near normal to severely reduced depending on size and duration


Exam Findings


Round, red-based appearing lesion at foveal center (Figure 1-5A), concurrent epiretinal membrane (ERM) may be present, Watzke-Allen sign: patient’s description of discontinuity in center of thin slit beam centered over hole on fundoscopy



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Figure 1-5. (A) A 74-year-old phakic patient with full-thickness macular hole. A round, red appearing foveal lesion was present. (B) SD-OCT revealed a full-thickness defect (*) with local pseudocysts (arrows).


Testing


OCT: current standard for diagnosis shows a full-thickness defect from ILM to RPE seen on at least one B-scan image; hole width (in microns) is measured at narrowest linear hole diameter; hole edges often appear rounded and may have cystic changes (Figure 1-5B)


Differential Diagnosis


ERM with pseudohole, lamellar macular hole, cystoid macular edema (CME), outer retinal pathologies (solar retinopathy, alkyl nitrate [“popper”] related maculopathy)


Management



VITREOMACULAR TRACTION


M. Ali Khan, MD


Characterized by abnormal vitreous adhesion to the macula resulting in anatomic distortion of fovea. The anatomic alteration differentiates VMT from vitreomacular adhesion (VMA).



  • Classification system

    • IVT classification9 (SD-OCT based system)

      • All of the following 3 features must be present on at least one B-scan ultrasound: (1) partial perifoveal vitreous detachment, (2) vitreous adhesion to macula within a 3-mm radius of fovea, (3) associated distortion of the fovea but without full-thickness defect
      • VMT can be further categorized by size of VMA (focal [≤ 1500 μm] or broad [> 1500 μm]) and presence or absence of concurrent macular disease

Signs and Symptoms


Decreased central vision, metamorphopsia, and/or a central blind spot (scotoma)


Exam Findings


Macular schisis, subretinal fluid, and cystic changes; concurrent ERM and other macular disease may be present


Testing



  • OCT: standard for diagnosis with IVTS classification system; features such as loss of foveal contour, macular schisis, subretinal fluid, and pseudocysts may be present (Figure 1-6)


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Figure 1-6. Representative examples of VMT. (A) Mild VMT demonstrating adhesion of the vitreous to the central macula (arrows) with edema limited to the inner retina. (B) More extensive foveal abnormality may be present, however, with larger cystic formation (*) and outer retinal disruption (arrow). (C) Concurrent ERM (arrow) with broad VMT may be present.

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