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Flashcards in Opthalmology III Deck (14)
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1

Anatomy of the retina

  • Photsensitive neurosensory tissue, has photoreceptors, support cells, and ganglia cella. These sit on the retinal pigment epithelium.
  • Macula
    • Fovea – avascular, cones
    • Foveola – only photoreceptors
  • Equatorial retina – mainly rods
  • Peripheral retina
    • Ora serrata
    • Pars plana (posterior ciliary body)
  • Retinal vascular includes central retinal artery and vien and capillaries

2

Anatomy/physiology of the choroid

  • located btwn the sclera and retina
  • represents the vascular layers of the eye
  • thickest @ its most posterior point; outlying areas thinner
  • provides oxygen and nourishment to the retina
  • acts as a heat sink
  • uveal tract = choroid + ciliary body + iris

3

Anatomy and physiology of the optic nerve

  • Optic nerve = CN II
  • Afferent
  • Synapses on the LGN
  • Midbrain controls accomodation and dilation
  • Surrounded by pia, arachnoid, and dura
  • Vasculature - opthalmic artery: pial capillaries, postererior ciliary arteries.
  • Responsible for phsyiologic blind spot

4

Risk facts, pathophysiology, and tyeps of Diabetic Retionopathy

  • Leading cause of blindness in the world
  • Risk factors: duration of diabetes, glycemic control (need to control well), blood pressure, acceleration during pregnancy
  • Risk vs. duration of Type II DM: 50% at 10 years, 90% at 30 years
  • Pathophysiology: microvascular injury, hemorrhage, leakage, ischemia, neovascularization
  • Types: proliferatie vs. nonproliferative

5

Nonproliferative vs. Proliferative Diabetic retinopathy

  • Non-proliferative: microaneurysms, flame hemorrhages, dot-blot hemorrhages, venous beading and dilation
    • Macular edema: #1 cause of vision loss in DM.  Overexpresion of VEGF.
    • Hard exudates - lipoprotein
    • Capillary non perfusion
  • Proliferative: new blood vessels growing, at risk for vision loss.  These can break and bleed.
    • Neovascularization on optic disc and retina
    • Fibrovascular proliferation (grow into vitreus)
    • Out of all patients with DM - 5-10% have this
    • Complications: Vitreus hemorrhage, tractional retinal detachment, neovscularization of iris → obstruct trabecular network → neovascular glaucoma

6

Management of diabetic neuropathy

  • Screening without retinopathy 1/yr, severe disease every 4/6 weeks
  • Glycemic control
  • BP control
  • Screening eye exams
  • Laser photocoagulation
  • Anti VEGF injections - avastin and lucenta
  • Pars Plana Vitrectomy 

7

Characteristics of hypertensive retinopathy

  • Vasoconstriction
    • Arteriole narrowing
  • Arteriosclerosis
    • Copper and silver wiring
    • A/V nicking
  • Retinal hemorrhage
  • Macular edema and exudate
  • Optic disc edema due to severe, acute HTN

8

Risk factors for age-related macular degeneration

  • Leading cause of blindness in patients over 50
  • Risk Factors
    • Age - much greater over 65 y.o.
    • Race - Caucasions
    • Gender- females
    • Tobacco smoking
    • Cardiovascular disease

9

Age-related macular degeneration disease types

  • general = disease of choroid
  • Nonexudative - dry form - 90% of patients have this form
    • Drusen - lipoprotein: hard/soft → spots to right
    • RPE (retinal pigment epithelium) Changes: Atrophy/ hyperpigmentation
    • Geographic atrophy → hypodense mid right, loss of cells
  • Wet AMD - 10% of patients have this form
    • More vision loss
    • Choroidal neovascularization into RPE
    • Macular edema and hemorrhage
    • Pigment epithelial detachment
    • Fibrotic discform scar if don’t respond to treatment → Right
    • Need injection of bavicuzimab every 6 wks indefinitely - Anti VEGF
      • w/out injection disease will recur

10

Risk factors and clinical presentation of glaucoma

  • Glaucoma=most common optic neuropathy
  • Risk Factors
    • Age
    • Elevated IOP
    • Race
    • Central corneal thickness
    • Myopia
    • Family History
  • Sx/Findings: elevated IOP (>24 generally find glaucoma), enlarged cup/disc or assymetry, optic disc hemorrhage, visual field defects → first peripheral then central vision
  • ==> Nerve fiber layer and optic disk injury
  • ==> Visual field loss

11

Management of glaucoma

  • Management: screening is key, disease is often asymptomatic until end stage.  
  • Lower IOP
  • Drops that decrease aqueous outflow, or increase production
  • Laser
  • Surgery: with or without drainage implants

12

Characteristics/presentation of anterior ischemic optic neuropathy

  • Infarction of optic disc
  • Acute
  • Non arteritic AION - painless
    • Afferent pupillary defect
    • Visual field defect
    • Optic disc edema
    • No specific treatment
    • Treat comorbidities
  • Arteritic AION
    • Giant cell areteritis
    • Symptoms:
      • Systempic symptoms - HA,fatigue
      • Jaw claudication
      • Scalp tenderness
      • Worse vision loss
      • Pallis Disc edema

13

Risk factors for (non arteritic) anterior ischemic neuropathy

  • Age 55-70
  • Race - caucasian
  • Disk at risk - small c/d ratio
  • CV problems

14

Dx/management of anterior ischemic optic neuropathy

  • Need temporal artery biopsy, start steroids
  • Other eye could infarct within 6 weeks - 30% of time
  • ESR, CRP, Temporal artery biopsy
  • Treatment: long term steroid, prevent progression, rare vision improvement