Opthalmology III

Question 1

Anatomy of the retina

Answer 1

• 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

Question 2

Anatomy/physiology of the choroid

Answer 2

• 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

Question 3

Anatomy and physiology of the optic nerve

Answer 3

• 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

Question 4

Risk facts, pathophysiology, and tyeps of Diabetic Retionopathy

Answer 4

• 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

Question 5

Nonproliferative vs. Proliferative Diabetic retinopathy

Answer 5

• 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

Question 6

Management of diabetic neuropathy

Answer 6

• 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

Question 7

Characteristics of hypertensive retinopathy

Answer 7

• 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

Question 8

Risk factors for age-related macular degeneration

Answer 8

• 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

Question 9

Age-related macular degeneration disease types

Answer 9

• 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

Question 10

Risk factors and clinical presentation of glaucoma

Answer 10

• 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

Question 11

Management of glaucoma

Answer 11

• 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

Question 12

Characteristics/presentation of anterior ischemic optic neuropathy

Answer 12

• 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

Question 13

Risk factors for (non arteritic) anterior ischemic neuropathy

Answer 13

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

Question 14

Dx/management of anterior ischemic optic neuropathy

Answer 14

• 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