The Retina Atf

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The Retina
Jason Ryan, MD, MPH
Retina and Macula
• Retina
• Inner layer of eye
• Contain photosensitive cells: rods and cones
• Major blood supply via choroid
• Macula AfraTafreeh.com
• Oval-shaped area near center of retina
• Contains fovea (largest amount of cone cells)
• High-resolution, color vision
• Both structures essential for normal vision
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Retina and Macula
Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine.

Fundoscopy
• Fundus = back of eye opposite lens
• Includes retina, optic disc, macula
• “Fundoscopy” = visual examination of fundus
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Ignis/Wikipedia
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Retinitis Pigmentosa
• Inherited retinal disorder
• Visual loss usually begins in childhood
• Loss of photoreceptors (rods and cones)
• Night and peripheral vision lost progressively
• Constricted visual field
• No cure – most patients legal blind by age 40
Retinitis Pigmentosa
Fundoscopy
• Intraretinal pigmentation in a bone-spicule pattern

• Form in retina where photoreceptors are missing
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Christian Hamel
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Retinitis
• Retinal edema/necrosis
• Floaters, ↓ vision
• Classic cause: Cytomegalovirus (CMV)
• Usually in HIV/AIDS (low CD4 <50)
• Also in transplant patients on immunosuppression
Retinitis
Fundoscopy
• Retinal hemorrhages
• Whitish appearance to retina
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Wikipedia/Public Domain
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Diabetic Retinopathy
• Can cause blindness among diabetics
• Pericyte degeneration
• Cells that wrap capillaries
• Microaneurysms
• Rupture → hemorrhage
• Annual screening for prevention
Nonproliferative retinopathy
• Most common form of diabetic retinopathy (95%)

• “Background retinopathy”
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• Microaneurysms (earliest sign)

• “Dot-and-blot hemorrhages”
• Damaged capillary → leakage of fluid
• Cotton-wool spots
• Nerve infarctions
• Occlusion of precapillary arterioles
• Also seen in hypertension
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"Blausen gallery 2014“

Wikiversity Journal of Medicine.
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• Hard exudates/macular edema

• Macular swelling
• Yellow exudates of fatty lipids
• Can lead to blindness in diabetics
National Eye Institute, National Institutes of Health

Public Domain
Proliferative retinopathy
• Vessel proliferation (“proliferative retinopathy”)

• Retinal ischemia → new vessel growth
• “Neovascularization”
• Abnormal vessels: friable, grow on surface of retina
• Can lead to retinal detachment
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• Can cause macular edema → blindness
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• Treatments:
• Photocoagulation (laser → stops vessel growth)
• Vitrectomy (bleeding/debris)
• Anti-VEGF inhibitors (intravitreal injections; ranibizumab)
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Retinal Detachment
• Retina peels away from underlying layer
• Loss of connection to choroid → ischemia
• Photoreceptors (rods/cones) degenerate
• Vision loss (curtain drawn down)
• Surgical emergency
Retinal Detachment
Fundoscopy
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Eyerounds.org; Elliott Sohn, MD Used with Permission

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Retinal Detachment
• Posterior vitreous membrane detachment
• Often precedes retinal detachment
• Vitreous shrinks with age → can pull on retina
• May cause retinal holes/tears
• Floaters (black spots)
• Flashes of light
Retinal Detachment
Risk Factors
• Myopia (near-sightedness)
• Larger eyes; thinner retinas
• Prior eye surgery or trauma
• Proliferative diabetic retinopathy
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Retinal Vein Occlusion

• Central or branch of retinal vein
• Can lead to visual loss
• Branch retinal vein occlusion (BRVO)
• Compression of the branch vein by retinal arterioles
• Occurs at arteriovenous crossing points
• Associated with arteriosclerosis
• Sclerotic arterioles compress veins in an arteriovenous sheath
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• Central retinal vein occlusion (CRVO)
• Usually a primary thrombus disorder
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Fundoscopy
• Engorged retinal veins and hemorrhages
Ku C Yong/Wikipedia
Retinal Artery Occlusion
• Leads to formation of a “cherry red spot”
• Red circular area of macula surrounded by halo
• Also seen in Tay Sachs Disease (lysosomal storage disease)
• Commonly caused by carotid artery atherosclerosis
• Internal carotid → ophthalmic → retinal
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• Cardiac source (thrombus)
• Giant cell arteritis
Jonathan Trobe, M.D./Wikipedia

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Papilledema
• Optic disc swelling
• Due to ↑ intracranial pressure
• i.e. mass effect
• Usually bilateral
• Blurred margins optic disc on fundoscopy
Warfieldian/OptometrusPrime
Macula
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BruceBlaus/Wikipedia Mikael Häggström/Wikipedia

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Macular Degeneration
• Macula = central vision
• Degeneration → visual disruption
• Distortion (metamorphopsia)
• Loss of central vision (central scotomas)
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• Dry
• More common (80%)
• Slowly progressive symptoms
• Wet
• Less common (10-15%)
• Symptoms may develop rapidly (days/weeks)
Dry Macular Degeneration
• Bruch's membrane
• Innermost layer of the choroid
• Beneath retina
• Retinal pigment epithelium
• Retina layer beneath photoreceptors
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• Next to choroid (Bruch’s membrane)
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Dry Macular Degeneration

• Accumulation of drusen
• Yellow extracellular material
• Form between Bruch’s membrane and RPE
• Gradual ↓ in vision
• No specific treatment
• Vitamins and antioxidant supplements may prevent
Drusen
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Image courtesy of Ipoliker

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Wet Macular Degeneration

• Break in Bruch’s membrane
• Blood vessels form beneath retina
• Leakage/hemorrhage
• Can progress rapidly to vision loss
• Treatments:
• Laser therapy
• Anti-VEGF (ranibizumab)
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AfraTafreeh.

Retina and Macula

Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine.

• Intraretinal pigmentation in a bone-spicule pattern

• Most common form of diabetic retinopathy (95%)

• Microaneurysms (earliest sign)

"Blausen gallery 2014“

• Hard exudates/macular edema

National Eye Institute, National Institutes of Health

• Vessel proliferation (“proliferative retinopathy”)

Eyerounds.org; Elliott Sohn, MD Used with Permission

Retinal Vein Occlusion

Retinal Vein Occlusion

• Engorged retinal veins and hemorrhages

Jonathan Trobe, M.D./Wikipedia

BruceBlaus/Wikipedia Mikael Häggström/Wikipedia

National Eye Institute, National Institutes of Health

Dry Macular Degeneration

Image courtesy of Ipoliker

Wet Macular Degeneration

National Eye Institute, National Institutes of Health

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