STEPTRACKERSPECIAL SENSES | PATHOLOGY + PHYSIOLOGY | HIGH-YIELD REVIEW

Retina & Vitreous

Vascular retinopathies, sudden painless vision loss, detachment, macular degeneration and the inherited retinal dystrophies.

FOCUS ON
Sudden painless monocular vision loss: CRAO (pale retina, cherry-red spot), CRVO ("blood and thunder"), retinal detachment (flashes, floaters, curtain), vitreous hemorrhage. Chronic: diabetic retinopathy (microaneurysms → neovascularization), hypertensive retinopathy (AV nicking, flame hemorrhages, papilledema in emergency), AMD (central loss, drusen; wet = VEGF).
DISORDER
MECHANISM · CAUSE
FUNDUS · FEATURES
CLUE · TREATMENT
Nonproliferative diabetic retinopathy
Hyperglycemia → pericyte loss, capillary leak, microaneurysms
Microaneurysms, dot-blot hemorrhages, hard exudates, macular edema
Annual dilated exam · glycemic and BP control
Proliferative diabetic retinopathy
Retinal ischemia → VEGF → fragile new vessels
Neovascularization → vitreous hemorrhage, tractional detachment, neovascular glaucoma
Anti-VEGF, panretinal laser
Hypertensive retinopathy
Arteriolosclerosis of retinal vessels
AV nicking, copper/silver wiring, flame hemorrhages, cotton-wool spots, exudates · emergency: papilledema
Mirrors renal and cerebral arteriolar damage
Central retinal artery occlusion
Embolus (carotid plaque, heart) or GCA
Sudden painless monocular loss; pale ischemic retina with cherry-red spot at the fovea; RAPD
Check ESR (giant cell arteritis) · stroke workup
Central retinal vein occlusion
Thrombosis at the lamina cribrosa: HTN, diabetes, glaucoma, hypercoagulable states
Sudden painless blur; diffuse hemorrhages, dilated tortuous veins, disc swelling ("blood and thunder")
Anti-VEGF for macular edema
Amaurosis fugax
Transient retinal emboli (carotid)
"Curtain" over one eye lasting minutes; Hollenhorst plaques (cholesterol)
TIA equivalent → carotid imaging
Retinal detachment
Retina separates from pigment epithelium: tear (myopia, trauma, cataract surgery), traction (diabetes), exudate
Flashes, new floaters, then a dark curtain; gray elevated retina
Emergency surgery, especially macula-on
Dry age-related macular degeneration
most common blindness in elderly (developed world)
Drusen + RPE atrophy (geographic atrophy); smoking, age, CFH variants
Gradual central vision loss; drusen
Antioxidant vitamins, stop smoking
Wet (neovascular) AMD
VEGF-driven choroidal neovascularization under the macula
Rapid central loss, metamorphopsia (straight lines bend on Amsler grid), subretinal hemorrhage
Intravitreal anti-VEGF (ranibizumab, aflibercept)
Retinitis pigmentosa
Inherited rod (then cone) photoreceptor degeneration; many genes
Night blindness first, tunnel vision; bone-spicule pigment, waxy disc, thin vessels
Abetalipoproteinemia, Refsum, Usher (with deafness)
Cherry-red spot without occlusion
Lipid storage in ganglion cells around the fovea
Tay-Sachs, Niemann-Pick (also CRAO)
Fovea has no ganglion cells → stays red
Retinopathy of prematurity
Hyperoxia then relative hypoxia → VEGF → abnormal vessels in immature retina
Premature infants on oxygen; detachment, blindness
Screening, laser, anti-VEGF

Mechanism — ischemia drives new vessels

Small-vessel injuryDiabetes, prematurity, vein occlusion
→
Retinal ischemia
→
HIF → VEGF
→
NeovascularizationBleeds, scars, pulls retina
→
Hemorrhage, detachment, glaucoma

Anti-VEGF injections and laser ablation of ischemic retina both remove the drive for new vessels.

Sudden painless vision loss

CAUSE
FUNDUS
CLUE
CRAO
Pale retina, cherry-red spot
Emboli, GCA
CRVO
Diffuse hemorrhages
HTN, hypercoagulable
Retinal detachment
Gray elevated retina
Flashes, floaters, curtain
Vitreous hemorrhage
No view of retina
Proliferative diabetic retinopathy
Ischemic optic neuropathy
Swollen pale disc
GCA (jaw claudication)
Wet AMD
Macular bleed
Elderly, distorted lines

How it's tested

COMMON CONFUSIONCRAO = pale retina with a cherry-red spot (no blood flow). CRVO = retina full of hemorrhages (blood can't leave).
THE TRAPAn older patient with sudden monocular blindness, headache and jaw pain has giant cell arteritis — start high-dose steroids before the temporal artery biopsy to save the other eye.
YOUR APPROACHSudden or gradual → painful or painless → central or peripheral loss → fundus picture → vascular, structural or degenerative cause → treatment.

If you see… think…

Diabetic with microaneurysms and hard exudates → nonproliferative retinopathy
New fragile vessels at the disc in a diabetic → proliferative retinopathy (VEGF)
AV nicking and copper wiring → hypertensive retinopathy
Sudden painless blindness, cherry-red spot → central retinal artery occlusion
"Blood and thunder" fundus → central retinal vein occlusion
Flashes, floaters, then a curtain over vision → retinal detachment
Elderly smoker, straight lines look wavy → wet AMD — anti-VEGF
Night blindness, tunnel vision, bone-spicule pigment → retinitis pigmentosa
Infant with cherry-red spot and developmental regression → Tay-Sachs
Premature infant on high oxygen, later retinal detachment → retinopathy of prematurity