Optho path Flashcards
Flame hemorrhages
Located in Nerve fiber layer (most superficial hemorrhage)
- Erythrocytes track along axons
Blot and dot hemorrhages
Located deeper in retina where axons perpendicular to RPE/Bruch’s membrane
Scaphoid (boat-shaped) hemorrhages
Hemorrhagic detachment of Inner Limiting membrane
Subhyaloid hemorrhage
Blood-retinal barrier
Inner retina: endothelial tight junctions
RPE apical tight junctions between layers
Outer retina= leaky fenestrated choriocapillaries
Hard exudates
Pools of proteinaceous fluid in outer plexiform layer (btwn inner and outer layer= watershed area)
Macular star figure= hard exudates in radial perifoveal Henle fibers
Cotton wool spots
“soft exudates”, really focal infarctions of NFL (neurofiber layer)
- Marker for ischemia, systemic disease
- Blockage of axoplasmic flow
Focally ballooned axon–> cytoid body (resembles nucleus)
- Formed when ischemic
Central retinal artery occlusion
“Mini-stroke” of retina
- Normally transparent to allow light to reach rods and cones
- Infarction of retinal cells–> opacification
Window of transparent retina shows underlying choroid= “cherry red spot”
Causes:
- Atherosclerosis of CRA at/posterior to lamina cribosa
- Emboli: cholesterol, platelet fibrin (carotids), Calficific, tumor (atrial myxoma in young patients
- Vasculitis (GCA, collagen vascular disease)
Central retinal vein occlusion
Massive intraocular hemorrhage= “squashed tomato sign”
Chronic HTN on retinal arterioles
Retinal arteriosclerosis
- Fibrosis due to HTN
Normal: Healthy retinal vessels are transparent
- Can only see BLOOD in vessels
Fibrosis–> opacifies vessel wall–> obscured blood column
- “copper wire” arteriolarsclerosis
In Malignant HTN–> Spasm of vessel walls
- Leads to necrosis
- Vascular incompetence
- Optic disc edema
Background diabetic retinopathy
Hard, soft exudates
Hemorrhages
Cotton wool spots= ischemia–> progresses to proliferative diabetic retinopathy
Early stages: capillary changes
- Pericytes are lost preferentially in early stages of diabetic retinopathy
- Pericytes have inhibitory effect on proliferation of endothelial cells
Later stages–> capillary nonperfusion
- Retinal ischemia–> VEGF upregulation
- Stimulates proliferation of new vessels
Proliferative diabetic retinopathy
Vitreoretinal neovascularization
- Leads to retinal detachment
- New vessels cannot invade vitreous gel
- Grow on back surface of vitreous when it detaches
Vessels–> fibrosis–> pulls retina anteriorly (with vitreous)–> detachment (traction)
Can see adhesions blocking aqueous drainage (VEGF–> neovascularization–> adhesions–> neovascular glaucoma)
Mucormycosis
Mold infection beginning in paranasal sinuses
- Invades eye
- ocular proptosis
- Eye no longer moves, must be removed
- See vascular infiltration by fungus
Retinal detachment
Outer 1/3 separated from choriocapilaris (loses nutrients)
- Leads to death of rods and cones if not promptly treated
- Can’t regenerate
Rhegmatogenous Retinal Detachment
Horseshoe tear–> vitroretinal traction–> detachment
- See flashes of light + floaters (BAD sign)
- Can develop retinal hole
- Increased risk in myopes (eye outgrows vitreous)
Exudative retinal detachment : seen in malignant melanoma
Coats disease
Abnormal retinal vessels–> leak
- Secondary retina detachment
- See cholesterol crystals and protein in sub-retinal space
Cataract
Opacification or optical dysfunction of crystalline lens
Four types:
- Normal development= nuclear sclerosis
- Lens adds new layers in periphery
- Cells in center eventually dehydrate–> accumulate yellow-brown pigment
Surgical correction: patients complain of “blue vision”
Ectopia lentis
Spontaneous dislocation of lens
Occurs in heritable connective tissue disease
Ex: Marfan’s= fibrillin-1 defect
Glaucoma
Risk factor:
- Elevation of IOP (intra-ocular pressure)
- Damages nerve as it enters globe through lamina cribosa
Excess aqueous humor produced by ciliary body
Blockage of drainage through trabecular meshwork–> Schlemm’s canal (most common type
Aqueous veins of asher= dilated veins on surface of eyeball draining excess aqueous humor
Can cause death of retinal ganglion cells
- Axonal atrophy
- Ganglion cells DON’T regenerate
- Surgery to protect/preserve what’s there
Mueller’s cells= span thickness of retina, only thing left once ganglion cells die
See cupping of optic nerve=
- Glaucomatous optic atrophy (bean pot)
Macula lutea (yellow spot/pigment on retina) - Protects against damaging blue light wave
Uveal Malignant Melanoma
Most common ocular tumor in Caucasians (US/European)
- 1,800 new cases yearly
- May be pigmented
Almond shape–> rupture through Bruch’s membrane–> mushroom shaped tumor
- *50% mortality
- Liver mets seen in 90%
Prognosis:
- Epithelioid cells present: 63% mortality in 15 years
- No epithelioid cells: 28% in 15 years
Retinoblastoma
Leukocoria= white pupil
- Classical manifestation
- Can also have physiological leukocoria (white pupil due to looking 15 degree angle in photo–> see nerve)
US mortality= almost 0%
Worldwide= 50% (poor/no access to care)
Resembles mini brain tumor
- Arises from inner retinal layer (endophytic)
- Arises from outer retinal layer (exophytic)–> detachment (can be confused with Coate’s disease
See enhanced mitotic activity
- Basophilic cells
- Cells outgrow blood supply–> die–> eosinophilic
- Apoptotic cells, scanty cytoplasm
- may see seondary calcification
Tumor= Blue Calcium= Purple Necrosis= pink
Photoreceptor Differentiation= Rosettes, Fleurettes
- Flexner-Wintersteiner rosettes
- Neoplastic rods and cones
- Tumor entirely composed of fleurettes= precursor to retinoblastoma
If tumor gets behind lamina cribosa= CHEMO
- Resect as much of nerve as possible
- Germline cases= bilateral retinoblastoma (occurs earlier)
Orbital lesions
Space occupying
- Cause ocular proptosis/exopthalmos
Direction of displacement= indicates location of orbital lesions
Ex. Mucocele (ethmoid)- eye lateral
Maxillary sinus- eye up
Enopthalmos
Due to blow-out fracture
- Eye sinks into space below
- Can also be caused by metastatic scirrhous breast carcinoma
Exopthalmos
Most common cause= Grave’s disease
- Patchy chronic inflammation sparing tendon, fat
- Enlarged EOMs–> proptosis
Cavernous Hemangioma
Benign tumor
Can cause proptosis
