- 2 disc diameters temporal to optic disc

- highest density or rods and cones

- contains foveola

Fovea

- darker than surrounding retina

- area of central vision

- receives its blood supply from the choroid

- susceptible to degeneration and resulting blindness

Macula

- contains only cones

- better visualized by approaching it from an angle

- 0.35 mm

Foveola

- during retinal artery occlusion, the macula appears in this way due to its alternate blood source

Cherry red

- extracellular by-products of retinal metabolism derived from RPE and deposited between RPE and Bruch's membrane

- two types can be present

Drusen

- small yellow, well demarcated deposits between RPE and Bruch's membrane

- can be found in people as young as 20's

- do not signify macular degeneration

Hard drusen

- larger than their counterpart and have indistinct borders

- presence indicates risk for age-related macular degen

- develop after 55 and are basis for mac degen

Soft drusen

Hard Drusen

- small yellow, well demarcated deposits

NO macular degeneration

Soft Drusen

- slightly larger w/ indistinct borders

Macular Degeneration

- incurable eye disease that is leading cause of blindness for people older than 55

- two basic types "wet" (20%) and "dry" (80%)

- accelerated by blue rays of the spectrum

(bright light, sunlight, reflection on ocean or desert)

Macular Degeneration

- choroidal neovascularization develops beneath the retina and macula

- vessels leak fluid, separate macula --> ischemia

- pt sees dark spot(s) in central vision, straight lines appear wavy

- if caught early, laser surgery can prevent extensive central vision loss

"Wet" Macular Degeneration

- preceeded by formation of soft drusen under macula

- thinning and drying of macula occurs

- central vision loss develops slowly w/ fluctuating vision

- visual loss is relentless and lasers can't help

"Dry" Macular Degeneration

- hypertension, smoking (second hand too), hereditary

Risk factors for "wet" macular degeneration

ingestion of

- fresh fruits, dark green, leafy vegetables

- vitamins C & E, beta-carotene, zinc oxide, cupric oxide

Delays or reduces severity of macular degeneration

- "white-centered" hemorrhages that occur in flame-shaped or round blot hemorrhages

(nerve fiber vs outer plexiform layers)

- central core is inflammatory cells or fibrous tissue

- associated with bacterial endocarditis

(and diabetes mellitus, hypertension, anemia, leukemia)

Roth spots

Roth Spot

- "white-centered" hemorrhages, central core of inflammatory or fibrous tissue

Bacterial endocarditis

Also:

diabetes mellitus, hypertension, anemia, leukemia, ocular trauma

- usually embolic in nature

- may involve CRAO or BRAO

- involved retina is pale

- transient monocular blindness (amaurosis fugax) if it is transient

- confers a higher risk for subsequent embolic stroke

Retinal arterial occlusions

- may be visible as glistening yellow spots that lodge at the Y shaped branch points within the retinal arteries

- lie totally within arterial blood column and represent cholesterol emboli originating from athermatous plaque in the ipsilateral carotid artery or heart valve

- 10-fold increase in stroke over 3.4 yrs

Hollenhorst plaques

- results in sudden, painless unilateral loss of vision

Central retinal artery occlusion (CRAO)

- results in sudden, painless unilateral loss of visual field opposite it

- superior branch --> inferior visual field

branch of central retinal artery occlusion (BRAO)

- leads to multiple hemorrhages in involved quadrants of retina that is drained

- pt's report sudden or gradual onset of painless blurry vision, loss of vision, or loss of visual field

- common in elderly, particularly hypertenisve/diabetic

- disc is edematous, flame-shapd hemorrhages and cotton wool spots appear

- be aware of neovascularization or acute glaucoma

Retinal vein occlusion (CRVO or BRVO)

Hollenhorst Plaque

- glistening yellow spots lodged at Y in retinal arteries

- cholesterol via carotids or heart valves

Increased risk of stroke

- significant increase in the viscosity of the blood that is seen in Waldenstrom's macroglobulinemia

- leads to stasis of blood in the smaller circulations

- retinal veins appear like links of sausage

Hyperviscosity syndrome

- results from separation of retina into two layers

(RPE and sensory retina)

Causes

- blunt head trauma, traction from retinal scar formation, or tearing from a vitreous detachment

- Pt complains of floaters and flashing lights, then curtain

Retinal detachment

- if retinal detachment involves fovea, pt will have defective visual acuity and this

Afferent pupillary defect

- Pt's with retinal detachments may have this on exam

lighter colored "red reflex"

- gel that fills posterior portion of the eye behind the lens

- major portion of eye's volume

- with age, it liquefies

- more firmly attached to optic nerve than retina

Vitreous

- opacities in front of the lens and opacities behind the lens move this way following eye movement

In front : With movement

Behind: Opposite movement

- extreme nearsightedness

- previous cataract surgery

- family history

- trauma

- diabetes

- vitreous detachment

Risk factors for retinal detachment

- consists of highly refractile calcium-lipid complexes that swirl through the vitreous with movement

- no visual impairment

- seen in men of middle age

Asteroid hyalosis