The physiologic cup  is a small white depression devoid of nerve fiers in the center of the optic disc from whcih retinal vessels appear to emerge.

hyperopic pt's: optic cup may appear to be non-existant (since optic disc is smaller)

myopia pt's: optic cup may appear to be more prominent (since optic disc is larger)

Opthalmic artery -> central retinal artery -> 4 quadrants of retina

Retinal nerves -> central Retinal artery

photoreceptors -> choroidal circulation

Retinal arteries are 2/3rds the caliber of the retinal veins

arteries are lighter in color than the darker veins

a light reflex can be seen coming from the artery that is 1/4 the width of the column of blood

Compare and contrast the fundoscopic findings of chronic hypertension with those of acute accelerated hypertension. Which fundoscopic finding of acute accelerated hypertension is the most likely to be reversible?

INSERT TABLE on pg. 311

chronic moderate hypertension:

1. Complete AV crossing changes (AV nicking)

2. Changes in the arteriolar light reflex (copper and silver wiring)

3. Tortuosity of arterioles

4. Diffuse arteriolar narrowing (AV ratio reduced to 1:3; 1:4, or less)

acute accelarated hypertension:

Neuroretinitis

• cotton wool exudates- ischemic swellings in the superficial nerve layer***Most likely to tbe reversible w/in 4-8 weeks of treatment

• hard exudates- protein or lipid deposits in the inner retinal layers that result from the transudation (leaking) of serum across the blood-brain barrier

• flame-shaped hemorrhages - occur in the superficial nerve fiber layer of retina and appear to run in parallel to the orientation of the nerve fibers; originate from retinal arterioles

• dot and blot hemorrhages - occur int the deeper nerve fiber layer; originate from venules

• diffuse and focal arteriolar narrowing - retinal arteries undergo vasospasm and constrictas part of the autoregulatory response to the elevated pressure

• papilledema - most serious manifestation

flame-shaped hemorrhages - occur in the superficial nerve fiber layer of retina and appear to run in parallel to the orientation of the nerve fibers; originate from retinal arterioles

dot and blot hemorrhages - occur int the deeper nerve fiber layer; originate from venules

Background (non-proliferative) diabetic retinopathy: earliest retinal changes that occur in diabetes

1. Microaneurysms*** - dilated capillaries that appear as small smooth, sharp red dots.

• Can cause macular edema, that decreases visual acuity.

2. Hard exudates

3. Blot hemorrhages

4. Cotton wool spots

5. Venous beading (retinal veins resemble a string of beads) - predict proliferative diabetic retinopathy

Proliferative diabetic retinopathy - final/most severe stage of diabetic retinal disease

1. Neovascularizaiton - proliferation of new retinal vessels that leak fluid (edema) and red cells (hemorrhage). Can result in blindness secondary to scar formation.

2. Retinal detachment secondary to scarring and fibrosis

3. Neovascular glaucoma - when the vessels proliferate over the surface of the iris and into the anterior chamber to occlude the aqueous outflow tract

The macula receives its blood from the choroid.

However, if the retinal artery gets occluded (retinal artery occlusion), then the macula has a cherry red appearance agains tthe pale retinal background.

Retinal arterial occlusion

If central retinal artery occluded (CRAO), then expect a cherry red macula, hollenhorst plaque (cholesterol emboli at Y-shaped branch points), and sudden and painless unilateral vision

If a branch of the central artery occluded (BRAO), then expect sudden, painless, unilateral loss of visual field on the field opposite of the retinal occlusion

If central retinal vein (CRVO) or brach of central vein (BRVO) is occluded, then multiple hemorrhages, painless blurry vision, loss of vision, or loss of visual field. Risk factors include HTN and DM. May lead to neovascularization and acute glaucoma.

retinal detachment - unilateral separation of the retina into two layers -- RPE and the sensory retina. History of blunt head trauma, retinal scar formation, or vitreous detachment. floaters and flashing lights. Visual loss described as "curtain coming down"

can be assoc. with afferent pupillary defect and ligher colored "red reflex"

vitreous detachment - flash of lights, floaters, opacities that move with the patient's head (if in front of the lens) or move opp. to direction of head (if behind the lens), asteriod hyalosis

Papilledema

Mechanism: increased intracranial pressure that leads to retardation of axoplasmic flow at the level of the lamina cribrosa; (2) occlusion of capillaries and venules that leads to presence of hemorrhages and edema in between axons

bilateral, doesn't affect vision

fundoscopy: disc margins blurred; flame-shaped hemorrhages and soft exudates

Optic neuritis

unilateral, ocular pain with eye movement, loss of central vision, afferent pupillary defect

Anterior ischemic optic neuropathy (AION)

Mechanism: decreased blood flow through the posterior ciliary arteries (which supply the photoreceptors and macula), sudden, painless, monocular blindness. Assoc. with DM and HTN. 5% due to temporal arteritis.

3rd Nerve palsy - "down and out"

Pupil-sparing: secondary to microvasucular infarction secondary to DM or HTN

Pupil-affected: secondary to the PComm aneurysm in the circle of Willis

4th Nerve palsy - vertical diplopia; patients tilt head

secondary to DM, HTN, or tumor compression

6th Nerve palsy - horizontal diplopia

secondary to increased intracranial pressure

microvascular infarctions secondary to DM

"roth spots" - white-centered hemorrhages - center of flame-shaped hemorrhages or in round blot hemorrhages

secondary to bacterial endocarditis, DM, HTN, anemia, luekemia, and ocular trauma

hollenhorst plaques - glistening yellow spots that lodge at Y shaped branch poins w/in the retinal arterial circulation

lie totally within the arterial blood column, and represent cholesterol emboli originating from an ulcerating atheromatous plaque w/in the ipsilateral carotid artery or from an abnormal heart valve

Seeing flashing lights may be indicative of retinal detachment. Patient should also see floaters and describe vision loss as if a curtain comes down and obscures the vision in one eye.

It also can be indicative of vitreal detachment. They occur with eye movement; usually resolve in a few weeks.

1. Presence or suspicion of neurologic or cerebrovascular disease (where you would want to see the pupillary signs)

2. Lens implants following cataract surgery

3. Anterior uveitis

4. Pts with Narrow angle -- can precipitate acute glaucoma