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Grand Rounds: Opthalmoscopic Diagnosis

nice opthalmo teaching website: http://www.kellogg.umich.edu/theeyeshaveit/index.html

Dr Barrett graduated from U of Rhode Island
If you were on a desert island what two pieces of diagnostic equipment would you bring?
opthalmoscope and stethoscope
today we focus on opthalmoscope
You can observe a lot just by watchin'. ==Yogi Berra

VALUE OF EXAM
can see anterior aspect of optic nerve
retina and its blood supply
red reflex tells about clear media of eye: cornea, anterior chamber, lens and vitreous

PHARM OF MYDRIATIC REAGENTS
sympathomimetic:
phenylephrine (neo synephrine)
is a catecholatmine selective alpha 1 agonist
short action
causes mydriasis without cycloplegia
fewer se's than with epi
use 2.5% avoid in hypertensive pts

or muscarinic blockers: atropine, tropicamide
block effects of acetylcholine (misosis)
causes mydriasis and cycloplegia (paralysis of ciliary muscle)
atropine .5% max effect 30-40 mins, duration 1-2 weeks
homatropine 2% max effect 20-40 mins, duration 2-3 days
scopolamine .25% max 20-45 mins, durat 4-7days (sea sickness patches)
phenylephrine 2.5% 20 mins 3 hours
tropicamide .5 ?? mins 3 hours derived from tropic acid, acts quickly, wears off quickly

CI FOR MYDRIATICS
narrow angle glaucoma
adverse rxns to ingredients
old intraocular lense implant (can dislodge)
aute angle closure attacks mb induced (rarely) by pupillary dilation,
usu sev hours after administration of drops, avoid by using weak agents, one drop of phenyleph
dosing: 1-2 drops at 15-20 mins before exam
pts with heavily pigmented irises may need larger doses
duke option = ?

ASSESSING IRIS SHADOW
who's more at risk for acute closed angle glaucoma?
has shadow with oblique light
mb avoid using mydriatic

OPTHALMOSCOPIC TECHNIQUE
do exam in dim room so pt can fix eyes on something but pupils are not constricted
take off all glasses
pt looks 5 degrees above horizon and 5 degrees medial
approach from a slightly temporal angle to avoid painful stim of macula
also helps locate optic disc first
start an arm's length away
locate red reflex
you have to get close to see well
knuckle on pts cheek is anchor on which to rotate
use arterioles to help find the disc if you don't land right on it

NORMAL EXAM
vasculature: veins & arteries in all four quadrans
arteries have light reflex
veins darker red
A:V ratio is .6-.8
AV crossings should be tihg because arterial walls are thin and transparent
cup to disc 1/3 to 1/2 (.5 of less)
pigmentation outside disc is normal variant
no red spots
no white spots
optic disc is yellow pinkish
macula is seen by pivoting laterally at end of exam
do last to minimize discomfort and miosis
mottled area of darker pigmentation

ABNORMAL EXAM FINDINGDS
diminished or absent red reflex: if missing is leukocoria (white pupil) dt cataract, retinoblastoma, corneal opacity, retinal detachment

AV nicking dt thickening of aa walls so they become opaque, seen as gap at AV crossing, dt hcronic and moderate HTN, sig stat relat btw degree of AV crossing changes and L ventricular hypertrophy. Later artery loks like it disappears completely at crossing. Earlier it is called tapering. AV ratio under .5

copper wire changes in pts with HTN and DM. when aa walls infiltrated with lipids and chol, also get more toruous, wider light reflex, bright coppery luster

silver wire arteries dt longstanding or severe HTN, narrows aa, wall becomes so opaque taht there is no light reflex, AV ratio is under .5 (usu over .8)

light colored spots: cotton wool spots, hard exudates, drusen

cotton wool spots are soft, indistinct, microinfartct in nerve layer of retina, lupus
hard exudates more circumscribed yellow accumulation deep to reitnal vessels, lipids
drusen are discrete round yellow deposits at Bruch's membrane, betw crhoroid and RPE (retinal pigment epithelium) early feature of age related macular degeneration, mb calcific

red spots are microaneurysms, blot and dot hemorhhages, flame and preretinal hemorrhages
microaneurisms are saccular outpouchings of retinal capillaries seen in DM
blot and dot in middle retinal layer, dog shart border, blot diffuse border, circular shape, assoc w/ DM
flame hem in superficial layer of retina and follow nerve fibers, seen in HTN and DM
preretinal hemorrhages: bleeding in most superficial aspet of retina, may have horizontal fluid level, dt tears in superficial retinal neovascularization, pt will have sig loss of vision, floaters
roth's spots are red spots with white cetners, assoc with subactue endocarditis, intracranila hemorrhage, leuckemias, are microemboli

dark spots are laser scars, retinal pigment epithelium hypertorphe, retinitis pigmentosa, melanomas, nevi
scarring post surgery is diffuse over most of eye
malignant melanoma: dark gray/black spots, mort rate not as high as skin melanoma
benign nevus: dark spot looks a lot like melanoma
retinitis pigmentose: degen dz of retina: night blindness, visual field constx, typical retinal appearance, mbdt vit A def, pale disc, intraretinal pigment, spicule

COMMON RETINAL PATHOLOGY

DIABETIC RETINOPATHY
**pearl: early in dz changes are in periphery
leading cause of blindness in pts 20-74
29% of pts with DM2 under 5 years
78% of DM pts over 15 years
very small capillaries are destroyed-->ischemia
-->neovascularization-->proliferative phase
abn new vessels grow from sfc of retina, do not relieve hypoxia
vision loss dt: scar tissue, scar contracture detaches retina, macular edema

non proliferative phase: (background retinopathy: normal visual acuity but also microaneurysms, small hemorrhages, venous beading, intraretainal microvascular abnormalities (IRMA, pattern doesn't look right), hard exudates (well circumscribed), divided into 4 stages: mild (microan & exudates), mod (extensive changes), sev (IRMA), very severe (has venous beading too)

proliferative: neovascularization around fundus (lots of fine aa, like hair), sudden onset of floaters (evidence of viteous hemorrhage, pt cannot see), always check acuity

DIABETIC MACULA EDEMA
hard to appreciate but if hard exudates around macula, think this
microaneurisms
hard exudates
loss of foveal light reflex

SCREENING RECOMMENDATIONS
within 5 years of 1st DM dx and annually after
over 3 at time of dx then annually

GLAUCOMA
chronic simple
aqueous humor can't leave via trabecular network into canal of Schlemm
trabecular network is what breaks down
neurotrans glutamate may damage optic cells
risks: Africans esp Carribean, older, DM, HTN, migraines, steroids, myopia, family hx
progressive cupping of optic nerve: cup to dis ration increases with loss of vision
change is meaningful so document ratios
ratios up to .7 can be normal variants
dx using tonometry and visual field changes
when cup takes over disk to .8 it's glaucoma
when vessels are pushed over to nasal aspect that's a bad sign
"nasalization"
other direction recorded as temporal

HYPERTENSIVE RETINOPATHY
turbulent blood flow damages intima-->atherosclerotic changes
1939 Ketih and Wagner came up with four stages:
I vascoconstrictive phase: narrowing arterioles
II sclerotic stage: copper wire changes, av nicking, scattered hemorrhages
III exudative stage: soft exudates, copper wire, sclerotic, flame hem, exudates, retinal edema
IV complications of sclerotic stage: same as 3 plus papilledema, silver wire changes, cotton wool spots, hard exudates, dot hemorrhages

if vision change:
ask about: eye pain, injection or photophobia
ddx: iritis, keratitis, acute closed angle glaucoma

MACULAR DEGENERATION
ARMD
dt age and lifestyle, nutritive choroid layer becomes inefficient
toxemia of the eye
buildup of lipfuscin, hyalin, deposits called drusen
leads to degen of RPE and choroid-->mod to sev vision loss
dx: use grid to see if lines bend, central visual acuity
types: dry and wet?
dry: 90%, drusen bodies around macula, causes gradual, mild to mod visual loss
scare them, diet, exercise, they can change course dt distal drusen
drusen: 4 types
hard, soft, basal lamina (these spread around retina more), cacified (glistening)
wet: to prevent, take lutein and zeaxanthine, no CIs for the nutrients that DrB knows of, he gives moderate doses

RETINAL DETACHMENT
risks: DM, myopia, ocular trauma
looks like shade pulled down
horseshoe tear can cause sig bleeding

OPTIC ATROPHY
disc is small and pale
etio: optic neuritis/MS, SOL, metabolic dz, ischemia, trauma, glaucoma
temporal arteritis-->ischemia and optic atrophy, artery mb painful

PAPILLEDEMA
sx: red enlarged disc, blurred disc margin, swelling without loss of cup but cup mb hard to recognize
clues for depth perception: slit view and diopters: if have to change focus to see
congestion of optic disc dt incr intraocular pressure
bilateral by definition
etio: tumor, hydrocephalus, malignant HTN, artery small compared to vein
visual acuity normal early, later transient impairment
diplopia from abducens deficit
visual fields testing will reveal incr blind spot (scotoma)

PRACTICE IS ESSENTIAL
diabetics and elderly at risk for vision loss
dt DM retinopathy, ARMD, cataracts, glaucoma
naturopathic docs should be screening

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