Eye
Ophthalmoscope
Normal-
+6 diopters to see the cornea
0 diopters to see the disc
go
more red to go deeper
if
the doctor wears glasses:
focus
on an object 20” away and bring it into sharp focus
this
is the diopter to start the examination of the cornea with,
record
your settings in your records, don’t adjust
Snellen
Chart
20
feet away- due to physics, this is equal to infinity for human optics
Children
3 and up can use an E chart
Children
less than 3, cover one eye and check their reaction [even infants]
Cover one eye at a time
If the child seems consistently displeased when one
eye is covered
But not the other
There is a difference in vision between the eyes.
The child will prefer the better eye to be
uncovered.
[see
strabismus]
numerator
is the distance of the patient from the chart
denominator
is the line read last, the distance the ‘norm’ could read that line from
20/200
is the worst on the Snellen
20/100
means the patient must stand at 20 feet to see what someone else can see from
100 feet
Snellen
chart must be used for sports and classrooms as distance vision is required.
recording
the Snellen Chart
record
the eyes OS- left eye OD- right eye OS- both eyes
be
sure to test with and without glasses
Method
I- the last line read with 50% accuracy
is the recorded line
Method
II – the entire line must be correct with the number of correct answers in the
next line
or
record the line with the most correct answers with the number of errors
Ex: 20/20 +1
the patient can read all of the 20/20 line and 1 more on the 20/15 line
Ex: 20/20 -1
the patient read all of the 20/20 line but missed one
20/20
is actually the lower end of normal vision
young
adults typically have 20/12 or 20/15
concurrent
referral is made when:
vision
is less than 20/20
acuity
is 20/40 or worse, especially in both eyes
[due
to compensation, the patient may not have realized there is a problem if only
one eye is affected]
acuity
difference of 2 lines or more between the eyes
even if the acuity is better than
20/40 in one or both eyes
complaints
that near vision is difficult but distance vision is OK
patients
with low vision
myopia: near-sighted [I can see MY book]
the
eye is too long
correction
is made with biconcave lens to push the focal point back onto the fundus
hyperopia: far-sighted
[hyper = greater]
the
eye is too short and the focal point has overshot the fundus
correction
biconvex lens
presbyopia: steady loss of accommodative power
begins
in childhood and progresses throughout life
near
vision is difficult as the lens is hardening and will not change adequately
pinhole
occluder- removes divergent rays
if
vision is still blurred- indicative of pathology not refractive error
squint
or strabismus- common condition in children
easily
treated by age three
difficult
to treat at age six
the
eyes are not aligned
their
optic axes cannot be directed to the same object
can
be unilateral, alternating, constant or periodic
due
to reduced visual acuity due to pathology or refractive problems, unequal
ocular muscle tone, oculomotor nerve lesion, paralysis, lesions
These
cause diplopia [double vision]
Amblyopia
then occurs
A reduced visual acuity as the brain
suppresses the information from the deviating eye
Binocular vision will not be present as one set of
neurologic information is ignored permanently.
This is cortical, not ocular, at this point. They will still perceive color and light from that eye but not
form or shape.
Retinal
vascular changes
Seen
in hypertensive, collagen disease, anemia, diabetes, arterial or venous
occlusion, etc.
All
show similar changes: irregularity or dilation of vessels, hemorrhages,
exudates, etc.
Capillary
closure
Abrupt
stoppage in a large area: the retina
becomes opaque with cloudy swelling and dies
Slow gradual decrease in perfusion, typically due to venous blockage, retinal collateral vessels are created to carry the flow. Think varicose veins.
Deep
capillaries [focal] = microaneurysms
Focal
lack of perfusion of deep capillaries in the vascular layers, they it looks
like petechiae
Focal
lack of perfusion of superficial capillaries- cotton wool exudates
The lack of perfusion occurs in the nerve fiber
layer
There is a decrease in the
axoplasmic flow in the axons
This is a serious sign if it
accompanies papilledema and macular edema
But can occur with hypertension of
preeclampsia.
If this is an isolated sign, just
monitor, resolves in app. 3 months.
Many
sites of poor perfusion [very sick retina] = neovascularization
Think really poor blood flow in the legs with
numerous spider veins trying to pick up the load.
These vessels are highly permeable and can lead to
retinal edema, exudates & hge.
They make loops and are irregular
Plasma
leaks in the deep layers of the retina = hard exudates
Can cause loss of sight if they are
in the macula
Severe
capillary damage
Deeper capillaries = dot
and blot hemorrhages
Superficial capillaries
= flame hemorrhages
Endothelial
incompetence occurs when there is damage within the layers of the retina
-see
microaneurysms and the exudates
laceration
of the eye: firm compress and transport
immediately
don’t try to look, orbital contents
may leak increasing the damage
foreign
particle: discussion
Red
eye
conjunctivitis:
inflammation of the bulbar or palpebral conjunctiva
allergic,
viral, bacterial
always
palpate the preauricular lymph node- swollen and tender in viral
bacterial-
highly contagious
itching
: allergy
acute
focal stabbing : foreign object
deep,
intense aching: glaucoma, uveitis, optic neuritis, referred pain from sinus,
vascular or tension headaches
burning,
irritation, sand - superficial irritation of the lids, conjunctiva, cornea,
sclera
photophobia:
not reliable but may signal intraocular [uveitis] or extraocular ds [ keratitis
or conjunctivitis]
fine,
straight, deep red vessels radiating from the limbus and are immobile when the
conjunctive is moved – uveitis and glaucoma
dark
red injection, tortuous vessels that move with the conjunctiva- viral,
bacterial or allergic
ANY
blurring or change in vision must be referred to specialist for examination -
possible
uveitis that can cause permanent scarring and damage to the eye
pink
eye: highly contagious
conjunctivitis, itching, pin k with
swelling, no pain unless keratitis [adenovirus]
pinhole will improve vision if the
acuity is affected
discharge: depends on etiology
warm compresses
red
eye: closed angle glaucoma
steamy cornea decreased acuity,
middilated unreactive pupil
aggravated by dark may have
sympathetic reactions [vomiting, etc.]
subconjunctival
hemorrhage: insignificant if not
related to trauma
no
change in acuity. Examine if occurs
repeatedly [due to blood disorder- clotting/dyscrasia]
eyelids
-
styes
chalazions
basal
cell carcinoma -DDx: styes and chalazions
look for dimple or ulceration, pearly, firm
appearance
small, gray nodule near the lid
margin with firm borders
possibly stalked or crusty
slow growing
becomes ulcerated with rolled edges and indurated
base
squamous-
more malignant but less frequent
looks like basal cell but not
symmetrical
goes to pre-auricular or
submaxillary lymph nodes
herpes
zoster opthalmia:
if the lower lid is involved then the pain pattern is that of the 2nd division
of the Trigeminal nerve
blisters infect the eye- keratitis, lid edema,
pseudoptosis, loss of corneal reflex ciliary and conjunctival injection,
corneal infiltration, pain and photophobia
burning pain, tender regional lymph nodes
Note: if a blister appears on the tip of the nose, the infection will
go into the eye
xanthelasma
papilledema
swelling
of the optic disc due to intracranial pressure, systemic diseases or ocular ds.
Occurs
slowly over weeks to months unless due to trauma
Vision
changes: 10-30 second attacks of hazy
vision or blindness with intact visual fields and acuity
Persistent
papilledema leads to optic atrophy
[optic
atrophy has contraction of visual fields, loss of vision and eventual
blindness.]
reddened,
swollen disc [requiring fewer red diopters]
decrease
in size of optic cup
eventual
blurring of margins
hemorrhages
around the disc
engorged
tortuous vessels around disc
due
to the changes in physiology, the following are likely to also be seen:
cotton wool exudates, hemorrhages,
and retinal edema
intracranial
causes: tumors, meningitis, brain
abscess or hemorrhage ocular: central retinal venous occlusion, extra-orbital
tumors
systemic:
leukemia, syphillis, congenital heart disease, severe anemia, tuberculosis
hypertension
optic
atrophy
terminal
result of papilledema or any disease affecting the optic nerve, chiasm or tract
due
to alcohol, syphilis, vascular ischemia [arteriosclerosis, emboli, etc.]
pale
with eventual blurring of margins
scoots
and complete blindness
Blepharitis
- infection
Redness,
edema and thickening of the margins of the eyelids- meibomian glands
Accompanied
by crusting, itching, photophobia, conjunctivitis and burning
Soften
crusting with warm, damp cloth
Can
be due to staph, seborrhea or allergies
If recurrent,
may cause a loss of eye lashes and scarring
Sty
–hordeolum
Bacterial
infection of meibomian glands, usually staph
Small red mass, possibly with yellow
head, on the lid margin or inside of eyelid
Rather painful, red, swollen and
tender lid
Spontaneous resolution
Recurs frequently
Warm damp cloths may bring it to a
head faster
Chalazion
Meibomian
gland inflames then enlarges due to granulomatous changes
Initially it looks like a hordeolum but after the
redness and pain resolves, a firm mass remains.
The skin moves easily over the mass and is not fixed
as it would be with a tumor.
Usually resolve in several months.
Hot damp compresses may speed resolution.
May require surgical removal if it does not resolve
in 6 week.
cellulitis
- infection
bacterial
infection of the skin requiring immediate intervention
conjunctivitis
-
look
at distribution and appearance
subconjunctival,
non-painful hge - few drops of blood under conjunctiva
occur spontaneously or secondary to
trauma
resolve 2-3 weeks
if recur repeatedly, R/O bleeding
disorder
if occur with pain, R/O conjunctivitis
conjunctivitis
- bacterial or viral
Bacterial
- diffuse redness and irritation, burning or relatively asymptotic
purulent discharge with crustiness
of lid margins, stuck together in AM
Viral
- same without purulent discharge
Can
be due to gonococcus, chlamydia, trachoma [type of chlamydia infection], herpes
simplex [typically with dendritic ulcer on cornea], fungal infection, uveitis
uvea
–the pigmented layers of the eye : choroid [thick vascular layers that feed
photoreceptors], ciliary body and iris
uveitis
- due to infection or allergy, commonly cause is unknown and the number of
possible etiologies is numerous
ant. uveitis:
iritis or iridocyclitis – deep pain and photophobia
if the iris is inflamed
the muscles are in spasm and the iris is small and irregular with induced
myopia [decreased vision] as the ciliary body [muscles] that move the lens are
inflamed too. Light will increase the
spasm and pain.
The limbus is injected- almost blue
red- these vessels are episcleral and not the conjunctival [more superficial]
and do not move when the conjunctiva is moved.
Diagnosis: need slit lamp
Post. Uveitis or choroiditis: macula
[significant visual loss] or choroid [may be asymptomatic]
Can accompany or cause angle close glaucoma
anterior
uveitis vs. posterior uveitis
anterior
- affects ciliary body ( ciliary muscles change shape of lens) [cyclitis]
and/or
iris [iritis] - inflammation can cause adhesions
ocular pain, photophobia, possible decrease
in vision, injection around corneal limbus
pupil is typically in spasm, eye is soft
from decreased production of aqueous humor
cornea not hazy as in acute closed angle
glaucoma, hazy vision from turbidity
dilation of pupil a must to prevent
adhesions with iris permanently stuck to the lens which further can obstruct
aqueous humor entry into ant. Chamber Þ closed angle glaucoma
posterior
- affects choroid [vascular layers of retina]
Retinal
Vessel Occlusions
Frequently
associated with hypertension
CRAO-
central retinal artery occlusion
emergency
ischemia
of the posterior fundus
Retinal
survival time is 100 minutes
Sudden
painless unilateral loss of vision reduced to hand movements
No
improvement with pinhole occluder
Cherry
red spot seen at the fovea in the macula
Fundus
is pale
Veins
are narrow
Pupil
is semidilated with poor response on direct but brisk response on indirect
Arterioles
are very thin
Causes: migraine, nicotine, oral contraceptives,
cranial arteritis, atherosclerotic plaques, endocarditis, cranial arteritis
An
embolus occurs at the cribiform plate leading to ischemic infarction of the
retina.
Have
the patient breathe into a paper bag to increase the carbon dioxide levels to
increase vasodilatation and preserve the retinal tissue.
CRVO
– central retinal venous occlusion
Non-emergent
The
optic disc is red and swollen with hemorrhages of the disc and the periphery
Dilation
and tortuosity of the venous system of the fundus.
The
fundus is red and edematous.
Painless
vision loss over several hours.
The
eye will create collateral circulation but these vessels leak causing the
hemorrhages.
Further,
the fluid leakage weakens the retina and the increase in the amount of vasculature
increases the intraocular pressure.
Management
is laser to reduce the number of vessels
Etiology: arteriosclerosis, glaucoma, diabetes
mellitus, elevated hematocrit, idiopathic.
Retinoblastoma
Malignant
tumor of embryonic tissue
Uni-
or bilateral
Diagnosis
is usually between 6 to 24 months
Yellow-white
to gray colored ‘red light’ reflex
And/or
strabismus is noted
Removal
of the eye is the only treatment known
Metastasis
to bone
Malignant
melanona
Most
frequent tumor of the uvea
Usually
unilateral
Mortality
50% after 10 years
Uneven
yellow-gray to gray-brown color with a mushroom or irregular shape
Lobulated
border with its own blood supply
Due
to elevation, look for a shadow or use slit to see bent light
Metastasizes
to liver
Benign
nevus
DDx
malignant melanoma
Usually
small, only 5 disc diameters big
[measure
with target lens]
borders
are smooth and feathery
slate
gray to black
rarely
enlarges
metastatic
carcinoma from breast
often
bilateral
indicates
widespread metastasis
dome-shaped
elevation without pigment derangement
use
slit lens
Eye
cornea
- 1 mm thick, tough
layers - 1.
epithelium [damage affects the water balance in collagen meshwork -
clouding], 2.
Bowman’s membrane -[hypothyroidism - calcium deposits, iron form foreign
bodies]
3. corneal stroma [scarring] [transparent because of alignment of
collagen fibers],
4. Descemet’s membrane [Wilson’s
disease - copper, gold poisoning, silver exposure]
5. endothelium
eye
has three chambers -
1.
Anterior - behind the cornea and in front of the iris - aqueous humor
2.
Posterior - between the iris and lens - aqueous humor
aqueous exits eye at Canal of Schlemm at angle between cornea
and iris
it communicates with the
venous system
ciliary body make aqueous humor and contains ciliary muscles
that move the lens via the
Zonule fibers which are ligamentous
3.
Vitreous chamber - behind the lens
not produced by the
mature eye
may be replaced by
saline solution or aqueous humor
Accommodation
Pupil
constrictor muscles - parasympathetic of CN 3 [oculomotor].
Pupil
dilator muscles - sympathetic of superior cervical ganglion
Ciliary
muscles act in same way to change focus
retina
is a layer of the eye - feed by the central retinal artery
if detached from next layer, which is
epithelium that adheres to the choroid, hypoxia occurs as the choroid feeds the photoreceptors by
diffusion
uvea
-choroid [thick vascular layers that feed photoreceptors], ciliary body and
iris
Hypertension
affects
arterioles
severity
of damage depends partly on the level of hypertension
and partly on how long the hypertension
has been present
and partly on the patient [some are
more prone to damage]
acute hypertension - relates to the amount of hypertension and occur
right away
changes relate to focal increases in muscle tone compensating for the
increased pressure
arterioles - tortuous and
narrow
pressure changes - ischemia
and vascular permeability
- swelling of optic axons - Þ cotton wool exudates
-
seepage of blood cells Þ flame hges
which outline the optic fibers
[flame
shaped because superficial layers]
High
blood pressure
Þ
Arteriolar narrowingÞ arteriolar narrowing with
local areas of
constrictionÞ hemorrhages and exudatesÞ papilledema
[scattered throughout]
chronic hypertension -
changes based on long term [years] of hypertension
arteriole changes [middle layer
thickens] - at first the light reflection broadens,
as thickening continues, pressure is put on the veins at AV
crossings causing nicking.
Further thickening of the
middle layer Þ silver Þ copper wire
Long
term high
blood pressureÞ broadened arteriolar light
reflexÞ A-V nickingÞ copper wireÞ silver wire
Diabetic retinopathy - diabetes affects veins
note:
venules lie deep within the retinal layers whereas the arterioles are in the
superficial layers of the fovea
veins dilateÞ pressure against arteriolesÞ AV nicking
ß ß
weakness of capillary wall
ß ß ß
ß ß microaneurysms, dot and blot hges
ß ß [roundish hges as deep within layers of
retina]
ß ß [hges scattered throughout fovea]
ß ß
ß hard exudates [products of cell dmg]
ß [shape due to depth within layers of tissue]
ß
ß
neovascularization
[can extend into vitreous humor and bleed]
Papilledema
increased
intracranial pressure
ß
venous obstruction at the optic disc
[loss of venous pulse at disc]
ß
dilation of
veins and capillaries [RED]
ß ß
hges edema
[near disc] ß
elevation
of disc
A
single hge or exudate is a strong sign of any disc pathology
disc
elevation and small cup size are not reliable signs of papilledema
they are significant if: it is an asymmetrical finding
1. signs of papilledema
[inflammation of
optic disc] Þ
DDx: papilledema /
papillitis
ß ß
ß ß
early
on severe Ú
vision acuity
usually
unaffected usually with
severe
deep pn
2. patient complains of severe pain pn behind eye,
marked loss of vision
no
signs of papilledema, fundus looks normal = optic neuritis
optic
neuritis - inflammation in the optic nerve but behind the disc, not visible
RETINAL DETACHMENT
fluid
collects betw the retinal and the pigment separating the layers
causes
interruption of diffusion from the choroid causing deoxygenation of the
photoreceptive layer Þ bizarre stimulation
partial
detachment Þ cc floaters, flashes of
light, curtain partially drawn
damage
can be irreversible - must be repaired within several days
myopics,
post-trauma and post-cataract surgery people are predisposed
Macular
degeneration
Several
types
Age-related
[older] and Mendelian dominant [younger people]
Age
related: most common cause of legal
blindness [less than 20/200] in over 65 yrs.
Almost
30% of those betw. 75 and 85
Lipofuscin
in retinal pigment in the macula
Appear
as yellow /white drusen
If
retina thins [dry macular degeneration]
If
new vessels grow they bleed and is called ‘wet’ causing visual distortion
Straight lines look wavy and
scotomas may appear
Current
research says increase bioflavinoids, etc.
Disease
of central vision and peripheral vision will remain
Mendelian
dominant type
Disease
of central vision and peripheral vision will remain
Early-
looks like egg yolk in the macula [vision good to normal]
Later- yolk [cyst] bursts and the macula looks like scramble eggs with burnt areas [scarring from heavy pigment deposits]