The eye

PUPILLARY REACTIONS
● Pupillary size changes in response
to light and to the effort of focusing
on a near object
LIGHT REACTIONS
● Direct Light reflex
● Consensual light reflex

Coincident with the pupillary
constriction:
● CONVERGENCE
● ACCOMODATION

When the person is looking downward to the right = Right Inferior rectus muscle (CN III)
Left
Superior Oblique muscle (CN IV)
If one of these muscles is paralyzed, the eye will deviate from its normal
position in that direction of gaze and the yes will no longer appear conjugate
or parallel

TECHNIQUES of EXAMINATION
Important Areas of Examination
● Visual Acuity
● Visual Fields
● Conjunctiva and sclera
● Cornea, lens, and pupils
● Extraocular Movements
● Fundi, including: Optic disc and cup, retina, and retinal vessels

1. Visual Acuity
● Test the acuity of central vision using Snellen
eye chart
● Procedure:
1. Position the pt 20ft from the chart
2. Ask the pt to cover one eye with a card and
to read the smallest line of print possible
3. Identify the smallest line of print where the
patient can identify more than half the
letters
4. Record the visual acuity designated at the
side of this line.

2. VISUAL FIELDS by CONFRONTATION
● For detection of lesions in the anterior and posterior visual pathway
○ Causes of anterior pathway defects include glaucoma, optic neuropathy, optic neuritis,
and glioma. Posterior pathway defects include stroke and chiasmal tumors
● Studies recommend combining two tests to achieve the best results : the
static finger wiggle test and the kinetic red target test

Static Finger Wiggle Test
Procedure:
1. Position yourself about an arm’s length away
from the pt
2. Close one eye and have the pt cover the
opposite eye while staring at your open eye
3. Place your hands about 2 ft apart out of pt’s
view, roughly lateral to the patient’s ears.
4. While in this position, wiggle your fingers and
slowly bring your moving fingers forward into
the pt’s center of view
5. Ask the pt to tell you as soon as he or she sees
your finger movt

Kinetic Red Target Test.
Procedure:
1. Facing the pt, move a 5mm red topped pin
inward beyond the boundary of each quadrant
along a line bisecting the horizontal and vertical
meridians
2. Ask the pt when the pin first appears to be red.

Position and Alignment of the Eyes
● Stand in front of the pt & survey the eyes for position & alignment. If one or both eyes
seem to protrude, assess them from the above.
Eyebrows
● Inspect eyebrows, noting their fullness, hair distribution, and any scaliness of the
underlying skin
Eyelids
● Note the position of the lids in relation to the eyeballs. Inspect for: width of the palpebral
fissures, edema of the lids, color of the lids, lesions condition & direction of of the eyelashes,
and adequacy of eyelid closure
Lacrimal Apparatus
● Briefly inspect the regions of the lacrimal gland and lacrimal sac for swelling

3. CONJUNCTIVA and SCLERA
● Inspect the sclera & palpebral
conjunctiva for color (A yellow
sclera indicates jaundice)
● Note the vascular pattern against
the white scleral background.
● Look for nodules or swelling.
● If you need a fuller view of the
eye, rest your thumb & finger on
the bones of the cheek and
brow, & spread the lids.

4. CORNEA, LENS, IRIS, and PUPILS
Cornea and Lens. With oblique lighting, inspect the cornea for opacities. Note any
opacities in the lens that maybe visible through the pupil
Iris. The markings should be clearly defined. With light shining directly from the
temporal side, look for crescentic shadow on the medial side of the iris. Because the iris
is normally fairly flat & forms a relatively open angle with the cornea, this lighting casts
no shadow.

Pupils. In a dim light, inspect the size, shape, and symmetry of both pupils. Measure the
pupils with card showing black circles of varying sizes, shown below & test the light
reaction. Note if the pupils are large (>5mm), small (<3mm), or unequal.

The Light Reaction
Ask the pt to look into the distance, & shine a bright light obliquely into each
pupil in turn.
Both the distant gaze and the oblique lighting help to prevent a near reaction.
Look for:
● Direct reaction (pupillary constriction in the same eye)
● Consensual reaction (pupillary constriction in the opposite eye)
Always darken the room & use bright light before deciding that a light reaction
is abnormal or absent

The Near Reaction
If the reaction to light is impaired or questionable, test the near reaction in both
dim & normal light.
● Hold your finger or pencil about 10cm from the pt’s eye.
● Ask the pt to look alternately at it and into the distance directly behind it.
● Watch for pupillary constriction with near effort & convergence of the
eyes.

Extraocular Muscles
•Standing about 2 feet directly in front of the patient, shine a
light into the patient’s eyes and ask the patient to look at it.
Inspect the light reflection in the corneas. They should be
visible slightly nasal to the center of the pupils.

Light Settings
● Large aperture is used for a dilated pupil after administering mydriatic
drops.
● Medium aperture is the standard for a non-dilated pupil in a dark room.
● Small aperture is for a constricted pupil in a well-lit room.
Ophthalmoscopic Examination

● Red free-used to look closely at the vasculature.
● Blue- Used to look for corneal abrasions or ulcers with fluorescein dye.
● Slit- Used to look at contour abnormalities of the cornea, lens or retina.
● Grid- Used to approximate the relative distance between retinal lesions.

● Wash your hands.
● Introduce yourself to the patient and explain what you are going to do.
● Position the patient so that the ophthalmoscope is held directly at the
level of the patient’s eye.
● Turn on the ophthalmoscope and set the light to the correct aperture.
● Dim the lights.
● Instruct the patient to focus on an object straight ahead on the wall.
● To exam the patient’s RIGHT eye, hold the ophthalmoscope in your RIGHT
hand and use your RIGHT eye to look through the instrument.

● Place your left hand on the patient’s head and place your thumb on
their eyebrow.
● Place yourself about 15 inches away from the patient and at an angle
15° lateral to the patient’s line of vision. Shine the light beam on the
pupil and look for the orange glow in the pupil—the red reflex.

● Now place the thumb of your other hand across the patient’s eyebrow,
which steadies your examining hand. Keeping the light beam focused on
the red reflex, move in with the ophthalmoscope on the 15° angle toward
the pupil until you are very close to it, almost touching the patient’s
eyelashes and the thumb of your other hand.
- Try to keep both eyes open and relaxed, as if gazing into the distance, to help
minimize any fluctuating blurriness as your eyes attempt to accommodate. -
You may need to lower the brightness of the light beam to make the
examination more comfortable for the patient, avoid hippus (spasm of the
pupil), and improve your observations.

Steps for Examining the Optic Disc and the Retina
❖ The optic disc is a round,
yellow-orange to creamy pink
structure with a pink
neuroretinal rim and central
depression that often takes
practice to locate. The
ophthalmoscope magnifies
the normal disc and retina
about 15 times and the
normal iris about 4 times. The
optic disc actually measures
about 1.5 mm.

Steps for Examining the Optic Disc
● First, locate the optic disc. Look for the round yellowish-orange structure
follow a blood vessel centrally until it enters the disc. The vessel size will
help you. The vessel size becomes progressively larger at each branch
point as you approach the disc.

● Now, bring the optic disc into sharp focus by adjusting the lens of your
ophthalmoscope. If both you and the patient have no refractive errors,
the retina should be in focus at 0 diopters.
● If structures are blurred, rotate the lens disc until you find the sharpest
focus.
○ if the patient is myopic (nearsighted), rotate the lens disc counterclockwise to
the minus diopters.
○ in a hyperopic (farsighted) patient, move the disc clockwise to the plus
diopters.

Inspect the optic disc. Note the following features:
● The sharpness or clarity of the disc outline. The nasal portion of the
disc margin may be somewhat blurred, a normal finding.
● The color of the disc, normally yellowish orange to creamy pink. White or
pigmented crescents may ring the disc, a normal finding.
● The size of the central physiologic cup, if present. It is usually yellowish
white. The horizontal diameter is usually less than half the horizontal
diameter of the disc.
● The comparative symmetry of the eyes and findings in the fundi.

Steps for Examining the Retina
● Inspect the retina, including arteries and veins as they extend to the
periphery, arteriovenous crossings, the fovea, and the macula. Distinguish
arteries from veins based on the features listed below.
Arteries Veins
Color Light red Dark red
Sze Smaller (2/3 to 3/4 the
diameter of veins)
Larger
Light reflex Bright Inconspicuous or absent

● Follow the vessels peripherally in each direction, noting their relative sizes
and the character of the arteriovenous crossings.
● Identify any lesions of the surrounding retina and note their size, shape,
color, and distribution. Lesions of the retina can be measured in terms of
“disc diameters” from the optic disc.

● Inspect the fovea and surrounding
macula. Direct your light beam
laterally or ask the patient to look
directly into the light.
● Inspect the anterior structures. Look
for opacities in the vitreous or lens.
Rotate the lens disc progressively to
diopters of around +10 or +12, so you
can focus on the more anterior
structures in the eye.

OPACITIES OF THE CORNEA AND LENS
Corneal/lens opacity is a disorder where in there is a transparent structure in front of the eyeball. This occurs when the cornea becomes scarred. Thus,
stops the light from passing through the cornea to the retina thereby causing the cornea appear white or cloudy in appearance
A. CORNEAL ARCUS
-A thin grayish white arc or circle
not quite at the edge of the
cornea
- suggests possible
hyperlipoproteinemia in young
adults (African Americans)
-this occurs because the lipids
forms around the iris because
of excessive levels of fat in
blood

B. KAYSER-FLEISCHER RING
-A golden to red brown ring, sometimes
shading to green or blue, from copper
deposition in the periphery of the cornea
-Found in Wilson Disease
-rare autosomal recessive mutation of
the ATO7B gene on chromosome 13
causing abnormal copper
transport,(ceruloplasmin) reduced biliary
copper excretion, and abnormal
accumulation of copper in the liver and
tissues throughout the body.

C. CORNEAL SCAR
-A superficial grayish white opacity
in the cornea, secondary to an old
injury or to inflammation
- Do not confuse with the opaque
lens of a cataract, visible on a
deeper plane and only through the
pupil

D. PTERYGIUM
- A triangular thickening of the bulbar
conjunctiva that grows slowly across
the outer surface of the cornea,
usually from the nasal side
-Reddening may occur. May interfere
with vision as it encroaches on the
pupil

E. CATARACTS
-Opacitiy of the lenses visible
through the pupil. Risk factors are
older age, smoking, diabetes,
corticosteroid use.
Nuclear cataracts: looks gray when
seen by a flashlight. If the pupil is
widely dilated, the gray opacity is
surrounded by a black rim.

F. PERIPHERAL CATARACT
- Produces spokelike shadows that
point— gray against black, as seen
with a flashlight, or black against red
with an ophthalmoscope

PUPILLARY ABNORMALITES
A. UNEQUAL PUPILS (ANISOCORIA)- The light reaction in bright and dim light identifies the
abnormal pupil.
Constriction to light and near effort is mediated by parasympathetic pathways, and
pupillary dilatation by sympathetic pathways
When anisocoria is greater in bright light than in dim light, the larger pupil cannot constrict
properly
-causes: blunt trauma to the eye, open-angle glaucoma and impaired parasympathetic
innervation to the iris, as in tonic pupil and oculomotor nerve (CN III) paralysis.
When anisocoria is greater in dim light, the smaller pupil cannot dilate properly
- as in Horner syndrome, caused by an interruption of the sympathetic innervation.

A. UNEQUAL PUPILS (ANISOCORIA)
● Tonic Pupil (Adie Pupil)
● Oculomotor Nerve (CN III)
Paralysis
● Horner Syndrome
● Small, Irregular Pupils (Argyll
Robertson Pupils).

Tonic Pupil (Adie Pupil)
-affects the pupil of the eye and ANS
-the pupil of the affected eye is larger than the
unaffected eye and usually unilateral
-the affected pupil constricts SLOWLY (tonic) when
exposed to bright light
-These changes reflect parasympathetic
denervation.
- Slow accommodation causes blurred vision
- There is the abnormality to focus from distant to
near objects and vise versa

● Oculomotor Nerve (CN III)
Paralysis
-The pupil is large and fixed to
light and near effort. Ptosis of
the upper eyelid(due to
impaired CN III innervation of
the levator palpebrae muscle)
and lateral deviation of the
eye downward and outward
are almost always present.

Horner Syndrome
-The affected pupil is small, unilateral, reacts briskly to light and near effort, but dilates slowly, especially in dim light
These findings reflect the classic triad of Horner syndrome—miosis, ptosis and anhydrosis
due to a lesion in the sympathetic pathways anywhere
from the hypothalamus through the brachial plexus and cervical ganglia into the oculasympathetic fibers of the eye.
Causes include:
ipsilateral brainstem lesions, neck and chest tumors affecting the ipsilateral sympathetic ganglia and orbital trauma or
migraines
- In congenital Horner syndrome, the involved iris is lighter in color than its fellow (heterochromia).

Small, Irregular Pupils (Argyll
Robertson Pupils)
- The pupils are small, irregular and
usually bilateral. They constrict with
near vision and dilate with far vision (a
normal near reaction) but do not react
to light, seen in neurosyphilis and rarely
in diabetes

B. EQUAL PUPILS AND ONE BLIND EYE
-Unilateral blindness does not cause anisocoria as long as the sympathetic and
parasympathetic innervation to both irises is normal. A light directed into the seeing eye
produces a direct reaction in that eye and a consensual reaction in the blind eye. A light
directed into the blind eye, however, causes no response in either eye. Normally, light
that is directed in one eye produces constriction in both eyes.

DYSCONJUGATE GAZE
A. Developmental Disorders-caused by an imbalance in ocular muscle
tone
Esotropia- form of strabisbus that is characterize by an inward turn of
one or both eyes while exotropia palabas or the outward eye turn

COVER AND UNCOVER TEST
RIGHT MONOCULAR ESOTROPIA

COVER AND UNCOVER TEST
LEFT EXOTROPIA

DYSCONJUGATE GAZE
B. Disorders of Cranial Nerves- New onset of dysconjugate gaze in adults
usually results from cranial nerve injuries, lesions, or abnormalities from
causes such as trauma, multiple sclerosis, syphilis, and others

NORMAL VARIATIONS OF OPTIC DISC
● PHYSIOLOGIC CUP - small whitish depression in the optic disc. Grayish
spots are often seen at its base.
the entry point for the retinal vessels. Although sometimes absent, the cup is
usually visible either centrally or toward the temporal side of the disc

RINGS AND CRESCENTS- often seen around the optic disc. These are
developmental variations that appear as either white sclera, black retinal
pigment, or both, especially along the temporal border of the disc

Medullated Nerve Fibers- Appearing as irregular white patches with
feathered margins, they obscure the disc edge and retinal vessels. They have
no pathologic significance

ABNORMALITIES OF THE OPTIC DISC

Special Techniques
Eye Protrusion (Proptosis or Exophthalmos)
● Stand behind the seated patient and inspect from above.
● Draw the upper lids gently upward, then compare the protrusion of the
eyes and the relationship of the corneas to the lower lids.
● Exophthalmometer: measures the distance between the lateral angle of
the orbit and an imaginary line across the most anterior point of the
cornea
● Upper limits of normal: 20 to 22 mm
● When protrusion exceeds normal, further evaluation by ultrasound or
computerized tomography scan often follows.

Special Techniques
Nasolacrimal Duct Obstruction
● Ask the patient to look up.
● Press on the lower lid close to the medial canthus, just inside the rim of
the bony orbit; this compresses the lacrimal sac.
● Look for ﬂuid regurgitated out of the puncta into the eye.
● Avoid this test if the area is inﬂamed and tender.

Special Techniques
Everting the Upper Eyelid to Search for a Foreign Body
● Ask the patient to look down and relax the eyes. Be reassuring and use
gentle deliberate movements. Raise the upper eyelid slightly so that the
lashes protrude, then grasp the upper eyelashes and pull them gently
down and forward.

Special Techniques
● Place a small stick such as a tongue blade or an applicator at least 1 cm
above the lid margin at the upper border of the tarsal plate. Push down
on the tongue blade as you raise the edge of the lid, thus everting the
eyelid or turning it “inside out.” Do not press on the eyeball itself.

Special Techniques
● Secure the upper lashes against the eyebrow with your thumb and
inspect the palpebral conjunctiva. After your inspection, grasp the upper
eyelashes and pull them gently forward. Ask the patient to look up. The
eyelid will return to its normal position.

Special Techniques
Swinging Flashlight Test
● Clinical test for functional impairment of the optic nerves
● In dim light, note the size of the pupils.
● After asking the patient to gaze into the distance, swing the beam of a
penlight for 1 to 2 seconds ﬁrst into one pupil, then into the other.
● Normally, each illuminated eye constricts promptly. The opposite eye also
constricts consensually.

Special Techniques
Swinging Flashlight Test
● Afferent pupillary defect, sometimes termed as Marcus Gunn pupil

Red Spots and Streaks in the Fundi
Superficial Retinal Hemorrhages—Small, linear, flame-shaped, red streaks in the fundi, shaped by the superficial
bundles of nerve fibers that radiate from the optic disc. Sometimes the hemorrhages occur in clusters and look like a
larger hemorrhage but can be identified by the linear streaking at the edges. These hemorrhages are seen in severe
hypertension, papilledema, and occlusion of the retinal vein, among other conditions. An occasional superficial
hemorrhage has a white center consisting of fibrin. White-centered retinal hemorrhages have many causes.

Preretinal Hemorrhage—Develops when blood escapes into the potential space between the retina and vitreous. This
hemorrhage is typically larger than retinal hemorrhages. Because it is anterior to the retina, it obscures any underlying
retinal vessels. In an erect patient, red cells settle, creating a horizontal line of demarcation between plasma above and
cells below. Causes include a sudden increase in intracranial pressure.

Deep Retinal Hemorrhages—Small, rounded, slightly irregular red spots that are sometimes called dot or blot
hemorrhages. They occur in a deeper layer of the retina than flame-shaped hemorrhages. Diabetes is a common cause.

Microaneurysms—Tiny, round, red spots commonly seen in and around the macular area. They are minute dilatations
of very small retinal vessels; the vascular connections are too small to be seen with an ophthalmoscope. A hallmark of
diabetic retinopathy.

Neovascularization—Refers to the formation of new blood vessels. They are more numerous, more tortuous, and
narrower than other blood vessels in the area and form disorderly looking red arcades. A common feature of the
proliferative stage of diabetic retinopathy. The vessels may grow into the vitreous, where retinal detachment or
hemorrhage may cause loss of vision.

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