Jarvis Chapter 14

Front 1

Snellen Eye Chart

Back 1

The Snellen alphabet chart is the most commonly used and accurate measure of visual acuity. It has lines of letters arranged in decreasing size.

Front 2

Place the Snellen alphabet chart in a well-lit spot at eye level. Position the person on a mark exactly 20 feet from the chart. Hand the person an opaque card with which to shield one eye at a time during the test; inadvertent peeking may result when shielding the eye with the person's own fingers (Fig. 14-9). If the person wears glasses or contact lenses, leave them on. Remove only reading glasses because they will blur distance vision. Ask the person to read through the chart to the smallest line of letters possible. Encourage the person to try the next smallest line also. (Note: Use a Snellen picture chart for people who cannot read letters. See p. 323.)

Back 2

Abnormal Findings

Note hesitancy, squinting, leaning forward, misreading letters.

Front 3

Record the result using the numeric fraction at the end of the last successful line read. Indicate whether the person missed any letters or if corrective lenses were worn—for example, “O.D.* 20/30-1, with glasses.”

Normal visual acuity is 20/20. Contrary to some people's impression, the numeric fraction is not a percentage of normal vision. Instead, the top number (numerator) indicates the distance the person is standing from the chart, and the denominator gives the distance at which a normal eye could have read that particular line. Thus “20/20” means, “You can read at 20 feet what the normal eye could have read at 20 feet.”

Back 3

Abnormal Findings

The larger the denominator, the poorer the vision. If vision is poorer than 20/30, refer to an ophthalmologist or optometrist. Impaired vision may be due to refractive error, opacity in the media (cornea, lens, vitreous), or disorder in the retina or optic pathway.

Front 4

Near Vision

For people over 40 years of age or for those who report increasing difficulty reading, test near vision with a handheld vision screener with various sizes of print (e.g., a Jaeger card) (Fig. 14-10). Hold the card in good light about 35 cm (14 inches) from the eye—this distance equals the print size on the 20-foot chart. Test each eye separately, with glasses on. A normal result is “14/14” in each eye, read without hesitancy and without moving the card closer or farther away. When no vision screening card is available, ask the person to read from a magazine or newspaper.

Back 4

Abnormal Findings

Presbyopia, the decrease in power of accommodation with aging, is suggested when the person moves the card farther away.

Front 5

TEST VISUAL FIELDS

Confrontation Test

Back 5

This is a gross measure of peripheral vision. It compares the person's peripheral vision with your own, assuming yours is normal (Fig. 14-11). Position yourself at eye level with the person, about 2 feet away. Direct the person to cover one eye with an opaque card, and with the other eye to look straight at you. Cover your own eye opposite to the person's covered one. You are testing the uncovered eye. Hold a pencil or your flicking finger as a target midline between you and the other person, and slowly advance it in from the periphery in several directions.

Front 6

Ask the person to say “now” as the target is first seen; this should be just as you see the object also. (This works with all but the temporal visual field, with which you would need a 6-foot arm to avoid being seen initially! With the temporal direction, start the object somewhat behind the person.) Estimate the angle between the anteroposterior axis of the eye and the peripheral axis where the object is first seen. Normal results are about 50 degrees upward, 90 degrees temporal, 70 degrees
and 60 degrees nasal (Fig. 14-12).

Back 6

Abnormal Findings

If the person is unable to see the object as examiner does, the test suggests peripheral field loss. Refer to an optometrist for more precise testing using a tangent screen (see Table 14-5 on p. 337).

Front 7

INSPECT EXTRAOCULAR MUSCLE FUNCTION

Corneal Light Reflex (The Hirschberg Test)

Assess the parallel alignment of the eye axes by shining a light toward the person's eyes. Direct the person to stare straight ahead as you hold the light about 30 cm (12 inches) away. Note the reflection of the light on the corneas; it should be in exactly the same spot on each eye. See the bright white dots in Fig. 14-29 for symmetry of the corneal light reflex.

Back 7

Abnormal Findings

Asymmetry of the light reflex indicates deviation in alignment from eye muscle weakness or paralysis. If you see this, perform the cover test.

Front 8

Cover Test

This test detects small degrees of deviated alignment by interrupting the fusion reflex that normally keeps the two eyes parallel. Ask the person to stare straight ahead at your nose even though the gaze may be interrupted. With an opaque card, cover one eye. As it is covered, note the uncovered eye. A normal response is a steady fixed gaze (Fig. 14-13, A).

Back 8

Abnormal Findings

If the eye jumps to fixate on the designated point, it was out of alignment before.

Front 9

Cover Test
Meanwhile, the macular image has been suppressed on the covered eye. If muscle weakness exists, the covered eye will drift into a relaxed position.

Now uncover the eye and observe it for movement. It should stare straight ahead (Fig. 14-13, B). If it jumps to re-establish fixation, eye muscle weakness exists. Repeat with the other eye.

Back 9

Abnormal Findings

A phoria is a mild weakness noted only when fusion is blocked. Tropia is more severe—a constant malalignment of the eyes (see Table 14-1).

Front 10

Diagnostic Positions Test

Leading the eyes through the six cardinal positions of gaze will elicit any muscle weakness during movement (Fig. 14-14). Ask the person to hold the head steady and to follow the movement of your finger, pen, or penlight only with the eyes. Hold the target back about 12 inches so the person can focus on it comfortably, and move it to each of the six positions, hold it momentarily, then back to center. Progress clockwise. A normal response is parallel tracking of the object with both eyes.

Back 10

Abnormal Findings

Eye movement is not parallel. Failure to follow in a certain direction indicates weakness of an extraocular muscle (EOM) or dysfunction of cranial nerve innervating it.

Front 11

Diagnostic Positions Test
In addition to parallel movement, note any nystagmus, a fine oscillating movement best seen around the iris. Mild nystagmus at extreme lateral gaze is normal; nystagmus at any other position is not.

Back 11

Abnormal Findings

Nystagmus occurs with disease of the semicircular canals in the ears, a paretic eye muscle, multiple sclerosis, or brain lesions.

Front 12

Diagnostic Positions Test
Finally, note that the upper eyelid continues to overlap the superior part of the iris, even during downward movement. You should not see a white rim of sclera between the lid and the iris. If noted, this is termed “lid lag.”

Back 12

Abnormal Findings

Lid lag occurs with hyperthyroidism.
.

Front 13

INSPECT EXTERNAL OCULAR STRUCTURES
General

Already you will have noted the person's ability to move around the room, with vision functioning well enough to avoid obstacles and to respond to your directions. Also note the facial expression; a relaxed expression accompanies adequate vision.

Back 13

Abnormal Findings

Groping with hands.

Squinting or craning forward.

Front 14

INSPECT EXTERNAL OCULAR STRUCTURES
Eyebrows

Normally the eyebrows are present bilaterally, move symmetrically as the facial expression changes, and have no scaling or lesions.

Back 14

Abnormal Findings

Absent lateral third of brow with hypothyroidism.

Unequal or absent movement with nerve damage.

Scaling with seborrhea.

Front 15

INSPECT EXTERNAL OCULAR STRUCTURES
Eyelids and Lashes

The upper lids normally overlap the superior part of the iris, and approximate completely with the lower lids when closed. The skin is intact without redness, swelling, discharge, or lesions

Back 15

Abnormal Findings

Lid lag with hyperthyroidism.

Incomplete closure creates risk for corneal damage.

Front 16

INSPECT EXTERNAL OCULAR STRUCTURES
Eyelids and Lashes
The palpebral fissures are horizontal in non-Asians, whereas Asians normally have an upward slant.

Back 16

Abnormal Findings

Ptosis, drooping of upper lid.

Periorbital edema, lesions (see Tables 14-2 and 14-3 on pp. 333 and 335).

Front 17

INSPECT EXTERNAL OCULAR STRUCTURES
Eyelids and Lashes
Note that the eyelashes are evenly distributed along the lid margins and curve outward.

Back 17

Abnormal Findings

Ectropion and entropion (see Table 14-2).

Front 18

INSPECT EXTERNAL OCULAR STRUCTURES
Eyeballs

The eyeballs are aligned normally in their sockets with no protrusion or sunken appearance. Blacks normally may have a slight protrusion of the eyeball beyond the supraorbital ridge.

Back 18

Abnormal Findings

Exophthalmos (protruding eyes) and enophthalmos (sunken eyes) (see Table 14-2).

Front 19

INSPECT EXTERNAL OCULAR STRUCTURES
Conjunctiva and Sclera

Ask the person to look up. Using your thumbs, slide the lower lids down along the bony orbital rim. Take care not to push against the eyeball. Inspect the exposed area (Fig. 14-15). The eyeball looks moist and glossy. Numerous small blood vessels normally show through the transparent conjunctiva. Otherwise, the conjunctivae are clear and show the normal color of the structure below—pink over the lower lids and white over the sclera. Note any color change, swelling, or lesions.

Back 19

Abnormal Findings

General reddening (see Table 14-6).

Cyanosis of the lower lids.

Pallor near the outer canthus of the lower lid may indicate anemia (the inner canthus normally contains less pigment).

Front 20

INSPECT EXTERNAL OCULAR STRUCTURES
Conjunctiva and Sclera
The sclera is china white, although blacks occasionally have a gray-blue or “muddy” color to the sclera. Also in dark-skinned people, you normally may see small brown macules (like freckles) on the sclera, which should not be confused with foreign bodies or petechiae. Last, blacks may have yellowish fatty deposits beneath the lids away from the cornea. Do not confuse these yellow spots with the overall scleral yellowing that accompanies jaundice.

Back 20

Abnormal Findings

Scleral icterus is an even yellowing of the sclera extending up to the cornea, indicating jaundice.

Tenderness, foreign body, discharge, or lesions.

Front 21

INSPECT EXTERNAL OCULAR STRUCTURES
Eversion of the Upper Lid

This maneuver is not part of the normal examination, but it is useful when you must inspect the conjunctiva of the upper lid, as with eye pain or suspicion of a foreign body. Most people are apprehensive of any eye manipulation. Enhance their cooperation by using a calm and gentle, yet deliberate, approach.

Back 21

1. Ask the person to keep both eyes open and look down. This relaxes the eyelid, whereas closing it would tense the orbicularis muscle.

2. Slide the upper lid up along the bony orbit to lift up the eyelashes.

3. Grasp the lashes between your thumb and forefinger and gently pull down and outward.

4. With your other hand, place the tip of an applicator stick on the upper lid above the level of the internal tarsal plates (Fig. 14-16).

5. Gently push down with the stick as you lift the lashes up. This uses the edge of the tarsal plate as a fulcrum and flips the lid inside out. Take special care not to push in on the eyeball.

6. Secure the everted position by holding the lashes against the bony orbital rim (Fig. 14-17).

7. Inspect for any color change, swelling, lesion, or foreign body.

8. To return to normal position, gently pull the lashes outward as the person looks up.

Front 22

INSPECT EXTERNAL OCULAR STRUCTURES
Lacrimal Apparatus

Ask the person to look down. With your thumbs, slide the outer part of the upper lid up along the bony orbit to expose under the lid. Inspect for any redness or swelling.

Back 22

Abnormal Findings

Swelling of the lacrimal gland may show as a visible bulge in the outer part of the upper lid.

Front 23

INSPECT EXTERNAL OCULAR STRUCTURES
Lacrimal Apparatus
Normally the puncta drain the tears into the lacrimal sac. Presence of excessive tearing may indicate blockage of the nasolacrimal duct. Check this by pressing the index finger against the sac, just inside the lower orbital rim, not against the side of the nose (Fig. 14-18). Pressure will slightly evert the lower lid, but there should be no other response to pressure.

Back 23

Abnormal Findings

Puncta red, swollen, tender to pressure.

Watch for any regurgitation of fluid out of the puncta, which confirms duct blockage.

Front 24

INSPECT ANTERIOR EYEBALL STRUCTURES

Cornea and Lens

Shine a light from the side across the cornea, and check for smoothness and clarity. This oblique view highlights any abnormal irregularities in the corneal surface. There should be no opacities (cloudiness) in the cornea, the anterior chamber, or the lens behind the pupil. Do not confuse an arcus senilis with an opacity. The arcus senilis is a normal finding in aging persons and is illustrated on p. 327.

Back 24

Abnormal Findings

A corneal abrasion causes irregular ridges in reflected light, producing a shattered look to light rays (see Table 14-7).

Front 25

INSPECT ANTERIOR EYEBALL STRUCTURES
Iris and Pupil

The iris normally appears flat, with a round regular shape and even coloration. Note the size, shape, and equality of the pupils. Normally the pupils appear round, regular, and of equal size in both eyes. In the adult, resting size is from 3 to 5 mm. A small number of people (5%) normally have pupils of two different sizes, which is termed anisocoria.

Back 25

Abnormal Findings

Irregular shape.

Although they may be normal, all unequally sized pupils call for a consideration of central nervous system injury.

Front 26

INSPECT ANTERIOR EYEBALL STRUCTURES
Iris and Pupil
To test the pupillary light reflex, darken the room and ask the person to gaze into the distance. (This dilates the pupils.) Advance a light in from the side* and note the response. Normally you will see (1) constriction of the same-sided pupil (a direct light reflex) and (2) simultaneous constriction of the other pupil (a consensual light reflex).

Back 26

Abnormal Findings

Dilated pupils.

Dilated and fixed pupils.

Constricted pupils.

Unequal or no response to light (see Table 14-4).

Front 27

INSPECT ANTERIOR EYEBALL STRUCTURES
Iris and Pupil
In the acute care setting, gauge the pupil size in millimeters, both before and after the light reflex. Recording the pupil size in millimeters is more accurate when many nurses and physicians care for the same person or when small changes may be significant signs of increasing intracranial pressure. Normally, the resting size is 3, 4, or 5 mm and decreases equally in response to light. A normal response is designated by:

R31=31L

This indicates that both pupils measure 3 mm in the resting state and that both constrict to 1 mm in response to light. A graduated scale printed on a handheld vision screener or taped onto a tongue blade facilitates your measurement (see Fig. 23-57 in Chapter 23).

Test for accommodation by asking the person to focus on a distant object (Fig. 14-19). This process dilates the pupils. Then have the person shift the gaze to a near object, such as your finger held about 7 to 8 cm (3 inches) from the nose. A normal response includes (1) pupillary constriction and (2) convergence of the axes of the eyes.

Back 27

Abnormal Findings

Absence of constriction or convergence.

Asymmetric response.

Front 28

Record the normal response to all these maneuvers as PERRLA, or Pupils Equal, Round, React to Light, and Accommodation.

Back 28

Always advance the light in from the side to test the light reflex. If you advance from the front, the pupils will constrict to accommodate for near vision. Thus you do not know what the pure response to the light would have been.

Front 29

media

Back 29

anterior chamber, lens, vitreous

Front 30

ocular fundus
.

Back 30

the internal surface of the retina

Front 31

Recall that the ophthalmoscope contains a set of lenses that control the focus

Back 31

The unit of strength of each lens is the diopter.

Front 32

red reflex, caused by the reflection of your ophthalmoscope light off the inner retina

Back 32

Begin about 25 cm (10 inches) away from the person at an angle about 15 degrees lateral to the person's line of vision. Note the red glow filling the person's pupil. This

Front 33

As you advance, adjust the lens to 16 and note any opacities in the media. These appear as dark shadows or black dots interrupting the red reflex. Normally, none are present.
.

Back 33

Abnormal Findings

Cataracts appear as opaque black areas against the red reflex (see Table 14-8).

Front 34

Optic Disc

The most prominent landmark is the optic disc, located on the nasal side of the retina. Explore these characteristics:

1. Color

2. Shape

3. Margins

4. Cup-disc ratio

Creamy yellow-orange to pink.

Round or oval.

Distinct and sharply demarcated, although the nasal edge may be slightly fuzzy.

Distinctness varies. When visible, physiologic cup is a brighter yellow-white than rest of the disc. Its width is not more than one half the disc diameter.

Back 34

Abnormal Findings

Pallor. Hyperemia.

Irregular.

Blurred margins.

Cup extending to the disc border (see Table 14-9).

Front 35

scleral crescent
pigment crescent

Back 35

Two normal variations may occur around the disc margins. A scleral crescent is a gray-white new moon shape (Fig. 14-24). It occurs when pigment is absent in the choroid layer and you are looking directly at the sclera. A pigment crescent is black; it is due to accumulation of pigment in the choroid.

Front 36

Retinal Vessels

This is the only place in the body where you can view blood vessels directly. Many systemic diseases that affect the vascular system show signs in the retinal vessels. Follow a paired artery and vein out to the periphery in the four quadrants (see Fig. 14-23), noting these points:

1. Number

2. Color

3. A: V ratio

4. Caliber

5. A-V (arteriovenous) crossing

6. Tortuosity

7. Pulsations

A paired artery and vein pass to each quadrant. Vessels look straighter at the nasal side.

Arteries are brighter red than veins. Also, they have the arterial light reflex, with a thin stripe of light down the middle.

The ratio comparing the artery-to-vein width is 2:3 or 4:5.

Arteries and veins show a regular decrease in caliber as they extend to periphery.

An artery and vein may cross paths. This is not significant if within 2 DD of disc and if no sign of interruption in blood flow is seen. There should be no indenting or displacing of vessel.

Mild vessel twisting when present in both eyes is usually congenital and not significant.

Present in veins near disc as their drainage meets the intermittent pressure of arterial systole. (Often hard to see.)

Back 36

Abnormal Findings

Absence of major vessels.

Arteries too constricted.

Veins dilated.

Focal constriction.

Neovascularization.

Crossings more than 2 DD away from disc.

Nicking or pinching of underlying vessel.

Vessel engorged peripheral to crossing (see Table 14-10).

Extreme tortuosity or marked asymmetry in two eyes.

Absent pulsations.

Front 37

General Background of the Fundus

The color normally varies from light red to dark brown-red, generally corresponding with the person's skin color. Your view of the fundus should be clear; no lesions should obstruct the retinal structures.

Back 37

Abnormal Findings

Abnormal lesions: hemorrhages, exudates, microaneurysms.

Front 38

Macula

The macula is 1 DD in size and located 2 DD temporal to the disc. Inspect this area last in the funduscopic examination. A bright light on this area of central vision causes some watering and discomfort and pupillary constriction. Note that the normal color of the area is somewhat darker than the rest of the fundus but is even and homogeneous. Clumped pigment may occur with aging.

Back 38

Abnormal Findings

Clumped pigment occurs with trauma or retinal detachment.

Front 39

Macula
Within the macula, you may note the foveal light reflex. This is a tiny white glistening dot reflecting your ophthalmoscope light.

Back 39

Abnormal Findings

Hemorrhage or exudate in the macula occurs with senile macular degeneration.

Front 40

The Aging Adult
cular Structures.

The eyebrows may show a loss of the outer one third to one half of hair because of a decrease in hair follicles. The remaining brow hair is coarse (Fig. 14-30). As a result of atrophy of elastic tissues, the skin around the eyes may show wrinkles or crow's feet. The upper lid may be so elongated as to rest on the lashes, resulting in a pseudoptosis.
The eyes may appear sunken from atrophy of the orbital fat. Also, the orbital fat may herniate, causing bulging at the lower lids and inner third of the upper lids.

Back 40

Abnormal Findings

Ectropion (lower lid dropping away) and entropion (lower lid turning in) (see Table 14-2).

Front 41

The Aging Adult
Ocular Strutures
The lacrimal apparatus may decrease tear production, causing the eyes to look dry and lusterless and the person to report a burning sensation. Pingueculae commonly show on the sclera (Fig. 14-31). These yellowish elevated nodules are due to a thickening of the bulbar conjunctiva from prolonged exposure to sun, wind, and dust. Pingueculae appear at the 3 and 9 o'clock positions—first on the nasal side, then on the temporal side

Back 41

Abnormal Findings

Distinguish pinguecula from the abnormal pterygium, also an opacity on the bulbar conjunctiva, but one that grows over the cornea (see Table 14-7, p. 339).

Front 42

The Aging Adult
Ocular Structures
arcus senilis

Back 42

The cornea may look cloudy with age. An arcus senilis is commonly seen around the cornea (Fig. 14-32). This is a gray-white arc or circle around the limbus; it is due to deposition of lipid material. As more lipid accumulates, the cornea may look thickened and raised, but the arcus has no effect on vision.

Front 43

The Aging Adult
Xanthelasma

Back 43

Xanthelasma are soft, raised yellow plaques occurring on the lids at the inner canthus (Fig. 14-33). They commonly occur around the fifth decade of life and more frequently in women. They occur with both high and normal blood levels of cholesterol and have no pathologic significance.

Front 44

The Aging Adult
Pupils

Back 44

Pupils are small in old age, and the pupillary light reflex may be slowed. The lens loses transparency and looks opaque.

Front 45

The Aging Adut
The Ocular Fundus.

Retinal structures generally have less shine. The blood vessels look paler, narrower, and attenuated. Arterioles appear paler and straighter, with a narrower light reflex. More arteriovenous crossing defects occur.

A normal development on the retinal surface is drusen, or benign degenerative hyaline deposits (Fig. 14-34). They are small, round, yellow dots that are scattered haphazardly on the retina. Although they do not occur in a pattern, they are usually symmetrically placed in the two eyes. They have no effect on vision.

Back 45

Abnormal Findings

Drusen are easily confused with the abnormal finding hard exudates, which occur with a more circular or linear pattern (see Table 14-10). Also, drusen in the macular area occur with macular degeneration