Assessment of the Eyes

The eye and the ear are sensory structures that connect us with the environment. They allow us to perceive our surroundings through sight and sound. Disorders of the eye and the ear can range from minor annoyances to life-threatening problems. Most problems do not result in acute illness; however, they may be associated with more serious neurological conditions such as brain tumor, stroke, or head injury.

No matter what the cause, visual and hearing problems can have a major impact on physiological functioning as well as psychological and social well-being. Early detection reduces the likelihood of problems related to social interaction.

Determining whether a patient has adequate vision and hearing is crucial before assessing mental status or providing instructions.The eyes and the ears are common sites of injury; they also exhibit structural variations as a result of age, cultural background, and genetic influences. Although, for the sake of clarity, the eyes and the ears are covered separately here, they are usually examined along with the head and neck because of their location.

A thorough assessment of the eyes and the ears includes vision and hearing screenings and examination of the external and internal structures.The assessment provides not only specific data about the eyes and the ears but also vital information on the health status of other systems.

Before you begin your assessment, an understanding of the anatomy and physiology of the eyes and the ears is essential. You need to be able to identify normal structures before you can identify abnormal findings, accurately perform the assessment, and correctly interpret your findings. This chapter covers assessment of the eyes first and then assessment of the ears.

Anatomy and Physiology Review: The Eye

The primary function of the eye is vision, including central and peripheral vision, near and distance vision, and differentiation of colors. To accomplish these tasks, the external and internal structures of the eye work together to receive and transmit images to the occipital lobe of the brain for interpretation.Visual difficulties can result from disease or injury to any of the structures involved in the visual pathway.

Structures and Functions of the Eye. The eye consists of internal and external structures that support or protect it.

How We See. The ability to see objects in the environment depends on light waves that reflect off images. Natural lighting produces gradations of shading that help to determine an object’s shape and position in the environment.The light rays pass through the cornea, anterior chamber, pupil, lens, and posterior chamber to the back of the eye (retina).The pupil,which is actually created by the aperture of a muscular layer of tissue called the iris,dilates or constricts to allow more or less light onto the retina.The lens, an elastic biconvex disc, bends the light waves entering the eye by either flattening or increasing the lens curvature.The precise functioning of the pupil and iris together allows a clear image to focus on the retina.

Several conditions result from variations in how or where the light rays entering the eye converge and focus. People with myopia (nearsightedness) need to hold objects close to the eye to see them clearly. In the myopic eye, the globe is elongated, causing light rays to focus in front of the retina.When the globe is shorter than normal, light rays focus at a point beyond the retina,producing a condition called hyperopia (farsightedness). People with hyperopia must move close objects farther away to see them clearly. Astigmatism is an irregular curvature of the lens or cornea that causes light rays to scatter, blurring images on the retina (Fig. 12.6).

The retina is rich in sensory neurons, which are necessary for reception and transmission of accurate images. The retina contains specialized nerve cells called rods, which are sensitive to dim light, and cone cells, which are sensitive to bright light and color. From the rods and cones of the retina, the visual image is transmitted to the optic disc,where the nerve fibers of the retina converge to enter the optic nerve.

Nerve fibers from the optic disc join to form the optic nerve.The neural impulses are then transmitted by the optic nerve to the optic track and optic radiations, where they are interpreted by the visual cortex. Nerve fibers from the nasal portion of each eye cross over to the opposite side of the brain at the optic chiasm. Fibers from the temporal portion of the retina of each eye do not cross over before being received by the visual cortex in the occipital lobe of the brain (Fig.12.7).

Interaction With Other Body Systems. The functions of the eyes are interconnected with those of the cardiovascular, musculoskeletal, and neurological systems.

The Cardiovascular System. The optic fundus is the only area in the body where blood vessels can be directly observed without using invasive techniques.Use of an ophthalmoscope provides direct visualization of the optic disc, where the vessels that supply the retina emerge.Changes in the optic disc, blood vessels, macula, and general background of the retina can reveal systemic problems with circulation as a result of chronic hypertension (HTN) or diabetes. Or they can reveal localized circulatory problems that occur with glaucoma, increased intracranial pressure, and other neurological problems.

The Musculoskeletal System. Movement of the eyes in a parallel or conjugate manner is made possible by the coordinated movement of the extraocular muscles. Each of the six extraocular muscles is responsible for rotating the eyes in a specific direction and maintaining the eyes’ conjugate movement. Each extraocular muscle is innervated by a specific cranial nerve (CN). The superior rectus, inferior rectus, medial rectus, and inferior oblique muscles are innervated by CN III.Damage to CN III can therefore result in limited range of movement in the upward, downward, nasal, and upper diagonal fields of vision.The remaining extraocular muscles, the lateral rectus and superior oblique, provide movement of the eye in the temporal lateral and nasal inferior direction, respectively. Damage to the nerves that innervate the lateral rectus muscle (CN VI) and the superior oblique muscle (CN IV) can result in limited eye movement in the corresponding directions.

Movement of the eyelid is controlled by another set of muscles, the orbicularis oculi and the levator palpebrae.The orbicularis oculi encircles the eyelids and is innervated by CN VII.Damage to the orbicularis oculi muscle or the part of the cranial nerve that innervates it results in an inability to close the eyelid completely.The ability to raise or open the eyelid depends on an intact CN III,which innervates the levator palpebrae muscle.

Constriction and relaxation of the muscular tissue of the iris and ciliary body allows visual adaptation.In a darkened environment,contraction of the smooth muscle of the iris causes the aperture of the iris or pupil to dilate.As a result,more light enters the retina and night vision is enhanced. In brightly lighted environments, the retina does not need to receive additional light; as a result, the pupil is constricted.

The ciliary body, located posterior to the outer edge of the iris, alters the shape of the lens and allows the eye to adjust to near or far objects, an occurrence referred to as accommodation. Constriction of the ciliary body results in flattening of the normal convex shape of the lens. Flattening of the lens facilitates the eye’s ability to focus on objects in the distance. Relaxation of the ciliary body allows the lens to assume its normal convex shape and facilitates focusing on near objects.Both the iris and the ciliary body can be affected by damage to CN III, resulting in pupil dilatation (mydriasis) and loss of accommodation.

The Neurological System. The ability to see images depends on an intact visual pathway.From the time when an image is received on the retina to the time when it is interpreted by the visual cortex, the neurological system plays a key role. Damage to the retina can result in diminished visual acuity or diminished color and night vision.Damage to the optic nerve, a source of retinal nervous tissue, can result in similar visual changes. Damage to specific points along the optic track or to the visual cortex can produce deficits in corresponding visual fields (Fig. 12.8).

The neurological system also innervates the extraocular eye muscles, which control the movement of the eyes, and the muscles of the eyelids, which control the opening and closing of the eyes.The cranial nerves responsible for innervation of each of the six extraocular muscles include CN III (oculomotor), CN IV (trochlear), and CN VI (abducens) (Fig. 12.9). Inability of these muscles to function properly is largely caused by damage to the nerves that innervate the muscles.

Increased intracranial pressure from intracranial tumors, head injuries, or severe intracranial hemorrhage may impinge on CN II (optic), CN III, CN IV, or CN VI, causing specific eye changes.The optic nerve innervates the retina and is surrounded by a meningeal sheath that is continuous with the meninges of the brain.When intracranial pressure increases, the pressure is transmitted from the brain to the optic disc,where swelling occurs.

Pressure on a specific part of the optic nerve tract can produce visual loss (hemianopia) on the ipsilateral (same side) or contralateral (opposite side) visual field, depending on the location of the injury or lesion.

Developmental, Cultural, and Ethnic Variations

Infants. Several variations may be noted in the eyes of infants.The shape, slope, spacing, and color of the eyes should be noted. Normal shape is oval. Slope is determined by drawing an imaginary line through the inner canthus to the occiput. Except in people of Asian descent, the slope line transects the outer canthus.Measurement of the distance between various structures of the eye can be plotted on a growth chart.Normal spacing measurements are plotted between the 10th and the 90th percentiles.

Infants usually open their eyes when held upright, permitting inspection of the iris,pupil,and sclera.The color of the iris after birth is normally blue-gray in light-skinned infants and brown in darker-skinned infants. Permanent eye color is usually established by 9 months of age.White specks in the iris called Brushfield spots can be a normal variant or a sign of Down syndrome. Edema of the eyelids and irritation of the conjunctiva may be caused by birth trauma or silver nitrate prophylaxis.The sclera is very thin at birth, so it may have a slightly blue undertone.

A gross assessment of visual acuity is made by testing for pupillary light reflexes and also by noting the infant’s behavior.The pupils should normally constrict to light. After 3 weeks, if no pupillary light reflex is present, blindness is indicated. However, the presence of pupillary reaction alone does not confirm an infant’s ability to see. A blink reflex in response to bright light and observing the infant for ability to follow objects or light with the eyes confirm that some degree of vision is intact. By 2 to 4 weeks, an infant should be able to fixate on an object and,by 1 month, to fixate and follow an object.An infant’s visual acuity is usually about 20/200;20/20 vision is usually achieved by school age.

During the first 1 to 2 months, infants’ eye movements are often disconjugate (not working in unison), making screening for strabismus difficult. Persistence of disconjugate eye movements after this time may indicate strabismus and warrants referral to a specialist. In infants, the fundoscopic examination is difficult but still important.The internal structures of the eye should be examined regularly during the first few years of life.One of the first things to note is the presence of a red reflex,which is a normal finding.Absence of a red reflex may indicate congenital cataracts or retinal detachment. The general background in infants is typically paler than that in adults because the blood vessels to the area are not fully developed. The macula is also not fully developed until about 1 year of age.

Toddlers. Visual acuity in toddlers is determined by the Allen test, which uses picture cards of seven common objects. The child should successfully identify three of the seven objects at a distance of 15 feet. If the child cannot do so, move closer until he or she is able to do so.

The corneal light reflex can provide an initial, rapid screening test for strabismus that can be followed by additional measures as the child grows. Untreated strabismus can lead to permanent visual damage. Eventually, the brain suppresses information from the affected eye, and visual acuity in that eye deteriorates.

Preschool Children. Between the ages 3 and 5, the Snellen E chart,which uses various sizes of Es facing in different directions, can usually be used to determine visual acuity.Normal visual acuity for a 3-year-old is approximately 20/40 or better. By the time the child is 4 years old, visual acuity should be about 20/30 or better.

School-Age Children. By the time a child is about 5 to 6 years old, normal visual acuity approximates that of the adult—20/20 in both eyes. You should continue using the Snellen E chart until the child has acquired reading skills and can easily verbalize the letters seen on the Snellen chart. Some degree of myopia (nearsightedness) often occurs during adolescence. Children should be screened for defects in color perception (colorblindness) between 4 and 8 years of age. Though many forms of color blindness exist, most cases involve inherited recessive X-linked traits in males that affect the ability to distinguish red and green.

Older Adults. Many changes in the structure and function of the eye occur with aging. Both central and peripheral visual acuity may be diminished with advanced age. Changes in near vision occur around the fourth and fifth decades, often resulting in decreased ability to focus clearly on near objects (presbyopia).The adult may compensate for these changes by holding near objects farther away.

External structures of the eye also undergo significant changes with advanced age. Tissues of the eyelids lose elasticity and fatty deposits, causing the eyes to appear sunken. The lower eyelid may sag away from the globe. The latter condition, called ectropion, is significant because the punctum,which drains the tears, is no longer in contact with the globe, resulting in constant tearing.The laxity that develops in the eyelids may also lead to an inward turning of the eyelids, referred to as entropion.With entropion, the punctum also may not be able to drain tears. In addition, the eyelashes may rub the conjunctiva and cornea, causing pain and injury to the cornea. Older adults also may experience dry eyes because of a decrease in tear production.

Changes in the internal structures of the eye are also common with aging.The lens becomes more opaque and yellowish, obscuring the transfer of light rays to the retina. This clouding of the lens is referred to as senile cataract. Arcus senilis, a white opaque ring around the edge of the cornea resulting from fat deposits, is a common benign finding. The older adult’s pupil size at rest is generally smaller than that of younger adults. Pupillary reaction to light and accommodation slow because of decreased ability to constrict and relax.The general background is paler, and the blood vessels of the eye may show signs of the same atherosclerotic processes that are occurring elsewhere throughout the body.Visual fields may be less than normal. Other visual changes that occur with aging reflect degeneration of the rods and cones. Color vision may be less vivid as a result of degeneration of the cones, and night vision may be impaired because of degeneration of the rods.

Several eye diseases also occur more commonly in older adults. Macular degeneration and glaucoma, the two leading causes of blindness in older adults, show a significant increase with aging.

People of Different Cultures and Ethnic Groups. Differences in physical characteristics of the eye and differences in the risk of certain eye diseases are found in various ethnic groups.People of Asian origin typically have an epicanthal fold at the medial canthus,giving the eyes an almond-shaped appearance. The outer canthus also may slant in an upward direction. In African Americans and others with normally dark skin, brown-pigmented spots on the sclera, referred to as muddy sclera, are common. In dark-skinned people, the color of the optic disc is also typically darker orange, and the retinal background is darker red than in fair-skinned people.An African American person’s sclera also may have a blue-gray appearance or a yellowish cast at the peripheral margins. The incidence and severity of glaucoma is greater in African Americans than in people of other races. Cataracts also occur with greater frequency in people living in sunny climates.

Performing the Eye Assessment. Assessment of the eye includes taking a thorough health history and performing a physical examination. Data obtained are combined and analyzed to determine the patient’s existing health status and to identify potential health risks and disorders of the eye.

Health History. The health history addresses the patient’s personal and family history of eye diseases and diseases that affect the eye. A comprehensive health history also allows the nurse to identify areas of the physical examination that require more or less depth. The health history will include biographical data, current health status,past health history, family history, a review of systems, a psychosocial profile, and a detailed eye history. If time is an issue and you are unable to perform a complete health history,perform a focused eye history.

Biographical Data. First, review the patient’s medical records, intake surveys, and other sources of data to identify her or his age, occupation, gender, and ethnic background. This information will help you decide what questions to ask and how to interpret subsequent history and examination findings. For example, the way you measure visual acuity and interpret the findings differs greatly with the patient’s age. The patient’s occupation can be a source of environmental risk for eye injury.Gender may be a factor in certain disorders such as colorblindness,which is more common in males. Knowledge of the patient’s race or ethnic group is useful when interpreting many physical examination findings.

Current Health Status. Begin by asking about the person’s chief complaint, asking him or her to describe the problem in his or her own words.Use the PQRST format to probe further about any symptoms reported. If the person has an eye problem, focus your questions on the eye symptoms prioritized later.

Symptom Analysis.

Vision Loss. Vision loss refers to the inability to see the shape, size, position,or color of objects. Vision loss may be complete, resulting in the inability to perceive light from dark,or incomplete, causing the person to see objects with varying degrees of detail.

Eye Pain. Eye pain is a subjective sensation of discomfort in the eye that may be caused by trauma, irritation, infection,or neurological conditions.

Double Vision. Double vision (diplopia) refers to seeing two overlapping images because of the inability of the eyes to focus on an object and to move in a conjugate manner.Double vision can be caused by a variety of conditions, including diseases of the cerebellum, cranial nerves, and extraocular muscles.

Eye Tearing. Tears are normally produced by the lacrimal gland, located along the upper outer orbit of the eye, and are distributed over the eye by blinking.Tearing is a discharge of clear,watery fluid as a result of the inability of the tears to drain through the punctum and into the nasolacrimal duct.Tearing occurs in a variety of conditions such as infections; irritation;and exposure to chemicals, irritants,or allergens.

Dry Eyes. Dry eyes occur when there is insufficient lubrication of the eye and the bulbar and palpebral conjunctiva become less moist. It often results in a subjective sensation of irritation, a gritty sensation or discomfort, especially during blinking.Dryness occurs from trauma to the eye surface or facial trigeminal nerve paralysis, in certain systemic diseases, or after taking certain medications.

Eye Drainage. Drainage from the eyes is abnormal and is commonly associated with eye infections or allergies.

Eye Appearance Changes. Changes in the appearance of the external eye, such as in the iris, anterior chamber, and sclera, can signal a variety of problems, including trauma, infection, and systemic disorders.

Blurred Vision. Blurred vision refers to an object’s shape and detail being indistinct and fuzzy. It can occur for near objects as well as for distant ones.

Past Health History. This section of the health history focuses on gathering relevant information about the patient’s past eye health and any injuries, diseases, or medications that could affect the eyes.The following are specific areas related to the eye that should be explored.

Family History. When gathering information on your patient’s family history, consider familial conditions that may affect the eyes.

Review of Systems. Changes in the structure and function of the eye may relate to every other system of the body.The review of systems (ROS) will help you identify problems in other systems that directly affect the eye and allow you to pick up on symptoms that you might have missed in your health history by triggering your patient’s memory.

Psychosocial Profile. The psychosocial profile may reveal patterns in the patient’s lifestyle that affect health, increase the risk of health problems, or influence adaptation to health problems. Obtaining a psychosocial profile includes asking the patient about activities of daily living, personal habits, relationships, roles, coping, and home and work environment.

Anatomical Landmarks. Before beginning your physical assessment of the eye, review the anatomical landmarks of the external eye (Fig. 12.10).

Physical Assessment. During the physical examination, you will assess the functions and structures of the body, including a focused examination of the eye.You will use the information obtained in the health history to guide you and help determine what body structures and functions should be focused upon. After you have explored the patient’s key health history information and determined what aspects should be explored, begin the physical examination.The purpose of the physical examination is to identify normal, age-appropriate structures and functions of the eye as well as potential and actual health problems.

Approach. To assess the eye, use the techniques of inspection and palpation. Begin by testing visual acuity and performing other assessments that can be completed while you stand at a distance from the patient. For visual acuity, test and record the findings for each eye separately and then together. Standard abbreviations for recording findings are OD for the right eye, OS for the left eye, and OU for both eyes.

Performing a General Survey. Before performing the eye assessment,perform a general survey, noting the patient’s overall appearance. Observe nutritional status,emotional status,and body habitus,noting changes that would relate to the eyes.Then inspect for use of corrective lenses,noticeable visual deficits, and gross eye abnormalities such as ptosis, exophthalmos, edema, and redness. Also take vital signs.A temperature elevation may indicate an infection and give the eyes a glazed appearance. High BP should alert you to look for vascular changes when performing the fundoscopic examination.

Performing a Head-to-Toe Physical Assessment. Now examine the patient for more specific signs of diseases affecting other organ systems that might have an impact on the eyes and vision.

Performing Physical Assessment of the Eye. A comprehensive physical examination of the eye involves assessing the functions, such as vision (distant, near, color, and peripheral), eye muscle functioning, and pupil reflexes, as well as inspecting the external and internal eye structures.The sequence for testing visual acuity progresses from testing done at a distance, such as the visual acuity examination, to observations made at close range, such as the ophthalmic examination. Proceeding in this sequence allows the patient to become comfortable with the nurse before examination at close range is performed. It also allows the nurse to establish the patient’s degree of visual functioning, which establishes a baseline for conducting the remainder of the examination. The ophthalmic examination often requires administration of mydriatic or pupil-dilating eye drops.

Visual Acuity Testing. Visual acuity testing involves determining distant, near, peripheral, and color vision. The Snellen eye chart is used to test distant vision in adults and children of school age.The patient stands 20 feet from the chart, covers one eye, and reads the smallest line of print.He or she continues reading successively smaller lines until he or she reads them incorrectly (no more than two mistakes allowed per line) or says that the print is too blurry to distinguish letters.Record the fraction next to the smallest line of letters that the patient read.The top number, or numerator, indicates the distance in feet from the chart, and the bottom number, or denominator, indicates the distance in feet that a person with normal vision would be able to read the chart. The higher the denominator, the worse the person’s distant vision.

Have the person cover the opposite eye and repeat the procedure. After testing each eye individually, test both eyes simultaneously and record the fraction next to the smallest line read.A pocket vision screener may also be used. The letters are scaled down and simulate the Snellen chart,but the card is held only 14 inches from the patient.

Near vision is tested using Jaeger cards, in which lines of text are repeated in progressively smaller fonts. Test each eye separately by having the patient cover one eye and read the smallest line of text while holding the card at a distance of 14 inches. If Jaeger cards are not available, an alternative method is to have the patient read a newspaper and then record how far away he or she holds it.

Color vision is tested using Ishihara’s embedded colors test, which consists of a series of cards displaying colored dots that contain an embedded colored figure or number. The patient is asked to identify the figure in each card.An alternative measure is to point to one of the red or green colored bars on the Snellen eye chart and ask the patient what color she or he sees (Fig. 12.11).

Peripheral vision in each eye is measured on two planes—horizontal and vertical—and in four directions—superior, inferior,medial (nasal), and lateral (temporal), using the confrontation test. The patient and nurse stand face to face, about 1 to 1^1⁄2 feet apart.Ask the patient to fix his or her gaze straight ahead and cover one eye at a time, using his or her hand or an opaque cover.Then wiggle your fingers or bring a pen or other small object from the periphery to the center of the visual field.Tell the patient to say “now” as soon as your hand or the object enters his or her peripheral vision.

Repeat this procedure in each of the four visual fields, moving in a clockwise direction. Be sure to start testing from positions that are outside the normal peripheral vision range; then slowly move your hand or the object into each of the four peripheral fields.Measure the degree of peripheral vision using the patient’s fixed gaze as a base (Fig. 12.12).

You can also test peripheral vision by comparing the patient’s peripheral vision with yours.This is helpful in detecting gross peripheral deficits, but the method is somewhat subjective because you have to assume that you have normal peripheral vision.

Assessment of the Extraocular Muscles. To perform the corneal light reflex test, instruct the patient to fix her or his gaze straight ahead. Shine a penlight at the bridge of the nose and note where the light reflects on the cornea of each eye. Using the face of a clock as a guide, determine if the light reflex appears at the same clock position in each eye.The corneal light reflex test determines if the eyes are being maintained in a conjugate position.

The cover/uncover test helps determine if there is a weakness in the eye muscles of one or both eyes that can result in disconjugate eye movement.To perform the test, have the patient fix his or her gaze straight ahead. Stand in front of the patient, cover one of his or her eyes with a piece of paper, and observe the uncovered eye for movement indicating re-fixation of the gaze.Remove the cover and observe the previously covered eye for movement indicating re-fixation of the gaze.Repeat the procedure for the other eye.The gaze should remain steady in each eye throughout the test.

Further testing of the extraocular muscles is done by testing for symmetrical (conjugate) rotation of the eyes, symmetrical movement of the upper eyelid, and nystagmus in the six cardinal fields of gaze test.The six cardinal fields of gaze tests the cranial nerves III, IV, and VI and the extraocular muscle.To perform this test, stand in front of the patient and instruct her or him to look straight ahead and follow your finger as you move slowly through the six cardinal fields.The patient should hold her or his head still and move only her or his eyes. Observe for smooth, symmetrical movement of the eyes and eyelids.

Assessment of the External Structures. The next phase of the eye examination involves inspection and palpation of external eye structures. Careful inspection and palpation can reveal a variety of eye disorders as well as systemic disorders that affect the eye.

Testing the pupils to determine reaction to light is important for evaluating neurological function. Increased intracranial pressure from a head injury, tumor, or stroke may manifest in specific pupillary changes. Other conditions such as hypoxia or brain death or the use of certain medications can also affect the papillary light reflex.

To test pupillary reflex, observe for direct (same side) and consensual (opposite side) response to a focused beam of light. Darken the room if possible.Then, using a penlight, flashlight, or ophthalmoscope light, shine the light onto one eye as you observe whether the pupil constricts (referred to as a direct response).Repeat the procedure and note whether the other eye exhibits a consensual response or constriction to light. Repeat the test for the opposite eye.

Inspection of the anterior chamber of the eye can reveal a variety of conditions including infection, trauma, and risk for glaucoma.The shadow test is useful in identifying a shallow anterior chamber, which is commonly seen in glaucoma.To inspect the anterior chamber using this test, have the patient look straight ahead. Hold your penlight at the temporal side of one eye at a 90-degree angle across the anterior chamber.Without moving the penlight, shine the light across the limbus of the eye, toward the nose. A crescent-shaped shadow on the nasal side of the iris indicates a shallow anterior chamber.

Assessment of the Internal Structures. The internal structures of the eyes are examined last.Using the ophthalmoscope permits the visualization of the red reflex, optic disc, blood vessels, general background, and macula (Fig. 12.13). Changes in the appearance of these structures can indicate localized eye disorders and eye trauma as well systemic health problems.

The first thing you should see with the ophthalmoscope is a red reflex over the pupil area,which is the reflection of light off the retina. Note the color and clarity of the red reflex. Now gradually move closer to the patient while holding the red reflex in sight.When you are approximately 2 inches from the eye, you should see either blood vessels or the general background of the retina. Follow the blood vessels nasally back to their origin at the optic disc. Now examine the optic disc for color, shape, discreteness of the disc margins, and a paler area near the center called the physiological cup.The optic disc is located nasally and has a yellow to yellow-orange color,with sharp distinct edges except for the nasal side,which may be slightly blurred.

Note the size of the physiological cup compared with the size of the optic disc (cup-to-disc ratio).The cup should be half the size of the disc or less.The cup is normally lighter or white in color. Follow the vessels as they leave the optic disc.Note the size of the arteries compared with the veins (AV ratio).Arteries will appear smaller and brighter red than veins and will have a light streak reflecting off them. Also note constriction of the vessels and whether or not any nicking is noted when vessels cross. Inspect the general background for color and lesions. Color should be a uniform yellow-orange-red color,depending on individual skin tone.The lighter the skin tone, the lighter the background.After inspecting the optic disc,vessels,and general background, examine the macula.The macula is a circular area of slightly darker pigmentation located about two disc diameters (DD) temporally from the optic disc. It is the site of central vision and the source of one of the most common causes of blindness,macular degeneration.

The macula is difficult to see, especially through undilated pupils.To see it,have the patient look directly into the ophthalmoscope light.This places the macula into direct view.

SUMMARY

■ The eyes are complex sensory organs that provide specialized functions crucial to neurosensory development in infancy; to the development of psychosocial,motor,and cognitive skills in childhood;and to the maintenance of those skills in adulthood.

■ A thorough health history provides direction for the physical examination, including exploration of factors that may be related to eye health.

■ A comprehensive history and physical examination enable early detection and treatment of sight problems.

■ Information from both the history and the physical examination is then analyzed to determine appropriate nursing diagnoses.