Assessment Of The Eyes And Vision

ASSESSMENT of the EYES and VISION The Human Eye

Eye Assessment Review of External Anatomy Review of Terms: • Eyelids- a protective fold of skin and muscle that can be closed to cover the front of the eyeball • Palpebral fissure- separation between the upper and lower eyelids. • Limbus- area in eyeball where cornea and sclera meets • Canthus- the corner or angle at each side of the eye • Tarsal Plates (strips of connective tissue that give the upper lid shape) • Meibomian glands- sebaceous gland in the eyelid • Conjunctiva (Bulbar and Palpebral • Lacrimal apparatus Extraocular Muscles • Give the eye straight and rotary motion • Each muscle is coordinated to ensure axes remain parallel • Muscles are: superior and inferior rectus, medial and lateral rectus and superior and inferior obliques • Human focus on one image only • Movement of the EOMs is by CN III, IV and VI Internal Anatomy • Eye is composed of three concentric coats 1. Outer fibrous layer called the Sclera 2. Middle vascular layer called the Choroid 3. Inner layer is the visual receptive layer called Retina • Cornea- clear, front part of the eye. The cornea is the first part of the eye that bends (or refracts) the light and provides most of the focusing power. • Pupil- a hole in the center of the iris that changes size in response to changes in lighting. It gets larger in dim lighting conditions and gets smaller in brighter lighting conditions.

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Internal Anatomy Retina- the visual receptive layer of the eye wherein light waves are changed into nerve impulses Optic disc -area where the fibers from the retina converge to form the optic nerve Retinal vessels – include a paired artery and vein extending to each quadrant Macula – located on the temporal side of the fundus. Receives and transmits light from the center of the visual field Visual Pathways and Visual Fields

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Light rays are refracted through the cornea>>aqueous humor>>lens>>vitreous body and strike the retina. The retina then transform the light stimulus into nerve impulses through the optic nerve and optic tract to the visual cortex of the occipital lobe • Image formed in the retina is upside down and reversed from its actual appearance in the outside world. Visual Reflexes Pupillary light reflex is normal constriction of the pupils when bright light shines on the retina • Direct light reflex (same eye) • consensual light reflex (other eye) reactions • Accomodation-adaptation of the eye for near vision Developmental Considerations • At birth, No macula until 4 months of age • 3-4 months - can fixate on a single image with both eyes. • Eyeball reaches full size by age 8 but consistency changes • During pregnancy, lacrimal gland function changes. Eyes may become more sensitive and dry. • Aging adult • Development of Arcus Senilis • Presbyopia ( decreased power of accomodation) • Cataract or lens opacity • Decreased adaptation to darkness • Glaucoma or increased ocular pressure • Macular degeneration- most common cause of blindness. Cause is unknown. 1. 2. 3. 4. 5.

History Visual difficulties-blurring, halos, blind spots, spots present, any loss of peripheral vision Pain-quality, onset, severity Strabismus or diplopia Redness or swelling Watering or discharge

6. Past history of ocular problems 7. Glaucoma? 8. Use of corrective lenses? 9. Last vision test 10. Medications 11. Aids of any kind? Additional History Infants and Children • Any vaginal infections at time of delivery • Developmental milestones • Vision testing at school? • Eye safety at home? Aging Adult • Any vision difficulties in taking stairs? Problems with vision at night? • Last eye exam? • Any eye dryness? Remedies? • History of cataracts? Loss of vision? • Decreased ability in reading or sewing? Eye Assessment • Should be carried out in an orderly fashion • Moving from the extraocular to the intraocular stuctures • Usually includes testing of associated cranial nerves & can be performed in the following order: 1. Determination of Visual Acuity 2. Determination of Visual Fields 3. Assessment of external eye & lacrimal apparatus 4. Evaluation of extraocular muscle function 5. Assessment of anterior segment structures 6. Assessment of posterior segment structures Planning • Place client in well lighted room • Nurse must be able to control natural and overhead lighting during some portions of the examination Delegation • Duly licensed doctors and assistive personnel (nurses) Equipment • Cotton tip applicator • Gauze square • Examination gloves • Millimeter ruler • Penlight • Snellen’s or E chart • Opaque card or occluder Implementation

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Explain procedure. Discuss how results will be used in planning further care Wash hands and apply gloves Provide privacy Inquire history Determination of Visual Acuity Measure of visual acuity tests Cranial Nerve II, is a measure of central vision measures how well you see at various distances. It is the familiar eye chart test. 1. Snellen chart-has number at the end of each line of letters indicates the degree of visual acuity when measured at a distance of 20 feet. The numerator 20 is the distance in feet between the chart and the client. The denominator 20 is the distance from which the normal eye can read the lettering, which correspond to the number at the end of each letter line; therefore the larger the denominator the poorer the vision. 2. Illiterate E chart-for those who are illiterate and unfamiliar with the western alphabet. The letter E faces in different directions. Determination of Visual Acuity Functional Vision Test – if client is unable to see top of line in Snellen chart (20/200)

1. Light perception- shine light at lateral position & turn off lightings. Record “LP” if positive 2. Hand movements- Move hand slowly back and forth at 1 ft, & stopping periodically. Ask client to tell you when hands stop moving. Record the vision “HM 1 ft” 3. Counting fingers- Hold some fingers from client’s face at 1 ft distance. Record “CF 1 ft” Determination of Visual Fields Confrontation Test- (Peripheral Vision) sit opposite client about one meter apart. Client covers one eye, you cover the opposite eye. Fully extend your arm midway between client and yourself, move it centrally with fingers waving. Have the client tell you when the moving fingers are first seen. Compare your responses. Somewhat imprecise test. • CN III, IV, VI test • Corneal Light Reflex-light 12” in front, look for light reflection in pupils, Should be even. • Cardinal fields- stand in front of the client & move finger or pencil through the 6 cardinal fields of gaze, take to extreme lateral positions • Common problems of the visual field 1. Scotoma (area of reduced vision), 2. Hemianopia (half of visual field lost), 3. Homonymous quadrantanopia (involving both eyes) Assessment of External Eye and Lacrimal Apparatus External examination of eyes consists of: •

1. inspection of the eyelids, surrounding tissues and palpebral fissure. 2. Palpation of the orbital rim may also be desirable, depending on the presenting signs and symptoms. 3. The conjunctiva and sclera can be inspected by having the individual look up, and shining a light while retracting the upper or lower eyelid. 4. The cornea and iris may be similarly inspected. Assessment of External Eye and Lacrimal Apparatus 1. Inspect the eyelids for position and symmetry. 2. Palpate the eyelids for the lacrimal glands. ` a. To examine the lacrimal gland, the examiner, lightly slide the pad of the index fingeragainst the client’s upper orbital rim. b. Inquire for any pain or tenderness. 3. Palpate for the nasolacrimal duct to check for obstruction. a. To assess the nasolacrimal duct, the examiner presses with the index finger against the client’s lower inner orbital rim, at the lacrimal sac, NOT AGAINST THE NOSE. b. In the presence of blockage, this will cause regurgitation of fluid in the puncta  Normal Findings: Eyelids  · Upper eyelids cover the small portion of the iris, cornea, and sclera when eyes are open. · No PTOSIS noted. (drooping of upper eyelids). · Meets completely when eyes are closed. · Symmetrical. Lacrimal Apparatus  · Lacrimal gland is normally non palpable. · No tenderness on palpation. · No regurgitation from the nasolacrimal duct Evaluation of Extraocular function • This test is an examination of the function of the eye muscles. A doctor observes the movement of the eyes in six specific directions. • Client are asked to sit or stand with your head erect and a forward gaze. Nurse will hold a pen or other object 12 inches in front of your face. Nurse will then move the object in several directions and ask client to follow it their eyes, without moving their head. • Normal Results Normal movement of the eyes in all directions. • What Abnormal Results Mean Eye movement disorders may be due to abnormalities of the muscles themselves or problems in the sections of the brain that control these muscles. Assessment of Anterior Segment Structures The anterior segment is the front third of the eye that includes the structures in front of the vitreous humor: the cornea, iris, ciliary body, and lens

Assessment of Eye Structures Implementation 1. Explain procedure. Discuss how results will be used in planning further care 2. Wash hands and apply gloves 3. Provide privacy 4. Inquire history Assessment of Eye Structures Eyebrows (hair and skin quality) Normal findings: • Hair evenly distributed, skin intact • Symmetrical eyebrows w/ equal movements • Deviations from Normal • Loss of hair, scaling/flakiness of skin • Unequal alignment / movement of eyebrows Assessment of Eye Structures Eyelashes Normal Findings: • Equally distributed, curled slightly outward Deviations: • Lashes turned inward Assessment of Eye Structures Eyelids Normal Findings: • Skin intact, no discharge, no discoloration • Lids close symmetrically • Approx. 15-20 involuntary blinks/minute, bilateral blinking • When lids open, no visible sclera above corneas. Upper/lower borders of cornea are slightly covered Deviations:

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Redness, swelling, flaking, crusting, discharge nodules/lesions Lids close asymmetrically, incompletely or painfully Infrequent blinking Ptosis, ectropion lower lids rolled out) or entropion (lower lids rolled in), rim of sclera visible between lid and iris Assessment of Eye Structures Bulbar conjunctiva-retract eyelids, exert pressure over upper & lower bony orbits and ask client to look up & down & sideways Normal Findings: • Transparent, sclera appears white (yellowish in darkskinned) Deviations from Normal: •

Jaundiced sclera (liver dis), excessively pale sclera, lesions/nodules (mechanical, chemical, allergic or bacterial damage) Assessment of Eye Structures Palpebral Conjunctiva- evert & retract both lower lids & ask client to look up. Normal Findings: o Shiny, smooth and pink/red Deviations from Normal: o Extremely pale (anemia), red (inflammation), nodules or lesions Assessment of Eye Structures Lacrimal Gland-inspect and palpate Normal Findings: • No swelling /tenderness over lacrimal gland Deviations from Normal: • swelling /tenderness over lacrimal gland Assessment of Eye Structures Lacrimal sac and nasolacrimal duct- inspect & palpate Normal Findings: • No edema & tearing Deviations from Normal: • Increased tearing, regurgitation of fluid on palpation of lacrimal sac Assessment of Eye Structures Cornea 1. Inspection: Ask client to look straight, hold penlight at oblique angle of eye & move light slowly across corneal surface. Normal Findings: • Shiny, smooth. Details of iris are visible • Arcus senilis (grayish w/ white ring around margin in older persons) 36