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Eyes - PowerPoint PPT Presentation

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External Anatomy

  • Sensory Organ for vision

    -Situated in bony, orbital cavity for protection

    • Eyelids= shades that add protection form injury, strong light , dust

    • Eyelashes= hairs to filter dust & dirt

External Anatomy

External Anatomy

  • Limbus border b/t the cornea & sclera

  • Palpebral fissures elliptical open space b/t lids

  • Canthus- corners of the eye where the lids meet, inner & outer

  • Caruncle sm. Fleshy mass containing sebaceous glands at inner canthus

  • Within the upper eyelid

    • Tarsal plates, connective tissue gives upper lid shape

    • Meibomian glands, in the plates, lubricate the lids, stops overflow of tears, airtight seal when lids closed

  • Exposed part of the eye

    • Conjunctiva, folded envelope b/t eyelids & eyeball

      • thin mucous membrane, transparent protective covering of the exposed part of the eye.

      • Palpebral conjunctiva lines the lids, is clear but has sm .bld. Vessels

      • Bulbar conjunctiva is over eyeball, white sclera show through, merges at limbus with cornea

  • Cornea clear, covers & protects iris & pupil

  • Lacrimal apparatus irrigates conjunctiva & cornea

    • 3 parts

      • Lacrimal gland, upper, outer corner of eye = tears

      • Puncta= inner canthus, tear drainage

      • Nasolacrimal duct= allows tears to drain from puncta to nasolacrimal sac. Tears then empty into the inferior meatus of the nose

Extraoccular muscles

  • 6 muscles

    • Attach eyeball to orbit

    • Straight and rotary movement

    • Four straight muscles

      • Superior rectus

      • Inferior rectus

      • Lateral rectus

      • Medial rectus

  • Two slanting/ oblique muscles

    • Superior

    • Inferior

      Humans have a Binocular, single image visual system Eyes normally move as a pair

  • Eye movement stimulated by Cranial Nerves

    • III Oculomotor

    • IV Trochlear

    • VI Abducens

Internal Anatomy

  • The eye has 3 layers, the outer & inner layer can be viewed using opthalmascope

    • Sclera (outer layer) tough, protective, white covering connects with the -

      • Cornea transparent, protects pupil & iris helps focus light on retina

  • Middle layer

    • Choroid dark pigmentation to prevent internal light reflection, supplies bld. to retina

    • Pupil PERRLA

    • Lens biconvex disc, transparent, thickness controlled by ciliary body, bulges = near; flattens = distant

    • Anterior chamber posterior to cornea, anterior to iris & lens, has aqueous humor supplies nutrients & drains wastes

  • Inner layer Retina visual receptive layer light waves changed to nerve impulses

    • Retinal structures

      • Optic disc retinal fibers meet & form optic nerve, nasal side of retina, creamy yellow orange to pink, round or oval shape, physiologic cup inside the disc for bld.vessels to enter & exit

      • Retina vessels paired arteries & veins

  • Macula temporal side of fundus, darker pigmented region, surround the fovea centralis

  • Fovea Centralis- area of sharpest & keenest vision, Very sensitive to light

Visual Pathways & Fields

  • Objects reflect light

  • Rays refracted by cornea, aqueous humor, lens, vitreous body and onto retina.

  • Light stimulus is changed to nerve impulses, travel thru optic nerve to visual cortex in occipital lobe

  • Image on retina is upside down & reversed. At the optic chiasm retinal fibers cross over. Right side of brain looks at left side of world.

Visual reflexes

  • Pupillary light reflex bright light = constriction

    • Direct light reflex

    • Consensual light reflex

  • Fixation ability to track an object & keep image on the fovea, can be impaired by drugs, alcohol, fatigue & inattention

  • Accomodation for near vision = pupil constriction & convergence of eyes

Subjective data

  • Vision difficulty

  • Pain

  • Strabismus, diplopia

  • Redness, swelling

  • Watering, discharge

  • Past history ocular problems

  • Glaucoma

  • Glasses/ contacts

  • Medications

  • Vision loss- coping mechanisms

  • Selfcare behaviors

Objective data The Physical Exam

  • Preparation

    • Position- sitting, head at eye level

  • Equipment

    • Snellen eye chart- visual acuity

    • Handheld visual screener-near vision

    • Opaque card

    • Penlight

    • Applicator stick

    • Ophthalmoscope

Test visual acuitySnellen eye chart

  • Stand 20 ft. from chart

  • Glasses / contacts (Document )

  • Remove eye wear, retest

  • Normal visual acuity is 20/20 top # is distance person is standing from the chart

  • Vision 20/30 refer to opthalmologist or optometrist

  • If unable to see largest letters, move to 10 feet record as 10/200

Test for near vision

  • Vision screener

  • People > 40yrs or difficulty reading

  • Test each eye with glasses

  • Hold card 14in. from eyes

  • Normal result 14 / 14

  • Test using any available reading material if no card available

  • Presbyopia is a normal physiological change in near vision occurs with aging = note if the person moves the card farther away

Test visual fieldsConfrontation test

  • Compares peripheral vision with a tester who has normal peripheral vision

  • 2 ft. apart, eye level

  • Tester & client cover opposite eyes

  • Tester advances finger in the periphery

    • Superiorly ( 50 degrees )

    • Inferiorly ( 70 degrees )

    • Temporally ( 90 degrees )

Inspect Extraoccular Muscle Function

  • Corneal light reflex

  • Cover test

  • Diagnostic positions test

    • 6 Cardinal Positions of Gaze

Inspect Extraocular Muscle Function

  • Corneal Light Reflex ( The Hirschberg Test) assesses parallel eye alignment

    • Shine light toward persons eyes

    • Tell to stare directly ahead

    • Hold light 12 in. away

    • Light should reflect on both corneas in same spot

  • Cover Test- detects deviated alignment

    • Stare straight at examiners nose

    • Cover 1 eye of the person being examined with opaque card

    • Normally the uncovered eye should maintain a steady, fixed gaze

    • Covered eye- should stare straight ahead when covered & then uncovered. If muscle weakness exists the covered eye will relax and then jump to fixed position when uncovered..

Diagnostic Positions Test

  • 6 cardinal positions of gaze

    • Determines muscle weakness during movement

    • Person must hold head steady

    • Follow movement of object (examiners finger, pen etc) only with eyes

    • Hold object 12 in. from person

    • Move thru each position, clockwise, hold , then back to center

    • Normal response= parallel tracking with both eyes

  • During this test be aware of Nystagmus-fine jerky movement seen around the iris

  • Mild nystagmus in extreme lateral gaze is normal but not normal in any other position

Inspect External Structures

  • General movement & facial expression (squinting?)

  • Eyebrows 2(bilateral), symmetrical (look the same; move the same)

  • Eyelids & Lashes present, approximate when closed, no redness, swelling, discharge, lesions?

  • Eyeballs- alignment, ? Protrusion? Sunken?

  • Conjunctiva & Sclera moist, glossy, clear, white sclera

  • Eversion of the upper eyelid FYI we will not do this examine in lab see pg. 312 for technique usually done for complaint of eye pain due to foreign body

  • Lacrimal Apparatus

    • Person looks down

    • Using thumbs, slide outer part of upper lid along bony orbit

    • Note redness or swelling

    • Press index finger against lacrimal sac at inner canthus

    • Normal response is slight eversion of lower lid, no tearing or discharge

Anterior Eyeball Structures

  • Cornea & lens

  • Iris & pupil

    • Size & shape

    • Pupillary light reflex

    • Accommodation

Cornea & Lens

  • Shine light from side across cornea

  • Check smoothness, clarity

  • Normally no opacities

Iris and Pupil

  • Iris = flat, round, regular, even color bilaterally.

  • Pupils = PERRLA

    • Resting size norm = 3-5mm

    • 5% population have pupils of 2 diff. Sizes called Anisocoria

  • Pupillary Light Reflex

    • Darken room

    • Person gazes straight ahead

    • Advance light from the side

      • Direct light reflex

      • Consensual light reflex

    • Measure pupil size before & after light reflex

    • Measurement R3/1 L3/1 =both pupils measure 3mm in resting state & 1mm with light

  • Accomodation

    • focus on distant object -dilatation of pupils

    • Shift gaze to near object pupils constrict & converge

  • Record the normal response to these tests as

  • PERRLA = Pupils Equal, Round, React to Light and Accomodation

Ocular Fundus (internal surface of retina)

  • Use Opthalmoscope- try keeping both eyes open- practice looking at a ring on your finger. Become familiar with the instrument before you examine your partners eyes

  • Diopter of opthalmoscope

    • Black numbers = +diopter, focus on near objects

    • Red numbers = - diopter, focus on further objects

  • Use ophthalmoscope in darkened room = dilates pupils

  • Remove examiners and persons eyeglasses but contact lenses may be left in.

  • Select lg. White aperture light

  • Person should focus on a distant object and try & remain still

  • Examiner hold ophthalmoscope in Right hand to right eye to eamine persons right eye

  • Begin 10in away at 150 lateralangle & advance

  • Keep sight of red reflex

  • Adjust lens to +6 as you advance till your foreheads almost touch. Adjust diopter to focus.

    • Normal vision set at 0. Nearsighted use red #s. Farsighted use black.

Retinal background

  • Light dark red normally

  • Note Lesions

    • Size, shape, color, distribution

Macula & Fovea Centralis

  • Last in Funduscopic exam

    • 1 DD in size

    • Darker than rest of fundus

    • Foveal light reflex

    • Exam last

Retinal Vessels

Read Aging & Developmental Considerations

Review Abnormalities of the Eyes

3 most common causes of decreased visual functioning in the older adult

  • Cataract (lens opacity)

  • Glaucoma (increased ocular pressure) = loss of peripheral vision

  • Macular degeneration (breakdown of cells in the macula lutea) = loss of central vision

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