Eyes

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Eyes
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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

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External Anatomy
External Anatomy
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• 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

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• 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

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• 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

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• Cornea clear, covers protects iris pupil

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• 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

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Extraoccular muscles

• 6 muscles
• Attach eyeball to orbit
• Straight and rotary movement
• Four straight muscles
• Superior rectus
• Inferior rectus
• Lateral rectus
• Medial rectus

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• Two slanting/ oblique muscles
• Superior
• Inferior
• Humans have a Binocular, single image visual
  system Eyes normally move as a pair

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• Eye movement stimulated by Cranial Nerves
• III Oculomotor
• IV Trochlear
• VI Abducens

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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

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• 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

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• 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

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• Macula temporal side of fundus, darker
  pigmented region, surround the fovea centralis
• Fovea Centralis- area of sharpest keenest
  vision, Very sensitive to light

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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.

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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

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Subjective data

• Vision difficulty
• Pain
• Strabismus, diplopia
• Redness, swelling
• Watering, discharge
• Past history ocular problems
• Glaucoma

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• Glasses/ contacts
• Medications
• Vision loss- coping mechanisms
• Selfcare behaviors

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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

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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

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Test for near vision

• Vision screener
• People gt 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

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

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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 )

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Inspect Extraoccular Muscle Function

• Corneal light reflex
• Cover test
• Diagnostic positions test
• 6 Cardinal Positions of Gaze

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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

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• 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..

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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

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• 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

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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

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• 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

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• 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

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Anterior Eyeball Structures

• Cornea lens
• Iris pupil
• Size shape
• Pupillary light reflex
• Accommodation

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Cornea Lens

• Shine light from side across cornea
• Check smoothness, clarity
• Normally no opacities

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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

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• 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

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• 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

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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

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• Diopter of opthalmoscope
• Black numbers diopter, focus on near objects
• Red numbers - diopter, focus on further objects
• Use ophthalmoscope in darkened room dilates
  pupils

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• 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

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• Begin 10in away at 150 lateral angle 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.

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Retinal background

• Light dark red normally
• Note Lesions
• Size, shape, color, distribution

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Macula Fovea Centralis

• Last in Funduscopic exam
• 1 DD in size
• Darker than rest of fundus
• Foveal light reflex
• Exam last

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Retinal Vessels
Arteries Veins
COLOR Light red Dark red
SIZE Smaller 2/3 to 4/5 diam. Of veins Larger
LIGHT REFLEX Bright Inconspicuous absent
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Read Aging Developmental Considerations

• Review Abnormalities of the Eyes

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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