NCM 101 - Eyes

• Numerator is the distance between the client and the snellen chart


  Visual acuity test
• Near vision test that is for 40 years old and above. Holding it should be at only 14 inches


  Jaeger Test
• The hardest layer of the eyes where the eye muscle are attached

  Sclera
• Middle layer of the eye

  Choroid
• plenty of arteries that will supply glucose and oxygen to the eye

  Choroid
• Inner layer of the eye

  Retina
• It dos not contain any arteries therefore the choroid will be the one to supply glucose and oxygen

  Retina
• The Retina consists of numerous layers of nerve cells, including the cells commonly called

  Rods and Cones
• This specialized nerve cells in the retina are often called to as

  Photoreceptors
• This nerve cells works on night time to see gray and white

  Rods
• This nerve cells works on daytime to see RBG colors

  Cones
• Iris

  Pupil

  Conjunctiva

  Sclera

  Upper and lower eyelid

  Parts of the external eye
• Circular muscle - to constrict the pupil when exposed to the light

  Iris
• To dilate the pupil to see at night or dim environments

  Radial muscle
• The central aperture of the iris

  Pupil
• muscles in the iris adjust to control the pupil’s size, which control the amount of light entering the eye
• A biconvex, transparent, avascular, encapsulated structure located immediately posterior to the iris.

  Lens
• functions to refract (bend) the light rays on to the retina

  Lens
• The lens bulges to focus on

  close objects
• The lens flattens to focus on

  far objects
• what time the baby can focus only on objects 1foot away

  first week to 3 months
• The babies able to see colors and perceive depth, and have the ability to focus with both eyes

  4 to 6 months
• babies have 20/20 vision adult level and can recognize people


  8 months
• They produce 3 months after delivery


  Tears and lacrimal glands
• Infants can cry the 1st month or 2 but no tears
• 1.5 ft distant from the baby, get a toy and move the ball to the right and left and observe the movement of the eye


  Fixation test for infants
• If the baby refuses to cover their eyes, the test will be considered failed and may be signs of abnormality
• Other name for corneal light reflex

  Hirschberg test
• Muscle strength and position of the eye can also be determined by light reflex
• CN III - Oculomotor nerve

  CN IV - Trochlear nerve

  CN VI - Abducens

  3 cranial nerve of the eye
• Cranial nerve responsible for the movement of the eye in upward and downward motion

  CN III - oculomotor nerve
• Cranial nerve that control the superior oblique muscle

  CN IV Trochlear nerve
• Cranial nerve that controls the eye lateral and medial


  CN VI Abducens
• Impaired vision 


  Myopia
• Distance between the snellen chart and the client

  Numerator
• The grade in what the client can only read

  Denominator
• What grade is when the client considered legally blind

  20/200
• Impaired near vision


  Presbyopia
• Indicated when the client moves the chart away from the eyes to focus on the print due to decreased accommodation and common over 45 years of age


  Presbyopia
• This is done to assess neurological disorders and peripheral vision

  Gross peripheral vision