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Vision Screening Eye and Vision Screening Procedures, Part 4 PowerPoint Presentation
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Vision Screening Eye and Vision Screening Procedures, Part 4

Vision Screening Eye and Vision Screening Procedures, Part 4

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Vision Screening Eye and Vision Screening Procedures, Part 4

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  1. Vision Screening Eye and Vision Screening Procedures, Part 4 Department of Blind and Vision Impaired Created by Carmen Valdes & Lisa Shearman 1

  2. DBVI EDUCATION COORDINATORS Contact List Bristol Regional Office: Richard Fanis (540)642-7300 Roanoke Regional Office: John McHugh (540)857-7122 Fairfax Regional Office: Vacant Contact: (703)277-3595 Staunton Regional Office: Lisa Shearman (540)332-7716 Norfolk Regional Office: Donna Cox (757)858-6724 Toll Free Number: (800)622-2155 Richmond Regional Office: Sue Cobb\ (804)371-3353 2

  3. Eye and Vision Screening Procedures Learning Objectives for Part 4: 1. Methods for testing vision for infants and toddlers. a. Testing for sensitivity to light. b. Testing eyes for reflexive reaction. c. Testing for convergence or looking at the exact same point in space. 3

  4. Vision Screening is Important  Children under three do not know how they should see. In addition, they cannot tell you how or what they see. Vision problems are not always obvious. Early identification through vision screening is crucial and should be followed up with appropriate referrals for further evaluation, correction and/or intervention services when vision concerns are present. Vision should be screened at birth, 6 months and again at three years. 4

  5. Types of Testing  Response to light An infant will blink in response to a bright light.  Pupil response Measuring the response of the pupil (the black center part of the eye) to shining a penlight in the eye is one way to test an infant's vision.  Ability to follow a target The most common vision acuity test in infants is a test to check their ability to look at and follow an object or toy.  Visually evoked response testing These are tests that stimulate the eyes with either a bright light or special pattern. The infant is connected to a special monitor with attachments on the infant's head. The machine then records electrical activity in the brain as the lights and patterns are shown to infants. 5

  6. More Types of Testing  Cover/Uncover test This test looks for movement and alignment of the eyes that may occur when a child is focusing on an object. One eye is covered with an opaque card while the child stares straight ahead, at which time the examiner observes the uncovered eye.  Visual acuity tests Specific tests and charts may be used to measure both near and distant vision. In the preschooler, these charts may consist of pictures or stories instead of letters of the alphabet.  Color testing This test helps determine color blindness in a child. 6

  7. Sensitivity to Light Test the infant or toddlers eyes by using the following steps: Dim lights or go to a dimly lit location then quickly flash a light into the child’s visual fields and then remove it Turn overhead lights on and off Pull shades up and down Bring child into a bright sunny window     Recommendations: Pass: Both eyes respond quickly Refer: Absent or sluggish response 7

  8. Pupils Constrict to Light You may be able to observe the pupils changing size (i.e. getting smaller when exposed to more light) by doing one or more of the following: Dim lights or go to a dimly lit location then aim a flashlight at the child’s forehead, between the eyes (less intrusive) Use colored caps on a penlight/flashlight, aim light between the eyes (less intrusive) Turn overhead lights on (minimal intrusion) Pull shades up (minimal intrusion) Bring child into a bright sunny window (minimal intrusion) Recommendations: Pass: Both eyes respond quickly Refer: Absent or sluggish response 8

  9. Dilated Pupils Note: If dilated pupils are observed in brightly lit environments or it is observed to be sluggish or absent, ask what medications the child is taking. Medications to control neurological issues may inhibit this response. If this is the case, it must be noted and considered during the screening. 9

  10. Displays Defensive Blink The following technique is used to check the eye reflexes: When you quickly open your fingers as your hand approaches child’s eyes, child blinks. Note: This is a safety mechanism. Absence of this behavior may indicate a sign of acuity difficulties. However, this behavior may be difficult to observe in a consistent manner. Recommendations: Pass: Yes Refer: If any other concerns are noticed. 10

  11. Corneal (light) Reflection Test The following steps are used to test the corneal reflection response: 1. Position penlight 12 -18 inches from the eyes, aimed at the nose. Reflection of the penlight should be observed in same position in each pupil, indicating alignment of eyes. 11

  12. Corneal (light) Reflection Test (2) You may also be able to observe this by watching the light reflection of one the following sources: Penlight/flashlight with colored caps on (less intrusive) Overhead lights (minimal intrusion) Sunlight coming from a window (minimal intrusion)    Recommendations: Pass: Reflection of light equal, same position in both eyes Refer: Reflection of light is NOT equal, different position in both eyes 12

  13. Convergence Convergence is the ability of both eyes to turn inwards together to view an object. This enables both eyes to be looking at the exact same point in space. This skill is essential to being able to pay adequate attention when reading. To test convergence move the light 12 to 16 inches away from the child’s nose; the eyes should cross. The reflection of the light from the front surface (cornea) of each eye should line up in the same place over each pupil. Recommendations: Pass: Both eyes follow to at least 4-6 inches from the nose Refer: One eye deviates or child looks away Normal Crossed left-eye Crossed right-eye 13

  14. Fixation on Object The Fixation (at 8-18 inches) tests the child’s eyes while focusing on an object or light. The examiner notes whether the child alternates, prefers fixation with one eye, or can hold fixation well with either eye. For instance, refusal of the child to have the right eye covered while not objecting to having the left eye covered is interpreted as evidence for reduced visual acuity in the left eye. Type of object to use:  4x5 inch object at 2 months old  1 inch object at 4 months old  Cereal at 6 months old Recommendations: Pass: Steady fixation Refer: Fleeting or not able to fixate 14