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113 Cards in this Set
- Front
- Back
VT used to help the development of proper visual function in young children
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Developmental VT
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ESOPHORIA:
1. where does the eye drift at rest? 2. what TWO things will help overcome the esophoria? 3. patients will tend to localize objects...? |
1. drift INWARD
2. NFV helps overcome esophoria (or else diplopia) 2. RELAXATION of accommodation reduces esophoria 3. patient localize object being CLOSER than they really are |
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VT designed to prevent visual problems that would otherwise occur
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Preventative VT
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What four pieces of information do you need to calculate the AC/A ratio?
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1) Patient's PD (cm)
2) Target Distance (m) 3) Far CT finding 4) Near CT finding |
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EXOPHORIA:
1. where does the eye drift at rest? 2. what TWO things will help overcome the exophoria? 3. patients will tend to localize objects...? |
1. drift OUTWARD
2. PFV helps overcome exophoria (or else diplopia) 2. STIMULATION of accommodation reduces exophoria 3. patient localize object being FURTHER AWAY than they really are |
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VT used to help with vision conditions that have already been identified
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Rehabilitative VT
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what are four causes of vertical imbalance (hyperphoria)
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1. trauma
2. high eso/exo 3. muscle palsy 4. congenital (CN IV or anatomical anomaly) |
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Used to enhance visual skills for sports, work and academic demands
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Enhancement VT
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HIGH AC/A ration will be more ____ at near.
LOW AC/A ratio will be more ____ at near. Convergence (excess or insufficiency) implies that the patient is going to have issues at ___________. DIvergence (excess or insufficiency) implies that the patient is going to have issues at ___________. |
HIGH AC/A = more ESO at near
LOW AC/A = more EXO at near Convergence - Near Point (Low AC/A ratio - If we have NP problems, we would expect more EXO at near) Divergence - Far Point |
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1. what is UNILATERAL cover test is used to detect?
2. what is ALTERNATING cover test is used to detect? |
1. unilateral => tropias
a. cover one eye and look at what the OTHER EYE is doing b. when one eye is covered the turned eye moved to pick up fusion 2. alternating => phorias a. cover one eye and look at what that SAME eye is doing after uncovering it b. make sure you cover long enough for the patient to BREAK FUSION |
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Name Peachey's 4 areas of VT
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1) Developmental
2) Preventative 3) Rehabilitative 4) Enhancement |
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How is the Gradient AC/A measured?
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The NEAR phoria is repeated with - 1.00 and + 1.00 lenses.
The difference in phoria measurement with and without the lenses give the AC/A ratio. |
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Morgan's Norms:
Distance BO |
blur/ break/ recovery:
9/19/10 |
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Hierarchy of training techniques designed to build more adequate VT skills
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Sequential training
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How do MINUS lenses effect the vergence posture?
How do PLUS lenses effect the vergence posture? |
PLUS increase the EXO posture (relaXes accommodation which stimulates DIVERGENCE)
MINUS increase the ESO posture (stimulates accommodation which stimulates CONVERGENCE) ***This holds true only if the change in the lens power affects the accommodative system*** |
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Morgan's Norms:
Distance BI |
blur/ break/ recovery:
x/7/4 |
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Therapy program develops depending on PROGRESS of the paitient
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Directional training
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For an uncorrected hyperope, when we correct with lenses, how do we change accommodation?
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Without glasses they are relatively ESO but when we put a (+) lens in front of their eye, the posture moves more toward EXO
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Morgan's Norms:
Near BO |
blur/ break/ recovery:
17/21/11 |
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Morgan's Norms:
Near BI |
blur/ break/ recovery:
13/21/13 |
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Morgan's Norms:
NRA PRA |
NRA: +2.00
PRA: -2.37 |
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do you use habitual near Rx for NPC??
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YES!!!
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what is the subjective and objective results for NPC...which one do you use
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subjective: patient confirms diplopia
objective: doc. see one eye turn OUT use whichever comes first |
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what are NORMAL breaks and recoveries for NPC
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normal break: 3-5cm
normal recovery: +/- 3cm from break point abnormal break: greater than 12cm (receded) |
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for unilateral cover test you must allow both eyes too...on the target
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FIXATE!!!
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A - 1.00 lens is placed in front of a fully corrected individual viewing a target at 40 cm. If the patient showed a 3XP without the lens and has and AC/A ratio of 4/1, what would the phoria through the -1.00 lens be?
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1EP
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how do you orient the Maddox Rod when testing vertical deviation? lateral deviation?
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vertical: orient lines vertically
lateral: orient lines horizontally |
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A + 1.00 lens is placed in front of a fully corrected individual viewing a target at 40 cm. If the patient showed a 3XP without the lens and has and AC/A ratio of 4/1, what would the phoria through the + 1.00 lens be?
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7XP
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Maddox rod is horizontal OD, the light appears left of streak...what is the diagnosis
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ESOphoria OD
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Maddox rod is horizontal OD, the light appears right of streak...what is the diagnosis
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EXOphoria OD
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VT techniques for fixation are performed in what way?
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Monocularly
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Maddox rod is horizontal OS, the light appears left of streak...what is the diagnosis
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EXOphoria OS
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Maddox rod is horizontal OS, the light appears right of streak...what is the diagnosis
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ESOphoria OS
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What does a high AC/A ratio mean in layman's terms?
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When I change the accommodative system, I am going to get a ton of change in the vergence system.
I am going from the far point to the target at near so accommodation is stimulated and thus convergence is stimulated (in the ESO direction). If we dissociate this patient and have them accommodate by +2.50 then they are going to OVER - Converge because they are over doing it for accommodation. |
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Maddox Rod: the light is above the streak
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right eye hyper or
left eye hypo |
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When can you start binocular skills in VT?
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Once monocular skills are adequate and equal between both eyes.
Little binocular training skills are needed once monocular skills are built. |
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Maddox Rod: the light is below the streak
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the left hyper or
right eye hypo |
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Which types of pursuits are easier to control, small or large?
What other ability does pursuit training develop? |
Small pursuits are easier to control
Visual attention |
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what is tonic accommodation
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1. absence of visual stimuli
2. range 0.50-1.00D 2. aka dark accommodation 3. explains night myopia 4. infrared autorefractor used to measure this 5. decreases with age (presbyopia) |
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what is the most accurate way to measure tonic accommodation...why?
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difference of gaussian grating (DOGG)
1. blur free 2. low center spatial freq 3. no blur driven or convergence accommodation 4. not completely precise, proximal accommodation is not eliminated |
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How long should it take to complete the Distance Hart Chart?
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15 seconds
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what is fatigue of accommodation
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1. inability of the ciliary muscle to maintain contraction while viewing a near object
2. more common in hyperopes (greater demand) 3. increased LAG (accommodative response is less than the accommodative stimulus) |
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what is failure of accommodation
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inability to produce or maintain an appropriate accommodative response
1. accommodative insufficiency 2. ill-sustained accommodation 3. presbyopia |
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what is accommodative inertia
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1. aka accommodative infacility
2. problem changing their accommodation (~1s) 3. worked induced MYOPIA 4. trouble relaxing accommodation after prolonged periods of near point work |
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Give an example of how you would PROVIDE ADEQUATE FEEDBACK during PURSUIT training?
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- Make patient aware of the purpose of the task at hand
- Make patient aware when pursuits are inaccurate - Use an AFTERIMAGE to "tag" the fovea to help give patient visual feedback as to the accuracy of their pursuits - Computer activities use auditory feedback as to how accurate their performance is - Encourage the patient to prove feedback as to how well they think they are doing |
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what is accommodative excess
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1. spasm
2. pseudomyopia 3. hyperaccommodation, HIGH LEAD (>0.40D) accommodative response GREATER than accommodative stimulus |
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hofsetters formulae
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max=25-(2/5)(age)
avg=18.5-(1/3)(age) min=15-(1/4)(age) |
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what is the purpose of Donder's Push Up technique
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1. to identify the maximum amount the patient can accommodate
2. bring target to the first sustained blur 3. MONOCULAR |
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what is a LEAD? LAG?
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Lead: for distant target we tend to over accommodate
Lag: for close near point objects the response is slightly less than the stimulus |
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what is the purpose of Minus Lens Technique
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1. target is fixed @ 40cm and minus lenses are introduced until the patient cannot clear the target.
2. the total amplitude is the total amount of minus lenses plus the 2.50D (40cm) 3. MONOCULAR |
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If the endpoint of the NRA is diplopia, what could be going on?
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Patient is a HIGH EXO with a LOW PRV
The patients eyes already tend to rest out, when you add plus lenses in front of the eye, accommodation relaxes and wants vergence to DIVERGE (EXO posture) and their eyes rest so far out is almost impossible for the PRV (CONVERGENCE) to bring them close enough to keep the target single. Essentially the PRV has start the race farther back |
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what is the difference between minus lens and push up technique
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(-) lens: fixed target, proximal stimulus remains constant, minification from the minus lens
push-ups: angular subtense of the letters keeps increasing as it is brought in (increasing relative mag) |
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If the patient is struggling or showing signs of frustration during pursuit VT, what should the examiner do?
In which 5 ways can this be done? |
Decrease difficulty of VT tasks
1) Increase interest in task 2) Reduce the task demand 3) Provide adequate feedback 4) Increase kinesthetic feedback 5) Reduce demands and distractions |
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which technique is more natural...minus lens or push up techinque
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PUSH UP
better results |
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How long should it take to complete the Distance Hart Chart?
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15 seconds
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what are the four types of vergences
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1. tonic: physiological position of rest of the ocular muscles (distance findings)
2. proximal: convergence that arises because of psychological awareness of obj 3. accommodative: convergence that occurs with a change in accommodation 4. fusional: responds to keep obj of regard single |
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what are characteristics of convergence insufficiency
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1. orthophoria to low exophoria @ distance
2. high exophoria @ near 3. receded NPC 4. low BO ranges 5. low NRA 6. low AC/A ratio good candidate for visual training |
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what are characteristics of convergence excess
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1. orthophoria to low exophoria @ distance
2. high esophoria @ near 3. normal NPC 4. low BI ranges 5. low PRA 6. high AC/A ratio 7. large lag of accommodation good candidate for bifocal Rx |
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what is AC/A ratio
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the ratio of accommodative convergence to the change in stimulus to accommodation...the measured convergence is divided by the accommodative stimulus
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how do you set up the phoropter to test for von graffe phorias at DISTANCE? NEAR?
which one is the measuring prism for Lateral Phoria? Vertical? |
Distance: 6 BD OS and 12 BI OD
Near: 6 BD OS and 15 BI OD Lateral: Base In is the Measuring Prism Vertical: Base Down is the Measuring Prism |
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how do you set up for PFV? NFV?
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1. put patient in phoropter
2. put both Risley Prisms at the 12:00 position 3. turn prism dials Temporally for Base IN (PFV) 4. turn prism dials Nasally for Base OUT (NFV) |
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What are the 5 ways you INCREASE the difficulty of PURSUIT therapy?
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1) Decreease the interest of the task
2) Increase task demand 3) Reduce Feedback 4) Reduce Kinesthetic Support 5) Increase demands for balance, cognition, and fusional vergence |
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for vergence testing...when is there NOT a blur??
what happens if the patient reports a blur in the specific test? |
DISTANCE BASE IN
x/7/4 if there is a BLUR the patient is ACCOMMODATING at the FAR POINT Dx: Accommodative Excess or PseudoMyopia |
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what are the normal values for NPC in adults? kids?
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adults: 5/7 cm
kids: break at 6cm |
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what does BCC tell you?
what is the expected values |
1. used to determine POSTURE of accommodation
2. +0.25 to +0.75 |
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For PRA, if the endpoint is diplopia, what is going on?
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HIGH ESO at near with LOW NRV
(-) lenses in front of the stimulates accommodation which then causes vergence to converge. To keep the target single, NRV must DIVERGE to counteract the convergence signal from accommodation. If the patient is a HIGH ESO meaning their posture is IN then they will have to work really hard to try and converge. |
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what is the BEST way to test accommodative posture in adults? in kids?
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adults: BCC
kids: MEM |
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What does a HIGH PRA mean?
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Patient could be suppressing an eye which in that case you are performing a MINUS LENS TO BLUR AMPLITUDE inadvertently.
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what is the set up for BCC
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1. 40cm using the cross cylinder target
2. +/- 0.50 in both eyes (JCC) 3. very dim illumination 4. add +2.00 over manifest 5. vertical lines should be darker 6. add minus until horizontal lines and vertical lines are the same (or when horizontal lines are darker) |
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What does a LOW PRA mean?
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1) Difficulty stimulating accommodation
2) High ESO at near compared to the distance |
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Give three examples of EARLY pursuit activities.
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EARLY pursuits are SMALL pursuit movements.
1) Thumb Pursuits (incorporate kinesthetic effect) 2) Rotating Pegboard (central target with pegboard) 3) Manual Pursuits (with or without kinesthetic support - emphasize small pursuits) |
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what is the purpose of NRA/PRA
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1. determine ADD
2. test patients range of accommodation under BINOCULAR influence 3. changes accommodation without changing vergence!! 4. check for overminus and indirectly evaluate vergence system |
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Give three examples of LATE pursuit activities.
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LATE pursuits are LARGE pursuit movements.
1) Groffman Visual Tracing 2) Rotating Pegboard (using outer target on the pegboard and increase the speed of the pegboard) 3) Flashlight Tag (emphasize large pursuits) |
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how does NRA and PRA indirectly test the vergence system
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1. when MINUS lens added, NEGATIVE relative vergence is needed to maintain alignment
2. when PLUS lenses are added, POSITIVE relative vergence is needed to maintain alignment. |
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what accommodative testing MUST be done to check for suppression
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binocular accommodative facility (BAF)
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What is the typical stopping point for PRA?
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- 2.50
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what are the three types of stereopsis testing in the randot book
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1. suppression check (R/L)
a. polarized glasses 2. Wirt Circles (Local) a. contains monocular cues 3. global stereopsis a. patient MUST be bifoveal to see target |
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What are 4 examples of EARLY saccadic activities?
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EARLY saccades are LARGE saccadic movements.
1) 4 Corner Fixations 2) Thumb Saccades 3) Wayne Saccadic Fixator 4) Distance Hart Chart |
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what are the two parallel neurological systems involved in ocular motor?
characteristic of each? |
magnocellular:
1. peripheral retina 2. fast system that senses MOTION 3. WHERE is the obj parvocellular: 1. central retina 2. senses color, shape and detail 3. WHAT is the obj |
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What 3 LATE saccadic activities?
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LATE saccadic activities involve SMALL saccades.
1) Michigan Tracking 2) Computer Saccadic Activites 3) Distance Hart Chart |
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What is the GOAL for balancing NRA/PRA?
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The goal is to determine a nearpoint lens that places the patient's posture of accommodation in the middle of the NRA and PRA for maximum comfort.
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what is the difference between the SCCO and NSUCO
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SCCO: sitting
NSUCO: standing |
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What are 7 methods of DECREASING difficulty of therapy tasks?
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1) Negate gravity by having the patient in the supine position or be seated
2) Move the target at a slower pace 3) Use a larger target 4) Increase the interest of the target or change the target more often 5) Use kinesthetic support (touch the target) 6) Encourage verbalization of the target 7) Perform therapy in a quiet room |
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in saccades what type of movement error is MOST COMMON
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undershooting
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What are 6 methods of INCREASING difficulty of therapy tasks?
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1) Remove kinesthetic support (do not allow patient to use finger)
2) Perform skill standing or on a balance board or on one leg 3) Increase target speed 4) Decrease size of target 5) Increase demands on the vergence and accommodation system 6) Increase cognitive demand |
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what is unique about the DEM testing
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1. tests AUTOMATICITY
2. determines if the patient has difficulty in recalling numbers |
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what are the FOUR possible outcomes of the DEM
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Type 1: Normal
Type 2: OMD only (normal vertical, low horizontal, high ratio) Type 3: AUTO only (low vertical and horizontal, normal ration) Type 4: OMD and AUTO (H>V, HIGH RATIO) |
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what does the ratio in DEM testing indicate
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Ratio= H/V
tiebreaker between type III and type IV vertical test for automaticity |
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what are the four categories of saccadic dysfunction
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1. velocity
2. accuracy 3. initiation 4. inappropriate saccade |
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What does the blur point represent?
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The blur point represent the point where the patient can no longer compensate for the prism - induced retinal disparity while maintaining stable accommodation
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what are 3 ways to manage OMD
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1. correct refractive error
2. PLUS lenses for NEAR 3. vision therapy |
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During the NRV/BI testing, blur will occur for what reasons?
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1) Low DIVERGENCE reserves like in ESO
2) Accommodation NOT being stimulated |
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what is the most common problem with PURSUITS?
when is this problem seen? |
COGWHEELING
1. steplike eye movements that replaces smooth ones 2. basal ganglion disease, Parkinson's and Cerebellar disease |
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what are FOUR examples of FIXATION therapy
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1. dotting O's
2. monocular stick in straw 3. AN star fixation 4. stationary peg board |
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What does a LOW NRV/BI finding mean?
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1) Near ESO (eyes rest in and therefore they have hard time DIVERGING out)
2) Difficulty STIMULATING accommodation |
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what are SIX examples of PURSUITS therapy
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1. thumb pursuits
2. manual pursuits 3. marsden ball 4. flashlight tag 5. rotating pegboard 6. visual tracing (groffman tracing) |
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What does a HIGH NRV/BI finding mean?
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1) Near EXO (eyes rest out and therefore have less to go when they DIVERGING out)
2) Difficulty RELAXING accommodation |
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what are FIVE examples of SACCADES therapy
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1. thumb saccades
2. four corner wall fixation 3. distance hart chart 4. saccadic workbook 5. michigan tracking |
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what are the steps in development of vision therapy
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1. fixation
2. small pursuits to larger pursuits 3. large saccades to small saccades 4. ocular therapy with accommodative and vergence therapy |
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During PRV/BO testing, what are some reasons blur occurs?
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1) Low CONVERGENCE ability like in HIGH EXO at Near
2) Difficulty RELAXING accommodation (NRA) |
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what are BIOCULAR techniques in OMD therapy
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activities that are done with both eyes open but the patient is not fused
ex: dissociating prism during marsden ball pursuits |
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PRV:
1. When does the blur occur? 2. What happens after the blur occurs? 3. When does diplopia occur? |
When accommodation can no longer act independently from the vergence system.
Accommodation then supports convergence to keep the target single. Diplopia occurs when PRV (causes they eyes to converge) and PAV can no longer keep up with the increasing amounts of convergence. |
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AC/A FORMULA
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AC/A=IPD(cm) + NFD(m)(Hn-Hf)
IDP: interpupillary distance (cm) NFD: near fixation distance (m) Hn: Near Phoria (eso +, exo -) Hf: Far Phoria (eso +, exo -) |
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LOW PRV/BO finding mean what?
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1) Near EXO
2) Difficulty RELAXING accommodation |
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scenerio:
1. patient is fixated on a target at 40cm 2. PLUS lens is introduced 3. what happens to the accommodation? 4. what does the vergence plane want to do? what will happen? 5. what has to occur for the vergence to not move |
1. accommodation is RELAXED
2. vergence plane wants to move with accommodation 3. if vergence is allowed to move with accommodation, DIPLOPIA will occur 4. positive relative vergence (PRV) must be stimulated to keep the target single |
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HIGH PRV/BO finding mean what?
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1) Near ESO
2) Difficulty STIMULATING accommodation |
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what is relative vergence
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vergence that functions INDEPENDENTLY from the accommodative system
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What is the vergence movement used to resolve retinal disparity of an image?
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Fusional Vergence
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In NRA/PRA, how do you test which system is having the difficulty (accommodation or vergence)
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1. COVER ONE EYE
2. if the target clears, problem with PRV/NRV not ACCOMMODATION |
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What term will be reserved for describing the vergence movements free from accommodation during fusional vergence testing (before the blur point)?
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Relative Vergence
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how do you balance NRA/PRA
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[(NRA+PRA)/2]+RPV
relative point value: 1. if done through manifest, RPV=0 2. if done through BCC, RPV=BCC |
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What encompasses both relative vergence and accommodative vergence?
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Total Vergence
(Positive or Negative) |
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scenerio:
1. patient is fixated on a target at 40cm 2. MINUS lens is introduced 3. what happens to the accommodation? 4. what does the vergence plane want to do? what will happen? 5. what has to occur for the vergence to not move |
1. accommodation is STIMULATED
2. vergence plane wants to move with accommodation 3. if vergence is allowed to move with accommodation, DIPLOPIA will occur 4. negative relative vergence (NRV) must be stimulated to keep the target single |