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45 Cards in this Set
- Front
- Back
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what is the general flow of vergence therapy
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1. Develop awareness of feedback cues early on in therapy
2. Smooth (Amplitude) 3. Step/"Jump" (Facility) 4. Integration (BIM/BOP) |
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vectograms use what type of glasses?
tranaglyphs use what type fo glasses? |
1. Vectograms = Polarized glasses
2. Tranaglyphs = Red/Green glasses |
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how do vectograms work?
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1. one vecto is seen with the OD, the other with OS
2. CONVERGENCE demand when OD vecto moves LEFT and OS vecto moves RIGHT 3. DIVERGENCE demand when OD vecto moves RIGHT and OS vecto moves LEFT |
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Prentice's Rule
- at 40cm - how much separation is 1 prism diopter - what happens when you change the working distance |
1. at 40 cm a 4mm target separation equals 1pd
2. increasing the working distance, decreases the vergence demand 3. decreasing the working distance, increases the vergence demand |
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explain SILO
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1. convergence, the object appears as if it is getting smaller and moving closer
2. divergence, the object appears as if it is getting bigger and moving away SILO is better in clinic than SOLI |
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SOLI is based on...
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prior VISUAL EXPERIENCE
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characteristics of the FIGURE 8 vecto gram
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1. single vectogram
2. BO to relative BI incorporated within the vectogram 3. pts. appreciate float and improve localization 4. LENSES and PRISM increase difficulty |
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characteristics of the QUOITS vecto gram
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1. peripheral target used in EARLY VT
2. less accommodative demand 3. early in VT, some blur can be allowed to encourage fusion 4. develop feedback cues: SILO, localization and float |
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characteristics of the CLOWN vecto gram
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1. contains CENTRAL and PERIPHERAL targets
2. contains relative BI demand at ortho setting 3. strong fusion target |
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characteristics of the MOTHER GOOSE vecto gram
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1. each target has a different vergence demand at ortho setting
2. weaker fusional stimulus than clown due to smaller target |
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characteristics of the CHICAGO SKYLINE vecto gram (4)
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1. plane has BI demand
2. buildings have BO demand 3. JUMP VERGENCE training 4. late therapy |
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characteristics of the SPIRANGLE vecto gram (3)
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1. advanced vectogram
2. move from center to periphery, the relative BO demand increases 3. STEP VERGENCE training |
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APERTURE RULE (5)
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1. 30BI - 30BO demand
2. single aperture forces the visual axis to cross (convergence training) 3. double aperture forces OD to view right target, and OS to view left target 4. small targets requiring voluntary control over accommodation and convergence 5. each card has about 2.5pd vergence demand for a 60 mm PD |
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disadvantages of Tranaglyphs vs. Vectograms (3)
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tranaglyphs:
1. use of R/G materials may cause significant inequalities in retinal luminance and my promote SUPPRESSION 2. images printed in outline only, stimulates less retina, and decrease the stimulus to fuse 3. should not use as a substitute for Vectograms |
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MINUS lenses in VERGENCE THERAPY
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Convergence:
- used to bring the plane of accommodation CLOSER to vergence, DECREASING THE DIFFICULTY Divergence: - used to move the plane of accommodation AWAY from vergence, INCREASING DIFFICULTY |
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PLUS lenses in VERGENCE THERAPY
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Convergence:
- used to move the plane of accommodation AWAY from vergence, INCREASING DIFFICULTY Divergence: - used to bring the plane of accommodation CLOSER to vergence, DECREASING DIFFICULTY |
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why do we use lenses in vergence therapy
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to increase or decrease the difficulty of the task
1. greater the separation between the two systems, the greater the demand on the vergence system 2. decreasing the distance betwen the plane of accommodation and vergence makes the task easier |
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what does Wick (1985) suggests for EXOPHORIC patients (4)
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1. emphasize target distance, optimize proximal vergence contribution to vergence
2. use Lg and Med targets to increase proximal vergence contribution 3. use of MAXIMUM HAND CONTACT 4. emphasize accuracy and stereopsis |
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what does Wick (1985) suggests for ESOPHORIC patients (3)
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1. AVOID HAND INVOLVEMENT
2. work with stereoscope where distance cannot be accurately judged 3. use targets that are moved further away |
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what should be the goals of vergence therapy (6)
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1. emphasize feedback cues
2. greatest blur/break/recovery values should be sought 3. develop flexibility between accommodation and vergence 4. emphasize target clarity and singularity with each procedure 5. fusing a range from 5-15pd for vergence facility 6. sustain vergence activity without discomfort |
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what is the CLASSIC MODEL of sequencing in vergence therapy (3)
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1. greater emphasis on in-instrument training
2. proved most effective in constant strabismus and nonstrabismic patients with a sensory obstacle (DEEP SUPPRESSION) 3. treat 1st then 2nd then 3rd degree fusion, in order |
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what is the BROCK-FLAX MODEL of sequencing in vergence therapy
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1. HIGHLY SUCCESSFUL for nonstrabismic conditions in which there is NO serious sensory impediment to fusion
2. large peripheral (in real space) then move to smaller targets 3. as therapy progresses reduce cues for stereopsis by using 2nd and 3rd degree targets |
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for vergence issue what conditions would you use PLUS lenses for?
why? |
1. CE because of the HIGH AC/A ratio
2. FALSE CI since primary cause of the high exo at near is an AI 3. BASIC ESOPHORIA |
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for vergence issue what conditions would you use MINUS lenses for?
why? |
1. patients with HIGH AC/A ratios who are strabismic in order to help regain ocular and sensory fusion
2. USE WITH VISION THERAPY |
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what is SHEARD'S CRITERION
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compensating fusional vergence should be twice the phoria
prism needed= 2/3(phoria) - 1/2(compensating vergence) |
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what is PERCIVAL CRITERION
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1. patient should be functioning in the middle third of their fusional vergence range
2. if calculated value is (-), no need for prism, patient already satisfies PC prism needed= 1/3(greater of lateral limits) - 1/3(lesser of lateral limits) |
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what is the 1:1 Rule for Esophoria
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1. the patient should have 1pd of BI RECOVERY for each prism diopter of esophoria
prism needed= (phoria - recovery value)/2 |
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what should be the first consideration in any accommodative or binocular disorder
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CORRECTION OF ANY REFRACTIVE ERROR
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what type of conditions are lenses essentially ineffective
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LOW AC/A RATIO!!!
-due to minor effect accommodation has on the vergence system |
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what is the PRIMARY TREATMENT for a CI?
secondary? |
VISION THERAPY
1. in cases where VT cannot be done, BI PRISM may be used 2. apparently BI don't really work |
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Pencil Push Up in respects to VT in patients with CI
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if used, the patient should be highly motivated, complaint, and PHYSIOLOGICAL DIPLOPIA must be emphasized
1. DOESN'T WORK FOR KIDS 2. barely helpful in adults |
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what test does CITT compare
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1. home based pencil push ups
2. home based computer vergence/accommodative and pencil push-ups 3. office-based vergence/accommdative therapy with home reinforcements 4. office-based placebo therapy |
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what are the inclusion criteria for the CITT
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1. age 9-17
2. exo at near at least 4PD greater than distance 3. NPC break greater than or equal to 6cm 4. Low PFV (failing Sheard's) or PFV less than or equal 15PD blur 5. CI symptom survey score of 16+ 6. 12 week per treatment |
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what are the results of the CITT study
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1. after 12 weeks of treatment OBVAT was the BEST
2. OBVAT shows improvement in NPC, PFV, and greater percentage of reaching criteria of success 3, OBVAT BEST FOR SYMPTOMATIC CI IN KIDS |
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what is the primary treatment for DI?
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PRISMS
1. correct refractive error, generally has little effect on the magnitude of the deviation due to the low AC/A ratio 2. prescribe maximum PLUS for hyperopia 3. VISION THERAPY if prism doesn't work |
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what is the general scheme for VT in a DI patient
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Early:
1. emphasize feedback cues and sense of diverging 2. Normalize NFV @ near (smooth) 3. Normalize accommodative function Middle: 1. Normalize near PFV (smooth) 2. Normalize near PFV and NFV facility (step/jump) Late: 1. Normalize smooth NFV at intermediate and far 2. Normalize NFV facility at intermediate and far |
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Example:
what would you prescribe for the patient using the 1:1 RULE? A patient with a 6EP has a 2PD of BI Recovery? |
(D-B)/2
(6-2)/2= 2 BO prescribing 2BO reduces the phoria to 4, and increases the recovery to 4 thus fulfilling the 1:1 rule. |
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what is the primary treatment for CE
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PLUS FOR NEAR
1. balance NRA/PRA 2. prescribe off the MEM 3. must do CT through the near add as well due to high AC/A |
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what is different about VT for DE
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1. therapy is performed at NEAR first because patient will be more successful at first
2. begin with THIRD degree fusion FIRST and work backwards |
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what is the general scheme of VT for BASIC PHORIAS
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1. establish a feeling of what they lack (ex: eso start with divergence)
2. smooth, step/jump, facility in that order. 3. start with the harder distances and work your way to the easier distances 4. at the end do all ranges of distances |
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what is the general scheme of VT for fusional vergence dysfunction
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1. same as VT for basic phoria but train BOTH PFV and NFV at the same time
2. smooth, step/jump, facility in that order 3. establish accommodation EARLY |
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what are the ADVANTAGES of graphical analysis
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1. one can visualize the relationship between test data
2. helps identify erroneous results |
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what are the DISADVANTAGES of graphical analysis
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1. FAILS TO IDENTIFY:
- AI, AE, and Ill sustained Accommodation - FVD and OMD 2. Does not include fixation disparity info 3. too precise of a method to apply to the human binocular system |
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in graphical analysis:
AC/A ratio in relation to the phoria line |
AC/A ratio is the INVERSE of the phoria line
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what are the FIVE geometric points of ZCSBV
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1. the lateral position of the graph represents the distance phoria
2. the height of the zone represents the accommodative amplitude 3. the AC/A ration is the INVERSE SLOPE of the phoria line 4. the positive width corresponds to PFV, it runs from the phoria line to the BO boundary 5. the negative width corresponds to NFV, it runs from the phoria line to the BI boundary |
