Heterophoria

Question 1

normal binocular vision

Answer 1

• both eyes simultaneously cooperating
• single perception of object
• fusing of images from the 2 eyes

Question 2

sensory fusion

Answer 2

integration of similar images at the cortex

Question 3

motor fusion

Answer 3

• motor alignement to sustain binocular vision
• tries to eliminate disparities of 2 images
• tries to FUSE as best as possible to make one image
• NEEDS vergence to produce one image

Question 4

convergence

Answer 4

tries to maintain binocular vision by ensuring images are on corresponding retinal areas of the eye so there is no disparity

Question 5

NPC

Answer 5

closest distance where the eyes can converge and maintain binocular vision

Question 6

cover-uncover

Answer 6

• presence of deviation ( ONLY DETECTS TROPIA)
• lateralitly
• frequency (constant/intermittent)

Question 7

intermittent tropia

Answer 7

shows when dilated or tired

Question 8

if there is ANY movement in cover/uncover…

Answer 8

tropia only

Question 9

alternating cover test

Answer 9

• direction
• magnitude
• distance and near

Question 10

Why is phoria only present on alternating cover test>

Answer 10

because fusion is broken

Question 11

heterophoria

Answer 11

tendency of the eyes to deviate when fusion is blocked

-when there is something to focus on, there is no tendency to deviate

Question 12

visual axes

Answer 12

from the fovea to the point of fixation

Question 13

symptoms associated with heterophoria if fusional amplitudes are not enough

Answer 13

• convergence insufficiency
• convergence excess
• divergence insufficiency
• divergence excess

Question 14

measurement of phorias and tropias

Answer 14

at distance and near

Question 15

maddox rod

Answer 15

used to measure horizontal and vertical phoria

rod dissociates the eye

Question 16

maddox rod phoria test (in space)

Answer 16

need: penlight, madox rod, prisms
- done cc
- hold penlight 40cm for near
- have pt look at muscle light for distance
- hold maddox rod over OD

Question 17

horizontal phoria

Answer 17

the grooves on the maddox rod are oriented horiztonally. The pt will see a vertical streak

Question 18

vertical phoria

Answer 18

the grooves are oriented vertically, giving a horizontal streak

Question 19

red line through the white light

Answer 19

ortho

Question 20

red line to the right of the light

Answer 20

eso, uncrossed diplopia

Question 21

red line to the left of the light

Answer 21

exo, crossed diplopia

Question 22

red line below the light

Answer 22

right hyper

Question 23

red line above the light

Answer 23

left hyper

Question 24

suppression

Answer 24

active deactivation of a retinal image in one eye by the visual cortex
-brain prefers to suppress and provide vision as close to binocular vision as possible

Question 25

alterante suppression in W4D

Answer 25

can see 3 then 4 dots

include when recording

Question 26

prims for R hyper

Answer 26

BU over OS

Question 27

prism for L hyper

Answer 27

use BD over OS

Question 28

Can maddox rod differentiate phoria from tropia?

Answer 28

no

Question 29

example of recorded maddox rod

Answer 29

DLP with red cc 4 XP, DVP ortho

NLP with red sc 5 XP, NVP 4 R hyperphoria

Question 30

expected findings in maddox rod

Answer 30

1 prism D to +/- 2 prism D at D

3 prism D +/- 3 prism D at N

Question 31

modified thorington phoria

Answer 31

uses thorington cards

• D at 10ft
• 40cm at near

Question 32

instructions for thorington phoria

Answer 32

• same as maddox rod
• cc
• hold maddox rod over OD
• ask where line is relative to the light
• DLP by modified thorington: 4 prism D, DVP ortho

Question 33

normal findings with thorington phoria

Answer 33

D: 1 pD XP +/- 2 pD
N: 3pD XP +/- 3 pD

Question 34

3 possible reflexes in Hirschberg

Answer 34

• center of pupil
• nasal to the pupil (ex, positive lambda)
• temporal to pupil (neg lambda, eso)

Question 35

what is normal corneal reflex in Hirschberg?

Answer 35

about 0.5mm nasal to the center of pupil