Unit 5

Question 1

types of deviation?

Answer 1

-eso
-exo
-hypo
-hyper

Question 2

3 binocular tests in free space

Answer 2

-cover test
-EOM
-ROM (range of motion)
-stereopsis

Question 3

binocular vision testing w. a phoropter?

Answer 3

von graefe

Question 4

why is binocular vision important?

Answer 4

1. single vision
2. steropsis
3. enlargement of the field of vision
4. compensation of the blind spot
5. prevents diplopia

Question 5

eso deviation

Answer 5

-inward misalignment
-BASE OUT PRISM
-can be refractive or nonrefractive

Question 6

accomodative esotropia

Answer 6

-most common type of childhood esotropia
-high hyperopid refractive errors
-treated by prescribing plus lenses, which may or may not fully correct the deviation

Question 7

Exo deviation

Answer 7

-outward misalignment
-Base IN prism
-Small exophoria (<10Δ), usually greater at near, is common in the normal population
-Also common for newborns to have a transient exotropia in the first few months

Question 8

convergence insufficiency (CI)

Answer 8

exo is larger at near
-may be treated using excercies or prisms

Question 9

hyper deviations

Answer 9

-upward misalignment
-Base DOWN prism

Question 10

hypo deviation

Answer 10

-downward misalignment
-Base UP prism

Question 11

Ocular motility /EOM testing

Answer 11

-Determine if the eyes acheive each position together.
~smoothly, accurate, fast and equal (SAFE)
-normal results will show equivalent movement of the eyes into each position
~documented as FULL
-if the eye do not move equally together, further EOM testing is needed

Question 12

stereopsis testing assesses??

Answer 12

-the ability to use both eyes
-the brains ability to fuse the slightly difference image from each eye into one three-dimensional image

Question 13

when is steropsis often done?

Answer 13

-during the pediatric screening
-adults who present with history of strabismus, new complaints of diplopia, or self-reported problems with depth perception should be tested

Question 14

how many positions do we analyze during EOM

Answer 14

9 positions of gaze

Question 15

von graefe method ; Lateral phoria

Answer 15

-Ensure prism adaptation has a minimal effect, the letters should only be made visible for brief 1 second flashes.
-Occlude the right eye with the handheld occluder, then remove and ask if the top letter is to the right or left of the bottom letter.
-Reduce the base in prism (in front of the right eye) accordingly until the letters line up ‘like buttons on a shirt

Question 16

von graefe method ; Vertical phoria

Answer 16

-usually measured after the distance lateral phoria
-reduce the base up prism in front of the left eye until the px reports that the two letters line up like headlights on a car

Question 17

3 systemic conditions with ocular involvement that can impact the prescription

Answer 17

-thyroid eye disease
-myasthenia gravis
-multiple sclerosis

Question 18

thyroid eye disease (TED)

Answer 18

-graves eye disease, graves orbitopathy
-autoimmune inflammatory disorder that can cause immune cells to infiltrate the EOMs
-there is swelling of the fat behind the eyeball cause the eye to buldge forward (EXOPHTHALMOS)
-may cause double vision
(prisms or patching may be used to relief diplopia)

Question 19

how much prism for von graefe

Answer 19

12 base in OD
6 base up OS

Question 20

Myashenia gravis

Answer 20

-an autoimmune disease that affects the transmission of impulses between nerves and muscles and results in muscle weakness
-about 90% of ppl with MG have ocular involvement (ptosis and diplopia are first signs)
-prisms or occlusion therapy may be needed

Question 21

multuple sclerosis

Answer 21

-chronic immune-mediated disease that attacks the central nervous system (MS damages myelin)
-interripts nerve impulses traveling to and from the brain, spinal cord and eye
-effects on the eye may include ; optic neuritis, nystagmus, diplopia

Question 22

what condition does an ice cube help with ?

Answer 22

Myasthenia Gravis

Question 23

what condition does optic neuritis relate to

Answer 23

Multiple Sclerosis

Question 24

Amblyopia

Answer 24

-early detection and treatment is so important
-if left untreated it can result in permanent visual defect or loss of depth perception
-if vision in the “good” eye is lost down the road, one might suddenly be unable to work or drive

Question 25

Spectacle correction in children

Answer 25

-primarily done by objective means until the age of 6
-limited cooperation
-questionable reliability
-must consider:
the pxs VA needs according to age
-accomodative elements
-risk of amblyopia

Question 26

many young children with strabismus are hyperopic or mnyopia

Answer 26

hyperopia and require glasses

Question 27

can gls fix children with fully accommodative esotropia

Answer 27

glasses fully correct the deviation
-GIVEN the full amount of plus and px wears FT

Question 28

can gls fix children with partially accomodative esotropia?

Answer 28

-gls lessen the deviation
-sx may be required

Question 29

do all children with starbismus have a refractive error?

Answer 29

no, some children may be emmetropic or have minimal refractive error.
-there would be little or no improvement in the strabismus or VA

Question 30

spectacle correction with prism

Answer 30

-adults are often prescribed prism to help control diplopia
-sometimes given a trial of fresnel prism
-range 1 to 40Prism
-can be orientated BD, BU, BI, BO

Question 31

convergence insufficiency

Answer 31

-most commonly prescribed eye exercises are used to treat convergence insufficiency
-Aim: to increase convergence ability
-taught in office and carried out at home
-BI prism may be used to help manage CI in severe cases

Question 32

CI exercise = Pencil push ups

Answer 32

-A pencil is held at arm’s length and brought toward the nose until the patient reports seeing double
-Goal is to keep the target clear and single
-Patient tries to get the target closer and closer each day

Question 33

Alternative CI excersises - Stereogram Cards

Answer 33

-a card consists of two similar images
-Patient holds the card at 40 cm and a pen in front of it at 20 cm
-Patient focuses on the pen, converging the eyes to elicit physiological diplopia
-Once the exercise is done easily the patient is asked to practice it without the pen
-used to fuse the two images into one

Question 34

excercise follow up visit

Answer 34

-specific data is used to evaluate the effectiveness of the treatment
~deviation
~near point convergence
~fusional convergence amplitudes

Question 35

allow comparions for pxs when a change in rx like..

Answer 35

-dial in the old and new values and have the px compare
-put the new rx in a trial frame and let them compare
-use flippers to illustrate a change in sphere over the current specs. This is useful when discussing an increase in ADD powers and verifying working distance

Question 36

is it normal to have large changes in astig?

Answer 36

these are no common and may suggest a refraction error/cortical cat/ lid lesions creating corneal distortions
-cyl changes are hard to adapt to especially if they are not oblique

Question 37

can myopia decrease?

Answer 37

yes, particulary in pxs in their 20-30s but be extremely careful especially if no symptoms

Question 38

things to know if they are refracting in a smaller room

Answer 38

-remember you may be only refracting at 20ft not infinity so the final result may be a little over plussed (ex; +0.17 with a 20ft correction)
-some practitioners may add an extra -0.25 to compensate for the shorter room