midterm Flashcards
in amblyopia, the best compensated visual acuity is _____ or worse in either or both eyes.
20/40
it is defined as a binocular or
monocular decrease in best corrected visual acuity (BCVA) due to pattern visual deprivation and/or abnormal binocular interaction during
visual immaturity for which there is no obvious ocular pathology or visual pathway defect and which in appropriate cases is reversible.
Amblyopia
Amblyopia is defined as a binocular or
monocular decrease in best corrected visual acuity (BCVA) due to _____________ during visual immaturity for which there is no obvious ocular pathology or visual pathway defect and which in appropriate cases is reversible (2)
-pattern visual deprivation
-abnormal binocular interaction
Before you diagnose a patient with amblyopia, make sure that he has no ocular __________(e.g. no glaucoma, no abnormalities during fundus or tumor, etc)
pathology
cause of amblyopia (1)
lack of proper eye development which results to Reduced Visual Acuity
meaning of:
lack of proper eye development which results to Reduced Visual Acuity
meaning something happened during the course of development. It may be during a critical period, at birth or 8-9 years old. there is a disease or an accident that may disrupt the proper development of the patient. It may lead to reduced visual acuity.
Categories of Amblyopia
(5)
-Strabismic Amblyopia
-Form Deprivation Amblyopia
-Anisometropia
-Isoametropia
-Refractive
types of form deprivation (3)
-Congenital Cataract
-Infantile Cataract
-ptosis
there is something that blocks the line of sight of the patient like congenital cataract or infantile cataract, or ptosis
Form Deprivation Amblyopia
when there is no input that can go inside the retina because the pupil is blocked
ptosis
unequal refractive error. usually you can consider if at least a 1.00D difference of right and left eye but if +1.00D, it doesn’t directly mean amblyopia, it must be
more than +1.00D
Anisometropia
chru or nope?
in anisometropia, If px is HYPEROPE: the patient is more prone to
develop amblyopia compared to Myope
chru.
ex: -5.00 and +5.00. Hyperope is more
prone to develop amblyopia compared to myope
approximately equal refractive error of both eyes but not necessarily equal
- ex: OD +5.25 and OS +5.00
Isoametropia
it is a type of amblyopia where in the higher the astigmatism, the higher the chance in developing amblyopia
Refractive
When both eyes are uncovered, both point towards the object of regard.
PHORIA
aka squint or tropia
STRABISMUS
chru or nope.
A strabismic patient does not perceive the world the same way, when the eye is turned, causing them to “suffer” from poor depth perception.
chru.
if a patient has strabismus, which of the 4 Circles of Skeffington is affected?
- Anti-gravity and Centering (major problem)
- Antigravity – answers the question WHERE AM I and where depth perception is concerned. So, if one eye is
turned then depth perception. - Centering – answers the question WHERE IS IT, and where binocular vision is concerned. If the patient has strab then the patient has problems in centering and binocular vision.
one eye is turned outwards, so if the
patient looks at the target, usually the target is placed BEHIND the real target.
Mismatch is present.
Exotropia
the target is perceived IN FRONT of the real target.
Esotropia
why is Brock string important?
Brock String is important because we can see how the patient localizes his space.
The patient cannot control his eyes due to: (5)
– POSTURE
– BALANCE
– CENTERING
– FIXATION
– IDENTIFICATION
the importance of centering (binocular vision) and anti gravity (depth perception) in strabismus
Binocular vision and depth perception are dependent upon visual development within these
2 circles. To accurately point both your eyes at an object, you must understand where you are and the distance between you and that object.
Not only are there interactions between all 4 circles, but experiencing depth perception will create feedback that enhances localization, centering, movement, and language.
chru or nope.
at 4 months of age, if the patient had fever or convulsions, there is a possibility that the patient may develop amblyopia or strabismus.
chru
how many months an infant develops binocular system?
4 months
Prevalence of amblyopia and strabismus.
- 4-6% of the population have amblyopia and/or strabismus.
prevalence of eso deviation
Eso deviations occur far more frequently than exo deviations, with a prevalence ratio of approximately three to one (3:1)
Esodeviation is more common rather than exo because exo deviation is associated with _______ (kids are more eso than exo)
neurological insult
Exo may be associated with _____ or _______
AV syndrome.
myasthenia gravis.
chru or nope.
There is no “critical period” in treating amblyopia and strabismus
chru.
We do not limit our patient in treating amblyopia and strab even if they’re in 30s, 40s, or 50s
however, there is a critical period in the development of amblyopia and strabismus at birth, or around 8-10 years old.
etiology/causes of Strabismus (3)
Anatomical
Optical
Innervational
due to impairment of cranial nerves III, IV, VI, which represent the majority of cases.
Innervational
(Strabismus cause)
refractive anisometropia, high RE, media opacities
- Optometrists can treat
- So if we identify that the patient’s strabismus is optical and we find out that he has a refractive error, we must first rule out the refractive error then we start from there
Optical –
abnormalities of EOM, ligaments, tendons, orbital contents.
optometrists must refer px to surgery
Anatomical
types of innervational cause of strab/ambly:
Paresis
Paralysis
paresis vs paralysis
Paresis - EOM has movement but is weak; there is just an innervational problem
Paralysis - the nerve is dead and the EOMs wont work. Also, during un
EOM has movement but is weak; there is just an innervational problem
Paresis
the nerve is dead and the EOMs wont work. Also, during uncover-cover, the eyes won’t move anymore
Paralysis
how to ensure that px eye muscles are not paralyzed?
perform cover tests and version tests.
before confirming that you can conduct vision rehabilitation for a strabismic patient, you must ensure that their eye muscles are not paralyzed by performing the tests above
chru or nope.
According to the Behavioral Optometry perspective, when strabismus is present, asymmetry in the body may be present.
chru.
how to distinguish a person has strab/ambly by only seeing their body language? (4)
-Observe their gait (manner of walking)
-stance
-titled shoulders
-compensatory head movement
Head Compensatory Movements (3)
- Face turn (either left or right) - horizontal deviation
- Chin elevation / depression - vertical deviation
- Head tilt to one shoulder (head tilt to right or left shoulder) - torsional deviation
a patient is right eso.
During primary gaze, the patient sees diplopia. To compensate, the px turns his head towards?
towards the right.
If a patient has hypertropia, which head compensatory movement is done?
chin depression is done
right movement of the head
eso OD
the socket cannot hold the whole bone so the tendency is there is displacement.
Hip dysplasia
the socket cannot hold the whole
bone so the tendency is there is displacement.
Hip dysplasia
patient may possibly lead in developing
amblyopia or strabismus because the normal development of px disrupted
Case 1: Born with incomplete hip development was put into a body cast for much of the first several months of life. Came in as a constant OD ET with a –6.00 in the OD and +0.50 OS. Afraid of driving off the right side of the road.
What are the problems?
- There is a problem in depth perception.
- The px has right esotropia
- the patient has no awareness of the right side of the road - There is a difference in the refractive error, the patient has antimetropia
is a condition in which one eye is myopic, while the fellow eye is hyperopic
Antimetropia
Born with incomplete hip development was put into a body cast for much of the first several months of life. Came in as a constant OD ET with a –6.00 in the OD and +0.50 OS. Afraid of driving off
the right side of the road.
Is there a difference in the image perceived by the patient between his right and left eyes?
Yes. However, the +0.50D doesn’t have an effect but the minus power (-6.00D) has an effect as it minifies the space
or image perceived. Thus, the patient’s space is more compressed. Px’s space is more compressed due to
- refractive error of high myopia in OD
- right esotropia
which method enables space compression?
MOTOR EQUIVALENCE
or CHALKBOARD CIRCLES.
procedure and materials for space compression
Materials: chalkboard and two chalks
Procedure: Have the patient look at the target and allow him to draw circles on his sides.