Ocular Motility/ Binocular Vision Flashcards
Deviation is greatest in which gaze for A-pattern exotropia?
Down gaze
Deviation is greater in which gaze for V-pattern exotropia?
Up gaze
Strabismus is either not present or is minimal in primary gaze, but is larger in both up-gaze and down gaze
X- pattern exotropia
Deviation is greater in which gaze for Y-pattern exotropia?
Superior gaze
* deviation absent or minimal in primary and down gaze
Patients with A-pattern exotropia or V-pattern exotropia will exhibit what head posture?
Chin tilt down
Patients with chin tilted up have what type of eye posture?
A-pattern esotropia and V-pattern esotropia
Head tilt to the right or left is typically observed in patients with?
Superior oblique palsy
DEM vertical component measures what?
Automaticity of number calling
Basic esophoria
Eso equal at distance and near (within~5PD)
Average AC/A
decreased distance and near NFV
Decreased vergence facility (base in hard)
Lag MEM
Decreased PRA
Poor binocular accommodative facility (hard to clear minus)
* BIM : base-in & minus are hard for EP
Symptoms of basic eso
Horizontal diplopia @ D&N
blur
Asthenopia, worse at end of day
Negative fusional vergence test with?
Base in
What is the most common accommodative disorder?
Accommodative insufficiency
Decreased amp of accommodation
Lag of accommodation on MEM
Poor monocular accommodative facility
Reduced PRA
Accommodative insufficiency
Hofstetter’s formula for minimum amp of accommodation
15 - 1/4(age)
Which VT techniques are used to help improve symptoms of accommodative insufficiency?
- Monocular lens clearing and sorting
- Monocular push-ups
What is always considered abnormal finding on MEM?
Any lead
*minus value
Expected values for MEM
+0.25 to +0.75 D lag
Treatment for accommodative insufficiency
Rx plus-power lenses for reading to help relax accommodation (therefore decreases demand)
Ex: +1.00
What is the initial step in managing amblyopia in children?
Full correction of refractive error with spectacles or contact lenses
you just prescribed full correction to your pediatric patient with anisometropic amblyopia, when do you wanna see them back?
4-6 weeks to re-evaluate VA before prescribing additional therapy
What is the most common type of muscular dystrophy associated with chronic progressive external ophthalmoplegia?
Myotonic dystrophy
* progressive weakening of muscles
* Christmas tree cataracts
True or false
Pupils are affected in chronic progressive external ophthalmoplegia
False
Pupils NOT affected
What is the main difference between CPEO and myasthenia gravis?
CPEO does not have diurnal variation of ptosis
** myasthenia gravis ptosis worse at end of day or after prolonged upgaze
RTC for CPEO
Monitor every 6 months
* no treatment, but managing symptoms is important
Tx/management of CPEO (3)
- Ocular lubricants for exposure keratopathy
- Basedown prism reading glasses if restriction in downward gaze
- RTC every 6 months
Inheritance pattern of CPEO
- Mitochondrial (Kearns-Sayre syndrome)
- Autosomal dominant
NFV
Negative fusional vergence
* base in, eyes diverging
Normal values
@D -/7/4 (July 4th!)
@N 13/21/13
PFV
Positive fusional vergence
* base out, eyes converging
Normal values
@D 9/19/10 (September 19, 2010)
@N 17/21/11
True or false
Patients with basic exophoria will be expected to have increased PFV @ distance and near
FALSE
* they will have decreased positive fusional vergence @ distance and near because with exo-posture harder to converge
What does MEM stand for in the context of accommodative testing?
MEM stands for Monocular Estimation Method
A technique used to assess the accommodative response of the patient’s visual system.
What is the primary purpose of the MEM technique?
To determine how the patient’s accommodative system responds when performing a near task
This is crucial for understanding visual function, especially in near vision activities.
Normal +0.50- +0.75
Lag: > +0.75
Lead: any minus (always abnormal)
In what lighting conditions is MEM performed?
Normal room illumination
This ensures a realistic setting for the patient during the test.
What type of material does the patient read during the MEM test?
Age-appropriate material
This ensures that the reading task is suitable for the patient’s reading level.
What is the significance of ‘with’ motion during MEM testing?
‘With’ motion indicates accommodative lag
It shows that the patient’s accommodation is not keeping up with the demand of near vision.
What type of lenses neutralize ‘with’ motion?
Plus-powered lenses
These lenses help in compensating for the lag in accommodation.
What does ‘against’ motion indicate in MEM testing?
Accommodative lead
This suggests that the patient is over-accommodating for the near task.
What type of lenses neutralize ‘against’ motion?
Minus-powered lenses
These lenses are used to counteract the excessive accommodation.
What MEM findings are considered abnormal?
Findings greater than +0.75
This indicates a significant lag in the accommodative system.
What does any lead in MEM findings indicate?
Considered abnormal
A lead suggests that the accommodative response is excessively strong.
What is the role of the clinician during the MEM test?
To determine the amount of accommodative lag or lead present
This assessment is crucial for diagnosing potential visual issues.
Fill in the blank: The lenses must be removed quickly during MEM testing to ensure that the patient does not _______.
accommodate through the introduced lens
This is important to maintain the accuracy of the test results.
True or false
Maddox rod testing can differentiate between a phoria and a tropia?
FLASE !!!
it can only determine the magnitude and direction of the deviation
What is accommodative esotropia?
A condition where one eye turns inward due to focusing efforts, typically occurring in young children.
At what ages does accommodative esotropia generally occur?
Between the ages of 2 and 5 years.
Can accommodative esotropia be observed in infants?
Yes, it can be observed in infants.
What is the typical level of hyperopia in patients with accommodative esotropia?
The mean level of hyperopia is roughly 4.75 D.
What range of deviations can occur with accommodative esotropia?
A large range in magnitude of intermittent or constant deviations.
What additional condition may patients with accommodative esotropia present with?
Amblyopia.
What factors influence the presentation of amblyopia in accommodative esotropia?
The frequency of the eye turn and the presence/degree of anisometropia.
True or False: Amblyopia is always present in patients with accommodative esotropia.
False.
Fill in the blank: Accommodative esotropia typically presents with variable levels of _______.
[hyperopia]
Oculomotor dysfunction
Patient has inappropriate saccadic eye movements or poor pursuits
* perform poorly on DEM
What is oculomotor dysfunction?
A condition in which a patient displays inappropriate saccadic eye movements or poor pursuits.
How do patients with oculomotor dysfunction perform on the Developmental Eye Movement Test (DEM)?
Patients perform poorly on the DEM test.
What is the procedure of the DEM test?
Patients read vertical rows of numbers followed by horizontal rows without moving their head or using a placeholder.
*vertical for automaticity
*horizontal for saccades
What types of errors are marked during the DEM test?
Errors are marked as omissions, substitutions, additions, or transpositions.
What scores are calculated from the DEM test?
Vertical score (time), adjusted horizontal score (time), ratio (horizontal time/vertical time), and total errors.
What is the significance of the percentile rank in the DEM test?
A percentile rank of less than 16 on the ratio/errors is considered a fail, and between the 16th and 36th percentile is considered suspect.
List some symptoms of oculomotor dysfunction while reading.
- Excessive head movement
- Frequent loss of place
- Constantly re-reading lines
- Skipping lines
- Using a placeholder/finger
- Decreased reading comprehension
- Omission of words or lines.
Fill in the blank: A percentile rank of less than _______ on the ratio/errors is considered a fail.
[16]
True or False: A percentile rank between the 16th and 36th percentile is considered normal.
False
What indicates a normal result in a DEM test?
The horizontal, vertical, and ratio are all within normal ranges.
What does a high horizontal portion and a normal vertical component indicate in a DEM test?
An oculomotor dysfunction.
What does it mean if both horizontal and vertical components are high but the ratio is normal in a DEM test?
A problem with automaticity (difficulty naming numbers).
What is indicated if a patient has high test times for both horizontal and vertical components along with an increased ratio in a DEM test?
The patient suffers from both oculomotor and automaticity issues.
Fill in the blank: A DEM test result is considered normal if all components are within _______.
[normal ranges].
Worth 4 dot test examines what type of fusion?
2nd degree fusion
* ability to superimpose like objects
What is 1st degree fusion?
Ability to superimpose two DISSIMILAR objects (like a square and a circle) such that the two objects are perceived to occupy the same space
What is 3rd degree fusion?
Ability to fuse 2 identical images separated by space resulting in perception of depth
* 3D movies are an example of this
Red lens test: patient sees red/whiteish pink light
No deviation, no suppression
Red lens test set up
- Red lens over dominant eye
- Trans illuminator at 50cm
- Pt reports what they see
Repeat at 40cm
Suppression at 40cm =peripheral suppression
Suppression at 6 meters but not at 40cm =central suppression
Shallow suppression
Suppression at moderate lighting but not at dim lighting
Deep suppression
Suppression at moderate and dim lighting
What is microtropia?
A small angle heterotropia of less than 5-10 prism diopters, usually associated with harmonious anomalous retinal correspondence, partial stereopsis, and mild amblyopia.
What is the typical nature of microtropias?
Microtropias are typically esotropic, but may also present as exotropia or vertical microtropia.
What is a common clinical presentation of microtropia?
Decreased visual acuity in one eye, not fully corrected by refraction.
What is the relationship between uncorrected anisometropia and microtropia?
Uncorrected anisometropia is present in nearly all cases of microtropias, commonly associated with hyperopia or hyperopic astigmatism.
What findings are typically revealed during a fundus examination in microtropia?
No ocular pathology is revealed.
What is usually evident in the affected eye of a patient with microtropia?
A central foveal suppression scotoma.
What is a common occurrence in patients with microtropia despite having a suppression scotoma?
Para-foveolar fixation.
What is the typical effect of microtropia on stereopsis?
Reduced stereopsis, rarely completely absent.
What correlation exists in microtropia?
A correlation exists between the angle of deviation and the degree of stereoacuity possible.
What tests should be carried out meticulously in suspected microtropia cases?
Cover test, cover-uncover test, and alternating cover test.
What is indicated by a positive alternating cover test in patients with central fixation?
Movement is observed.
What is ‘microtropia without identity’?
Eccentric fixation and anomalous retinal correspondence where the angle of anomaly is not equal to the degree of eccentric fixation, resulting in a positive alternating cover test.
What is ‘microtropia with identity’?
Eccentric fixation and anomalous retinal correspondence where the angle of anomaly is equal to the degree of eccentricity, resulting in a negative alternating cover test.
What may raise suspicion for microtropia?
Reduced unilateral visual acuity with binocular single vision.
What confirms the diagnosis of microtropia if there is non-foveolar fixation?
The diagnosis of microtropia may be confirmed.
What is the purpose of the 4-Diopter Base-Out Prism Test?
To diagnose foveal suppression and microtropia
Microtropia is a form of strabismus where the misalignment is subtle.
What type of prism is typically used in the 4-Diopter Base-Out Prism Test?
4-diopter prism
The orientation is typically base-out because most microtropias are esotropias.
What is the initial action of the patient during the test?
The patient fixates on a penlight
What happens to the light rays when the prism is kept in front of the right eye?
The rays of light deviate towards the base of the prism
This causes the light to move away from the fovea in the right eye.
According to Hering’s Law, what occurs after the right eye adducts?
An equal abduction movement of the left eye occurs
What must the left eye do to re-fixate the light on the fovea?
The left eye must adduct
What occurs if a prism is placed before the left eye of a patient with right eye microtropia?
Adduction movement of the left eye occurs, leading to equal abduction of the right eye
This confirms foveal suppression in the microtropic right eye.
What happens when a prism is placed before the right eye of a patient with a microtropia?
There will be no movement at all
This confirms the diagnosis of microtropia as the light is still within the central suppression area.
What does anomalous correspondence (AC) occur under?
Binocular fusion
What typically happens to a patient with strabismus regarding their vision?
They either see diplopia or suppress the image from the strabismic eye
What indicates that a patient has anomalous correspondence?
The ability to fuse the images in each eye despite strabismus
What is the purpose of anomalous correspondence in the visual system?
To reorganize the visual direction of the deviating eye
In anomalous correspondence, what becomes the corresponding point to the fovea of the fellow eye?
A non-foveal point
What problem does anomalous correspondence help to overcome?
Confusion and diplopia
What is harmonious anomalous correspondence?
A sub-category of anomalous correspondence where sensory adaptation compensates for the angle of strabismus
Why is it called ‘harmonious’ anomalous correspondence?
Because the angle of anomaly is equal to the objective angle of strabismus
What can be measured on a cover test in cases of harmonious anomalous correspondence?
No subjective angle of strabismus
What is it called when another part of the retina (other than the fovea) is used for fixation?
Eccentric fixation
Eccentric fixation can occur under both monocular and binocular viewing conditions.
Under what viewing conditions is eccentric fixation best diagnosed?
Monocular viewing conditions
Eccentric fixation can be present in both monocular and binocular conditions but is best assessed monocularly.
In esotropia, which retinal point is typically used for fixation?
A point on the nasal retina
Esotropia is characterized by inward eye deviation.
In exotropes, which retinal point is generally used for fixation?
A temporal retinal point
Exotropia is characterized by outward eye deviation.
What additional displacement is often observed in the eccentric fixation point?
Vertical displacement
The eccentric fixation point may be displaced vertically in addition to its lateral position.
What is the easiest way to diagnose eccentric fixation?
Visuoscopy with a direct ophthalmoscope
This method involves observing the foveal light reflex while the patient looks at a target.
What should be done to the eye not being tested during the diagnosis of eccentric fixation?
It should be occluded
This ensures that the patient focuses solely with the eye being tested.
What indicates that a patient is using a different point of the retina to fixate in eccentric fixation?
The foveal light reflex will not be centered
This observation shows that fixation is not occurring at the fovea.
What is the eccentric fixation point?
The retinal point located at the center of the fixation target
This point reflects where the patient is actually fixing their gaze.
What factors should be noted about the eccentric fixation point?
Direction relative to the fovea, magnitude, and fixation stability
Each of these factors provides insight into the nature of the eccentric fixation.
What is refractive amblyopia?
Refractive amblyopia results from either isometropic or anisometropic uncorrected refractive errors.
Isometropic refers to high but approximately equal refractive errors, while anisometropic refers to significantly unequal refractive errors.
What is the impact of isometropic refractive errors on visual development?
Isometropic refractive errors create a blurred image on both retinas, leading to a subtle type of form deprivation that can delay normal neurophysiologic development of the visual pathway and visual cortex.
This form deprivation can affect visual acuity.
What range of visual acuity loss can patients with isometropic amblyopia experience?
Patients can have visual acuity loss ranging from 20/25 to 20/200, with the majority having 20/50 acuity or better.
This indicates a variety of severity in visual impairment.
What causes anisometropic amblyopia?
Anisometropic amblyopia is caused by uncorrected refractive errors where the difference between the major meridians of each eye causes a clinically significant blurred image in the eye with the greater refractive error.
This disparity affects visual processing.
How does the degree of anisometropia relate to visual acuity loss?
Typically, the greater the anisometropia, the more severe the visual acuity loss will be.
This relationship highlights the importance of correcting refractive errors.
Which type of anisometropia carries a greater risk of amblyopia?
Patients with hyperopic anisometropia are at greater risk than those with larger amounts of myopic anisometropia.
This is because hyperopes use the less hyperopic eye for fixation at all distances.
What are the potentially amblyogenic refractive errors according to AOA Clinical Practice Guidelines?
The potentially amblyogenic refractive errors include:
* Isoametropia
* Hyperopia: >5.00 D
* Myopia: >8.00 D
* Astigmatism: >2.50 D
* Anisometropia:
* Hyperopia: >1.00 D
* Myopia: >3.00 D
* Astigmatism: >1.50 D
These thresholds indicate significant refractive errors that may lead to amblyopia.
Astigmatic dial without prescription which set of lines perceived clearest?
Habitual Rx axis OD: 009, OD: 171
Use rule of 30 in reverse
(Rule of 30 states axis can be calculated by multiplying lowest clock hour pt sees clearly by 30)
*pt axis is around 180 both eyes
180/30=6
Therefore the lowest clock hour the patient will see clearly is 6:00, thus pat will see 6:00 to 12:00 line the clearest
What is the function of the lateral rectus muscle?
Abducts the eye
Abduction refers to moving the eye away from the midline of the body.
What is the function of the medial rectus muscle?
Adducts the eye
Adduction refers to moving the eye towards the midline of the body.
What are the functions of the superior rectus muscle?
Supraducts, medially rotates (intorsion), and adducts the eye
Supraducting involves moving the eye upwards.
What are the functions of the inferior rectus muscle?
Infraducts, laterally rotates (extorsion), and adducts the eye
Infraducting involves moving the eye downwards.
*depression, extorsion, ADDuction
What are the functions of the superior oblique muscle?
Medially rotates (intorsion), infraducts, and abducts the eye
The superior oblique muscle primarily aids in the downward movement of the eye.
What are the functions of the inferior oblique muscle?
Laterally rotates (extorsion), supraducts, and abducts the eye
The inferior oblique muscle primarily assists in the upward movement of the eye.
What is the main issue in divergence insufficiency?
The patient does not diverge enough at distance.
Patients may experience symptoms like diplopia and asthenopia with prolonged distance activities.
What symptoms might patients with divergence insufficiency report?
Diplopia and asthenopia.
Symptoms typically worsen with prolonged distance activities.
In divergence insufficiency, how do the exophoria measurements differ at distance versus near?
Larger at distance than at near by at least 3 PD with a low AC/A ratio.
This indicates a problem with distance vision.
What is the treatment recommendation for patients with divergence insufficiency?
Prescribe as much plus as possible and consider BO prisms for distance.
Spectacle lenses have minimal therapeutic effect since it’s a distance issue.
What is the goal of vision therapy for divergence insufficiency?
Increase divergence ranges at distance using BI prisms and minus lenses.
What does the term ‘divergence excess’ indicate?
The patient is diverging too much at distance.
This condition is characterized by a high AC/A ratio.
What symptoms might parents notice in children with divergence excess?
One eye turning out and closing one eye in bright light.
How do exophoria measurements present in divergence excess at distance compared to near?
Larger at distance than at near by at least 5 PD with a high AC/A ratio.
What is the recommended management for myopia and hyperopia in divergence excess?
Correct for myopia and only hyperopia over +1.50D.
What is the effect of minus lenses on patients with divergence excess?
Minus lenses will reduce distance divergence, especially due to the high AC/A ratio.
What is the typical response of patients with divergence excess to vision therapy?
They respond well to vision therapy aimed at decreasing divergence ranges at distance.
What is rarely prescribed for patients with divergence excess and why?
Prism is rarely prescribed because vision therapy is usually successful.
What are Morgan’s Expecteds related to exophoria?
Expected findings include:
* Distance lateral phoria
* Near lateral phoria
* AC/A ratio 4:1 +/-2
* BO and Bl at Distance
* BO and Bl at Near
* Near Point of Convergence (NPC)
* NRA and PRA
What is the AC/A ratio in Morgan’s Expecteds?
4:1 +/-2
What are the expected values for BO at Distance according to Morgan’s Expecteds?
9/19/10
What are the expected values for Bl at Distance according to Morgan’s Expecteds?
7/4
What are the expected values for BO at Near according to Morgan’s Expecteds?
17/21/11
What are the expected values for Bl at Near according to Morgan’s Expecteds?
13/21/13
What are the expected values for Near Point of Convergence (NPC) in Morgan’s Expecteds?
Break 5, Recovery 7
What is the expected NRA value in Morgan’s Expecteds?
+2.50
What is the expected PRA value in Morgan’s Expecteds?
-3.00
How is the minimum amplitude of accommodation calculated?
A = 15 - ¼(Age)
What is the expected Monocular Accommodative Facility?
11 cycles per minute (cpm)
What is the expected Binocular Accommodative Facility?
11 cycles per minute (cpm)
What indicates a failed Monocular Estimation Method (MEM) test?
If the patient reports seeing double
What is considered a normal MEM result?
Plano to +0.75D (small lag of accommodation)
What is considered an abnormal MEM result?
+1.00D or more (high lag of accommodation)
* Any minus (low lead of accommodation)
True or False: It is normal to be esophoric.
False
What is the expected break for vergence amplitude?
About 20
