MODULE 7: BINOCULAR VISION ANOMALIES Flashcards
The system of sensory motor co-operation between the eyes
Binocular vision
Bifoveal fixation/simultaneous Perception→ Fusion→ Streopsis
Binocular single vision
Occurs when there is a problem in the coordinated use of the eyes as a pair
Binocular vision anomalies
Type of deviation
Compensated/decompensated
Heterophoria
Type of deviation
Constant/intermittent
Strabismus
Laterality of strabismus:
Unilateral, alternating
Devation test distances
Far, inter, near
Direction of deviation in heterophoria
Exo, eso, hyper, cyclo
Direction of deviation in strabismus
Eso, eso, hyper, hypo, cyclo
Tendency for the eyes to move out of alignment when one is covered or when they view dissimilar objects
Heterophoria
Heterophoria is also known as
Latent strabismus/latent squint
Types of heterophoria
Basic eso/exo
Near eso/exo
Distance eso/exo
Convergence insufficiency
esophoria is similar at distance and near
Basic esophoria
esophoria is similar at distance and near
Distance esophoria
Divergence weakness
Distance esophoria
Convergence excess
Near esophoria
esophoria is significantly greater at near
Near esophoria
exophoria is similar at distance and near
Basic exophoria
Divergence excess
Distance exophoria
exophoria is significantly greater at distance than at near
Distance exophoria
Convergence weakness
Near exophoria
exophoria is significantly greater at near than distance
Near exophoria
characterized by remote NPC (more remote than 8-10cm
Convergence insufficiency
Convergence insuffiency is characterized by remote NPC, more remote than
8-10cm
Other terms for strabismus
Tropia, squint
Occurs when visual axes are misaligned/ manifest deviation
Strabismus
Classification of strabismus - frequency
Constant, intermittent
Classification of strabismus involving the same eye
Unilateral
Classification of strabismus
If the turning eye is sometimes the right eye and other times the left eye
Alternating
Classifications of strabismus
Unilateral, bilateral, alternating, constant, intermittent
angle of squint is the same in all directions of gaze
Concomitant
angle of squint is the same in all directions of gaze
CONCOMITANT
Types of strabismus
Exotropia
Esotropia
Hypertropia
Hypotropia
Cyclotropia
Strabismus less than 10 prisms diopters in size
Microtropia
characteristics must be present when diagnosing microtropia:
- angle less than 10 prism diopter
- VA of amblyopic eye must be atleast one line worse than non amblyopic eye
- eccentric fixation
- HARC detected by Bagolini lens
True or false
In microtropia, there is no treatment required
True
Regular, repetitive and involuntary movement of the eye. Onset in the first 6 months of life
Nystagmus
Early onset nystagmus occurs in first 6 months, secondary to sensory visual defect such as
congenital cataracts, albinism
apparent until one eye is covered, occurs in 1st year of life
Latent nystagmus
Involuntary movement of the eye caused by trauma or lesion affecting motor pathways
Acquired nystagmus
Types of nystagmus
Pendular
Jerk
Mixed
Direction of nystagmus
horizontal, vertical, torsional or combination
Amplitude of nystagmus
Small, moderately large
Frequency of nystagmus
Slow, moderate or fast
Constancy of nystagmus
Constant, intermittent or periodic
Conjugacy of nystagmus
- Conjugate (both eyes movements approximately parallel)
- disjuntive (eyes move independently)
- monocular
Both eyes movements approximately parallel
Conjugate
Eyes move independently
Disjunctive
does nystagmus increase or change with occlusion of one eye
Latent component
does nystagmus increase or decrease in any field of gaze or convergence
Position of gaze changes
Problems characterized by an inadequate amplitude or control of accommodation
Accommodative anomalies
Accommodative anomaly
Symptom: near blur
Accommodative Insufficiency
Accommodative anomaly
Symptom: Difficulty changing focus
Accommodative infacility
Accommodative anomaly
Symptom: near blur towards the end of the day
Accommodative fatigue
Accommodative anomaly
Symptom: Transient blur of distance or near vision
Accommodative spasm (excess)
Accommodative anomaly
Accommodative amplitude: low
Accommodative insufficiency
Accommodative anomaly
Accommodative amplitude: Normal
Accommodative infacility
Accommodative anomaly
Accommodative amplitude: Declines with repeating testing
Accommodative fatigue
Accommodative anomaly
Accommodative amplitude: normal
Accommodative spasm (excess)
Accommodative anomaly
Accommodative facility: May be slow with (-) lenses
Acc insufficiency
Accommodative anomaly
Accommodative facility: poor
Acc infacility
Accommodative anomaly
Accommodative facility: Declines with repeat testing
Acc fatigue
Accommodative anomaly
Accommodative facility: May be slow with (+) lenses
Acc spasm
Accommodative anomaly
Accommodative lag: Need high (+) (>+0.75)
Acc insuffiency
Accommodative anomaly
Accommodative lag: normal
Acc infacility
Accommodative anomaly
Accommodative lag: Initially OK, increasing plus after much near vision
Acc fatigue
Accommodative anomaly
Accommodative lag: Need (-) lenses
Acc spasm