Ocular Deviations

Heterophoria

A deviation kept latent by the fusion reflex

Heterotropia

A manifest deviation of the eyesStrabismusSquint“cock eyed”

Heterophoria

Orthophoria: the visual axes remain in alignment when fusion is prevented

Esophoria: the visual axes converge from alignment when fusion is prevented

Exophoria: the visual axes diverge from alignment when fusion is prevented

Clinical Records

It is not necessary to specify the eye as a phoria is “shared”

Record the size in ∆Record the distance the test was

performedDistance 5SOPNear 2XOP

Esophoria

Heterophoria

Orthophoria: the visual axes remain in alignment when fusion is prevented

Hyperphoria: one line of sight is higher than the other when fusion is prevented

Hypophoria: one line of sight is lower than the other when fusion is prevented

Vertical Phorias

A right hyperphoria is the same as a left hypophoria

It is important to specify the eye

Clinical Records

It is necessary to specify the eye in vertical phorias

Record the size in ∆Record the distance the test was

performedDistance 5RHyperphoriaNear 2L/R

Rotations

Excyclophoria: upper poles of the corneas deviate outwards when fusion is prevented

Incyclophoria: upper poles of the corneas deviate inwards when fusion is prevented

Cyclodeviations

Physiological Exophoria

At near it is usual for the phoria to be relatively more divergent than the distance phoria

Accommodative lag gives less drive through AC/A

Small XOP common at near

Aetiology

Static or AnatomicalKinetic or AccommodativeNeurogenicInnervational

Vergence system

Convergence insufficiencyConvergence ExcessDivergence insufficiencyDivergence excess

Convergence Insufficiency

Distance 3XOPNear 12XOPBreaks from XOP to XOTOrthoptic therapy helps

Convergence Excess

Distance Rx typically hyperopicDistance 4SOPNear 18SOPHigh AC/A ratioCan be controlled with Rx

Convergence Excess

Divergence Excess

Distance 15XOPDistance Intermittant XOTNear 5XOPPatient not aware when

Strabismus presentResponds to orthoptic therapy

Divergence Excess

Divergence Insufficiency

Distance 8SOPNear 2XOP

Heterotropia

Incomitant

Concomitant

Incomitant Strabismus

The angle of deviation varies with direction of gaze

Paralytic in originAngle of squint largest when eyes

turned in direction of affected muscleAssessment of ocular motility

essentialOften need to be referred

Incomitant Squint

Abnormal Head Posture

Concomitant Strabismus

Angle of deviation is constant for all directions of gaze

May be intermittantOften an accommodative element

(Donder’s squint)Alternating strabismusCongenitalChildhood

Heterotropia

Esotropia: the visual axes converge from alignment

Exotropia: the visual axes diverge from alignment

Esotropia

Accommodative Esotropia

Accommodative Esotropia

Alternating Esotropia

Exotropia

Exotropia

Clinical Records

It is necessary to specify the eye in strabismus

Record the size in ∆Record the distance the test was

performedDistance 5RSOTNear 2LXOTAlt D & N, prefers R fix

Heterotropia

Hypertropia: one line of sight is higher than the other

Hypotropia: one line of sight is lower than the other

Hypertropia

Hypotropia

Clinical Records

It is necessary to specify the eye in strabismus

Record the size in ∆Record the distance the test was

performedDistance 15RHyperTNear 10LHypoTAlt D & N, prefers R fix

Clinical Tests

Cover testOcular motilityAdditional tests as required

Summary

Phoria or Tropia?Tropia: incomitant or

concomitant?Incomitant: Old or New?Work in a systematic manner