Incomitant deviations

_ a deviation tha changes in magitude with direction of gaze (NOT W/ viewing distances)

• deviation = biggest in direction of max action of msc

• target = pen torch ( esp. to see corneal refllexes) + non acomodative

• for child = small toy

• tip of pen for px if uncomfortable ( can cause latent dev to decompensate.

technique

• 50cm

• head stationary + remove specs

• px reports any pain/dip (subjective) + observe you mvt ( objective)

• do 6 cardinal points then up and down ( doesnt isolate individual msc) OR H pattern

• alternating cover test at angle of gaze

• shows type and direction

• if ophoria, px wont report dip bz motility is not a dissociated test

• if tropia, px might supress = no reported diplopia

1. underaction of affected msc

2. overaction of contralateral synergist

3. overaction of ipsilateral antagonist

4. underaction of contralateral antagonist

Ad: spread of comitance = easier to manage to prism or surgery

Disad: difficult to diagnose on Hess

to compensate for limited FOV of binocular single vision

head will point in direction of max action of affected msc to avoid eye turning in that direction.

type and direction should be noted: AHP turn,tilt,lift or chin depress

** straighten head before performing motility

AHP can be due to shyness, hearing impairment, arthritis, habit

RE and LE plot will look similar in size

Full msc sequalae doesn't develop

Just overaction of contralateral synergist seen

Px 50cm away

Examiner holds red, px holds green torch

Use red green goggles, green over eye being tested

Point the red torch at a specific point indicated on chart and instruct px to shine their green torch over the red one

Plot where px points green torch on recording chart and join points together

Esotropia on abduction of affected eye

Hypertropia on down and in of affected eye

Cause- trauma and microvascular disease

Bielchowsky head tilt- head will turn away from affected side to avoid vertical dev

Can be unilateral or bilateral

Congenital or acquired (trauma to long thin Trochlear nerve/ diabetes/hypertension)

Px often have vertical dip worse on downgaze + AHP

Rare occurance- aberrant regeneration

• Regrowth of damaged nerve fibres and incorrectly go to superior and inferior branches

• Lids may rise on attempted depression and aB/aDduction

• Pupils constrict on elevation and depression

• Convergence on elevation

Aneurysm = emergency ref

Tumour, trauma= urgent

Microvascular = urgent

Urgent referral if recent onset

Vertical prism

Botox- short term

Surgery

1. Congenital (6th nerve normally acquired)

2. Affects lateral rectus ( similar to 6th nerve palsy)

3. Due to absence of 6th nerve nucleus (palsy due to lack of innervation)

4. Limited abduction ( same as palsy)

5. Retraction of globe - differentiate

6. Widening of palp aperture on aBduction

7. Upshoot in elevation in aBduction

1. Limited elevation in aDduction ( 4th palsy has limited depression in aDduction)

2. IO normal but restricted by SO (ipsilateral antagonist) unable to relax

3. Downshoot of affected eye on aDduction

Thyroid eye disease