Vertical & horizontal strabismus of uncertain cause OMC Fumitaka Nonaka I will present two cases which showed vertical and horizontal strabismus of uncertain and unusual cause.

Case 1 14yo Female RE drifting upwards intermittently for some years, no diplopia CT: D+N XT with RH RE poorly reacting to direct light Other examinations: unremarkable POH, PMH: nil CT brain & orbit: normal (not viewed) TFT: normal 14yo Female presented with drifting right eye, upward intermittently for some years, no diplopia. Cover test showed exotropia with right hypertropia. Right pupil reacted poorly to direct light. CT was reported elsewhere as normal

Can I ask someone to describe findings of these photos?

RXT RH RIR- RMR- In primary position, she showed right exotropia with right hypertropia, underaction of right medial rectus and underaction of the right inferior rectus. Right pupil was larger than the left.

On Examination VA -0.50 = 6/8 -0.50 = 6/6 Pupil: R>L 12ΔXT RH16Δ Distance Near -1 -3 She had mild R amblyopia. Prism cover test showed exotropia with right hypertropia at distance and near. Near XT much greater than distance.

MRI RMR RIR LIR LMR Coronal view of MRI T1 and T2 revealed smaller medial rectus and inferior rectus on the right compared to the left. RIO was not reliably seen. Other muscles seem to be symmetric.

Palsy of the inferior division of the third nerve Superior division Inferior division Levator SR MR IR IO Sphincter pupillae Ciliary muscle This is a case of palsy of the inferior division of the 3rd nerve. The inferior division of the third nerve supplies the medial rectus, inferior rectus, inferior oblique and pupil. In this case, the motility findings, the pupil change and the findings of MRI fit with the diagnosis of “palsy of inferior division of the right third nerve”. This is an uncommon pattern, and as we will see this needs to be recognised as it has a specific surgical treatment

Case 2 16yo Male Re: worsening head tilt to right Noticed LE Amblyopia since 2yo PMH: Developmental delay PFH: sister with squint Here is a second case with some similarity. This is a 16-year-old male who presented with worsening head tilt to right. Left amblyopia has been recognised since age 2. He has developmental delay & attends a special school.

Dominant RE can’t depress especially in R-gaze L Pseudo ptosis Large LXT, L hypo Dominant RE can’t depress especially in R-gaze Photos show large L exotropia with L hypotropia and left pseudoptosis in primary gaze. Right eye can’t depress, especially in right gaze. Right eye doesn’t aDduct normally. Fumi: In this slide, change RH everywhere to L hypo. His R is dominant and the main clinical problem is L XT and L hypo

On Examination 6/9 s gls 6/28 Pupil: ?some asymmetry reaction L>R L Pseudo ptosis Pupil showed poor reaction to light. Prism cover test showed 25 prism dioptre L exotropia with L hypotropia of 25 prism dioptre. Distance 25ΔLXT LHypo 25Δ RE can’t depress especially in R-gaze

CT CT shows smaller medial rectus and inferior rectus on the right compared with the left. . Therefore, like the previous case, palsy of the inferior division of the right third nerve is the likeliest explanation. Here the paretic eye is also the dominant eye – there must have been some sensory benefit earlier in his visual development that enabled this.

Treatment Dr Kushner reported the efficacy of “Knapp’s surgical procedure” Simultaneous transposition of SR toward the insertion of MR LR toward the insertion of IR + Tenotomy of SO tendon All 5 patients were free from diplopia in primary position (follow up ranged from 3 to 10 years after surgery) Pre-op Post-op The late Phil Knapp invented the transposition operation for elevator deficiency that is usually referred to as a Knapp transposition. He also invented this transposition operation for inferior division 3rd nerve palsy. Dr Kushner reported the efficacy of this procedure in 5 patients. He transposed superior rectus to the insertion of medial rectus to provide a ‘rubber band’ pull nasally. He transposed the lateral rectus to the insertion of inferior rectus to provide a ‘rubber band’ pull inferiorly. The superior oblique is always tight because of the inferior oblique palsy, and requires tenotomy. All of Kushner’s 5 patients had the paretic eye centralised with a modest zone of centralised single vision BSV + Surgical Treatment of Paralysis of the Inferior Division of the Oculomotor Nerve. J Kushner, Arch Ophthalmol. 1999;117:485-489 Knapp’s surgical procedure

This is an important diagnosis to make. It has a Two cases of congenital inferior division oculomotor palsy were presented. This is an important diagnosis to make. It has a very specific & usually successful treatment. Two cases of congenital inferior division of oculomotor palsy were presented. Other causes of inferior division palsy we have seen include ophthalmoplegic migraine. This is a rare condition, and almost certainly very under-recognised. It is an important diagnosis to make as it has a very specific and usually successful treatment.