Step 1: Determine which eye is hypertropic in primary position. If there is right hypertropia in primary position, then the depressors of the R eye (IR/SO) or the elevators of the L eye are weak (SR/IO).
Step 2: Determine whether the hypertropia increases on right or left gaze. The vertical rectus muscles have their greatest vertical action when the eye is abducted. The oblique muscles have their greatest vertical action when the eye is adducted.
Step 3: Determine whether the hypertropia increases on right or left head tilt. During right head tilt, the right eye intorts (SO/SR) and the left eye extorts (IO/IR).
When a healthy individual tilts their head, the superior oblique and superior rectus muscles of the eye closest to the shoulder keep the eye level. The inferior oblique and inferior rectus muscles keep the other eye level. In patients with superior oblique palsy, the superior rectus muscle’s action is not counteracted by the superior oblique muscles. This leads to vertical deviation of the affected eye when the head is tilted towards the affected eye. However, there is no deviation when the head is tilted towards the unaffected eye because the superior oblique muscle is not stimulated in the affected eye, but rather it is stimulated in the unaffected eye.[6] When there is a discrepancy in ocular deviation based on which way the head is tilted, the patient is diagnosed with unilateral palsy of the superior oblique muscle due to damage in the Trochlear Nerve.[citation needed]
People with superior oblique palsy on one side experience double vision, which is improved or even abolished by tilting the head towards the shoulder on the unaffected side. Tilting the head towards the shoulder on the affected side will make the double vision worse by causing increased separation of the two images seen by the patient.[citation needed]
Lateralization of side of defect based on Parks-Bielschowsky three-step test:
Ipsilesional central gaze hypertropia
Vertical diplopia greater in contralesional than ipsilesional gaze
Vertical diplopia greater in ipsilesional than contralesional head tilt [7]
Historyedit
The physiologic basis of the head tilt test was explained by Alfred Bielschowsky and Hofmann[8] in 1935.[9] However, Nagel described it 30 years prior to Bielschowsky when he noted that the combined action of the superior rectus muscle and the superior oblique muscle of one eye and of the inferior rectus and inferior oblique muscles in the fellow eye causes incycloduction and excycloduction.[10] The procedure that we now follow was given by Marshall M. Parks.[11]
Referencesedit
^Yeung, Pauline HN; Lam, Andrew KC (10 September 1998). "Fourth nerve palsy with monovision". Clinical and Experimental Optometry. 81 (5): 206–209. doi:10.1111/j.1444-0938.1998.tb06737.x. PMID 12482321. S2CID 25092239.
^Elliott, David B. "6.16: Identifying the Defective Muscle: Parks 3-Step Test". Clinical Procedures in Primary Eye Care (4th ed.). Retrieved 2 February 2014. citing von Noorden GK: Binocular vision and ocular motility: Theory and management of strabismus. London, CV Mosby, 2002.
^Yanoff, Myron; Duker, Jay S. (13 December 2013). Ophthalmology: Expert Consult: Online and Print. Elsevier Health Sciences. p. 1220. ISBN978-1-4557-3984-4.
^Wang, Frederick M. (PDF): 6. Archived from the original (PDF) on 28 May 2010. Retrieved 2 February 2014. {{cite journal}}: Cite journal requires |journal= (help)
^Helveston, Eugene M. (ed.). "Diagnosis and Classification of Superior Oblique Palsy". Project ORBIS International Inc. Retrieved 2 February 2014.
^Manchandia, Ajay M. (November 12, 2014). "Sensitivity of the three-step test in diagnosis of superior oblique palsy". Journal of AAPOS. 18 (6): 567–571. doi:10.1016/j.jaapos.2014.08.007. PMC4268244. PMID 25459202.
^1 citing Spielmann A: A translucent occluder for study of eye position under unilateral or bilateral cover test. Am Orthopt J 36:65, 1986.
Kushner, BJ (Jan 1989). "Errors in the three-step test in the diagnosis of vertical strabismus". Ophthalmology. 96 (1): 127–32. doi:10.1016/s0161-6420(89)32933-2. PMID 2919044.
External linksedit
Park's three-step test
April 12, 2024
parks, bielschowsky, three, step, test, also, known, park, three, step, test, bielschowsky, head, tilt, test, method, used, isolate, paretic, extraocular, muscle, particularly, superior, oblique, muscle, trochlear, nerve, fourth, cranial, nerve, acquired, vert. The Parks Bielschowsky three step test 1 also known as Park s three step test or Bielschowsky head tilt test 2 is a method used to isolate the paretic extraocular muscle particularly superior oblique muscle and trochlear nerve fourth cranial nerve 3 in acquired vertical double vision 4 It was originally described by Marshall M Parks 5 Parks Bielschowsky three step testSynonymsPark s three step test Bielschowsky head tilt testTest ofExtraocular muscle Contents 1 Bielschowsky s head tilt test 2 History 3 References 4 Further reading 5 External linksBielschowsky s head tilt test editStep 1 Determine which eye is hypertropic in primary position If there is right hypertropia in primary position then the depressors of the R eye IR SO or the elevators of the L eye are weak SR IO Step 2 Determine whether the hypertropia increases on right or left gaze The vertical rectus muscles have their greatest vertical action when the eye is abducted The oblique muscles have their greatest vertical action when the eye is adducted Step 3 Determine whether the hypertropia increases on right or left head tilt During right head tilt the right eye intorts SO SR and the left eye extorts IO IR When a healthy individual tilts their head the superior oblique and superior rectus muscles of the eye closest to the shoulder keep the eye level The inferior oblique and inferior rectus muscles keep the other eye level In patients with superior oblique palsy the superior rectus muscle s action is not counteracted by the superior oblique muscles This leads to vertical deviation of the affected eye when the head is tilted towards the affected eye However there is no deviation when the head is tilted towards the unaffected eye because the superior oblique muscle is not stimulated in the affected eye but rather it is stimulated in the unaffected eye 6 When there is a discrepancy in ocular deviation based on which way the head is tilted the patient is diagnosed with unilateral palsy of the superior oblique muscle due to damage in the Trochlear Nerve citation needed People with superior oblique palsy on one side experience double vision which is improved or even abolished by tilting the head towards the shoulder on the unaffected side Tilting the head towards the shoulder on the affected side will make the double vision worse by causing increased separation of the two images seen by the patient citation needed Lateralization of side of defect based on Parks Bielschowsky three step test Ipsilesional central gaze hypertropia Vertical diplopia greater in contralesional than ipsilesional gaze Vertical diplopia greater in ipsilesional than contralesional head tilt 7 History editThe physiologic basis of the head tilt test was explained by Alfred Bielschowsky and Hofmann 8 in 1935 9 However Nagel described it 30 years prior to Bielschowsky when he noted that the combined action of the superior rectus muscle and the superior oblique muscle of one eye and of the inferior rectus and inferior oblique muscles in the fellow eye causes incycloduction and excycloduction 10 The procedure that we now follow was given by Marshall M Parks 11 References edit Yeung Pauline HN Lam Andrew KC 10 September 1998 Fourth nerve palsy with monovision Clinical and Experimental Optometry 81 5 206 209 doi 10 1111 j 1444 0938 1998 tb06737 x PMID 12482321 S2CID 25092239 Elliott David B 6 16 Identifying the Defective Muscle Parks 3 Step Test Clinical Procedures in Primary Eye Care 4th ed Retrieved 2 February 2014 citing von Noorden GK Binocular vision and ocular motility Theory and management of strabismus London CV Mosby 2002 Yanoff Myron Duker Jay S 13 December 2013 Ophthalmology Expert Consult Online and Print Elsevier Health Sciences p 1220 ISBN 978 1 4557 3984 4 Wang Frederick M Strabismus PDF 6 Archived from the original PDF on 28 May 2010 Retrieved 2 February 2014 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Helveston Eugene M ed Diagnosis and Classification of Superior Oblique Palsy Project ORBIS International Inc Retrieved 2 February 2014 Head Tilt Test Head Tilt Test Orbis Telemedicine 2003 Web 08 Dec 2011 lt http telemedicine orbis org bins content page asp cid 735 2858 4397 2804 3110 3021 3037 gt Manchandia Ajay M November 12 2014 Sensitivity of the three step test in diagnosis of superior oblique palsy Journal of AAPOS 18 6 567 571 doi 10 1016 j jaapos 2014 08 007 PMC 4268244 PMID 25459202 1 citing Spielmann A A translucent occluder for study of eye position under unilateral or bilateral cover test Am Orthopt J 36 65 1986 Trochlear Nerve Palsy on eMedicine 1 citing Harwerth RS Smith EL 3rd Boltz RL Crawford ML von Noorden GK 1983 Behavioral studies on the effect of abnormal early visual experience in monkeys temporal modulation sensitivity Vision Research 23 12 1511 7 doi 10 1016 0042 6989 83 90163 3 PMID 6666052 S2CID 23006792 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint numeric names authors list link Head Tilt Test Retrieved 2 February 2014 Further reading editKushner BJ Jan 1989 Errors in the three step test in the diagnosis of vertical strabismus Ophthalmology 96 1 127 32 doi 10 1016 s0161 6420 89 32933 2 PMID 2919044 External links editPark s three step test Retrieved from https en wikipedia org w index php title Parks Bielschowsky three step test amp oldid 1194122997, wikipedia, wiki, book, books, library,
