Bielschowsky parks three step test presentation

It will help better understanding and diagnosis of single cyclo-vertical muscle palsy

1. Parks-Bielschowsky -3 step test Sudama kharbind

2. Bielchowsky park-3 step It was first described by Bielschowsky in 1935 and later popularized by Marshall M. Parks. It is a diagnostic test used to identify which muscle is paretic in the case of an acquired hypertropia. The three-step test, also known as the Parks-Bielschowsky three-step test or the Parks-Helveston three-step test . This test is most useful in diagnosing superior oblique palsies in clinical practice

3. Bielschowsky park-3  It is designed for the diagnosis of a single paretic vertical muscle and is unreliable when there are multiple paretic muscles or in restrictive strabismus Performed in three step. Aim-To diagnose which cyclovertical muscle is paralyzed/palsied.

4. Bielschowsky's head tilt test Step 1: Determine which eye is hypertropic in primary position. Step 2: Determine whether the hypertropia increases on right or left gaze. Step 3: Determine whether the hypertropia increases on right or left head tilt.

5. Eg: Right hypertropia increase left gaze and right head tilt

6. Step 1. Which eye is hypertropic? In the patient in Figure 1, the right eye is hypertropic (RHT). When trying to isolate which muscle is paretic in a right hypertropia, it must be either one of the depressors of the right eye or one of the elevators of the left eye. Therefore, we have deduced from step 1 that the paretic muscle must be one of the following cyclovertical muscles: Right superior oblique Right inferior rectus Left inferior oblique Left superior rectus

7. Step 2. Does the hypertropia increase in right gaze or left gaze? Hypertropia increases in left gaze Understanding cyclovertical muscle field of action is crucial Isolating prime mover muscles in cardinal positions Paretic muscle elevates left eye or depresses right eye in left gaze Right superior oblique and left superior rectus meet criteria for paretic muscles

8. Step 3. Does the hypertropia increase in right head tilt or left head tilt? Final step in determining paretic muscle Right hypertropia worse in left gaze Deviation increases on right head tilt, decreases on left Implicates right superior oblique as paretic Right superior oblique and rectus work together Paretic superior oblique causes right eye elevation Otolith system adjusts eyes during head tilt Right eye moves upward due to paresis Right hypertropia decreases significantly in left tilt Positive three-step test for right superior oblique palsy

9. What are the condition in which parks-3 step test is inapplicable? Multiple cyclovertical muscle palsies Restrictive squint (Eg. Thyroid ophthalmopathy, Duane’s retraction syndrome, Brown syndrome, Orbital fracture with muscle entrapment) Dissociated vertical deviation (DVD) Squint resurgery Skew deviation Mysthenia gravis

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