| Past Issue | Volume 8, Number 3, June 2006 | | Vertical Misalignment and its Comparison with Head Tilt in Patients with Peripheral Lateral Rectus Palsy |
Jitendra Jethani, Abhishek Dagar, Perumalsamy Vijayalakshmi, Kartik Prakash
Aravind Eye Hospital, Madurai, India
Aim: Isolated unilateral abducens palsy is reportedly associated with a subtle hyperdeviation. The pattern of this often unrecognised associated vertical deviation is described and the affected and unaffected sides compared on head tilt.
Methods: In a prospective consecutive case series, 20 patients with isolated unilateral abducens paresis were tested for hyperdeviation. Maddox rod and prism test and prism cover test were done in the 9 diagnostic positions to evaluate hyperdeviation after neutralising the primary esotropia. The tests were repeated during static lateral head tilt to either side. A negative Bielshowsky's head tilt test in all the patients and lack of relative ocular torsion on double Maddox rod test were not compatible with vertical muscle palsy.
Results: The mean horizontal deviation was 22.7 pd (SD, 11.9 pd) on prism cover test. Hyperdeviation was present in all patients. The mean hyperdeviation of the affected eye was 5.0 pd (SD, 2.1 pd; range, 3 to 8 pd) in the primary position of the prism cover test. The mean vertical deviation by Maddox rod and prism test was 5.7 pd (SD, 2.7 pd). Head tilt to the affected side revealed a mean deviation of 4.6 pd (SD, 2.4 pd) and head tilt to the unaffected side revealed a mean deviation of 4.8 pd (SD, 1.9 pd) with prism cover test. Head tilt to the affected side revealed a mean vertical deviation of 5.0 pd (SD, 2.6 pd) and head tilt to the unaffected side resulted in mean deviation of 5.1 pd (SD, 2.6 pd) by Maddox rod and prism test. Mann-Whitney test revealed a p value of 0.495 for the alternate prism cover test and 0.909 for the Maddox rod and prism test. No significant difference was found between head tilt to the affected and unaffected side. The side of the abducens paresis did not correspond significantly to the side of the hyperdeviation in the primary position.
Conclusion: Small hyperphoria of the affected eye is expected in lateral rectus paresis. The relationship between this hyperdeviation, lateral head tilt, and peripheral and central sixth nerve palsy was not found in this study. The amount of deviation may not depend on the head tilt in peripheral sixth nerve palsy.
Key words: Abducens nerve diseases, Esotropia, Exotropia, Oculomotor nerve diseases
Asian J Ophthalmol 2006;8:102-4.
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