Sivakumar, K (2009) Analysis of surgical management of A-V pattern deviations. Masters thesis, Madras Medical College, Chennai.
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Abstract
INTRODUCTION: Binocular single vision (BSV) is one of the hallmarks of the human race that has bestowed on it the supremacy in the hierarchy of the animal kingdom. BSV is accomplished by a perfect sensorimotor coordination of the two eyes both at rest and during movement. The two dimensional images of an object formed at the fovea of each eye, transmitted to the respective visual cortex are processed and perceived as three dimensional percept. This requires constant and controlled activity of the appropriate muscles to maintain fixation on the object. It also requires the accomodational mechanism to maintain clear view even as the object moves closer or farther. HISTORICAL REVIEW: Hippocrates, the father of medicine differentiated between concomitant and paralytic squint and stressed the hereditary aspects. 1743-George.L.deBuffon recommended occlusion of the normal eye to force the squinting eye to use. 1900 Worth and Black invented the amblyoscope 1914 Ettles introduced synoptophore 1978 Campbell introduced CAM treatment for stimulating the macula of the eye with eccentric fixation. AIM OF THE STUDY: To study the efficiency of transposition of the horizontal and the oblique muscle surgeries in correction A-V pattern. MATERIALS AND METHODS: In this prospective study, 25 cases A-V patterns that underwent surgery at the regional institute of ophthalmology, Chennai were studied. INCLUSION CRITERIA: 1. Primary non paralytic heterotropia with A&V pattern. 2. 2-25yrs age group with A&V pattern. EXCLUSION CRITERIA: 1. Paralytic exotropia 2. Severe Amblyopic cases 3. Restrictive syndrome 4. Cases that had undergone previous surgery 5. Cases associated with congenital anomalies. A routine ophthalmic examination and a thorough orthoptic evaluation were carried out in all the patients. The deviation at different distances and different gazes was quantitated. using the prism bar cover test. The status of binocular single vision was assessed using the synoptophore, Worth four-dot. The type of fixation as to whether it was central or eccentric was assessed. Refraction was done using atropine 1% or cyclopentolate 0.5% drops. Pre-operative orthoptic treatment was given when considered necessary. SUMMARY: Analysis of the efficiency of transposition surgery of horizontal and oblique muscle in correction A-V pattern yielded the following inferences. A-V pattern with no oblique overaction Vertical upshifting and downshifting of medial and lateral recti along with recession – resection had a favourable outcome in A-V patterns with no oblique overaction. A-V patterns with minimal oblique overaction Vertical upshifting and downshifting of horizontal recti along with recession – resection was also effective in patients with A-V patterns with minimal obliqure over action. For whom weakening of oblique muscle was not needed. A-V pattrns with severe oblique overaction Weakening of oblique muscle in A-V Patterns with severe oblique overaction along with recession – resection surgery had a favourable outcome. Improvement in visual acuity: Transposition of horizontal oblique muscle surgeries yielded an improvement in visual acuity postoperatively in both A-V patterns with and without oblique over action. Improvement of amblyopia: Transposition of horizontal and oblique muscle surgeries also yielded an improvement of vision in amblyopic cases in both A-V patterns with and without oblique over action. Gain in binocular single vision: Transposition of horizontal and oblique muscle surgeries showed gain in BSV in patients with A-V patterns with and without oblique over action. CONCLUSIONS: 1. Vertical transposition of horizontal muscle along with recession and resection was effective in A-V patterns in no oblique muscle over action. 2. Vertical transposition of horizontal muscle along with recession-resection was also effective in A-V patterns with minimal oblique muscle over action. 3. Oblique muscle weakening was not necessary in A-V patterns with minimal oblique muscle overaction. 4. Weakening of oblique muscle was effective in patients with A-V patterns with severe oblique muscle overaction along with recession – resection surgery. 5. Patients who underwent transposition of horizontal and oblique muscle surgeries for AV patterns had an improvement in visual acuity. 6. Patients who underwent transposition of horizontal and oblique muscle surgery for AV patterns also had an improvement in amblyopia. 7. Patients who underwent transposition of horizontal and oblique muscle surgery for AV patterns also had a gain in BSV.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Binocular single vision; A-V pattern deviations; surgical management |
| Subjects: | MEDICAL > Ophthalmology |
| Depositing User: | Devi S |
| Date Deposited: | 08 Sep 2017 06:19 |
| Last Modified: | 08 Sep 2017 06:22 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/3098 |
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