Strabismus - Fundamentals of Clinical Ophthalmology.pdf

More documents

Recommendations

Info

STRABISMUS overacting in a V pattern. If there is no oblique overaction, transpose the horizontal recti, the medial recti to the apex of the pattern, and the lateral recti to the base. 4. Oblique surgery in the adult is less forgiving than in the child. (a) (b) Figure 7.11 Underaction of left superior oblique in child with left coronal synostosis. Tightening superior oblique tendon laxity improved field of binocular single vision with improved ocular posture without an acquired Brown’s syndrome. (a) Preoperative. (b) postoperative Adjustable sutures Adjustable sutures increase the chance of ideal surgical alignment with one operation, decreasing the need for reoperation or staged repairs. More sophisticated surgical techniques and materials have stimulated their increased use. Different techniques involve two-stage procedures where the final alignment is achieved postoperatively with external sutures, or the procedure completed with the patient awake. 17 In our experience, using adjustable sutures has led to better judgement in the operating room, leading to a minority of patients needing further postoperative adjustment (Figure 7.12). preferred to superior oblique tucks. In neurogenic cases ipsilateral superior rectus recession is useful where a long-standing superior oblique palsy has resulted in tightness of the tendon of the superior rectus. The superior oblique tightening procedure (Harada–Ito) is our preferred option where torsion is the main problem. Summary of management of A and V patterns 1. Observe the vertical movements of the eyes with accommodation controlled, preferably doing the test at distance and asking the patient to maintain fixation by depressing and elevating the chin. The eyes will move in the opposite directions and measurements can be made. 2. Consider whether the pattern is severe enough to treat. 3. Operate on the superior obliques if overacting in an A pattern and inferior obliques if Botulinum chemodenervation Studies have shown botulinum toxin to be helpful in small to moderate esotropia and exotropia (less than 40 D), active thyroid disease if surgery is inappropriate and postoperative residual strabismus after several weeks. There has been less evidence for use in A and V patterns, DVD or oblique muscle disorders. Success has ranged from 30% to 70% depending on the size of deviation. 18 Sequelae and complications of strabismus surgery Anaesthesia In early childhood, an anaesthetist well experienced in paediatric anaesthesia is essential. Usually day surgery is all that is required. Children need to be prepared for hospital, to have their favourite toy with them and to have their parents with them during 86
THERAPY OF STRABISMUS induction and there for them when they awake. Surgeons need to constantly be aware of the oculocardiac reflex, particularly early in the operation. For patients known to be at risk of malignant hyperthermia who require a general anaesthetic, agents such as halothane and succinyl choline muscle relaxants should be avoided. Malignant hyperthermia is a rare hereditary disorder characterised by gross hypermetabolic state in skeletal muscle and may be fatal. Unexpected tachycardia and pyrexia under anaesthesia may indicate malignant hyperthermia. (a) Ocular alignment Ocular alignment may be anticipated in 85% of straightforward cases. Failure to respond as anticipated reflects the reality that biological responses are not 100% predictable. Informed consent of the patient and parents should include explanation that departures from the anticipated response are not complications but part of the natural history of the condition, which in most cases are readily dealt with by a further procedure. It is important for the clinician to be aware of the risk of inducing an A pattern by confusion of DVD with inferior oblique overaction and weakening of the inferior oblique muscle. Other risks include operating without taking account of the patient’s accommodation in accommodative squint or intermittent exotropia. Alignment problems may cause postoperative diplopia, including thyroid patients who still have active disease. Overcorrection of exo or eso deviations is perhaps the commonest alignment problem to consider. The younger the child, the more at risk is any potential for binocular vision with fusion. The more mature the visual system, the greater the risk of persistent diplopia. Clinical decisions can be difficult. For example, a child of 2 years presents with intermittent exotropia. Such cases often have excellent fusion potential with normal binocular vision and bifoveal fusion for near. Early surgery may result in overcorrection, (b) Figure 7.12 This patient had a long-standing left sixth nerve palsy associated with hypertension, development of cataract and reduced vision from 6/12 to 6/60. She had a 15° strabismus corrected by medial rectus recession using adjustable sutures with a good cosmetic result esotropia, disruption of fusion and amblyopia. If it is a small overcorrection the result may be microsquint with retention of peripheral fusion, monofixation syndrome and loss of bifoveal fusion for near although more constant alignment at distance. On the other hand deferring surgery until after age 4 years is more likely to be associated with retention of bifoveal fusion for near but less stable deviation for distance. In the older patient with a mature visual system overcorrection will be accompanied by 87
Page 1 and 2:
Fundamentals of Clinical Ophthalmol
Page 3 and 4:
Fundamentals of Clinical Ophthalmol
Page 5 and 6:
© BMJ Books 2003 BMJ Books is an i
Page 7 and 8:
CONTENTS Sequelae of strabismus in
Page 10:
Preface This book has been written
Page 13 and 14:
Foreword We should welcome the fine
Page 15:
Section I Neurophysiological substr
Page 18 and 19:
STRABISMUS dim reflex whereas the m
Page 20 and 21:
STRABISMUS compared to the image on
Page 22 and 23:
STRABISMUS Chiasm ON LGN ON M LGN P
Page 24 and 25:
STRABISMUS Table 2.1 Actions of the
Page 26 and 27:
STRABISMUS Table 2.2 Types of eye m
Page 28 and 29:
3 Consequences of breakdown of bino
Page 30 and 31:
STRABISMUS Bifoveal fusion Normal B
Page 32 and 33:
STRABISMUS • Secondly, in the bin
Page 35 and 36:
Section II Strabismus in the decade
Page 37 and 38:
4 Childhood onset of strabismus Chi
Page 39 and 40:
CHILDHOOD ONSET OF STRABISMUS indic
Page 41 and 42:
CHILDHOOD ONSET OF STRABISMUS (a) (
Page 43 and 44:
CHILDHOOD ONSET OF STRABISMUS In ad
Page 45 and 46:
CHILDHOOD ONSET OF STRABISMUS may b
Page 47 and 48:
CHILDHOOD ONSET OF STRABISMUS retin
Page 49 and 50: CHILDHOOD ONSET OF STRABISMUS (a) (
Page 51 and 52: CHILDHOOD ONSET OF STRABISMUS Figur
Page 53 and 54: CHILDHOOD ONSET OF STRABISMUS (a) (
Page 55 and 56: Transient skew deviation CHILDHOOD
Page 57 and 58: CHILDHOOD ONSET OF STRABISMUS add w
Page 59 and 60: CHILDHOOD ONSET OF STRABISMUS Spasm
Page 61 and 62: 5 Adult strabismus Introduction The
Page 63 and 64: ADULT STRABISMUS Case example An ad
Page 65 and 66: ADULT STRABISMUS patient presenting
Page 67 and 68: ADULT STRABISMUS such as in older p
Page 69: Section III Management of strabismu
Page 72 and 73: STRABISMUS ● the pattern of the a
Page 74 and 75: STRABISMUS Figure 6.5 An example of
Page 76 and 77: STRABISMUS Sensory evaluation - bin
Page 78 and 79: STRABISMUS Normal R L Normal binocu
Page 80 and 81: STRABISMUS torsional deviations can
Page 82 and 83: STRABISMUS (a) (b) (c) (d) Figure 6
Page 84 and 85: 7 Therapy of strabismus Non-surgica
Page 86 and 87: STRABISMUS of the eye with good vis
Page 88 and 89: STRABISMUS other forms of non-surgi
Page 90 and 91: STRABISMUS (a) (b) (c) (d) (e) Figu
Page 92 and 93: STRABISMUS In attempting to elevate
Page 94 and 95: STRABISMUS drawn underneath the lat
Page 96 and 97: STRABISMUS Figure 7.7 Recession wit
Page 98 and 99: STRABISMUS MR MR LR LR LR LR MR MR
Page 102 and 103: STRABISMUS more persistent diplopia
Page 104 and 105: STRABISMUS microscope. Inflammation
Page 106 and 107: STRABISMUS Strabismus Malalignment
Page 108 and 109: INDEX surgical correction 83-6 see
Page 110 and 111: INDEX horizontal 54 “horror fusio
Page 112 and 113: INDEX esotropia 31, 31 monofixation
Page 114 and 115: INDEX oculocutaneous albinism 43 oc
Page 116: INDEX vertical muscle surgery 83-6,
show all

Strabismus - Fundamentals of Clinical Ophthalmology.pdf

Create successful ePaper yourself

Delete template?

Save as template?