SUMMARYThe results of squint surgery in 42 children with primary, non-paralytic, childhood exotropia are analysed. A 'favourable outcome', defined as a final alignment for near and distance within ±10 dioptres of straight, or within ±20 dioptres of straight with evidence of bi nocular single vision, was achieved in 39 (93%) children.The factors affecting the final outcome are discussed, including age of onset, age at the time of surgery, pre operative and post-operative amblyopia, refractive error, anisometropia, the surgical procedures used, and post operative ocular alignment.Exotropia in childhood may be primary, secondary, con secutive or paralytic. 1 Primary childhood exotropia may be constant, when the exotropia is manifest for both near and distance, or intermittent, when the exotropia is mani fest for either near or distance. Intermittent distance exo tropia may be either true or simulated depending on the amount of exophoria controlled for near by accommo dation and fusional forces.2We reviewed children who underwent strabismus sur gery for primary childhood exotropia at the Birmingham Children's Hospital, in order to determine the results achieved, to identify the factors associated with favour able and less favourable outcomes, and to consider this information in the planning of future surgery for this condition. PATIENTS AND METHODSThe case notes of consecutive patients undergoing surgery for childhood exotropia at the Birmingham Children's Hospital in the 5 year period between January 1982 and December 1986 were reviewed. Any child with paralytic or consecutive exotropia, neurological disorder, ocular pathology, or a post-operative follow-up period of less than 24 months, was excluded. Information was obtained from the pre-operative examination, and from examin- Eye (1994) 8, 632-637 © 1994 Royal College of Ophthalmologists ations at 2 weeks, at 3-6 months, and at yearly intervals thereafter until discharge.True distance exotropia was defined as an exotropia at distance which exceeded the exophoria at near by more than 10 dioptres; simulated distance exotropia was con sidered present when the difference was 10 dioptres or less.3Amblyopia was defined as a difference of two lines or more between the monocular visual acuities. Anisometro pia was defined as a spherical or cylindrical difference of greater than 1.0 dioptre between the two eyes.4 All refrac tions were undertaken under cycloplegia using either cyclopentolate or atropine. Binocular single vision was assessed using tests of motor and sensory fusion as described in a previous publication, and one or more of these tests of motor or sensory fusion were used at each pre-operative or post -operative examination.5 A 'favourable outcome' was defined as a final align ment for near and distance within ± 10 dioptres of straight, or within ±20 dioptres of straight with evidence of bi nocular single vision.Statistical analysis was performed using medians and the non-parametric Mann-Whitney test for comparing continuous variables, and the chi-squared tes...

into (1) orthotropia or asymptomatic heterophoria with subnormal binocular vision, (2) microtropia, (3) small angle (<20 dioptres) and cosmetically acceptable residual esotropia or consecutive exotropia, and (4) large angle (>20 dioptres) residual esotropia or consecutive exotropia that requires additional surgery. However others have categorised as cosmetically acceptable only those aligned within 10 dioptres of straight and furthermore alignment within 10 dioptres of straight prior to 24 months ofage may significantly improve the prospects ofdeveloping binocular single vision.3The initial surgical procedures used to attain alignment include monocular recessionresection,4 bimedial rectus recessions,5 and three and four horizontal muscle surgery,6 any of which may be combined with conjunctival recessions7 and/or inferior oblique muscle surgery.8 We reviewed children under our care who underwent surgery for congenital esotropia, and who had a follow-up of at least 2 years, to determine the results achieved, to identify the factors associated with satisfactory and less satisfactory outcomes, and to consider this information in the planning of future surgery for this condition.

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SUMMARYThe results of squint surgery in 118 children with non paralytic childhood esotropia are analysed. A 'favour able outcome', defined as a final alignment within ±10 dioptres of straight, or within ±20 dioptres of straight if there was evidence of binocular single vision, was achieved in 86 (72.9%) children. The factors affecting the final outcome are discussed, including age of onset, age at the time of surgery, pre-operative and post-operative amblyopia, refractive error, anisometropia, the surgical procedures used, and post-operative ocular alignment.Esotropia in childhood may be congenital or acquired.Congenital esotropia is a well-defined entity with an onset prior to 6 months of age, characterised by a large stable angle and a limited potential for binocular single vision. 1 Acquired childhood esotropia may be paralytic or non-paralytic.Non-paralytic or concomitant childhood esotropia, which is neither congenital nor secondary to ocular path ology, can be divided into three main groups:1. Accommodative esotropia, which may be fully accom modative, partially accommodative, or accommoda tive with convergence excess.2. Non-accommodative esotropia. 3. Esotropia associated with neurological dysfunction, in particular cerebral palsy, hydrocephalus and develop mental delay.We reviewed children in these three categories who under went strabismus surgery at the Birmingham Children's Hospital, in order to determine the results achieved, to identify the factors associated with favourable and less favourable outcomes, and to consider this information in the planning of future surgery for these conditions. PATIENTS AND METHODSThe case notes of consecutive patients undergoing surgery RESULTSThe inclusion criteria were fulfilled by 118 patients, com prising 24 (20.3%) with accommodative esotropia with convergence excess, 17 (14.4%) with partially accommo dative esotropia, 62 (52.5%) with non-accommodative esotropia and 15 (12.7%) with esotropia associated with neurological dysfunction. No patient underwent surgery

SummaryThe restoration or maintenance of useful binocular single vision (BSV) represents the ideal outcome in the management of a squinting child. However, in planning such management it is essential to have a clear appreciation of the likelihood of attaining that goal , and what factors will help in its attainment.Using both a literature review and some preliminary information from our own patient database we examine the prospects for BSV in different strabismus groups.We also discuss the techniques available to allow prediction of which children are candidates for the development of BSV following squint correction.The ideal outcome in the management of a squinting child is the restoration or establish ment of binocular single vision (BSV) and motor fusion. With these goals secured the strabismus surgeon can look forward to the long-term stability of the surgical result. If these objectives cannot be achieved then the natural progression towards divergence with increasing agel will tend to give rise to increas ing numbers of cosmetically unsatisfactory results and to late surgical correction of con secutive exotropia with the attendant risk of intractable diplopia.Our surgical objectives, be they orthopho ria, deliberate undercorrection or deliberate overcorrection should, therefore, be guided by the expectation of useful BSV resulting from treatment. This review examines some of the theoretical considerations reiating to different types of straol'2>ffius, ano. sup plements those considerations with infor mation obtained from interrogation of our own patient database. The database consists of consecutive patients followed for at least five years, and while currently small, provides useful additional information. We also exam ine some of the ways in which the likelihood of developing BSV may be predicted in any indi vidual child. Esotropia(a) Congenital! Early Infantile An extensive literature on this group of patients has flourished, largely because it represents a discrete, easily identified cohort. The major discussion centres on the timing of surgical intervention, the prospects for BSV and the quality of BSV obtained.2.3.4.5 When evaluating such reports care must be exer cised in assessing the different results reported using different tests of BSV. Particu larly, as Harcourt and Mein point out, the presence of motor fusion in the early post operative period does not necessarily corre late with stable BSV later.6 Nonetheless, it does appear that a significant proportion of such children will develop microtropia with stereopsis if corrected to within 10 prism dioptres by two years of age/ and that this outcome greatly reduces the risk of consecCorrespondence to: