Infantile esotropia: results in the neurologic impaired and "normal" child at NCMH (six years)

Association between Gestational Age, Birth Weight, Parental Age at Childbirth, Mode of Delivery, and Infantile Esotropia

SIGNIFICANCE

This study investigated the potential perinatal risk factors associated with infantile esotropia in a Chinese population, including advanced parental age at childbirth and mode of delivery. The findings may be significant in developing better intervention strategies for infantile esotropia.

PURPOSE

This study aimed to investigate the associations between gestational age, birth weight, parental age at childbirth, mode of delivery, family history of strabismus, and infantile esotropia in the Chinese population.

METHODS

Ninety-nine patients with infantile esotropia and 117 control subjects were enrolled between March 2018 and March 2021. Detailed questionnaires were administered to parents to collect relevant information. Univariate and multivariate logistic regression models were used to identify possible risk factors of infantile esotropia. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.

RESULTS

Infantile esotropia was associated with low birth weight (<2500 g; OR, 4.235; 95% CI, 1.460 to 12.287; P = .008) and emergency cesarean delivery (OR, 2.230; 95% CI, 1.127 to 4.413; P = .02).

CONCLUSIONS

The findings suggest that low birth weight and emergency cesarean deliveries are risk factors for infantile esotropia, highlighting a need for collaborative care between obstetricians, pediatricians, and vision care providers.

The Effects of Brain Damage on Visual Functioning in Children

This article reviews the research literature on the direct effects of brain damage on the visual functioning of children and the electrodiagnostic tests used to diagnose them. Although the studies documented that brain damage affects visual functioning, they suggested that the prognosis for good functional vision after remedial intervention is more optimistic than was previously thought. They also found that electrodiagnostic testing is a valuable tool, but that the use of a combination of tests yields a more complete picture of the effects than does any single test.

Comparison of Surgical Success for Infantile Esotropia and Strabismus Associated with Neurological Impairment

PURPOSE

Surgery for strabismus associated with neurological impairment is assumed to have unsatisfactory results in comparison with other strabismus cases. The aim of this study is to compare the surgical success rates of infantile esotropia (IE) and strabismus associated with neurological impairment.

METHODS

The records of 103 patients that received operations for IE and strabismus associated with neurological impairment between January 1994 and May 2014 were reviewed retrospectively. The angles of deviation and surgical success rates were evaluated at preoperative, 1-month postoperative, and 24-month postoperative visits.

RESULTS

Forty-five patients received operations for strabismus associated with neurological impairment (25 patients with esotropia and 20 patients with exotropia) and 58 patients for IE. Mean preoperative angles of deviation in cases with neurological impairment were 42 prism diopters (PD) for esotropia, 44.7 PD for exotropia, and 44.4 PD for IE. One patient from each group had consecutive deviation at first visit, and at last visit, 3 patients with neurological impairment and 5 patients with IE had consecutive deviations. Surgical success rates at the end of the second year were 52% for esotropia and 50% for exotropia in patients with neurological impairment and 56.8% for IE cases.

CONCLUSION

This study was unable to find the differences between surgical success rates in IE and strabismus associated with neurological impairment.

Clinical outcomes of botulinum toxin injection in patients with cerebral palsy and esotropia

PURPOSE

To assess the efficacy of botulinum toxin (Novotox) injection in patients with cerebral palsy (CP) and esotropia.

PATIENTS AND METHODS

In a non-comparative, prospective interventional case series botulinum toxin injection was done in 44 patients with CP and esotropia. A single dose of botulinum toxin was injected in both medial rectus muscles of all patients and was repeated in 12 patients. Angle of deviation within 10 prism diopters (PD) of orthotropia was defined as a successful outcome.

RESULT

Forty-four patients (21 males) with the mean age of 47.56 ± 35.86 months were included in the study. The mean esotropia in all patients was 52.27 ± 18.40 PD (25-123 PD). The range of follow-up was 12-24 months. Thirty patients (68.18%) were treated successfully one year after surgery. The rates of success, consecutive exotropia, and residual esotropia were 61.4%, 13.63%, and 25% in the last follow-up, respectively. The logistic regression showed statistically significant results between success result and lower age, higher pre-injection deviation, one month post-injection deviation, and severe ptosis. Complications included subconjunctival hemorrhage and ptosis.

CONCLUSION

Botulinum toxin injection is reasonably less invasive with light anesthesia, scar free, and a therapeutic alternative for the patient with esotropia and CP. Therefore, it can provide more possible surgical options in future.

Long-term surgical outcomes of infantile-onset esotropia in preterm patients compared with full-term patients

BACKGROUND/AIMS

To compare surgical outcomes between preterm and full-term patients with infantile-onset esotropia.

METHODS

This study included 56 preterm and 162 full-term patients with infantile-onset esotropia who underwent strabismus surgery. The extent of surgery was reduced by 0.5 mm per muscle in preterm patients who were born at <30 weeks of gestation. Surgical outcomes over time, including surgical success, overcorrection rate, undercorrection rate and surgical dose-response were compared between preterm and full-term patients.

RESULTS

The Cox proportional hazards regression model and competing risk analysis showed no statistically significant differences in the rate of surgical success or undercorrection over time between preterm and full-term patients. However, the final overcorrection rate was greater in preterm children than in full-term children (p=0.019). The average surgical dose-response was 3.99 prism dioptres (PD)/mm in full-term children and 4.40 PD/mm in preterm children.

CONCLUSIONS

The results of this study showed a favourable outcome using a mildly reduced amount of surgery in preterm patients with infantile-onset esotropia. Surgical dose-response was significantly greater in preterm patients than in full-term patients.

Strabismus surgery for children with developmental delay

PURPOSE OF REVIEW

To describe recent evidence regarding the surgical approach of strabismus in children with various forms of developmental delay.

RECENT FINDINGS

There remains variability in surgical outcomes with or without dose adjustment in strabismus surgery for children with developmental delay. However, this should not deter one from performing surgery - even early surgery, as fusional potential remains possible, which can especially impact the quality of vision and quality of life in developmentally delayed children.Future prospective, comparative, long-term studies with larger sample sizes for strabismus surgery in children with developmental delay are still needed.

SUMMARY

Strabismus is one of the most common ophthalmologic findings in children with developmental delay. Surgical correction of strabismus in children with developmental delay is well tolerated and effective, although it remains slightly less predictable, which can depend on the specific type of delay or underlying neurological deficit. Careful consideration of types and severity of developmental delay and attempts to measure binocular potential can help guide the timing, dosage, and type of treatment.Reoperations tend to be more frequently encountered in this population, and this higher degree of variability should be addressed in the consent process.Considering adjusting the surgical dosage in this population, taking careful preoperative measurements, and checking for fusional potential should be taken into account when managing children with developmental delay.

Esotropia surgery in children with Down syndrome

PURPOSE

To evaluate postoperative alignment in children with and without Down syndrome after surgical correction of esotropia.

METHODS

The medical records of consecutive patients with Down syndrome who underwent corrective surgery for esotropia between August 1992 and July 2012 were retrospectively reviewed. Age range for eligibility was between 8 months and 17 years at surgery. The control group comprised randomly selected, age-matched patients without Down syndrome who underwent the same surgical procedure. Postoperative alignment within 10(Δ) of orthotropia at 6 months' follow-up and at the final postoperative visit was considered a successful outcome.

RESULTS

A total of 17 children with Down syndrome and 27 control subjects were included. The control group and Down syndrome group did not differ significantly in either postoperative follow-up (5.2 ± 3.2 versus 5.6 ± 5.2 years, respectively) or magnitude of deviation before surgery (40 ± 18.2(Δ) versus 39 ± 12.8(Δ), respectively). Surgical success was achieved in 76% of patients with Down syndrome and in 85% of control patients at 6 months' follow-up.

CONCLUSIONS

In this patient cohort, good surgical outcomes were achieved in children with esotropia and Down syndrome compared with those with esotropia but without Down syndrome using the same surgical technique.

Cerebral Palsy for the Pediatric Eye Care Team Part II: Diagnosis and Treatment of Ocular Motor Deficits

INTRODUCTION

Cerebral palsy is a term used to describe a spectrum of neurological deficits resulting from damage to the developing nervous system. This paper, the second in a series of three articles, will present frequency, diagnosis, and management of the ocular motor deficits associated with CP. Topics for discussion will include the prevalence and type of strabismus, the effect of CP on eye movement systems, the efficacy of vision therapy for eye movement deficits, and strabismus surgery.

METHODS

In 2002, a retrospective chart review of all cases of cerebral palsy referred to the St. Louis Children's Hospital Eye Center was done. Detailed data on the sensory and motor deficits documented in these children was collected. Also recorded was the management strategy and response to treatment.

RESULTS

Of the 131 cases reviewed (mean age 5.2 years at presentation), 84 (64%) had strabismus: 55% esotropia and 27% exotropia. Of those patients tested for eye movement disorders 67 (61%) had evidence of instability of fixation; 85% of the patients had a pursuit deficit; and 80% had some type of deficit in performing saccades. Vergence was affected in 45% of our patients. Of the patients who underwent strabismus surgery, 67% achieved success after a mean number of 2.1 surgeries. Surgical success was associated with mild or moderate CP (P <.0005), and a stable preoperative angle. Six percent of our patients underwent vision therapy for strabismus or eye movement anomalies under the direction of an outside optometrist.

CONCLUSION

Infantile strabismus is significantly more common in children with CP than in the general pediatric population. Disorders of eye movements are also very common. Based on our experience and review of the literature there is no convincing evidence that vision therapy significantly improves eye movements or visual functioning. Approximately 2 of every 3 cases of nonaccommodative strabismus associated with CP can be successfully managed with conventional strabismus surgery, though most children will require at least two surgeries to achieve alignment.

Outcomes of strabismus surgery for esotropia in children with Down syndrome compared with matched controls

PURPOSE

Strabismus surgery dosages used in children with various neurodevelopmental disorders have been the subject of controversy. Few data have been reported regarding surgical results in individuals with Down syndrome (DS).

METHODS

A retrospective, case-control study was performed in which children with DS and previous bilateral medial rectus recession surgery were matched with similar control patients without DS. Surgical results were compared using a random coefficients model for repeated measurements for each group.

RESULTS

Sixteen patients with DS were matched with 16 control patients. Mean preoperative esotropia was 28.4 prism diopters (PD) in the DS group and 27.9 PD in the control group. No significant difference was found in surgical dosages between the two groups (P = .2402). Median surgical dosage was 4.4 mm in the DS group and 4.5 mm in the control group. Preoperative and 4-month and 24-month postoperative mean angles of esotropia were not different between groups (P = .8050). The 4-month postoperative mean angles of esotropia for the DS and control groups were 3.15 and 2.66 PD, respectively. The 24-month mean angles of esotropia for the DS and control groups were 7.09 and 6.60 PD, respectively.

CONCLUSION

Standard bilateral medial rectus recession surgical dosages need not be modified for individuals with DS.

Long-term results of esotropia surgery in children with developmental delay

PURPOSE

To assess the long-term results of esotropia surgery in children with developmental delay who were operated on with reduced surgical dosages.

METHODS

This was a retrospective analysis of children with developmental delay who had undergone surgery for esotropia during a 16-year period. The pre- and postoperative angle of deviation was calculated for each subject as the mean of distant and near angles measured by a cover test or the Krimsky measurement. The main outcome measure was surgical success, categorized as esotropia or exotropia of ≤ 10(Δ).

RESULTS

The chart review identified 24 children who met inclusion criteria, with a mean age of 2.8 ± 2.5 years (range, 0.8-10 years). The mean angle of preoperative esotropia was 49.8(Δ) ± 13.3(Δ). All patients had bilateral medial rectus muscle recessions, with a mean surgical dosage of 5.1 ± 0.7 mm per muscle, on average 0.75 mm less than the standard amount. The average postoperative follow-up was 5.3 ± 3 years (range, 1-13 years). Surgical success was achieved in 9 of 24 children (37.5%) after one operation. Among the 15 failures, 10 (66.6%) were undercorrected, and 5 (33.3%) developed consecutive exotropia. Of these, 8 (53%) agreed to a second procedure. The overall surgical success rate for all patients after all procedures was 63%.

CONCLUSIONS

Although the initial success rate is low with reduced surgical amounts in children with developmental delays, and some children become exotropic on long-term follow-up, satisfactory results may be achieved with additional procedures.

Best age for surgery for infantile esotropia

Infantile esotropia (IE) is defined as an esotropia before the age of 6 months, with a large angle, latent nystagmus, dissociated vertical deviation, limitation of abduction, and reduced binocular vision, without neurological disorder. Prematurity, low birth weight, and low Apgar scores are significant risk factors for IE. US standard age of first surgery is 12-18 months, in Europe 2-3 years. The only study to date with prospectively assigned early- and late-surgery groups and evaluation according to intention-to-treat, was the European Early vs. Late Infantile Strabismus Surgery Study (ELISSS). In that study 13.5% of children operated around 20 months vs. 3.9% (P = 0.001) of those operated around 49 months had gross stereopsis (Titmus Housefly) at age 6. The reoperation rate was 28.7% in children operated early vs. 24.6% in those operated late. Unexpectedly, 8% in the early group vs. 20% in the late group had not been operated at age 6, although all had been eligible for surgery at baseline at 11 SD 3.7 months. In most of these children the angle of strabismus decreased spontaneously. In a meta-regression analysis of the ELISSS and 12 other studies we found that reoperation rates were 60-80% for children first operated around age 1 and 25% for children operated around age 4. Based on these findings, the endpoints to consider when contemplating best age for surgery in an individual child with IE should be: (1) degree of binocular vision restored or retained, (2) postoperative angle and long-term stability of the angle and (3) number of operations needed or chance of spontaneous regression. IE is characterized by lack of binocular connections in the visual cortex that cannot develop, e.g. because the eyes squint, or do not develop, e.g. after perinatal hypoxia. As the cause of IE, whether motor or sensory, is a determinant of surgical outcome, a subdivision of IE according to cause is needed. As similarities exist between IE and cerebral palsy we propose to adapt the working definition formulated by the Surveillance of Cerebral Palsy in Europe and define IE as "a group of permanent, but not unchanging, disorders with strabismus and disability of fusional vergence and binocular vision, due to a nonprogressive interference, lesion, or maldevelopment of the immature brain, the orbit, the eyes, or its muscles, that can be differentiated according to location, extent, and timing of the period of development."

Predictive value of age, angle, and refraction on rate of reoperation and rate of spontaneous resolution in infantile esotropia

In the Early vs. Late Infantile Strabismus Surgery Study (ELISSS), 13.5% of children operated at 20 months vs. 3.9% of those operated at age 4 had gross binocular vision (Titmus Housefly). Reoperation rates were 28.7% in the former vs. 24.6% in the latter group and, although all were eligible for surgery at baseline at 11 SD 3.7 months, 8% in the early group vs. 20% in the late group were never operated, mostly because their angle decreased spontaneously. We assessed the predictive value of age, angle, and refraction in these matters.

METHODS

The ELISSS reoperation rates were first compared with those found in nine series of consecutive cases in nine university clinics operated during one particular year, between 6 and 23 years previously. Logistic regression was used to estimate the effect of postoperative angle and clinic on the chance of reoperation. Secondly, a meta-regression analysis was done of these and other reported reoperation rates. The mean age at operation and the mean duration of follow-up were regressed on the logistically transformed reported reoperation rates. Finally, to estimate the chance of spontaneous decrease of the angle without surgery, a random-effects model was fitted on the 6-monthly orthoptic measurements of angle and refraction in the ELISSS that antedated surgery, loss to follow-up, or final examination. In the random-effects model (see online-only supplement link or visit, www.simonsz.net), for ELISSS patients the random effect was defined as the deviation of the average angle, the fixed effect. A vector was defined based on age and spherical equivalent of the patient. The variance around the prediction consisted of uncertainty in the estimations, random effects, and residuals.

RESULTS

In the retrospective study, 204 patients who had been first operated between 6 and 23 years previously were eligible. A reoperation had been performed in 32 (19.3%) of the remaining 166 children who were 4.33 SD 1.35 years old at first surgery. The reoperation rate was 7.3% for those with a postoperative angle of -4° to +4° (N = 82), 25% for postoperative divergence > 5°, and 29% for postoperative convergence 10° to 14°. Strabismologists overestimated the reoperation rates at double. In the meta-regression analysis, 12 studies were included. Reoperation rates were between 60% and 80% for children first operated around age 1 and approximately 25% for children operated around age 4 (best fit: -0.221 Ln [age in months] + 1.1069; R(2) = 0.5725). Finally, in the predictions of random-effects model, a small angle at age 1 and hyperopia of approximately +4 increased the chance of spontaneous decrease of the angle into a microstrabismus.

DISCUSSION

The benefit of early surgery for gross binocular vision is balanced by a higher reoperation rate and an occasional child being operated that would have had a spontaneous decrease into a microstrabismus without surgery. The fact that, in the ELISSS, hyperopia was associated with a decrease of the angle underscores the benefit of early refractive correction.

Predictability of strabismus surgery in children with developmental disorders and/or psychomotor retardation

BACKGROUND

Children with developmental disorders and/or psychomotor delay may respond differently to strabismus surgery than children who develop normally, but the literature is conflicting.

METHODS

We studied 37 patients with spasm, trisomy 21, prematurity, epilepsy, psychomotor retardation, and/or hydrocephalus (study group) and 67 control patients, all between 14 months and 14 years of age. All received a recession of one or both medial rectus muscles (Rc-surgery) or a monocular recession-resection of medial-lateral rectus muscles (RcRs-surgery) for esotropia. Rc-surgery was performed in cases with convergence excess. Spectacles were prescribed prior to surgery for all hyperopia > 2D, all partly accommodative esotropia, and all myopia.

RESULTS

(effect per mm of surgery): For Rc-surgery, after 2 months follow-up, at 2.5 m fixation distance, the effects (change of angle per millimeter of surgery, mean + or - SD) were 2.07 + or - 0.82 degrees /mm (study group) and 1.07 + or - 0.74 degrees /mm (control group) (P < 0.001). At 30 cm fixation distance, the effects were 2.42 + or - 0.79 degrees /mm (study group) and 1.53 + or - 1.00 degrees /mm (control group) (P < 0.001). Effects at infinity were similar to those at 2.5 m. Because of this larger effect on near angles, convergence excess decreased after surgery in both study and control groups. For RcRs-surgery, at 2.5 m fixation distance, the effects were 1.78 + or - 0.43 degrees /mm (study group) and 1.78 + or - 0.42 degrees /mm (control group) (P = 0.741). At 30 cm fixation distance, the effects were 1.82 + or - 0.39 degrees /mm (study group) and 1.84 + or - 0.58 degrees /mm (control group) (P = 0.918). At fixation distance infinity, results were similar to those at 2.5 m. For both Rc-surgery and RcRs-surgery, reported differences were similar after one year follow-up. Success of surgery: After 2 months of follow-up, esotropia between 0-6 degrees was present, for Rc-surgery in 64% in the study group (with adjusted dosages) and 93% in the control group; and for RcRs-surgery in 66% in the study group and 88% in the control group.

CONCLUSIONS

Rc-surgery in children with developmental disorders and/or psychomotor delay has a larger effect per mm of surgery than in normal children. RcRs-surgery has a similar effect in delayed and normal children.

Strabismus surgery outcome among children and young adults with Down syndrome

PURPOSE

To evaluate postoperative alignment after strabismus surgery in children with Down syndrome.

METHODS

A retrospective analysis of 15 consecutive cases of children with Down syndrome who underwent surgery for strabismus between 1990 and 2008. Follow-up was at least 6 months (range, 0.5-16 years).

RESULTS

All children underwent surgery for esotropia. The mean preoperative angle of deviation was 37.6Delta. Of the 15 children, 14 underwent surgical procedure for strabismus according to standard surgical tables. Surgical success (within 10Delta of orthophoria) was achieved in 12 of 14 children (85.7%). The remaining 2 children (14.3%) had residual esotropia.

CONCLUSIONS

Good surgical motor outcomes were achieved in children with Down syndrome after strabismus surgery following standard surgical tables. The tendency toward overcorrection reported in children with central nervous system disorders was not observed in our study. We suggest use of the same surgical calculations as used in children with normal development when treating children with Down syndrome and esotropia.

Strabismus, Binocular Functions and Ocular Motility in Children with Hydrocephalus

PURPOSE

To investigate heterotropia, heterophoria, head posture, nystagmus, stereo acuity, ocular motility and near point of convergence (NPC) in children with hydrocephalus treated surgically before 1 year of age. In addition, the effects of being born with hydrocephalus, the effect of the etiology of hydrocephalus, number of shunt revisions and the size of the ventricles on these variables were studied.

METHODS

A population-based study was performed in 75 children and the results were compared with the results of an age- and sex-matched group (comp group) (n = 140).

RESULTS

Heterotropia 68.9% (comp group 3.6%; p < 0.001), abnormal head posture 41.3% (comp group 0; p < 0.001), nystagmus 44.0% (comp group 0; p < 0.001), stereo acuity < or =60'' 33.8% (comp group 97.1%; p < 0.001) and ocular motility defects 69.7% (comp group 0.7%; p < 0.001) were more common among children with hydrocephalus than in the comparison group. Children with overt hydrocephalus at birth had significantly more heterotropia (p = 0.0006), esotropia (p = 0.002), abnormal head posture (p = 0.02) and motility defects (p = 0.003) compared to those with hydrocephalus developing during the first year of life. The etiology, number of shunt revisions and the size of the ventricles had no significant effect on any of the investigated variables.

CONCLUSIONS

Children with hydrocephalus surgically treated before the age of one year commonly present orthoptic abnormalities. The etiology of hydrocephalus, number of shunt revisions and ventricle size seem to be of minor importance compared with the age of onset of hydrocephalus with regard to the risk for orthoptic abnormalities.

Unsuspected periventricular leukomalacia in children with strabismus: a case series

PURPOSE

We report a case series of seven patients who presented with strabismus and no apparent known neurological deficit.

METHODS

A retrospective review of notes was performed on all patients presenting at the Royal Liverpool Children's Hospital (Alder Hey) with strabismus, in whom subsequent investigation revealed the presence of periventricular leukomalacia (PVL).

RESULTS

All seven patients presented with esotropia. One patient also had dissociated vertical deviation. A history of premature birth was elicited in six cases; however, one patient had been born at 42 weeks. Apparently uncomplicated routine surgery produced unexpectedly poor results.

CONCLUSIONS

Patients with undiagnosed PVL may present to the ophthalmologist with strabismus and no other apparent neurological abnormality. Where it is suspected that the patient may have suffered a significant hypoxic-ischaemic event, the ophthalmologist should have a low threshold for investigating with magnetic resonance imaging, particularly if the patient shows unexpected outcomes following appropriate treatment. Patients and parents should be counselled on possible suboptimal results prior to the offer of surgical correction of strabismus.

Bilateral medial rectus muscle recession: results in children with developmental delay compared with normally developed children

PURPOSE

We sought to compare bimedial rectus muscle recession (BMR) results for esotropia in children with developmental delay with the results in normal children.

METHODS

A retrospective analysis of all the children that underwent standard BMR surgery for esotropia during a 10 year period was undertaken. The surgical results of children with developmental delay were compared with those of normal children.

RESULTS

In the developmentally delayed group, the mean angle of esotropia before surgery was 53+/-12 PD, the mean amount of medial rectus recession was 5.4+/-0.56 mm, 0.84 mm less than the standard amount of recession, and at the last follow-up visit only 56% achieved surgical success (within 10 PD of orthophoria). Among the failures, 86% were undercorrected, only one patient developed consecutive exotropia after surgery. In the developmentally intact group, the mean angle of esotropia before surgery was 37.4+/-8 PD, the mean amount of medial rectus recession was 5.2+/-0.65 mm, and 94% achieved surgical success. Among surgical failures, we observed only a single case of overcorrection.

CONCLUSION

A higher rate of surgical failure was found in developmentally delayed children who received a smaller recession amount of the medial rectus muscles when compared with the developmentally normal children who received a standard amount of recession. The main reason for surgical failure in the developmentally delayed group, in a follow-up period of 2 years, was undercorrection of the angle of esotropia. It seems that decreasing the surgical table by a certain amount in children with developmental delay may lead to undercorrection. Therefore, we need to delineate the ideal amount of surgery in this unique group of individuals.

Two-muscle surgery for congenital esotropia: rate of reoperation in patients with small versus large angles of deviation

INTRODUCTION

Standard surgical treatment of congenital esotropia (CET) in patients with preoperative angles of deviation measuring </=50 PD is well defined. However, there is controversy over the management of larger angles of esotropia. Some surgeons prefer to operate on 3 or 4 horizontal rectus muscles, while others prefer to perform large recessions of the medial rectus muscles alone. The purpose of this study was to compare the rate of reoperation after bilateral medial rectus muscle recession of smaller angle (< or =50 PD) CET with the rate of reoperation after surgery for larger angle (>50 PD) CET.

METHODS

Medical records of 102 patients who underwent bilateral medial rectus muscle recessions between January 1991 and December 1997 were reviewed. Patients were excluded if neurologic abnormalities or developmental delays were documented before the operation, if major structural abnormalities of the eye were present, or if less than 1-month follow-up after surgery was documented. The remaining 56 patients were assigned to either the larger angle (>50 PD) or smaller angle (< or =50 PD) group, based on the magnitude of their preoperative esotropia. Rates of reoperation for residual CET, for consecutive exotropia or dissociated horizontal deviation, or for dissociated vertical deviation with or without oblique muscle dysfunction were determined for each group.

RESULTS

Forty of 56 patients (71%) were assigned to the smaller angle group and 16 of 56 patients (29%) to the larger angle group. In the larger angle group, 4 patients (25%) underwent surgery for residual esotropia. In the smaller angle group, 8 patients (19%) underwent surgery for residual esotropia, 8 (19%) underwent surgery for consecutive exotropia or dissociated horizontal deviation, and 8 (19%) underwent surgery for dissociated vertical deviation or oblique muscle dysfunction.

CONCLUSION

The success rate for ocular realignment in patients with CET by using bilateral medial rectus muscle recession did not appear to diminish when applied to deviations greater than 50 PD as compared with smaller angle deviations. Surgery on 3 or 4 horizontal rectus muscles may be unnecessary in the treatment of patients with very large angles of CET.

Developmental delay and poverty in the strabismus clinic

BACKGROUND

Strabismus and poverty are more common among developmentally delayed children. Poverty is difficult to define, but qualification for Medicaid benefits has been used as an indicator in the past.

METHODS

There was a retrospective review of 95 patients with strabismus younger than 7 years who were seen in the Department of Pediatric Ophthalmology at the Albany Medical Center for a 12-month period and were reviewed for the presence or absence of developmental delay. These patients were selected from 2 groups: one with Medicaid coverage and one without.

RESULTS

Developmental delays were noted in 13 patients without Medicaid (27.0%) and in 26 patients with Medicaid (55.3%) (P = .0096). Patients with Medicaid were less likely to name Allen pictures by age 3 years (P = .0003).

CONCLUSIONS

Poverty is more commonly associated with delays in patients with strabismus, and this should alert ophthalmologists who work with Medicaid patients to seek to identify the presence of developmental delay in managing the care of these patients.

Congenital esotropia in Olmsted County, Minnesota

OBJECTIVE

To determine the birth prevalence of and risk factors associated with congenital esotropia.

DESIGN

Population-based prevalence study with nested case-control study.

PARTICIPANTS

All residents of Olmsted County, Minnesota who were diagnosed with congenital esotropia and born between January 1, 1980 and December 31, 1989 (n = 47). Control subjects were chosen by selecting the next two sequential births to parents residing in Olmsted County, Minnesota (n = 94).

METHODS

Cases were identified through the Medical Diagnostic Index of Mayo and the Rochester Epidemiology Project. The community medical records were reviewed to confirm case status and ascertain risk factor information.

MAIN OUTCOME MEASURE

Birth prevalence of congenital esotropia.

RESULTS

Forty-seven cases were identified from 17,536 live births, for a birth prevalence of 27 per 10,000 (95% confidence interval [CI], 20-35). Congenital esotropia was associated with prematurity (odds ratio [OR], 11.5; 95% CI, 3.4-39.2), a birth weight less than 2500 grams (OR, 4.6; 95% CI, 1.7-12.9), a low Apgar score at 1 minute (OR, 4.3; 95% CI, 1.7-11.2) and at 5 minutes (OR, 6.3; 95% CI, 1.3-30.7), and a family history of strabismus (OR, 3.5; 95% CI, 1.5-8.3).

CONCLUSIONS

The birth prevalence of congenital esotropia in Olmsted County, Minnesota is lower than previous estimates. Prematurity, low birth weight, low Apgar scores, and a family history of strabismus are significant risk factors for congenital esotropia.

Strabismus in children with cerebral palsy

In 48 children with cerebral palsy the characteristics of the squint and amblyopia were analyzed, also with respect to the features of cerebral palsy and to birth weight. Strabismus of congenital esotropia type was found to be common, as was also exotropia of early onset. Spontaneous alternation or an accommodative component of the squint was present only in a few cases. There was no evidence of an accumulation of any strabismus type in the different subgroups of cerebral palsy, whereas amblyopia or an obvious risk for amblyopia was found in the great majority of the cases. Some kind of amblyopia treatment was given to 34. Most of them showed improvement of the visual capacity which encourages treatment of amblyopia, even in children with cerebral palsy.

Exaggerated effect of bilateral medial rectus recession in developmentally delayed children

Many have suggested that the esotropia associated with developmental delay should be considered separately. However, the esotropia surgery recommended for developmentally delayed children has been similar to that performed in normal children. We have noticed a tendency for developmentally delayed children to develop consecutive exotropia following bilateral medial rectus recessions. Of 94 children undergoing such surgery between 1981 and 1991, 31 were developmentally delayed. Follow up ranged from 7 months to 202 months (mean 24 months). Surgical effect, defined as the change in alignment following each amount of surgery, was greater in the developmentally delayed group than in control subjects (P = .002). The increase in effect of the same amount of surgery in a developmentally delayed patient averaged 5.28 prism diopters, but was much larger in specific instances. Variability of effect was more marked among developmentally delayed children. We conclude that bilateral medial rectus recessions in developmentally delayed children may be better postponed in some cases, deferred for smaller angles, or decreased in amount.

The outcome of strabismus surgery in childhood esotropia

The results of squint surgery in 118 children with non-paralytic childhood esotropia are analysed. A 'favourable 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.

Abnormal motoric laterality in strabismus and a hypothesis concerning its neurological origins

A survey of the literature concerning motoric laterality in strabismus was undertaken. The assessment of manual and ocular dominance was based on a total of eleven studies conducted between 1934 and 1986. The average percentage of right-handedness in strabismics was 73.8%, whereas the average percentage of right-eyedness was 46.9%. Both figures are significantly lower than those obtained for the normal population. It is hypothesized that reduced right dominance in strabismics results from dysfunction of the otoliths and/or their higher brainstem pathways.

Results of early surgery for infantile esotropia in normal and neurologically impaired infants

A prospective study was performed over a 4-year period of 56 infants presenting with infantile esotropia to assess development of binocularity after surgical alignment before 2 years of age. In 50% of cases infantile esotropia was associated with neurological problems or prematurity. Forty-three cases have undergone surgery (mean age 15.7 months +/- 3.46); 86% were aligned (+/- 10 dioptres) at 2 years. Eighty-seven per cent of normal children and 74% of children with neurological problems or prematurity were aligned at last follow-up (mean 27.2 months since surgery). Tests of fusion and stereopsis have to date been possible upon 21 'successfully' aligned infants and although most have evidence of peripheral sensory fusion none showed stereopsis to more than one test. Although early surgery achieves a good cosmetic result in normal children and those with neurological problems, our findings question its ability to promote the development of even gross stereopsis in most children.

Congenital esotropia

Congenital esotropia represents the most common type of strabismus. Its pathogenesis, however, remains uncertain. It is typically characterized as a large angle, constant esotropia with onset during the first six months of life. Associated clinical findings include normal refractive errors for age, amblyopia, dissociated vertical deviation, inferior oblique muscle overaction and nystagmus. It must be distinguished from Duane's retraction syndrome, Moebius syndrome, nystagmus blockage syndrome, and early onset accommodative esotropia, as well as other causes of esotropia in infancy. The surgical management may involve recession of both medial recti muscles, unilateral recession of a medial rectus muscle and a resection of a lateral rectus muscle or three or four muscle surgery.