Long-term follow-up of congenital esotropia in a population-based cohort

Long-term Motor and Sensory Outcomes After Unilateral Medial Rectus Recession-Lateral Rectus Resection for Infantile Esotropia

PURPOSE

To report long-term motor and sensory outcomes after unilateral medial rectus recession-lateral rectus resection for infantile esotropia.

METHODS

The medical records of patients who had undergone unilateral medial rectus recession-lateral rectus resection for infantile esotropia and were followed up postoperatively for a minimum of 10 years were reviewed retrospectively.

RESULTS

A total of 100 patients were included. The mean age at surgery was 2.9 ± 2.2 years (range: 2.5 months to 9.0 years). The mean postoperative follow-up was 15.7 ± 4.4 years (range:10.0 to 27.5 years). Overall, 54 patients (54%) had surgical success at their last follow-up visit. Age at first surgery, strabismus duration, degree of hyperopia, preoperative size of deviation, presence of dissociated vertical deviation, inferior oblique overaction, or both dissociated vertical deviation and inferior oblique overaction, and the number of esotropia surgeries did not predict motor outcome after surgery. Consecutive exotropia developed in 43% of patients (constant in 18% and intermittent in 25%). Residual and recurrent esotropia occurred in 20% and 21% of patients, respectively. Refractive accommodative esotropia developed in 17% of patients and there was a high accommodation convergence/accommodation ratio esotropia in 2%. Peripheral binocular single vision was achieved in 54% of patients and stereopsis in 1%. Patients with 1.5 years or less of strabismus duration had better chances of achieving peripheral binocular single vision.

CONCLUSIONS

Nearly half of the patients with infantile esotropia achieved a successful long-term motor outcome and peripheral binocular single vision. Consecutive exotropia occurred frequently. Recurrent esotropia and refractive accommodative esotropia developed in some patients, and a high accommodation convergence/accommodation ratio esotropia in a few. Stereopsis outcome was extremely poor. [J Pediatr Ophthalmol Strabismus. 2024;61(2):106-113.].

The incidence, clinical features, and management of essential infantile esotropia in the United Kingdom. A British Ophthalmology Surveillance Unit (BOSU) study

BACKGROUND/OBJECTIVES

A national study was undertaken through the British ophthalmology surveillance unit (BOSU) to determine the incidence, presenting features and management of essential infantile esotropia (EIE) in the UK.

METHODS

Data from a prospective national observational study of newly diagnosed EIE presenting to clinicians in the United Kingdom over a 12-month period were collected. Cases with a confirmed diagnosis by a clinician of a constant, non-accommodative esotropia ≥20 prism dioptres (PD), presenting at ≤12 months, with no neurological or ocular abnormalities were identified through BOSU. Follow-up data were collected at 12 months.

RESULTS

A total of 57 cases were reported giving an incidence of EIE of 1 in 12,828 live births. The mean age of diagnosis and intervention were 7.05 ± 2.6 months (range 2-12) and 14.7 ± 4.9 months (range 6.5-28.1), respectively. Management was surgical in 59.6%, botulinum toxin alone in 22.8%, and 17.5% were observed. The preoperative angle of esotropia was smaller in the observation group (P = 0.04). The postoperative angle of esotropia was not statistically significant between botulinum toxin or surgery (P = 0.3), although the age of intervention was earlier in the botulinum group (P = 0.007). Early intervention (before 12 months of age) did not influence the post-intervention motor outcomes between 0 and 10 prism dioptres of esotropia (P = 0.78).

CONCLUSIONS

The incidence of EIE in the UK is considerably lower than reported in other population-based studies. The preferred method of treatment was surgical with earlier intervention in those treated with botulinum toxin. An early age of intervention (<12 months) did not influence motor outcomes.

Occurrence and subsequent development of vertical deviations in patients treated surgically for infantile esotropia

Purpose

The purpose of this study was to evaluate the onset of dissociated vertical deviation (DVD) and inferior oblique overaction (IOOA), their subsequent development, and their correlation with pre and postoperative parameters.

Methods

Medical records of patients with infantile esotropia who underwent surgery between 2005 and 2017 were retrospectively reviewed. DVD and IOOA were measured before and after surgery. Patients were divided into two groups based on horizontal and vertical deviation at the time of presentation: those with infantile esotropia only (group A) and patients with infantile esotropia who developed vertical deviation (group B).

Results

Out of a total of 102 patients, DVD occurrence was seen in 53 patients (51.9%) and IOOA was seen in 50 patients (48.04%). DVD was seen in 22 patients at the time of initial examination and in 31 patients postoperatively. IOOA at presentation was seen in 45 patients (44.1%) and 5 patients (8.8%) postoperatively. No statistical difference was found in the age of surgery, angle of deviation, mean follow-up, and mean refractive error within both groups. The postoperative motor outcome was statistically comparable between the two groups (P = 0.29). Sensory outcomes of fusion (P = 0.048) and stereopsis (P-value = 0.00063) were better in group A.

Conclusion

No correlation was found between the age of occurrence and development of vertical deviation with refractive error, angle of deviation, age, or type of surgery. We found that motor outcomes are not affected but sensory outcomes are affected in patients with vertical deviations. This indicates that DVD and IOOA are developed due to inherent disruption of fusion and stereopsis.

Effect of Fibroblast Growth Factor 2 on Extraocular Muscle Structure and Function

Purpose

Mutations in the fibroblast growth factor (FGF) receptor can result in strabismus, but little is known about how FGFs affect extraocular muscle structure and function. These were assessed after short-term and long-term exposure to exogenously applied FGF2 to determine the effect of enhanced signaling.

Methods

One superior rectus muscle of adult rabbits received either a series of three injections of 500 ng, 1 µg, or 5 µg FGF2 and examined after 1 week, or received sustained treatment with FGF2 and examined after 1, 2, or 3 months. Muscles were assessed for alterations in force generation, myofiber size, and satellite cell number after each treatment.

Results

One week after the 5 µg FGF2 injections, treated muscles showed significantly increased force generation compared with naïve controls, which correlated with increased myofiber cross-sectional areas and Pax7-positive satellite cells. In contrast, 3 months of sustained FGF2 treatment resulted in decreased force generation, which correlated with decreased myofiber size and decreased satellite cells compared with naïve control and the untreated contralateral side.

Conclusions

FGF2 had distinctly different effects when short-term and long-term treatments were compared. The decreased size and ability to generate force correlated with decreased myofiber areas seen in individuals with Apert syndrome, where there is sustained activation of FGF signaling. Knowing more about signaling pathways critical for extraocular muscle function, development, and disease will pave the way for improved treatment options for strabismus patients with FGF abnormalities in craniofacial disease, which also may be applicable to other strabismus patients.

Surgical outcomes and occurrence of associated vertical strabismus during a 10-year follow-up in patients with infantile esotropia

Purpose:

Authors analyzed long-term surgical outcomes of infantile esotropia and the occurrence of associated strabismus, inferior oblique overaction (IOOA), and dissociated vertical deviation (DVD). Clinical factors related to the occurrence of IOOA and DVD in patients with infantile esotropia were also evaluated.

Methods:

Medical records of patients with infantile esotropia, who underwent surgery between 1995 and 2008, were reviewed retrospectively. Included patients were followed for at least 10 years. The incidence and age at development of IOOA and DVD were analyzed. To evaluate predisposing factors for developing IOOA or DVD, patients were divided into two groups: those with infantile esotropia only (group A) and those who developed IOOA or DVD (group B).

Results:

A total of 122 patients were enrolled and mean follow-up period was 16.0 years (range: 10–32 years). The mean number of surgeries was 1.7 (range: 1–5), and 64 (52.5%) patients achieved optimal horizontal alignment (esotropia <10 prism diopters [PD] and orthotropia). Fifty (41.0%) patients developed IOOA at a median age of 3 years (range: 1–21 years); 54 (44.3%) developed DVD at a median age of 5 years (range: 1–25 years). Patients in group B underwent more horizontal surgeries than those in group A (P = 0.028), and favorable surgical outcomes between the two groups were not different at final visit. There were no other significant differences in clinical factors between the two groups.

Conclusion:

Approximately, 52.5% of patients achieved favorable surgical outcomes through 1.7 surgeries during the 10-year follow-up period. DVD tended to develop at a later age than IOOA, and in some cases, up to 20 years after diagnosis of infantile esotropia. To achieve favorable horizontal alignment at final visit, patients with associated vertical strabismus underwent more horizontal muscle surgeries than patients with infantile esotropia only. The presence of IOOA/DVD may affect horizontal alignment outcomes.

Childhood Onset Strabismus: A Neurotrophic Factor Hypothesis

Strabismus is a genetically heterogeneous disorder with complex molecular and neurophysiological causes. Evidence in the literature suggests a strong role for motor innervation in the etiology of strabismus, which connects central neural processes to the peripheral extraocular muscles. Current treatments of strabismus through surgery show that an inherent sensorimotor plasticity in the ocular motor system decreases the effectiveness of treatment, often driving eye alignment back toward its misaligned pre-surgical state by altering extraocular muscle tonus. There is recent interest in capitalizing on existing biological processes in extraocular muscles to overcome these compensatory mechanisms. Neurotrophins are trophic factors that regulate survival and development in neurons and muscle, including extraocular muscles. Local administration of neurotrophins to extraocular muscles partially reversed strabismus in an animal model of strabismus. The hypothesis is that sustained release of neurotrophins gives more time for the ocular motor system to adapt to a slow change in alignment in the desired direction. The effect of neurotrophins on extraocular muscles is complex, as different neurotrophic factors have diverse effects on extraocular muscle contraction profiles, patterns of innervation, and density of extraocular muscle precursor cells. Neurotrophic factors show promise as a therapeutic option for strabismus, which may help to improve treatment outcomes and offset devastating amblyopia and psychosocial effects of disease in strabismus patients.

Effects of Surgical Timing on Surgical Success and Long-term Motor and Sensory Outcomes of Infantile Esotropia

PURPOSE

To investigate the effect of surgical timing on long-term motor and sensory outcomes in patients with infantile esotropia.

METHODS

The medical records of patients who underwent strabismus surgery for infantile esotropia were reviewed retrospectively. The patients were divided into three groups according to age at the time of surgery: early group (6 to 11 months), late group (12 to 17 months), and very late group (18 to 27 months). The main outcome measures were final alignment, surgical success rate (the angle of deviation at final follow-up of ≤ 10 prism diopters [PD] of esotropia, no exotropia and no need for reoperation), stereoacuity, visual acuity, and the number of reoperations required during the follow-up.

RESULTS

A total of 79 patients (44 female, 35 male) met the inclusion criteria. The surgical success rate was 25.9%, 23.1%, and 53.8% in the three groups, respectively (P = .035). After a mean follow-up of 96 months, the average number of operations per child was 1.7 ± 0.9, 1.6 ± 0.6, and 1.4 ± 0.6 in the three groups, respectively (P = .020). The measurable stereopsis rate was higher in the early group (37% vs 3.8% and 3.8%, respectively) (P = .001). The amblyopia rate was similar between groups.

CONCLUSIONS

The results show that performing surgery later in life in patients with infantile esotropia increases the motor success rate of surgery. In addition, orthophoria is achieved with fewer surgical operations. However, earlier surgery may improve stereopsis. [J Pediatr Ophthalmol Strabismus. 2020;57(5):319-325.].

Outcome of Esotropia Surgery in 2 Tertiary Hospitals in Cameroon

Purpose

To evaluate the ocular alignment following esotropia surgery in our setting.

Patients and Methods

We conducted a cross sectional descriptive study which spanned 19 years, from October 1999 to September 2018 at the Douala General Hospital and the Yaoundé Central Hospital. Complete medical records of patients who underwent surgery for esotropia during the study period were included. Data collected included age at diagnosis, sex, age of onset of esotropia, age at surgery, refractive error, type of surgery performed, pre and post-operative angle of deviation. The outcome was considered good when the postoperative angle was ≤10 prism diopters (PD).

Results

Four hundred and ninety patients with primary esotropia were seen during the study period. Only 155 returned for follow-up after wearing the full cycloplegic correction for a minimum period of 3 months. Accommodative esotropia was found in 32 cases (20.6%). Among the 123 cases requiring surgery, 63 cases underwent surgery (51.2%). Fifty-nine complete records were included (59.3% females and 40.7% males). The mean age at the time of diagnosis was 6.5 ± 6.1 years and the mean age at the time of surgery was 8.7 ± 6.1 years. The mean preoperative angle at distance was 42.8 ±10.8 PD. The outcome was good in 91.5% of cases. No factor influenced the outcome of surgery.

Conclusion

The outcome of esotropia surgery was good in this study. This could serve to increase patient motivation to accept surgery in our setting.

Long term motor and sensory outcome after surgery for infantile esotropia and risk factors for residual and consecutive deviations

Purpose: To present long-term motor and sensory outcomes after surgery for infantile esotropia and assess risk factors for residual and consecutive deviations.Methods: Data of infantile esotropia patients operated between 2002 and 2016 with minimum follow-up of 2 years were retrospectively reviewed.Results: Among a total of 62 patients, 35 had a successful motor outcome (alignment within 10 PD from orthotropia) after one surgery (Group A), while 27 required horizontal reoperation (Group B). Patients with residual esotropia had larger preoperative angle of deviation (P = .005) and younger age at first surgery (P = .01), while consecutive exotropia was associated with longer follow-up (P = .03) and higher rate of DVD (P = .003) compared to patients in Group A. Stereopsis was present in 30.3% of patients in Group A and associated with younger age at first surgery (P = .03).Conclusions: Successful motor alignment may be obtained with single surgery in infantile esotropia; however, reoperations are common. Younger age at first surgery may be associated with both higher rate of stereopsis and risk of reoperation. Careful preoperative assessment and surgical timing, with long-term postoperative follow-up is required to achieve satisfactory outcome.

Accuracy of the Ultrasound Biomicroscopy Bag/Balloon Technique in Locating Horizontal Extraocular Muscle Insertions Before and After Strabismus Surgery

PURPOSE

To investigate the accuracy of high frequency ultrasound biomicroscopy using the bag/balloon technique to locate recti muscle insertions before and after strabismus surgery.

METHODS

This was a prospective masked study. The distance from the limbus to horizontal recti muscle insertions was measured by caliper intraoperatively and ultrasound biomicroscopy preoperatively and during follow-up. Accuracy was defined as the difference between ultrasound biomicroscopy and caliper measurements.

RESULTS

Thirty-nine muscles (19 medial rectus and 20 lateral rectus) of 22 patients were included. The mean age of the patients was 34.7 ± 15.5 years (range: 18 to 78 years). Follow-up measurements were available for 25 muscles: 12 muscles were recessed and 13 were resected/advanced. Twelve of the included muscles underwent prior surgery. There was a strong correlation between preoperative mean ultrasound biomicroscopy and caliper measurements (P < .001, r_p = 0.872) without significant difference between the accuracy of identification of medial rectus and lateral rectus muscles (P = .116 and .377, respectively). On average, postoperative ultrasound biomicroscopy measurements of recessed muscles were 1.15 mm greater than caliper measurements at the end of surgery (P = .003), whereas the mean difference in the resected muscles was not statistically significant (-0.07 mm, P > .999). Overall, in 16 of 25 muscles (64%), the differences between the postoperative measurements and the end of surgery measurements were less than 1 mm. There was no correlation between the accuracy and the time of ultrasound biomicroscopy after surgery (P = .516).

CONCLUSIONS

The ultrasound biomicroscopy bag/balloon technique is an accurate and reliable method of locating recti muscle insertions before and after strabismus surgery. Ultrasound biomicroscopy may assist strabismologists in planning repeated operations. [J Pediatr Ophthalmol Strabismus. 2020;57(1):12-20.].

Neural Plasticity Following Surgical Correction of Strabismus in Monkeys

Purpose

Although widely practiced, surgical treatment of strabismus has varying levels of success and permanence. In this study we investigated adaptive responses within the brain and the extraocular muscles (EOM) that occur following surgery and therefore determine long-term success of the treatment.

Methods

Single cell responses were collected from cells in the oculomotor and abducens nuclei before and after two monkeys (M1, M2) with exotropia (divergent strabismus) underwent a strabismus correction surgery that involved weakening of the lateral rectus (LR) and strengthening of the medial rectus (MR) muscle of one eye. Eye movement and neuronal data were collected for up to 10 months after surgery during a monocular viewing smooth-pursuit task. These data were fit with a first-order equation and resulting coefficients were used to estimate the population neuronal drive (ND) to each EOM of both eyes.

Results

Surgery resulted in a ∼70% reduction in strabismus angle in both animals that reverted toward presurgical misalignment by approximately 6 months after treatment. In the first month after surgery, the ND to the treated MR reduced in one animal and ND to the LR increased in the other animal, both indicating active neural plasticity that reduced the effectiveness of the treatment. Adaptive changes in ND to the untreated eye were also identified.

Conclusions

Active neural and muscle plasticity corresponding to both the treated and the untreated eye determines longitudinal success following surgical correction of strabismus. Outcome of surgical treatment could be improved by identifying ways to enhance “positive” adaptation and limit “negative” adaptation.

Clinical evidence supporting the use of donor sclera as spacer material in complicated cases of strabismus surgery - retrospective evaluation of surgical results in 117 patients with thyroid-associated ophthalmopathy or congenital strabismus

PURPOSE

To examine the outcome of the use of donor sclera as spacer material in complicated cases of strabismus surgery.

METHODS

A retrospective cohort study on patients with complicated thyroid-associated ophthalmopathy (TAO) (n = 42) or congenital strabismus (n = 75). Patients underwent strabismus surgery during 1994-2014. The surgical results were evaluated in terms of the reduction in the angle of deviation, the need for re-operation, complications and patient satisfaction.

RESULTS

The majority of the TAO patients underwent surgery for vertical strabismus (n = 25). The vertical angle of deviation in the primary position was significantly reduced from a median of 23 prism dioptres (PD) to 2 PD (n = 35, p < 0.001). The horizontal angle of deviation in primary position for TAO patients with esotropia was significantly reduced, from a median of 35 PD to 2 PD (n = 17, p < 0.001). The majority of the congenital cases had horizontal strabismus (esotropia = 29, exotropia = 27). The angle of deviation in esotropia was reduced from a median of 29 PD to 8 PD (n = 36, p < 0.001) and in exotropia from 30 PD to 10 PD (n = 34, p < 0.001). Most of the patients were satisfied with the outcome of surgery, and only 12% required re-operation within 2 years.

CONCLUSION

This is the first clinical study on the use of donor sclera as spacer material in complicated cases of strabismus surgery. The surgical results were good in terms of the reduction in the angle of deviation, the need for re-operation, complications and patient satisfaction, supporting the use of donor sclera for strabismus surgery.

Outcomes of esotropia surgery in Saudi Arabia: An audit from a single center

Purpose

To monitor the outcomes of surgical correction of esotropia in order to improve preoperative counselling for patients and their families.

Methods

A retrospective review audit of the medical charts at King Fahad Medical City. All patients treated surgically to correct esotropia, from January 2007 to December 2013. All operated cases were included regardless of age and esotropia etiology. The study used a goal-determined metric to assess the outcomes of strabismus surgery > 6 months post-operatively, and on last follow-up. The risk factors for poor surgical outcomes were identified using a Pareto chart.

Results

A total of 99 cases with sufficient documentation to determine the surgical goal were included in the analysis. The goal was to improve eye contact (cosmetic correction) in 77.8% cases, to establish binocularity in 15.2% cases, to resolve diplopia for 4% cases, and to improve anomalous head posture for 3%. The overall outcome was excellent for 70.7% at the first follow-up and for 57.6% at the final visit. Simultaneous vertical muscle surgery and/or superior oblique muscle palsy were risk factors for poor outcome (odds ratio 3.15, 95% CI 1.11–8.99).

Conclusions

Excellent outcome of esotropia surgery in this study is comparable to outcomes reported internationally using the goal determined metrics. Quality improvement processes like the Pareto chart are simple to use and helpful for determining the risk factors associated with poor surgical outcomes after esotropia correction from different etiology.

Improvement of Eye Alignment in Adult Strabismic Monkeys by Sustained IGF-1 Treatment

Purpose

The goal of this study was to determine if continuous application of insulin-like growth factor-1 (IGF-1) could improve eye alignment of adult strabismic nonhuman primates and to assess possible mechanisms of effect.

Methods

A continuous release pellet of IGF-1 was placed on one medial rectus muscle in two adult nonhuman primates (M1, M2) rendered exotropic by the alternating monocular occlusion method during the first months of life. Eye alignment and eye movements were recorded for 3 months, after which M1 was euthanized, and the lateral and medial rectus muscles were removed for morphometric analysis of fiber size, nerve, and neuromuscular density.

Results

Monkey 1 showed a 40% reduction in strabismus angle, a reduction of exotropia of approximately 11° to 14° after 3 months. Monkey 2 showed a 15% improvement, with a reduction of its exotropia by approximately 3°. The treated medial rectus muscle of M1 showed increased mean myofiber cross-sectional areas. Increases in myofiber size also were seen in the contralateral medial rectus and lateral rectus muscles. Similarly, nerve density increased in the contralateral medial rectus and yoked lateral rectus.

Conclusions

This study demonstrates that in adult nonhuman primates with a sensory-induced exotropia in infancy, continuous IGF-1 treatment improves eye alignment, resulting in muscle fiber enlargement and altered innervational density that includes the untreated muscles. This supports the view that there is sufficient plasticity in the adult ocular motor system to allow continuous IGF-1 treatment over months to produce improvement in eye alignment in early-onset strabismus.

Infantile esotropia: risk factors associated with reoperation

The aim of this study was to identify clinical and demographic factors associated with misalignment after first surgery performed on children affected by infantile esotropia to evaluate the reoperation rate. A retrospective study was carried out, analyzing data from 525 children who underwent bilateral medial recti recession, bilateral lateral recti resection, and inferior oblique recession and anteroposition by the same surgeon (AM). Postoperative evaluation included assessment of motor alignment at approximately 3 months, 6 months, 1 year, and 5 years. Statistical analysis was performed with a logistical regression model in which the dependent variable was the presence/absence of reoperation. We found that late surgery (after 3 years of age) and a family history of strabismus are associated with a higher risk of reoperation, while some clinical factors, including some classically associated with worst motor outcome as preoperative angle, dissociated vertical deviation, and amblyopia, did not influence the incidence of reoperation in infantile esotropia. Male patients and patients with hyperopia in preoperative examinations have a significantly decreased reoperation rate.

Surgical Results of Symmetric and Asymmetric Surgeries and Dose-Response in Patients with Infantile Esotropia

Objectives:

To evaluate the results of symmetric and asymmetric surgery and responses to surgical amounts in patients with infantile esotropia.

Materials and Methods:

The records of patients with infantile esotropia who underwent bilateral medial rectus recession (symmetric surgery) and unilateral medial rectus recession with lateral rectus resection (asymmetric surgery) were analyzed. The results of the cases with symmetric (group 1) and asymmetric (group 2), successful (group 3) and failed (group 4) surgeries were compared, and responses to the amount of surgery were investigated.

Results:

There were no significant differences between group 1 (n=71) and group 2 (n=13) cases in terms of gender, refraction, preoperative distance deviation, anisometropia and postoperative deviation angles, binocular vision, surgical success or follow-up period (p>0.05). The rate of amblyopia, near deviation and amount of surgery were higher in group 2 cases (p<0.05). Between group 3 (n=64) and group 4 subjects (n=20), no significant differences were detected in terms of gender, surgical age, refraction, amblyopia, anisometropia, preoperative deviation angles, the number of symmetric and asymmetric surgeries, the amount of surgery, or postoperative binocular vision (p>0.05). The average postoperative follow-up period was 15.41±19.93 months (range, 6-98 months) in group 3 cases and 40.45±40.06 months (range, 6-143 months) in group 4 cases (p=0.000). No significant difference was detected in the amount of deviation corrected per 1 mm of surgical procedure between the successful cases in the symmetric and asymmetric groups (p>0.05).

Conclusion:

Symmetric or asymmetric surgery may be preferable in patients with infantile esotropia according to the clinical features. It is necessary for every clinic to review its own dose-response results.

Planning Strabismus Surgery: How to Avoid Pitfalls and Complications

BACKGROUND AND PURPOSE

Good surgical results following strabismus surgery depend on several factors. In this article, detailed steps for planning strabismus surgery will be reviewed for basic horizontal strabismus surgery, vertical, and oblique muscle surgeries. The thought process behind each case will be presented to help in selecting the best surgical approach to optimize postoperative results.

PATIENTS AND METHOD

The surgical planning for strabismus will be developed with clinical examples from easy cases to more complex ones. Preoperative pictures of the ocular alignment are an integral part of planning surgery and help in documenting the strabismus before and after surgery.

RESULTS

Three cases of strabismus cases will be reviewed with several key factors for planning surgery, including visual acuity, refractive error, potential for stereovision, and risk of postoperative diplopia. The most important factor is accurate orthoptic measurements. The surgical planning for each patient is detailed along with preoperative pictures.

CONCLUSION

Strabismus surgery results can be improved by careful preoperative planning. The surgeon has the ability to discern potential pitfalls that can alter the surgical outcome. Surgical planning allows a dedicated time of reflection before surgery, foreseeing potential problems, and avoiding them during the surgery.

Long-term Cosmetic Alignment Following Surgery for Esotropia Versus Exotropia in Childhood: A Comparison Using Survival Curves

PURPOSE

Although long-term results following repair of esotropia and exotropia in childhood have been reported, the two entities have never been directly compared.

METHODS

Records of all children younger than 18 years who underwent horizontal strabismus surgery from 2000 through 2012 were reviewed. Children with structural eye pathology, severe vision loss, neurologic disorders, and incomitant or combined horizontal and vertical deviations were excluded. Failure was defined by a second horizontal surgery or a primary position deviation greater than 20 prism diopters (PD) at any time during follow-up (as long as 10 years). A threshold of 20 PD was chosen because families often consider deviations important enough to warrant a first or second surgery if it is larger but not if it is smaller.

RESULTS

Of 317 children, 235 with esotropia had surgery at a mean age of 42 months and 82 with exotropia had surgery at a mean age of 60 months. Overall, surgery was successful in 78% of those with esotropia and 65% of those with exotropia. A second surgery was performed in 29 (12%) of those with esotropia and 15 (18%) of those with exotropia. The mean deviation at last follow-up, using absolute values, was 9 PD for esotropia and 10 PD for exotropia. Survival curve success was better for esotropia (P = .008).

CONCLUSION

By survival curve analysis, success was more likely among children with esotropia. Many "failures" slipped beyond the 20 PD threshold only transiently and had deviations that were not noticeable to family or friends. Overall, children did reasonably well long-term following surgery for both esotropia and exotropia. Only 14% of the entire group required a second surgery during an average of 41 months of follow-up.

Essential infantile esotropia: postoperative motor outcomes and inferential analysis of strabismus surgery

BACKGROUND

The aim of this retrospective study is a long-term evaluation of postoperative motor outcomes and the inferential analysis of strabismus surgery in infant eyes with essential infantile esotropia.

METHODS

576 patients were compatible with the criteria: confirmed EIE diagnosis, angle ≥ 30 pD, absence of associated ocular anomalies, onset by 6 months of age, absence of hyperopia > 3 Diopters, operation before age 4. Preoperative deviation classes (30-40 pD, 41-59 pD, ≥ 60 pD) were established, different types of surgery were performed. Follow-up was conducted for 5 years after surgery. Longitudinal data were analyzed using general linear mixed models stratified according to the class of pre-operative deviation. A random intercept and a random slope with time (in months) was assumed with an unstructured within subject correlation structure for repeated measurements.

RESULTS

In patients with preoperative angle ≤ 40 pD, a significant interaction effect for intervention by time (F5,155.9 = 3.56, p = 0.004) and a significant intervention effect (F5,226.1 = 6.41, p < 0.001) on residual deviation were observed; only the intervention 5 showed a residual deviation inside the limits of a partial success. In Class 41-59, a significant interaction effect for intervention by time (F4,166.7 = 5.16, p = 0.001), intervention (F4,178.1 = 2.48, p = 0.046) and time (F1,174.6 = 9.99, p = 0.002) on residual deviation were observed; intervention 7 had the highest degree of stability showing an outcome within the range of a partial success. In Class ≥ 60 pD no significant effect for intervention (F4,213.9 = 0.74, p = 0.567), time (F1,169.5 = 0.33, p = 0.569) or intervention by time (F4,160.9 = 1.08, p = 0.368) on residual deviation was observed; intervention 3,6 and 7 resulted in a residual deviation within the range of a partial success.

CONCLUSIONS

We suggest, where possible, a two-horizontal muscles approach in small angle EIE, while a multiple muscles surgery in large angle EIE.

Evaluation of the utility of hospital databases to provide data in assessing the quality of strabismus surgery

AIMS AND BACKGROUND

Rates of re-operation, which may be related to an unsatisfactory surgical outcome, can provide a long-term index of the quality of strabismus surgery. This study aims to evaluate the utility of the Scottish Morbidity Records (SMR1) in determining nature and rates of re-operation for strabismus at the Royal Hospital for Sick Children (RHSC), Glasgow.

METHODS

SMR1 data on strabismus surgery performed on children aged between 0 and 17 years at the RHSC, Glasgow, between January 2000 and March 2009 were analysed.

RESULTS

In total, 1376 strabismus procedures were carried out on 1274 individuals. The median time between first and subsequent procedures was 19 months; the commonest reasons being under-correction or recurrence. The Kaplan-Meier rate of undergoing re-operation was 7.4% after 9 years with a 95% confidence interval of 5.4-9.9%.

CONCLUSIONS

The SMR1 is a useful source of hospital-based and population data. With supplementation from parallel databases, routine administrative databases like the SMR1 can provide better quality data to inform practice.

Three horizontal muscle surgery for large-angle infantile esotropia: validation of a table of amounts of surgery

PURPOSE

To validate a table of amounts of three horizontal muscle surgery in patients with large-angle infantile esotropia (≥60 prism dioptres, PD).

METHODS

A prospective interventional case series reporting the postoperative alignment of 51 patients (27 male, 24 female) over a 15-year period was conducted. Surgery amounts were according to a published table developed on a previous patient cohort (n=49), using bilateral medial rectus recession with graded unilateral lateral rectus resection. Kaplan-Meier life-table survival curves were formulated for success to orthotropia (±10 PD) after one and subsequent horizontal muscle surgeries for up to 8 years follow-up.

RESULTS

The median preoperative deviation was 65 PD (range 60-80 PD) and median age at surgery was 11.8 months (range 5.1 months-3.6 years). Surgical success to orthotropia (±10 PD) after one surgery was 100% at 2 months, 95.7% at 6 months, 91.3% at 12 months, 77.8% at 4 years, and 73.6% at 8 years. Postoperative failure requiring further horizontal surgery occurred in 17.6% (residual esotropia 4, consecutive exotropia 5).

CONCLUSIONS

Our second cohort has reproduced the success rate of the previous cohort (77.8% vs 77.1% at 4 years). If the published table of surgical amounts is used, three horizontal muscle surgery in large-angle infantile esotropia (≥60 PD) appears to have a good long-term success rate, and does not lead to the high rates of either residual esotropia or consecutive exotropia reported by others in the literature.

Long-term follow-up of acquired nonaccommodative esotropia in a population-based cohort

PURPOSE

To describe the clinical characteristics and long-term outcomes of children diagnosed over a 30-year period with acquired nonaccommodative esotropia (ANAET).

DESIGN

Retrospective chart review of a population-based cohort.

PARTICIPANTS

All pediatric (<19 years of age) residents of Olmsted County, Minnesota, who were diagnosed with ANAET from January 1, 1965, to December 31, 1994.

METHODS

The medical records of all potential patients identified by the resources of the Rochester Epidemiology Project were reviewed.

MAIN OUTCOME MEASURES

Incidence, clinical characteristics, and long-term motor and sensory outcomes of children with ANAET.

RESULTS

A total of 174 children were diagnosed during the 30-year period, yielding an incidence of 1 in 287 live births. The median age at diagnosis for the 174 patients was 4.0 years (range, 10 months to 18.2 years), and 61% (107) were male (P = 0.009). Although 11% (8/75) of those queried were diplopic, none of the 174 was subsequently diagnosed with an intracranial lesion. During a mean follow-up of 10.9 years (range, 0 days to 37 years), 127 patients (73%) underwent strabismus surgery (mean, 1 surgery; range, 0-3 surgeries). Among the 127 patients who underwent surgery, the median final stereoacuity was 3000 seconds of arc, including 8 patients (6.3%) with ≥ 50 seconds of arc. Patients who were older (>44 months) at ANAET diagnosis (P = 0.005) and without amblyopia at their initial examination (P < 0.001) were more likely to achieve excellent final stereopsis.

CONCLUSIONS

In this population-based cohort, ANAET occurred in 1 in 287 children and was more prevalent among male children. Although diplopia was relatively common, none of the children were found to have an intracranial malignancy. Most patients achieved good motor and sensory outcomes, with the best results among those with a later onset of their deviation and no amblyopia.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Effects of recession versus tenotomy surgery without recession in adult rabbit extraocular muscle

PURPOSE

Surgical recession of an extraocular muscle (EOM) posterior to its original insertion is a common form of strabismus surgery, weakening the rotational force exerted by the muscle on the globe and improving eye alignment. The purpose of this study was to assess myosin heavy chain (MyHC) isoform expression and satellite cell activity as defined by Pax7 expression in recessed EOMs of adult rabbits compared with that in muscles tenotomized but not recessed and with that in normal control muscles.

METHODS

The scleral insertion of the superior rectus muscle was detached and sutured either 7 mm posterior to its original insertion site (recession surgery) or at the same site (tenotomy). One day before euthanization, the rabbits received bromodeoxyuridine (BrdU) injections. After 7 and 14 days, selected EOMs from both orbits were examined for changes in fast, slow, neonatal, and developmental MyHC isoform expression, Pax7 expression, and BrdU incorporation.

RESULTS

Recession and tenotomy surgery resulted in similar changes in the surgical EOMs. These included a decreased proportion of fast MyHC myofibers, an increased proportion of slow MyHC myofibers, and increased BrdU-positive satellite cells. Similar changes were seen in the non-operated contralateral superior rectus muscles. The ipsilateral inferior rectus showed reciprocal changes to the surgical superior rectus muscles.

CONCLUSIONS

The EOMs are extremely adaptive to changes induced by recession and tenotomy surgery, responding with modulations in fiber remodeling and myosin expression. These adaptive responses could be manipulated to improve surgical success rates.