Best age for surgery for infantile esotropia

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.

The Role of Visual Factors in Dyslexia

What are the causes of dyslexia? Decades of research reflect a determined search for a single cause where a common assumption is that dyslexia is a consequence of problems with converting phonological information into lexical codes. But reading is a highly complex activity requiring many well-functioning mechanisms, and several different visual problems have been documented in dyslexic readers. We critically review evidence from various sources for the role of visual factors in dyslexia, from magnocellular dysfunction through accounts based on abnormal eye movements and attentional processing, to recent proposals that problems with high-level vision contribute to dyslexia. We believe that the role of visual problems in dyslexia has been underestimated in the literature, to the detriment of the understanding and treatment of the disorder. We propose that rather than focusing on a single core cause, the role of visual factors in dyslexia fits well with risk and resilience models that assume that several variables interact throughout prenatal and postnatal development to either promote or hinder efficient reading.

Timing of surgery in essential infantile esotropia - What more do we know since the turn of the century?

This review summarizes the results and interpretations of studies pertaining to the long-standing debate regarding the timing of surgery in infantile esotropia, more recently referred to as essential infantile esotropia. A systematic search of studies from the year 2000 onward pertaining to the timing of surgery in infantile esotropia as listed in PubMed, Google Scholar, and the Cochrane database was performed. Appropriate cross-references from the articles were also included. Data collected included demographics, presentation, time of surgery, complications, and outcomes. Very early surgery, that is, within 6 months of the onset of infantile esotropia, offers significant advantages in terms of the quality of stereopsis and binocular vision as well as promoting the development of cortical visual processing, thereby benefiting cortical development in human infants. However, the postoperative alignment was not found to be significantly different in the very early, early, or late surgery groups. The reduction in the incidence of manifest dissociated vertical deviation postoperatively in the very early surgery group also showed measurable benefits. The results of this recent literature review demonstrated that very early surgery, within 6 months of misalignment, showed demonstrable benefits in essential infantile esotropia.

[Three-muscle surgery for large angle esotropia]

BACKGROUND

Bilateral medial rectus muscle recession with or without Cüppers' posterior fixation suture and recess and resect surgery are used to correct for large angle esotropia. There are only few reports on three muscle surgery (3MS). We analyzed the results of 3MS.

PATIENTS AND METHODS

Between June 2016 and May 2020, 61 patients received 3MS for esotropia ≥ 27° (50 PD) together with oblique muscle surgery, if needed. Angles of strabismus were measured by simultaneous prism and cover testing (SPCT) and alternating prism and cover testing (APCT) at 5 m and 0.3 m. Grading was around 0.51 mm/degree (at 5 m). Medium-term results of 57 patients were available.

RESULTS

Medians and ranges (min-max) were: age, 6 years (3-56 years). Preoperative APCT, far 34° (27-45°), near 36° (27-50°). Amount of surgery, 17 mm (15-21 mm), oblique muscle recession in 21 cases. The APCT after 5 months (3-24 months), far 2° (-10-18), near 2° (-8-18). Success rates (absolute deviation ≤ 6° [10 PD]), APCT far 68%, near 67%, SPCT far 79%, near 74%. Exotropia > 6° occurred in 4 cases (7%) at far and 3 (5%) at near, esotropia > 6° in 14 cases (25%) at far and 16 (28%) at near.

CONCLUSION

The use of 3MS is a suitable first step procedure to correct for large angle esotropia.

Comparing Botulinum Toxin Injections with Extraocular Muscle Surgery in Toddlers with Esotropia: A Retrospective Analysis

BACKGROUND

In toddlers with esotropia, early alignment of the visual axes either with extraocular muscle surgery (EOMS) or botulinum toxin injections (BTIs) into both medial rectus muscles may result in improved depth perception. We compared the outcome of BTIs with EOMS in toddlers in order to gain further insight into the advantages and disadvantages of either method.

PATIENTS AND METHODS

In this retrospective study, our encrypted database was searched for toddlers with esotropia aged 35 months or younger at the time of initial treatment with either BTIs or EOMS and who had a follow-up of at least 2 years. We analyzed the angle of deviation, dose effect (DE), and binocularity as well as the number of interventions.

RESULTS

We identified 26 toddlers who received their first treatment for esotropia within the first 35 months of life: 16 with BTIs (9 males, 7 females) and 10 with EOMS (3 males, 7 females). Mean follow-up was considerably longer in the EOMS (87.7 months) than in the BTI group (35.7 months). Age at first intervention was 22.8 months in the BTI and 24.1 months in the EOMS group, and each toddler wore its full cycloplegic refraction. Mean angle at treatment was 41.25 prism diopters (PD) in the BTI compared to 52.9 PD in the EOMS group. The BTI group received an average of 1.68 BTIs, with a mean dosage of 14.5 IU Botox and a mean DE (mDE) of 1.8 PD/IU. In the EOMS group, the average number of surgeries was 1.4, with a mean dosage of 16.85 mm and a mDE of 3.14 PD/mm surgery. Some degree of binocularity could be observed in 9 (56%) of the BTI (5 × Bagolini positive, 2 × 550″, 2 × 220″) and in 4 (40%) of the EOMS group (2 × 3600″, 1 × 550″, 1 × 300″). By the end of the BTI group follow-up, four toddlers electively underwent EOMS rather than a 3rd BTI (followed by a 3rd BTI in 1), which resulted in the appearance of measurable binocularity in all four (1 × Bagolini positive, 1 × 220″, 1 × 200″, 1 × 60″).

CONCLUSIONS

Our results show that BTIs are a viable treatment alternative in early esotropia. Even if EOMS is ultimately required, some binocularity may develop as the visual axes are aligned for some time in the sensitive phase owing to the effects of Botox. Moreover, less surgical dosage is needed than would have otherwise been necessary to treat the original angle of deviation. BTIs are faster, less invasive, and present as an effective alternative when patient compliance is too low to reliably measure the angle of deviation, which is essential for the planning of EOMS.

Motor and Visual-spatial Cognitive Abilities in Children Treated for Infantile Esotropia

While many studies have investigated links between motor and visual spatial cognitive abilities in typically developing children, only a few studies have tested this link among children with innate handicaps. Therefore, we assessed motor abilities (using the M-ABC-2) and visual spatial cognitive skills (using the Block Design subtest of the WPPSI-III and a picture mental rotation task, PRT) of 5-7 year old typically developing children (n= 17) and same-aged children with severe deficits in stereopsis due to infantile esotropia (n= 17). Compared to the typically developing children, children with esotropia showed significantly poorer motor performances, especially in manual dexterity and ball skills, and significantly poorer and slower performance on the visual spatial cognitive tasks. Especially the girls treated for infantile esotropia needed more time to mentally rotate the pictures of the PRT correctly. Overall, this study showed that perceptual, motor and cognitive processes are interconnected and that children treated for infantile esotropia had an increased risk of motor and visual spatial cognitive deficits.

Long-Term Effects of Botulinum Toxin in Large-Angle Infantile Esotropia

Purpose

The purpose of this study is the motor outcome analysis of early Botulinum toxin (BT) treatment in patients affected by large-angle infantile esotropia (IE).

Patients and Methods

Retrospective analysis of 130 medical charts of IE patients who underwent BT injections between 2004 and 2019 was performed. All patients underwent BT injections within 13 months of age.

Results

Thirty patients, matching the inclusion criteria, were included in the study. Twenty-eight patients showing residual ET ≥25 PD (34.3±6.6 PD ranged from 25 to 50) underwent surgery.

Conclusion

Our result after 1 Botulinum toxin injection showed a very low success rate (6.7%) at last follow-up (28.3±7.2 months). Our data would suggest one Botulinum toxin injection in children affected by large-angle infantile esotropia allows a significant reduction of deviation but does not avoid the need for surgical treatment.

Strabismus Surgery for Esotropia, Down Syndrome and Developmental Delay; Is an Altered Surgical Dose Required? A Literature Review

Background and Purpose:

There is a high rate of strabismus, in particular esotropia, in children with Down syndrome or developmental delay, which frequently requires surgical correction. A paper in 1994 advocated that the surgical dose be adjusted due to an altered response in these children. The aim of this literature review is to evaluate the available evidence to establish whether an altered surgical approach is required in either population.

Methods:

A literature review was conducted using PubMed and Web of Knowledge. Only English language papers were eligible for inclusion. The papers were collated in chronological order for analysis, and their references searched for further relevant papers. Forward citation searches were also undertaken.

Results:

A 2 × 2 comparison is made between publications on Down syndrome (in isolation) and developmental delay populations (including Down syndrome) with adjusted versus non-adjusted surgery. Published surgical success rates on esotropia from unaltered surgical doses range from 62.0%–85.7% (four papers) in the Down syndrome cohort, with none of the adjusted surgeries having a successful outcome. Surgical success rates from adjusted surgical doses in developmental delay cohort range from 37.5%–86.0% (seven papers), with one unadjusted surgical success rate of 76.0%. The results across the studies are summarised in a table and discussed.

Conclusions:

An exaggerated surgical effect in individuals with developmental delay has been reported, and this population may benefit from a reduced surgical dose. Published research does not support giving a reduced surgical dose in individuals with Down syndrome, but more research needs to be done to make a definitive conclusion.

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.

Development of a core outcome set for amblyopia, strabismus and ocular motility disorders: a review to identify outcome measures

BACKGROUND

Core Outcome Sets (COS) are defined as the minimum sets of outcomes that should be measured and reported in all randomised controlled trials to facilitate combination and comparability of research. The aim of this review is to produce an item bank of previously reported outcome measures from published studies in amblyopia, strabismus and ocular motility disorders to initiate the development of COS.

METHODS

A review was conducted to identify articles reporting outcome measures for amblyopia, strabismus and ocular motility disorders. Using systematic methods according to the COMET handbook we searched key electronic bibliographic databases from 1st January 2011 to 27th September 2016 using MESH terms and alternatives indicating the different subtypes of amblyopia, strabismus and ocular motility disorders in relation to treatment outcomes and all synonyms. We included Cochrane reviews, other systematic reviews, controlled trials, non-systematic reviews and retrospective studies. Data was extracted to tabulate demographics of included studies, primary and secondary outcomes, methods of measurement and their time points.

RESULTS

A total of 142 studies were included; 42 in amblyopia, 33 in strabismus, and 68 in ocular motility disorders (one study overlap between amblyopia and strabismus). We identified ten main outcome measure domains for amblyopia, 14 for strabismus, and ten common "visual or motility" outcome measure domains for ocular motility disorders. Within the domains, we found variable nomenclature being used and diversity in methods and timings of measurements.

CONCLUSION

This review highlights discrepancies in outcome measure reporting within published literature for amblyopia, strabismus and ocular motility and it generated an item bank of the most commonly used and reported outcome measures for each of the three conditions from recent literature to start the process of COS development. Consensus among all stakeholders including patients and professionals is recommended to establish a useful COS.

Stereopsis: are we assessing it in enough depth?

The assessment of stereoacuity is an integral part of the ophthalmic assessment, with the responses used to inform clinical management decisions. Stereoacuity impacts on many aspects of life, but there are discrepancies reported where people without measurable stereoacuity report appreciating 3-D vision. This could be due, in part, to the presentation of the stimuli. A literature review was undertaken to evaluate current assessment techniques, how they relate to patient outcomes, identify the limitations of current tests and discuss how they could be improved. Recent evidence has been collated on currently available tests, used commonly within vision clinics, with normative data provided allowing responses to the tests to be interpreted. The relevance of the results is evaluated in relation to a range of outcomes, where a reduced level of stereopsis has a negative impact on the ability of an individual to perform many tasks, and can lead to an increase in difficulty interacting in the world. Current tests are limited in the aspects of stereoacuity they assess and their ability to precisely measure stereopsis. The world is not static, yet clinical tests are limited to measuring static stereoacuity, even though higher grades of depth perception can be identified in the presence of changing depth. Presentation methods of stereoacuity tests have remained similar over time, with a limited number of disparity levels assessed. New assessment methods are becoming available that include automated staircase testing to present multiple levels of disparity using digital technology. Current clinical tests are limited in their presentation, and are poor at detecting/measuring stereoacuity in those with limited stereopsis. Given the relevance of the stereoacuity measurement to management choices and functional outcomes, new testing methods would be beneficial to fully assess stereoacuity, both static and dynamic.

Strabismus-associated myopia. Review

INTRODUCTION

The treatment of strabismus associated with myopia is often a therapeutic challenge for the ophthalmologist. The strabismus associated with myopia has certain peculiarities and there are even certain types of strabismus that occur exclusively in myopia, such as strabismus fixus, requiring treatments with specific surgical techniques.

MATERIALS AND METHODS

It is important to make a correct differential diagnosis, because there are many conditions described with this association. A review is presented of strabismus associated with myopia, together with its treatment adjusted to refractive error.

RESULTS

Measurements of strabismus may be altered by the prismatic effect of the spectacles. Surgical results may be unpredictable if myopia is not taken into account. Better results were obtained with the techniques of anatomical replacement described by Yokoyama than with traditional retro-insertion-resection.

CONCLUSION

For the diagnosis and appropriate treatment of strabismus, it is important to make a correct measurement of the angle of deviation, and perform image tests prior to surgery in certain cases. The anatomical characteristics of the myopic eye should also be taken into account during surgery.

Outcome of early surgery in infantile esotropia: Our experience in tertiary care hospital

BACKGROUND

Infantile esotropia is a convergent strabismus presenting before 6 months of age and is the most common strabismus disorder presenting in the ophthalmology OPD. The dilemma of whether to go for early surgery and how early has been a matter of research for the last 50 years. We describe our results of surgery in infantile esotropia at variable age groups, as well as with different reoperation rates and compare with the results in western literature.

METHODS

A prospective study was carried out through a review of 113 cases operated for infantile esotropia between February 2013 and August 2014. The variables studied were: age at surgery, type of fixation, refractive error, associated nystagmus, inferior oblique overaction or dissociated vertical deviation (DVD), type of surgery performed and pre- and postoperative deviation angles.

RESULTS

There were 67 male and 46 female cases of infantile esotropia. The age group of patients varied from 6 months to 12 years. Latent nystagmus was seen in 22 cases, inferior oblique overaction in 49 cases and DVD (mild) in 14 cases. Bimedial rectus recession was done in 78 cases and recession-resection in non-dominant eye in remaining 35 cases. The postoperative residual deviation was <10 PD in 102 cases, between 10 and 16 PD in 5 cases and more than 16 PD in 6 cases. Only 6 cases (5.3%) required reoperation for correction of residual deviation.

CONCLUSION

The authors recommend surgery before 12 months in all cases of infantile esotropia. The reoperation rates in the current study were considerably low.

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.

Strabismus and the Oculomotor System: Insights from Macaque Models

Disrupting binocular vision in infancy leads to strabismus and oftentimes to a variety of associated visual sensory deficits and oculomotor abnormalities. Investigation of this disorder has been aided by the development of various animal models, each of which has advantages and disadvantages. In comparison to studies of binocular visual responses in cortical structures, investigations of neural oculomotor structures that mediate the misalignment and abnormalities of eye movements have been more recent, and these studies have shown that different brain areas are intimately involved in driving several aspects of the strabismic condition, including horizontal misalignment, dissociated deviations, A and V patterns of strabismus, disconjugate eye movements, nystagmus, and fixation switch. The responses of cells in visual and oculomotor areas that potentially drive the sensory deficits and also eye alignment and eye movement abnormalities follow a general theme of disrupted calibration, lower sensitivity, and poorer specificity compared with the normally developed visual oculomotor system.

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.

Essential Infantile Esotropia: Postoperative Sensory Outcomes of Strabismus Surgery

BACKGROUND

The optimum age for Essential Infantile Esotropia surgery is a controversial subject. Sensory status was evaluated in patients who underwent surgery at different ages in a retrospective study. The setting of the study is the ophthalmology department of a teaching hospital.

METHODS

Different clinical characters were analyzed pre- and postoperatively; nine different surgeries were performed. A total of 188 patients presented valid postoperative sensorial data, divided in two groups: surgery at ≤2 years (n=69) or >2 years (n=119). Sensory status was dichotomized in binocular single vision (BSV) and exclusion. Univariate differences were assessed with the chi-square test (or Fisher exact test). To identify the independent role of factors associated with the sensory status, all variables showing in univariate analyses a significant association (p<0.05) with the outcome variable were entered into a multivariate logistic regression model. All statistical tests were two-sided.

RESULTS

Multivariate analysis confirmed that children operated >2 years were 0.4 times less likely to obtain BSV compared with children operated at ≤2 years (AOR. 0.38, 95% C.I. 0.17-0.89, p=0.025). Patients operated on by OO MR rec.+ OO LR res. + OO IO rec.-ap. (intervention type 6) were about 11 times more likely to have BSV than those by OO rec.MR + unilateral res. LR (operation type 2); AOR.: 10.67, 95% C.I.: 1.34 - 85.29, p=0.026). Twenty-nine patients (12.1%) operated at ≤2 years of age underwent a reoperation, compared to 33 (8.6%) who underwent surgery after two years (p>0.05).

CONCLUSIONS

Our findings suggest to perform EIE surgery between age 1 and 2 and, when indicated, to prefer a six-muscle approach in order to achieve a better sensory function.

Surgical treatment for residual or recurrent strabismus

Although the surgical treatment is a relatively effective and predictable method for correcting residual or recurrent strabismus, such as posterior fixation sutures, medial rectus marginal myotomy, unilateral or bilateral rectus re-recession and resection, unilateral lateral rectus recession and adjustable suture, no standard protocol is established for the surgical style. Different surgical approaches have been recommended for correcting residual or recurrent strabismus. The choice of the surgical procedure depends on the former operation pattern and the surgical dosages applied on the patients, residual or recurrent angle of deviation and the operator's preference and experience. This review attempts to outline recent publications and current opinion in the management of residual or recurrent esotropia and exotropia.

Strabismus surgery before versus after completion of amblyopia therapy in children

BACKGROUND

Normal visual development occurs when the brain is able to integrate the visual input from each of the two eyes to form a single three-dimensional image. The process of development of complete three-dimensional vision begins at birth and is almost complete by 24 months of age. The development of this binocular vision is hindered by any abnormality that prevents the brain from receiving a clear, similar image from each eye, due to decreased vision (e.g. amblyopia), or due to misalignment of the two eyes (strabismus or squint) in infancy and early childhood. Currently, practice patterns for management of a child with both strabismus and amblyopia are not standardized.

OBJECTIVES

To study the functional and anatomic (ocular alignment) outcomes of strabismus surgery before completion of amblyopia therapy as compared with surgery after completion of amblyopia therapy in children under seven years of age.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2014), EMBASE (January 1980 to July 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to July 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 24 July 2014. A manual search for articles from a review of the references of the selected publications and conference abstracts was completed to identify any additional relevant studies.

SELECTION CRITERIA

We searched for randomized controlled trials (RCTs) that provided data on strabismus surgery in children less than seven years of age, performed after initiation of, but before completion of amblyopia therapy, as compared with strabismus surgery after completion of amblyopia therapy.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies identified from the electronic and manual searches.

MAIN RESULTS

There were no RCTs that fit our inclusion criteria and so no analysis was possible.

AUTHORS' CONCLUSIONS

As there are no RCTs currently available and the best existing evidence is only from non-randomized studies, there is a need for prospective RCTs to investigate strabismus surgery in the presence of strabismic amblyopia. The optimal timing of when to perform strabismus surgery in children with amblyopia is unknown.

The relationship of age when motor alignment is achieved and the subsequent development of stereopsis in infantile esotropia

PURPOSE

To determine the oldest age beyond which the chance of developing stereopsis is not possible even with excellent motor alignment in patients with infantile esotropia.

METHODS

The medical records of children with infantile esotropia who underwent a single operation and had alignment within 10(Δ) of orthotropia at all follow-up examinations were retrospectively reviewed. Patients were assessed for stereopsis after the age of 48 months.

RESULTS

A total of 38 children were included. There was a statistically significant inverse correlation between age at surgery and final stereopsis (r = 0.494, P = 0.002). There was a significant difference at mean age at surgery between patients having stereopsis better than 1000 arcsec and those having no stereopsis (P = 0.002). Post hoc power analysis revealed a value of 85%. Receiver operating characteristic curve analysis revealed that the optimum cut-off value of the age at surgery for predicting stereopsis was 16 months (Youden index = 0.474; area under ROC curve, 0.784; 95% CI: 0.62-0.90; P = 0.0002).

CONCLUSIONS

Surgery for infantile esotropia is most likely to result in measureable stereopsis if patient age at alignment is not more than 16 months.

Analysis of risk factors for consecutive exotropia and review of the literature

PURPOSE

To evaluate the possible risk factors in patients with consecutive exotropia following esotropia surgery.

METHODS

Medical records of patients who had comitant esotropia surgery between June 1999 and April 2011 were reviewed. Those who developed consecutive exotropia composed the exotropia group; patients matched for age and duration of follow-up who did not develop consecutive exotropia composed the no exotropia group. The charts of the patients were reviewed and possible risk factors for development of consecutive exotropia were investigated.

RESULTS

The average ages of 47 patients in the exotropia group and 54 patients in the no exotropia group were 10.8 ± 8.7 years (range: 1 to 41 years) and 8.5 ± 6.3 years (range: 1 to 30 years), respectively (P = .292). Amblyopia was detected in 31 (66%) and 12 (22.2%) patients in the exotropia and no exotropia groups, respectively (P = .004). Anisometropia was observed in 20 patients (42.6%) in the exotropia group and 5 patients (9.3%) in the no exotropia group (P = .003). Preoperative average esodeviation values were 42.5 ± 8.3 prism diopters (PD) (range: 25 to 60 PD) in the exotropia group and 42 ± 9.4 PD (range: 20 to 65 PD) in the no exotropia group (P = .673). Postoperative deviations were 32.8 ± 23 PD exotropia (range: 10 to 90 PD exotropia) in the exotropia group and 4.4 ± 4.2 PD esotropia (range: 0 to 10 PD esotropia) in the no exotropia group (P = .000). Asymmetric surgery had been performed in 61.7% of the exotropia group (n = 29) and 9.3% of the no exotropia group (n = 5) (P = .000). Limitation of adduction was detected in 14 patients (29.8%) in the exotropia group; none was noted in the no exotropia group (P = .000). The mean interval between the initial surgery and the onset of consecutive exotropia was 11.1 ± 15.1 months (range: 0 to 126 months).

CONCLUSIONS

Anisometropia, amblyopia, asymmetric surgery, and postoperative adduction deficit were associated with the development of consecutive exotropia. Long-term follow-up should be considered because consecutive exotropia can develop after months or years.

The prevalence of reoperation and related risk factors among patients with congenital esotropia

PURPOSE

To determine the prevalence rate and related risk factors of reoperation among patients with congenital esotropia.

METHODS

One hundred fifty-seven children with congenital esotropia were divided into two groups after at least one operation: children with deviation within 10 PD (n = 89; success group) and those with deviation greater than 10 PD or history of reoperation (n = 68; failure group). The relationship of risk factors such as age at first operation and primary congenital esotropia of less than 30 or more than 50 PD and accompanying factors such as inferior oblique muscle overaction (> +1), dissociated vertical deviation, lateral rectus muscle underaction, and A-V pattern with reoperation were studied. Final sensory status of children 5 years and older was evaluated by Worth 4-dot and Titmus tests.

RESULTS

Reoperation was indicated in 32.4% of children who had residual esotropia greater than 15 PD after 3 months following their first operation. Congenital esotropia greater than 30 PD (P = .002) and lateral rectus muscle underaction of −1 to −2 (P < .005), were statistically different between the two groups. Initial operation at younger than 3 years was more likely to achieve gross stereopsis in children 5 years and older (P = .032).

CONCLUSION

Congenital esotropia greater than 30 PD and lateral rectus muscle underaction were found to be risk factors of reoperation.