Spontaneous consecutive extropia in children with motor fusion

Nonsurgical Consecutive Exotropia Following Childhood Esotropia: A Multicentered Study

PURPOSE

Nonsurgical consecutive exotropia (NCX) occurs when an esotropia (ET) spontaneously converts to exotropia (XT) without surgical intervention. Although NCX is considered to occur in early-onset accommodative ET with high hyperopia, consensus on causation is lacking. We report the clinical characteristics of NCX and assess the response to conservative management.

DESIGN

Retrospective, multicenter, observational case series.

METHODS

Patients aged 6 months and older with an initial diagnosis of ET who converted to XT without surgical intervention. Sensory strabismus was excluded. Age, visual acuity, cycloplegic refraction, glasses prescriptions, deviation, and binocular vision were collected.

RESULTS

Forty-nine children were included with a mean age of 3.5 ± 1.6 years and 8.4 ± 3.6 years at the time of ET and NCX, respectively. Mean refractive error was +4.40 ± 2.13 diopters (D) and +4.05 ± 2.74 D at the time of ET and NCX, respectively. Accommodative ET occurred in 60% of cases, and only 35.7% were high hyperopes. All but 1 patient presented with XT at distance. In response to the XT, a mean decrease in hyperopic prescription of 1.55 ± 0.48 D was given (N = 17); only 1 case reverted to ET. Eventually, 43% underwent XT surgery, with similar rates between those who had refractive management and those who did not.

CONCLUSIONS

NCX occurs in both accommodative and nonaccommodative ET; high hyperopia is present in only one-third of cases. On average, drift to XT occurs within 5 years. Refractive management has a modest result. No predictive risk factors were identified. Our findings challenge hyperopia-linked theories of causation. Nonrefractive explanations, such as the role of the vergence system, deserve further study.

Characteristics and risk factors for spontaneous and postoperative consecutive exotropia in children with esotropia

Background

To investigate the risk factors for the development of consecutive exotropia (CXT) by comparing patients with spontaneous or postoperative CXT during follow-up with another group of patients who had no deviation or less than 10 prism dioptre (PD) esotropia.

Methods

In this retrospective cohort study, 6 patients with spontaneous CXT (group A), 13 patients with postoperative CXT (group B), and 39 patients with no exotropia (group C) were enrolled. Probable risk factors for CXT were evaluated among the groups. Kruskal-Wallis H test was used to determine if any significant differences were present among the groups. Fisher's exact test or Mann-Whitney U test was used for univariate analyses to compare differences between case groups or between case and control groups. The Bonferroni method was used to conduct multiple comparisons.

Results

The follow-up period of spontaneous CXT patients was significantly longer than that of postoperative CXT and nonconsecutive exotropia patients (p = 0.035 and p < 0.001, respectively). The interval between alignment and CXT onset in spontaneous CXT patients was slightly longer than that in postoperative CXT patients, but not significantly difference (6.50 vs. 5.00 years, p = 0.072). Vertical deviation was associated with a high risk of postoperative CXT (p = 0.001). Most [38 (97.44%)] nonconsecutive exotropia patients had fusion; conversely, the absence of fusion function (p < 0.001) as well as stereoacuity (p = 0.029) were associated with a high risk of CXT.

Conclusion

Vertical deviation and poor binocular function are strongly associated with a high risk of CXT. Children with spontaneous CXT are highly recommended to be followed-up long-term, while they maintain long-term ocular alignment before developing consecutive exotropia from comitant esotropia (CE).

Risk factors for spontaneous consecutive exotropia in children with refractive and nonrefractive accommodative esotropia

PURPOSE

To investigate the risk factors for development of spontaneous consecutive exotropia (ScXT) among patients with refractive and nonrefractive accommodative esotropia (AET).

STUDY DESIGN

Retrospective.

METHODS

Patients who were diagnosed with AET were reviewed from January, 2000 to December, 2016. The patients who developed ScXT after well corrected hyperopia were defined as exodeviation group (n = 51), and the patients who did not show exodeviation and were well controlled with eyeglasses were defined as the control group (n = 117). The changes in cycloplegic refraction, mean angle deviation at initial visit, time till the first correction of esodeviation, presence of amblyopia and accompanying strabismus were compared between the two groups.

RESULTS

The mean interval from the first visit to correction of esodeviation under 8 PD in the exodeviation group was shorter than of the control group (P = 0.008). Patients in the exodeviation group showed more dissociated vertical deviation (DVD) (P = 0.015) and faster reduction in hyperopia per year (more hyperopic eye: P = 0.006; less hyperopic eye: P = 0.034) than the patients in the control group. Exodeviation was found mean 42.31 ± 41.13 months after hyperopia correction. There were no differences in angle deviation at initial visit, and presence of amblyopia.

CONCLUSION

ScXT can be found in AET with faster reduction in hyperopia per year, accompanied by DVD, or in eyes with esodeviation corrected in relatively shorter time. It can be noted even in patients with good alignment over a long-term, so long-term follow-up is recommended.

Spontaneous consecutive esotropia

PURPOSE

Although less frequent than consecutive exotropia, consecutive esotropia is a well-known type of strabismus when it follows the surgical correction of an exotropia. Spontaneous conversion from initial constant, large-angle exotropia beyond the age of 3 months to esotropia or orthophoria, however, is not common. We describe a series of infants who presented a spontaneous evolution from a large-angle infantile exotropia to either an orthophoria or a spontaneously consecutive esotropia.

METHODS

Cases of infants examined in the pediatric neuro-ophthalmology clinic of a tertiary ophthalmology department between 2009 and 2015, and having presented an early large-angle exotropia that spontaneously converted into an esotropia or orthophoria-i.e., without any previous surgery or botulinum toxin injection-were studied.

RESULTS

Ten cases (6 M:4 F) were followed up. Median age at first exotropia assessment was 3.88 months (SD = 6.35). Median age at spontaneous conversion to esotropia or orthophoria was 7.23 months (SD = 14.73). Six patients suffered from severe neurologic or metabolic diseases, three had neonatal respiratory distress syndrome, and one was healthy.

CONCLUSION

Spontaneous conversion from initial large-angle exotropia to esotropia or orthophoria can be encountered. The cerebral maturation of visual structures probably accounts for this uncommon strabismus sequence.

Clinical risk factors for the development of consecutive exotropia: a comparative clinical study

AIM

To compare a group of patients with consecutive exotropia with patients who had ≤10 prism diopters (PD) esotropia or no deviation postoperatively in terms of probable clinical risk factors for the development of consecutive exotropia.

METHODS

The study recruited fourteen patients who developed consecutive exodeviation during follow-up period after the correction of esotropia who were categorized as group 1 and thirty-one patients who had still ≤10 PD esotropia or no deviation at the final visit that were considered as group 2. Clinical risk factors leading the development of consecutive deviation were analyzed as the main outcome measures.

RESULTS

The mean age of patients was 4.57±3.11y in group 1 and 5.10±3.52y in group 2 (P=0.634). There was no significant difference of preoperative near and distant deviations among two groups (P=0.835, 0.928 respectively). The mean amount of medial rectus recession and lateral rectus resection was similar in both groups (P=0.412, 0.648 respectively). Convergence insufficiency and neurological diseases were more frequent in group 1 (P=0.007, 0.045). Accompanying neurological disease was found to be as a significant factor increasing the risk of the development of consecutive exotropia significantly [odds ratios (OR): 5.75 (1.04-31.93)].

CONCLUSION

Accompanying neurological disease appears to be a significant clinical risk factor for the development of consecutive exodeviation during postoperative follow-up after the correction of esotropia. However, larger studies are needed in order to interpret the results to the clinical practice and to ascertain other concurrent risk factors.