Stability of near stereoacuity in childhood intermittent exotropia

doi:10.1016/j.jaapos.2011.06.008

Journal of American Association for Pediatric Ophthalmology and Strabismus

Volume 15, Issue 5, October 2011, Pages 462-467

Presented in part at the 36th Annual Meeting of the American Association for Pediatric Ophthalmology and Strabismus, Orlando, Florida, April 14-18, 2010.

https://doi.org/10.1016/j.jaapos.2011.06.008 Get rights and content

Purpose

To investigate the course of near stereoacuity in a cohort of children with untreated intermittent exotropia.

Methods

A total of 95 children ages 2-16 years with untreated intermittent exotropia were identified who had measurements of near stereoacuity using the Preschool Randot (PSR) test on at least 2 successive examinations, with no intervening treatment. Deterioration was defined as a drop of at least 3 octaves, as determined by test–retest data. Alternative secondary analyses were performed defining deterioration as a drop of at least 2 octaves or as a transition from normal to subnormal. The main outcome measure was the deterioration rate calculated at 1 and 2 years using a Kaplan-Meier survival analysis.

Results

For near stereoacuity, the rate of decreasing 3 or more octaves was 2% (95% CI, 0%-6%) at 1 year and 7% (95% CI, 0%-16%) at 2 years. The alternative secondary analyses revealed similar low deterioration rates. In most cases of apparent deterioration, near stereoacuity returned to baseline levels without treatment.

Conclusions

For children with untreated intermittent exotropia, deterioration in near stereoacuity at 1 and 2 years is infrequent. Therefore, performing surgery for intermittent exotropia to proactively prevent deterioration of near stereoacuity cannot be justified. Retesting stereoacuity is critical to determine whether any measured decrease in stereoacuity is real.

Section snippets

Subjects and Methods

Children with previously untreated distance-type (divergence excess or pseudo divergence excess) or basic-type intermittent exotropia and at least 2 consecutive measures of near stereoacuity measured using the Preschool Randot test without intervening treatment were retrospectively identified. Children with convergence insufficiency-type intermittent exotropia were excluded (near angle more than 10^Δ greater than distance angle on prism and alternate cover test).

In this retrospective study, all

Results

Ninety-five children with intermittent exotropia, ages 2-16 years (median 5, quartiles 4 and 7) were identified. The number of examinations per child ranged from 2 to 12 (median, 3; quartiles, 2 to 4) and the median duration between first and last observations was 15 months (range, 0.5-76 months; quartiles, 7-27 months). The median angle of deviation at the first examination when the prism and alternate cover test was used at distance was 25^Δ (range, 10^Δ to 40^Δ) and at near was 15^Δ (range, 0^Δ

Discussion

Deterioration of near stereoacuity was infrequent in untreated intermittent exotropia at 2 years of follow-up, based on both our primary and secondary analyses. Deterioration was particularly infrequent when considering that patients initially classified as deteriorated almost all returned to their original level without treatment.

The question of whether intermittent exotropia deteriorates without treatment has been the focus of previous reports18, 19, 20, 21, 22, 23, 24, 25; nevertheless,

References (32)

A.D. Abroms et al.
Timely surgery in intermittent and constant exotropia for superior sensory outcome
Am J Ophthalmol
(2001)
J.A. Pratt-Johnson et al.
Early surgery in intermittent exotropia
Am J Ophthalmol
(1977)
R.A. Stathacopoulos et al.
Distance stereoacuity. Assessing control in intermittent exotropia
Ophthalmology
(1993)
C. Yildirim et al.
Distance stereoacuity norms for the mentor B-VAT II-SG video acuity tester in young children and young adults
J AAPOS
(1998)
J.M. Holmes et al.
New tests of distance stereoacuity and their role in evaluating intermittent exotropia
Ophthalmology
(2007)
W.E. Adams et al.
Improvement in distance stereoacuity following surgery for intermittent exotropia
J AAPOS
(2008)
D.A. Leske et al.
Maximum angle of horizontal strabismus consistent with true stereopsis
J AAPOS
(2004)
W.E. Adams et al.
Defining real change in measures of stereoacuity
Ophthalmology
(2009)
E. Birch et al.
Randot Preschool Stereoacuity Test: Normative data and validity
J AAPOS
(2008)
S.R. Hatt et al.
Classification and misclassification of sensory monofixation in intermittent exotropia
Am J Ophthalmol
(2010)

K.J. Nusz et al.

The course of intermittent exotropia in a population-based cohort

Ophthalmology

(2006)

K.G. Romanchuk et al.

The natural history of surgically untreated intermittent exotropia—looking into the distant future

J AAPOS

(2006)

A. Chia et al.

A retrospective review of 287 consecutive children in Singapore presenting with intermittent exotropia

J AAPOS

(2005)

S.R. Hatt et al.

The effects of strabismus on quality of life in adults

Am J Ophthalmol

(2007)

P. Sharma et al.

Evaluation of distance and near stereoacuity and fusional vergence in intermittent exotropia

Indian J Ophthalmol

(2008)

R.P. Rutstein et al.

The clinical course of intermittent exotropia

Optom Vis Sci

(2003)

Cited by (48)

Different surgical outcomes in infantile exotropia according to onset time
2019, Journal of AAPOS
Citation Excerpt :
Nevertheless, to our knowledge, no previous study has compared surgical outcomes of patients with infantile exotropia grouped by age of onset. Although high levels of binocular function could be achieved in patients with infantile exotropia, previous research has reported decreased binocular sensory function in early-onset exotropia compared to that of childhood intermittent exotropia.3,5,6,9,17,18 In the present study, bifoveal fixation with stereoacuity of at least 60 arcsec was achieved in 67.9% of patients (74/109) for whom sensory outcomes was possible.
To determine whether age of onset influences surgical outcomes in infantile exotropia.
The medical records of patients at our tertiary care facility who underwent bilateral lateral rectus recession for infantile exotropia during the period 2004-2013 were reviewed retrospectively. Patients were grouped by onset age: 6 months or earlier (E6 group) or later than 6 months (L6 group). Motor outcomes, near stereoacuity, and distance fusional status in both groups were evaluated.
A total of 134 patients were included: 35 in the E6 group and 99 in the L6 group. At a mean follow-up of 4.6 years, recurrence occurred in 12 (34%) of the E6 group and 38 (38%) of the L6 group (P = 0.496). Overcorrection occurred in 3 (9%) of the E6 group and in 4 (4%) of the L6 group (P = 0.341). In the analysis of 109 patients eligible for sensory examinations, the E6 group demonstrated a higher proportion of patients with reduced stereoacuity of 80 arcsec or worse (54% vs 25% [P = 0.007]) and suppression (46% vs 12% [P < 0.001]) compared with those in the L6 group. In logistic regression analyses, onset of ≤6 months was significantly associated with reduced stereoacuity (OR = 6.42) and suppression (OR = 37.67) but not with recurrence or overcorrection.
In our study cohort, age of onset ≤6 months was associated with worse sensory prognosis for children with infantile exotropia but not with a difference in motor outcomes.
Three-Year Observation of Children 3 to 10 Years of Age with Untreated Intermittent Exotropia
2019, Ophthalmology
Citation Excerpt :
Finally, deterioration on the basis of stereoacuity similarly seems to have been overestimated because of the high degree of test–retest variability when measuring stereoacuity in children with IXT,17 which is partly attributable to the characteristic intermittency of the disease. We defined deterioration of stereoacuity as a 2-octave decrease, whereas others have reported a threshold of 3 octaves for real change in IXT.17,20 The 2-octave definition may have biased our study to finding “deterioration” when the reduction in stereoacuity actually was within normal variability.
To describe the course of intermittent exotropia (IXT) in children followed up without treatment for 3 years.
Observation arm from randomized trial of short-term occlusion versus observation.
One hundred eighty-three children 3 to 10 years of age with previously untreated IXT and 400 seconds of arc (arcsec) or better near stereoacuity.
Participants were to receive no treatment unless deterioration criteria were met at a follow-up visit occurring at 3 months, 6 months, or 6-month intervals thereafter for 3 years.
The primary outcome was deterioration by 3 years, defined as meeting motor criterion (constant exotropia ≥10 prism diopters [Δ] at distance and near) or near stereoacuity criterion (≥2-octave decrease from best previous measure). For the primary analysis, participants also were considered to have deteriorated if treatment was prescribed without meeting either deterioration criterion.
The cumulative probability of protocol-specified deterioration by 3 years was 15% (95% confidence interval, 10%–22%), but that was likely an overestimate, partly because of misclassification. Among 25 deteriorations, 2 met motor deterioration, 11 met stereoacuity deterioration, and 12 started treatment without meeting either criteria (7 for social concern, 1 for diplopia, 4 for other reasons). Among the 132 participants who completed the 3-year visit and had not been treated during the study, only 1 (<1%) met motor or stereoacuity deterioration criteria at 3 years. Of the 4 participants completing the 3-year visit who met deterioration criteria previously and had not started treatment, none still met deterioration criteria. Between the baseline and 3-year examination for these 132 patients, improvement occurred in distance and near stereoacuity (mean improvement, 0.14 and 0.14 logarithm of arcsec; P ≤ 0.001 and P ≤ 0.001, respectively), distance exotropia control (mean improvement, 0.6 points; P ≤ 0.001), and distance exodeviation magnitude (mean improvement, 2.2 Δ; P = 0.002).
Among children 3 to 10 years of age with IXT for whom surgery was not considered to be the immediately necessary treatment, stereoacuity deterioration or progression to constant exotropia over 3 years was uncommon, and exotropia control, stereoacuity, and magnitude of deviation remained stable or improved slightly.
Quality of life in intermittent exotropia for Korean children and their parents
2023, BMC Ophthalmology
Divergence excess and basic exotropia types of intermittent exotropia: a major review. Part 1: prevalence, classification, risk factors, natural history and clinical characteristics
2023, Strabismus
Assessment of distance-near control disparity in basic and divergence excess paediatric intermittent exotropia
2023, Clinical and Experimental Optometry
Comparison of alternate part-time patching and pencil push-up training for patients with intermittent exotropia
2022, BMC Ophthalmology

View all citing articles on Scopus

: Supported by National Institutes of Health Grant EY015799 and EY018810 (JMH), Research to Prevent Blindness, Inc, New York, NY (JMH as Olga Keith Weiss Scholar and an unrestricted grant to the Department of Ophthalmology, Mayo Clinic), and Mayo Foundation, Rochester, Minnesota. None of the sponsors or funding organizations had a role in the design or conduct of this research. No authors have any financial/conflicting interests to disclose.

View full text

Major ArticleStability of near stereoacuity in childhood intermittent exotropia

Purpose

Methods

Results

Conclusions

Section snippets

Subjects and Methods

Results

Discussion

Am J Ophthalmol

Am J Ophthalmol

Ophthalmology

J AAPOS

Ophthalmology

J AAPOS

J AAPOS

Ophthalmology

J AAPOS

Am J Ophthalmol

Ophthalmology

J AAPOS

J AAPOS

Am J Ophthalmol

Evaluation of distance and near stereoacuity and fusional vergence in intermittent exotropia

Indian J Ophthalmol

The clinical course of intermittent exotropia

Optom Vis Sci

Major Article
Stability of near stereoacuity in childhood intermittent exotropia