Effects of Bilateral Medial Rectus Resection on Motor Outcomes in Infantile Exotropia.

Purpose: To evaluate the effects of bilateral medial rectus resection (BMRres) on motor outcomes in infantile exotropia. Methods: We evaluated 19 cases of infantile exotropia surgery. The mean age at surgical alignment was 4.8±3.4 years (range, 1.5-11.8 years). The surgical procedures included BMRres (5 cases), BMRres with unilateral lateral rectus recession (ULRR) (3 cases), bilateral lateral rectus recession (BLRR) (8 cases), unilateral lateral rectus recession and medial rectus resection (uniRandR) with contralateral lateral rectus recession (2 cases), and uniRandR (1 case). After dividing the cases into two groups (BMRres group, n=8; other group, n=11), the outcomes at 1 day and at 1, 3, and 6 months after surgery were compared. Surgical outcomes were defined as (1) success: distant esotropia ≤5 prism diopters (Δ) or exotropia ≤10Δ, (2) recurrence: exotropia >10Δ, or (3) overcorrection: esotropia >5Δ. Results: Although postoperative distant deviations at 1 day were not different between the two groups, the BMRres group showed smaller distant deviations at 1, 3, and 6 months than the other group (p=0.015, 0.019, and 0.006, respectively). Success rates of the BMRres and other groups were 88% and 73% at 1 day, 100% and 36% at 1 month, 88% and 27% at 3 months, 88% and 18% at 6 months, respectively. Although there were no significant differences between the two groups within 3 months after surgery, surgical outcomes in the BMRres group 6 months after surgery were significantly better than those in the other group (p=0.003). Conclusion: BMRres is a better procedure than others for infantile exotropia to achieve desirable motor outcomes after surgery.

Abnormal biorbital angle in children with infantile exotropia.

PURPOSE: The causative factors of infantile exotropia are unknown. The purpose of this study was to investigate the relationships between the biorbital angle and the pathogenesis of infantile exotropia. STUDY DESIGN: Retrospective. METHODS: Of all patients diagnosed as infantile exotropia with onset prior to 12 months of age between 2010 and 2017, 31 patients without any neurological disorders or developmental delay were identified. The angle between both lateral walls of the orbit, defined as the biorbital angle, was measured in the horizontal plane at the optic nerve and where the horizontal extraocular muscles appeared on axial magnetic resonance imaging (MRI) or computed tomography (CT) of the orbit. These patients' data were compared with those of 129 ophthalmologically normal children. All subjects of this study were Japanese. RESULTS: The mean biorbital angle was significantly larger in patients with infantile exotropia than in the normal children (106.6 ± 5.7° vs 94.2 ± 5.1°, p < 0.001). Of the patients with infantile exotropia, 21 (68%) had an angle outside the 95% confidence interval calculated in normal children. All cases were divided into a constant (15 cases) and intermittent (16 cases) group; there was no significant difference between them in the mean biorbital angles (107.9 ± 5.6° vs 105.4 ± 5.8°, p = 0.224). No correlations were identified between the biorbital angle and the angle of exodeviation, either distant or near. CONCLUSIONS: Children with infantile exotropia have a larger biorbital angle. This anatomical abnormality may be an associate factor of infantile exotropia.

Relationship between stereopsis outcome and timing of surgical alignment in infantile esotropia.

PURPOSE: To clarify the relationship between stereopsis outcome and timing of surgical alignment in infantile esotropia. METHODS: The medical records of otherwise healthy patients with infantile esotropia who underwent surgery by 8 years of age were divided into the following groups according to age at time of surgery: very early surgery (≤8 months), early surgery (>8 to ≤24 months) and late surgery (>24 months). Binocular response and stereopsis were compared between groups. RESULTS: A total of 76 patients were included: 22 in the very early group, 30 in the early group, and 24 in the late group. Binocular response at near was found in 96% of the very early group and in 80% of the early group, significantly higher than the 50% of the late group (P < 0.001 and P < 0.05 [Dunn test], resp.). Stereopsis was present in 77% of the very early group, significantly higher than the 20% of the early group and 13% of the late group (P < 0.001 [Dunn test]). A significant correlation was also found between age (months) at surgery and stereopsis (seconds) outcome (logarithmic fit: y = 2539.4ln(x) + 147.2; R2 = 0.2691; P < 0.001). CONCLUSIONS: In this study cohort, earlier surgery was associated with better binocularity in patients with infantile esotropia. Our results suggest that very early surgery, at ≤8 months, can improve the chance for postoperative stereopsis, with the caveat that some infants might have had spontaneous esotropia resolution.

Developmental change of the biorbital angle in normal Japanese infants.

Purpose: To investigate postnatal changes in the biorbital angle in normal Japanese children. Subjects and methods: Axial imaging of the orbit in the transverse plane of the horizontal extraocular muscles was obtained in 129 ophthalmologically healthy infants (age ranging from a few months to 11 years). The opening angle between both lateral walls of the orbit was defined as the biorbital angle. Results: The mean biorbital angle in 11 infants less than a year of age was 105.0°±6.0°. The mean biorbital angles for each of the subsequent age groups were 97.7°±3.1°, 96.2°±4.0°, 96.3°±4.1°, 92.8°±3.8°, 92.3°±2.3°, 93.1°±2.8°, 91.5°±3.9°, 91.9°±2.3°, 91.4°±2.3°, and 90.9°±3.1°. The mean biorbital angle in infants less than a year old was significantly larger than those found in the groups of infants older than 1 year (P<0.01, Newman-Keuls test). Conclusion: The biorbital angle in infants less than a year old was larger than that found in infants older than 1 year, with this larger biorbital angle potentially the causative factor of the observed exotropia seen in 70%-80% of newborns gradually disappearing in most cases by 2-4 months of age.

Modified method for assessment of the binocular fusional field in patients with suppression.

PURPOSE: To evaluate the usefulness of a new system using a modified Goldmann perimeter and Bagolini striated glasses for quantitative assessment of the binocular fusional field (BFF) in patients with suppression. METHODS: The BFF was assessed quantitatively in ten normal patients aged 10 to 15 years by using a modified Goldmann perimeter equipped with a xenon light source. Subjective perception was elicited with the use of a crossed or single oblique streak through Bagolini striated glasses. The BFF in 15 strabismic patients with suppression were analyzed at their initial visit and at their last visit after therapy. RESULTS: In normal patients, extent points of the BFF on every 15 degrees meridian ranged from 48 degrees to 56 degrees . The normal BFF drawn from these average points was approximately equal to the previously published normal format of binocular single vision for strabismic patients with diplopia. Additionally, this scoring system for BFF provided quantitatively objective information during the course of their extraocular disorder in 15 strabismic patients with suppression. CONCLUSION: This new method of assessing BFF in patients with suppression can be helpful for evaluation of quantitative effects in the course of treatment for an extraocular disorder and compensatory abnormal head position.

Effects of vertical offsets of the horizontal rectus muscles in V-pattern exotropia without oblique dysfunction.

PURPOSE: To investigate the effects of vertical offsets of the horizontal rectus muscle in V-pattern exotropia without oblique dysfunction. METHODS: A computerized patient database was searched for patients treated with full tendon offsets for V-pattern strabismus from 2002 to 2007. Patients with clinically significant inferior oblique overaction were excluded. Surgery included upward transposition of lateral rectus muscles and/or downward transposition of medial rectus muscles. Medical records were retrospectively analyzed for alignment in the primary position, 30 degrees upgaze, and 30 degrees downgaze before and 3 months after surgery. The main outcome measure was the change in V pattern after surgery. RESULTS: The search identified 11 patients who met inclusion criteria. Of these, 6 underwent bilateral lateral rectus recessions, 1 had 3-muscle surgery, and 4 had monocular recession-resection surgery. The preoperative V-pattern (horizontal) deviation between upgaze and downgaze was 22.2(Delta)+/-5.0(Delta). Postoperative deviation at 3 months was 3.5(Delta)+/-3.9(Delta), a decrease of 18.9(Delta)+/-7.5(Delta). Postoperatively, no patient had an A-pattern deviation or subjective torsional disturbance. The amount of V-pattern correction was closely correlated with the size of the preoperative V pattern (r=0.84). CONCLUSIONS: In patients with V-pattern exotropia without inferior oblique dysfunction, vertical offsets of the horizontal rectus muscles effectively corrected the pattern deviation. The amount of correction was closely correlated with the size of the preoperative V pattern.