Yoonae A. Cho

Consecutive Esotropia in Intermittent Esotropia Patients with Immediate Postoperative Overcorrection More Than 17 Prism Diopters

Purpose To report the incidence and the factors of consecutive esotropia (ET) in patients with immediate postoperative overcorrection of at least 17 prism diopters (PD) after surgery for intermittent exotropia (X(T)). Methods Four-hundred-five patients under the age of 18 were included in this study. They underwent bilateral lateral rectus recession (LROU-rec) or unilateral recession-resection (R&R) for X(T). On postoperative day one, the patients with at least 17 PD overcorrection were classified as group 1 and those with less than 17 PD as group 2. Age, refractive error, type of surgery, lateral incomitancy, and the incidence of consecutive ET were analyzed for each group. Results Group 1 consisted of 116 patients (28.6%) and group 2 consisted of 289 (71.4%). At the six-month follow-up visit, consecutive ET had developed in 16 patients (13.8%) in group 1, and in five patients (1.7%) in group 2 (p<0.001). The occurrence of consecutive ET was not related to age at the time of surgery (p=0.46 in group 1 ; p=0.54 in group 2), refractive error (p=0.18 in group 1 ; p=0.08 in group 2), or the type of surgery (p=0.69 in group 1 ; p=1.00 in group 2). The incidence in group 1 was 23.8% in patients with lateral incomitancy and 8.1% in patients without lateral incomitancy (p<0.05). In group 2, the incidence was 4.4% in patients with lateral incomitancy and 0.5% in patients without lateral incomitancy (p=0.04). Conclusions Consecutive ET developed in 13.8% of patients with immediate overcorrection of at least 17 PD. Lateral incomitancy was the most important risk factor.

Antielevation Syndrome after Unilateral Anteriorization of the Inferior Oblique Muscle

Purpose To report antielevation syndrome with restriction of elevation on abduction in the operated eye and overaction (OA) of the inferior oblique muscle (IO) of the contralateral eye after unilateral IO anteriorization (AT). Methods Medical records were reviewed retrospectively in 8 of 24 patients who underwent unilateral IOAT. Four patients were referred from other hospitals after the same surgery. Results Four patients had infantile esotropes. The rest showed accommodative esotropia, superior oblique palsy, exotropia, and consecutive exotropia. The mean amount of hyperdeviation was 16.3 PD (10 ~ 30). The mean restriction of elevation on abduction in the operated eye was -1.6 (-1 ~ -4) and IOOA of the contralateral eye was +2.7 (+2 ~ +3). IOAT of nonoperated eyes in 4 patients, IO weakening procedure of anteriorized eyes in 2 patients, and IO myectomy on an eye with IOAT in 1 patient were performed. Ocular motility was improved after surgery in all patients. Conclusions Unilateral IOAT may result in antielevation syndrome. Therefore bilateral IOAT is recommended to balance antielevation in both eyes. A meticulous caution is needed when performing unilateral IOAT.

Influence of stereopsis and abnormal binocular vision on ocular and systemic discomfort while watching 3D television

PurposeTo evaluate the degree of three-dimensional (3D) perception and ocular and systemic discomfort in patients with abnormal binocular vision (ABV), and their relationship to stereoacuity while watching a 3D television (TV).MethodsPatients with strabismus, amblyopia, or anisometropia older than 9 years were recruited for the ABV group (98 subjects). Normal volunteers were enrolled in the control group (32 subjects). Best-corrected visual acuity, refractive errors, angle of strabismus, and stereoacuity were measured. After watching 3D TV for 20 min, a survey was conducted to evaluate the degree of 3D perception, and ocular and systemic discomfort while watching 3D TV.ResultsOne hundred and thirty subjects were enrolled in this study. The ABV group included 49 patients with strabismus, 22 with amblyopia, and 27 with anisometropia. The ABV group showed worse stereoacuity at near and distant fixation (P<0.001). Ocular and systemic discomfort was, however, not different between the two groups. Fifty-three subjects in the ABV group and all subjects in the control group showed good stereopsis (60 s of arc or better at near), and they reported more dizziness, headache, eye fatigue, and pain (P<0.05) than the other 45 subjects with decreased stereopsis. The subjects with good stereopsis in the ABV group felt more eye fatigue than those in the control group (P=0.031). The subjects with decreased stereopsis showed more difficulty with 3D perception (P<0.001).ConclusionsThe subjects with abnormal stereopsis showed decreased 3D perception while watching 3D TV. However, ocular and systemic discomfort was more closely related to better stereopsis.

Clinical evaluation of cessation of hyperopia in 123 children with accommodative esotropia treated with glasses for best corrected vision

Purpose:  This study aimed to determine age at successful cessation of hyperopic glasses, the influence of hyperopia on the esotropic angle and age at discontinuation of glasses in accommodative esotropia (AE) patients.

Vertical Rectus Muscles Transposition in Large Exotropia with Medial Rectus Muscle Transection Following Endoscopic Sinus Surgery

Purpose To evaluate the effect of transposition procedures on the vertical rectus muscle (VRM) in the patients who underwent a medial rectus muscle (MR) transection after endoscopic sinus surgery (ESS). Methods In 4 patients with exotropia (XT) and a lack of adduction after ESS, orbital CT or MRI revealed a complete transection of the midportion of the MR. Full-tendon VRM transposition was performed within 3 months after injury (early surgery) in 2 patients with 40Δ XT. Two patients with 70Δ and 85Δ XT underwent an X-type augmented Hümmelsheim procedure, which involved pulling each half-tendon and crossing it through the undersurface of the severed MR to the other end of the MR insertion, concurrently with an ipsilateral lateral rectus (LR) recession 11 months and 36 months after ESS, respectively. The adduction deficits were divided into -1 through to -8. The patients were followed up for more than than 1.5 years. Results Postoperatively, 3 patients showed orthophoria and no diplopia in the primary position. The adduction deficits improved to -3.5 or -4. One patient who underwent an X-type augmented Hümmelsheim procedure showed a residual XT of 25Δ. Conclusions VRM transposition is effective in correcting a large XT secondary to a MR transection after ESS. When a longstanding large-angle XT with severe contracture of the ipsilateral LR and massive scarring of the adjacent tissues is present, the X-type augmented Hümmelsheim procedure coupled with an ipsilateral LR recession had an augmenting effect.

The ultrastructural changes of tendon axonal profiles of medial rectus muscles according to duration in patients with intermittent exotropia

PurposeThe goal of this study was to investigate the ultrastructural changes of tendon axonal profiles of medial recti in patients with intermittent exotropia at different ages. In addition, we compared the patterns of degeneration with those of secondary exotropia over time.MethodsThirteen patients, with different ages, with exotropia who had undergone surgery were included in this study and divided into two groups. Eight patients had intermittent or constant exotropia; their age ranged from 6 to 45 years and they had exotropia since childhood without amblyopia, these patients were assigned to group A. The other five patients with sensory exotropia ranged in age from 15 to 52 years; they did not have exotropia until a visual insult and had poor vision in one eye, these patients were assigned to group B. All patients had the medial recti resected (3–5.5 mm) to obtain tissue samples. All specimens were examined with an electron microscope.ResultsSchwann cell degeneration was observed with increased neurofilament density, axonal vacuoles and hydropic swelling of the Schwann cells in two patients less than 10 years of age in group A. The other six patients were more than 10 years of age in group A, and it was not possible to identify the tendon axonal profiles or neural structures in the medial recti specimens of these patients. For group B, all patients had intact proprioceptor structures including Schwann cells. However, the collagen diameter decreased and density increased within the capsule according to the duration of exotropia.ConclusionSchwann cell degeneration of tendon proprioceptors in the medial rectus might induce the degeneration of proprioceptors in patients with intermittent exotropia over time.

The advancement of the medial rectus muscle for consecutive exotropia.

OBJECTIVE To characterize the dose effect of the advancement of the medial rectus muscle (MR) for consecutive exotropia (XT) after corrective surgery for infantile esotropia (ET) and provide a guide for achieving orthotropia. DESIGN Retrospective cohort study. PARTICIPANTS Seventy-seven patients with consecutive XT that developed after surgery for infantile ET. METHODS All patients underwent advancement of the unilateral or bilateral MR and were followed up for at least 1 year. The angle of deviation and stereopsis were retrospectively reviewed from patient records. RESULTS At the time of surgery for infantile ET, the mean eso-angle was 52.2 ± 13.10 prism diopters (PD; mean age, 28.5 ± 16.97 months). The exo-angle of consecutive XT was 25.6 ± 8.47 PD (mean age at surgery, 132.7 ± 82.32 months). The mean deviation was 1.8 ± 10.40 PD XT at the final follow-up (47.0 ± 43.57 months). The corrective effect of the exo-angle for a 1-mm advancement of the MR was 3.1 PD at 1 year after surgery and 2.9 PD at the last follow-up. There was a significant positive relationship between the preoperative exo-angle and the corrective effect of the 1-mm advancement of the MR at the last follow-up (r = 0.367, p < 0.05). Postoperatively, orthotropia was present in 79.2% of patients, re-exodrift in 16.9%, and ET in 3.9%. Favourable stereopsis was achieved in 73.2%. CONCLUSIONS MR advancement was effective for treating consecutive XT, followed by recession of the MR for infantile ET, achieving favourable stereopsis. The corrective value was 3 PD per 1-mm advancement of the MR.

Postoperative minimal overcorrection in the surgical management of intermittent exotropia

Purpose To investigate the effect of initial postoperative minimal overcorrection on the result of the surgical management of intermittent exotropia based on long-term follow-up results. Methods 111 patients who underwent surgery for intermittent exotropia and were followed up for at least 5 years after surgery were retrospectively reviewed. The outcome was judged to be successful when there was 10 prism dioptres (PD) or less of exodeviation and less than 5 PD of esodeviation without any reoperation at the final follow-up visit. We evaluated the success, recurrence, overcorrection rate and the duration of diplopia according to their initial deviation. Results We divided patients into four groups based on their initial deviation: orthophoria or undercorrection (Ortho group, 31 patients), minimally overcorrected at 5 PD or less (MO group, 20 patients), usually overcorrected between 6 PD and 10 PD (UO group, 35 patients), and highly overcorrected at more than 10 PD (HO group, 25 patients). The success rate was 43–60% between the four groups (p=0.52). The recurrence rate was 28–57% (p=0.105), but post hoc analysis showed borderline p values between the Ortho and HO group (p=0.024). No overcorrection was noted in the Ortho and MO groups (p=0.04). The duration of diplopia was 0–2.5 weeks, showing statistically significant difference among groups (p<0.001). Conclusions The amount of initial postoperative overcorrection may not predict the long-term success rate. However, the MO group showed a lower recurrence rate than the Ortho group and also showed no overcorrection and a shorter duration of postoperative diplopia than the UO and HO groups.

Postoperative Stabilization of the Strabismic Angle in Intermittent Exotropia

Purpose To analyze the postoperative strabismic angle for five years or more and to investigate when the angle stabilized in intermittent exotropia. Methods We retrospectively reviewed the clinical records of 89 patients who had undergone surgery for intermittent exotropia. The postoperative strabismic angles measured were analyzed at one-year intervals up to five years postoperatively. We divided them into two groups according to their age at the time of surgery. Group 1 was less than 5 years of age, while Group 2 participants were 5 years of age or older. Results For our 89 total patients, average exo-angles were 7.8 ± 7.26, 7.9 ± 7.51, 9.5 ± 7.05, 10.1 ± 6.87, and 9.4 ± 6.90 prism diopters at one, two, three, four, and five years postoperatively, respectively. Average exo-angles between postoperative year one and year three, as well as between postoperative year two and year three, were statistically significant (p = 0.015, 0.022). However, the angles were not statistically significant between postoperative year three and year four or between years three and five, respectively (p = 0.707, p = 0.948). The stabilization characteristics of the angle were somewhat different according to age group. In Group 1, the average exo-angle in postoperative years one and three were statistically significant (p = 0.016), but the angle in the same period was not statistically significant in Group 2 (p = 0.203). Conclusions There was no significant interval change after three years postoperatively in intermittent exotropia, but if the patients age at surgery was 5 years or higher, no significant change of exo-angle was found following postoperative year one in this study.

Three-dimensional display-induced transient myopia and the difference in myopic shift between crossed and uncrossed disparities.

PURPOSE To investigate whether three-dimensional (3D) images cause nearwork-induced transient myopia (NITM) more than 2D images and whether there is any difference between 3D images with crossed and uncrossed disparities in the development of NITM. METHODS Twenty-five volunteers, enrolled in this study, watched 2D and 3D movies and read 3D texts with crossed and uncrossed disparities for 2 to 3 hours with spectacle correction. The viewing distance was 50 to 70 cm. The refractive error was measured before and after each visual task. If there was a myopic shift after a task, the refractive error was measured at 3-minute intervals until it was resolved. The changes in the refractive error and the amount of NITM were evaluated and compared. RESULTS The mean age of volunteers was 27.8 ± 2.87 years, and the mean refractive error before the visual tasks was -4.19 ± 2.87 diopters (D). Thirteen subjects (52%) showed NITM after watching a 2D movie, whereas 20 subjects (80%) had NITM after a 3D movie (P = 0.037). The mean extent of NITM was 0.36 ± 0.27 D after watching a 3D movie and 0.10 ± 0.28 D after a 2D movie (P = 0.002). The 3D text with crossed disparity significantly induced NITM (P < 0.001), but that with uncrossed disparity did not. There was a tendency for the NITM to persist longer after subjects watched a 3D movie than after a 2D movie. CONCLUSIONS Viewing 3D images with crossed disparity induced a greater degree of NITM than 2D images. These results suggest that the greater NITM induced by 3D images may have a greater effect on the development and progression of permanent myopia.