Influence of Watching 3D Television on Refractive Error in Children with Exodeviation

PURPOSE: To investigate the effects of watching three-dimensional (3D) television (TV) on the angle of deviation and refractive error in children with exodeviation. METHODS: Twenty-three volunteers with exodeviation, aged 6 to 12 years, without any ocular abnormalities other than refractive error and exodeviation were recruited for this study. The subjects watched 3D TV for 50 minutes at a viewing distance of 2.8 meters. The image disparity of 3D contents was -1 to 1 degree. Refractive errors were measured before and immediately after watching TV and after a 10-minute rest. The changes in angle of deviation were also obtained. Refractive errors and angle of deviation before and after watching 3D TV were compared. RESULTS: The mean age of the subjects was 9.30 +/- 1.58 years. The mean baseline angle of deviation was 13.04 +/- 5.25 (6-30) prism diopters (PD), which did not change significantly immediately after watching 3D TV and after a 10-minute rest (p = 0.452). The mean refractive errors were -2.15 +/- 1.55 D in the right eye and -2.06 +/- 1.55 D in the left eye before and changed to -2.14 +/- 1.57 D and -2.11 +/- 1.45 D, respectively, immediately after watching 3D TV. After a 10 minute rest, the mean refractive errors were 2.14 +/- 1.53 D in the right eye and -2.07 +/- 1.53 D in the left eye. All changes in refractive errors were not statistically significant (p = 0.991 in right eye, 0.495 in left eye). The amount of myopic shift in both eyes immediately after watching 3D TV was correlated with the angle of exodeviation (r = 0.468, p = 0.024). However, the correlation disappeared after a 10-minute rest (r = 0.345, p = 0.107). CONCLUSIONS: Watching properly made 3D contents on 3D TV for 50 minutes at more than 2.8 meters of viewing distance did not affect the refractive error in children with exodeviation. Further studies on the relationship between the amount of myopic shift and the angle of exodeviation are necessary.

The Effect of Bilateral Slanted Lateral Rectus Recession in Exotropia with Near-Far Disparity

PURPOSE: To evaluate the efficacy of slanted recession of the lateral rectus (LR) muscle for exodeviation with larger deviation angle at near than far fixation. METHODS: A retrospective chart review was conducted of 31 patients. Seventeen patients underwent slanted LR recession, the upper fiber of the LR was recessed according to the distance deviation angle and the lower fiber was recessed according to the near deviation. Fourteen patients underwent classic recession. To evaluate the effect of slant LR recession, postoperative ocular alignment between them was checked at 1 week, 1 month, 3 months and 6 months after operation. RESULTS: At the postoperative 6 months, bilateral slanted LR recession reduced the mean exodeviation at near from 33.82 PD to 7.29 PD, and same amount recession group reduced 33.67 PD to 11.13 PD. The far deviation change was from 25.59 PD to 2.59 PD, 23.67 PD to 4.00 PD in each group. The change of near-distance difference was from 10.29 PD to 4.71 PD in slanted recession group, and 9.67 PD to 7.93 PD in same amount recession group, showed that slanted recession group reduced angle more significantly (p = 0.002). Success rate was 35% in bilateral slanted LR recession group, 7% in classic recession group, showed that slanted recession group had significantly high success rate (p < 0.05). CONCLUSIONS: Bilateral slanted LR recession effectively reduces near and distance exodeviation angle, and reduces near-distance incomitance more superior to classic bilateral LR recession technique.

Analysis of the Effects of Medial Rectus Muscle Resection for Recurrent Exotropia

PURPOSE: The purpose of this paper is to investigate how much correction is obtained per millimeter of medial rectus (MR) resection for recurrent exotropia after bilateral lateral rectus (BLR) recession, and to determine the difference in the effects between unilateral and bilateral resection, and the influence of previous lateral rectus (LR) recession on the effects of MR resection. METHODS: A total of 59 patients who had undergone MR resection after BLR recession were included in this study. The unilateral group consisted of 38 patients and bilateral group, 21 patients. Thirty patients in the unilateral group were divided into two groups: patients who had undergone previous LR recession of 7 mm or greater (21 patients) and less than 7 mm (9 patients). Main outcome measures were average deviation corrected per millimeter of MR resection at 1 month postoperative. RESULTS: The average effect of MR resection was 4.2 prism diopters (PD, 2.0 to 6.7 PD)/mm. The average effect in the unilateral group was 4.2 PD/mm and 4.1 PD/mm in the bilateral group. There was no significant difference between groups (P = 0.60). The average effect in the recession 7 mm or greater group was 4.0 PD/mm, and the average effect in the recession less than 7 mm group was 4.2 PD/mm (P = 0.698). CONCLUSIONS: The effect of MR resection per millimeter was variable. The laterality and previous amount of LR recession did not influence the effect of MR resection. These variable outcomes dictate that caution be exercised when MR resection is performed for recurrent exotropia.

Analysis of the Effects of Medial Rectus Muscle Resection for Recurrent Exotropia

PURPOSE: The purpose of this paper is to investigate how much correction is obtained per millimeter of medial rectus (MR) resection for recurrent exotropia after bilateral lateral rectus (BLR) recession, and to determine the difference in the effects between unilateral and bilateral resection, and the influence of previous lateral rectus (LR) recession on the effects of MR resection. METHODS: A total of 59 patients who had undergone MR resection after BLR recession were included in this study. The unilateral group consisted of 38 patients and bilateral group, 21 patients. Thirty patients in the unilateral group were divided into two groups: patients who had undergone previous LR recession of 7 mm or greater (21 patients) and less than 7 mm (9 patients). Main outcome measures were average deviation corrected per millimeter of MR resection at 1 month postoperative. RESULTS: The average effect of MR resection was 4.2 prism diopters (PD, 2.0 to 6.7 PD)/mm. The average effect in the unilateral group was 4.2 PD/mm and 4.1 PD/mm in the bilateral group. There was no significant difference between groups (P = 0.60). The average effect in the recession 7 mm or greater group was 4.0 PD/mm, and the average effect in the recession less than 7 mm group was 4.2 PD/mm (P = 0.698). CONCLUSIONS: The effect of MR resection per millimeter was variable. The laterality and previous amount of LR recession did not influence the effect of MR resection. These variable outcomes dictate that caution be exercised when MR resection is performed for recurrent exotropia.

The Clinical Course of Consecutive Esotropia after Surgical Correction

PURPOSE: To investigate the clinical course in patients who underwent surgical correction of consecutive esotropia. METHODS: The medical records of 13 patients who underwent surgical correction of consecutive esotropia were reviewed retrospectively. The authors investigated the deviation and surgical method at the time of exotropia surgery. During the follow up period, the authors also studied incidence of amblyopia development, the effect of occlusion therapy, surgical methods for consecutive esotropia, and postoperative change of deviation. RESULTS: The average exodeviation was 27.1 prism diopter (PD). Bilateral lateral rectus muscle recession was performed in all patients. In all patients, alternate occlusion was tried from 2 weeks after development of consecutive esotropia. However, there was no effect on 7 patients. None of the patients developed amblyopia. Surgery for consecutive esotropia was performed on the average 15.3 months after exotropia surgery. The average esodeviation was 21.1PD. Medial rectus muscle recession was performed in 10 patients and lateral rectus muscle advancement in 3 patients. The average deviation of the subject group immediately after surgery was 1.2PD esodeviation, 0.9PD esodeviation one month after surgery, 2.4PD exodeviation 6 months after surgery, and 4.7PD exodeviation at the last follow up, and it showed a tendency to progress to exodeviation as the follow up period increased. Ten patients (76.9%) showed deviation within 8PD at the last follow up. CONCLUSIONS: The success rate of surgical correction for consecutive esotropia was a favorable outcome. But, careful decisions of the surgical method and amount is needed because the conversion of exodeviation during long-term follow-up is possible.

The Change of Exodeviation in the Seated and Supine Position

PURPOSE: To evaluate changes in exodeviation in the seated and supine position during adjustable suture strabismus surgery. METHODS: We measured the deviation angle at distances of 6 m, 2 m, and 33 cm in the seated position and at 2 m, and 33 cm in the supine position by the alternate prism cover test in fifty patients with exotropia. RESULTS: The mean deviation angle was 25.41+/-7.08 PD at 6 m, 25.51+/-7.08 PD at 2 m and 28.09+/-7.54 PD at 33 cm in the seated position. The mean deviation angle in the supine position was 24.68+/-7.40 PD at 2 m, and 27.29+/-8.09 PD at 33 cm. There was no significant difference in exodeviation at the same measuring distance between the seated and supine positions. A significant difference between the exodeviation at 6 m in the seated position and the exodeviation at 2 m in the supine position did not exist. CONCLUSIONS: The distant deviation angle at 6 m in the seated position can be replaced by the deviation angle measured by fixating a target at the ceiling in the supine position during adjustable suture strabismus surgery for exotropia.

Clinical Characteristics of Exodeviation

PURPOSE: In order to evaluate the incidence and clinical characteristics of exodeviation according to the Kushner's classification. METHODS: We prospectively studied the 820 patients with exodeviation from 1998 to 2003. One hundred thirty patients with systemic abnormalities, eye disease except exodeviation, or histories of previous strabismus operations were excluded. Best-corrected visual acuity, alternate prism cover test or Krimsky test, duction/ versions, funduscopy, and cycloplegic refraction were performed in every patient, and Bielschowsky phenomenon, Worth 4 dot test and Titmus stereotest, in possible patients. We categorized exodeviations according to the Kushner's classification. RESULTS: Of the remaining 690 patients with exodeviation, 318 were male and 372 were female. Age of onset of exodeviation was 3.9 years. Basic exodeviation was most common (76.5%), and followed by tenacious proximal fusion (7.1%), convergence insufficiency (2.8%), proximal convergence (0.6%), pseudo-convergence insufficiency (0.6%) and high AC/A ratio (0.4%). Binocular fusion both at near and at distance was observed in 30% (148 patients) of the patients. The incidence of amblyopia and dissociated vertical deviation was 13.9% and 8.5%, respectively. Bielschowsky phenomenon was observed mostly in patients with early-onset exodeviation. CONCLUSIONS: Basic exodeviation was most commonly observed, followed by tenacious proximal fusion and convergence insufficiency. Patients with exodeviation showed an onset age of 3.9 years and accompanied by an amblyopia and dissociated vertical deviation in 14% and 5%, respectively. One third of the patients showed binocular fusion.

Long Term Surgical Results after Early Surgery for Infantile Esotropia Before and After 1 year of Age

PURPOSE: To analyze the long term surgical results after early surgery for infantile esotropia before and after 1 year of age and to investigate postoperative eye alignments. METHODS: This retrospective study included 46 patients with infantile esotropia who underwent surgery before 2 years of age and were followed up for a minimum of 5 years. Subjects were divided into 2 groups: those who underwent surgery before 1 year of age (n=22, group 1), and the ones who underwent surgery between 1 year of age and 2 years of age (n=24, group 2). RESULTS: Long term postoperative alignment between two groups was not statistically significant. In postoperative stereopsis test, 11 patients (78.6%) of group 1 and 7 patients (41.2%) of group 2 had stereopsis and the patients of group 1 had more favorable stereoacuity than the patients of group 2. These differences were statistically significant, respectively (p=0.039). In postoperative eye alignment, patients of group 1 showed tendency to become exodeviated to esodeviated and patients of group 2 showed tendency to become esodeviated to exodeviated. These differences were statistically significant, respectively (p=0.023, p=0.042). CONCLUSIONS: To achieve better binocular function, early surgical alignment before 1 year of age is more recommended. Because early surgery before and after 1 year of age displays contradictory postoperative eye alignment, close follow up and careful consideration at reoperation is recommended.

Assessment of Esotropia more than 10PD after Surgery of Intermittent Exotropia

PURPOSE: To assess factors which are related to consecutive esotropia after surgery of intermittent exotropia. METHODS: We reviewed medical records of intermittent exotropia patients who had undergone surgery from January 1995 to February 2002, and followed for over 3 months. Patients who developed consecutive esotropia of more than 10 prism diopters (PD) were included in this study. RESULTS: Postoperatively esotropia deveolped in 101 of 1222 patients (8.3%), and persisted for more than 3 months in 32 patients (2.6%). Mean age at operation was 6.02 +/- 2.21 years old. Mean angle of exodeviation at operation was 29.67 +/- 6.16 PD. The incidence of esotropia was high when the angle of preoperative exodeviation was 30-35 PD, and age at operation was less than 6 years. Duration of esotropia was longer when the preoperative exodeviation angle was 30-35 prism diopter, and age at operation was more than 7 years. There was no significant relationship between overcorrected esotropia and amblyopia, inferior oblique muscle overaction, lateral incommitance, or stereopsis. CONCLUSIONS: Factors related to prolonged consecutive esotropia following surgery of intermittent esotropia were the preoperative exodeviation angle of 30-35 PD, and age at operation of more than 7 years.

Evaluation of Factors Influencing Stereoacuity in Exodeviation

The purpose of this study was to evaluate factors influencing stereoacuity in exodeviation. We examined the visual acuity, refractive error, angle of exodeviation, fusional status with the Worth-4-dot test, and stereoacuity with the Titmus test preoperatively in 139 exodeviated patients who had undergone operation from August 1994 to February 1997. We evaluated the association of stereoacuity to the following factors with chi-square test: sex, age at surgery, visual acuity, type and degree of refractive error, associated hypertropia, angle of exodeviation, and fusional status.The stereoacuity was normal-under 100 second of arc, when age at surgery was under 8 years, when visual acuity was 0.6 or better, when abgle of exodeviation was under 40 prowm and when fusion was intact at near only or both(p<0.05). There was no statistical significance between sex, type or degree of refractive error, associated hypertropia, and stereoacuity.Of these, age at surgery and fusional status were found to be independent factors influencing stereoacuity with discriminant analysis test. In conclusion, in aspect of perserving normal stereoacuity, age atsurgery and fusional status are important factors in the surgical criteria of exotropia.

The Effect of Monocular recession and Resection in Exodeviations: Comparison between Primary, Right, Left, Up, Down and Near Gaze

In order to evaluate the incidence of lateral incomitance after monocular recession and resection and compare the amount of correction achieved by monocular recession and resection according to the gaze direction and distance in exodeviations, we measured the angle of deviation in primary, right, left, up, down and near gaze before and after monocular recession and resection. Lateral incomitance was developed in11.4%(9/79) after monocular recession and resection. The amount of correction of the deviation toward the side of operated eye was larger than that of the deviation in primary position(p=0.002), but the amount of correction of the deviation toward the side of non-operated eye, up, down and near gaze was all smaller than that of the deviation in primary position(all, p<0.01).

The Effect of Bilateral Lateral Rectus Recession

We presented the clinical evaluation to identify the amount of correction after surgery for 135 patients with exodeviation who had surgical correction at Kyungpook National University Hospital from January 1989 to December 1993. The following results were obtained. Of 135 patients, female occupies 51.1%, male occupies 48.9% of the patients and in 53% of the patients, exodeviation was noticed when the patients were under the age of 3 years. Visual acuity of 0.7 or better were found in 76.7%. Intermittent exodeviation was found in 97% and constant exodeviation was found in 3% of the patients. Preoperative angles between 21 delta and 40 delta were in 82.3%. The average amount of prism diopters corrected after operation was 26.4 delta, 34.6 delta, 43.2 delta and 51.1 delta in 6~7mm, 7~8mm, 8~9mm and 9~10mm recession group. Cosmetically satisfactory results(+/-10 delta esoor exodeviation) were obtained in 76.5% of the patients.

Clinical Analysis of Surgical Results in Exodeviation

One hundred and ninty patients with exodeviation were treated with surgical procedures and were followed up 9.6 months in average. We analyzed the surgical results according to 6 factors, such as age at onset, age at surgery, type of exodeviation, amount of exoangle, the difference between near and far exoangle and the length of postoperative follow-up period. The surgical results were as follows; 59.5% satisfactory, 28.4% undercorrected and 12.1 % overcorrected. Two out of the 6 factors, the difference between near and far exoangle and the length of postoperative follow-up period had influence on the final surgical results (p<0.02). The difference between near and far exoangle within 10 delta had better surgical result than that of over 11 delta difference. There was a tendency to become exotropic with a long term follow-up period (2-67 months).

Large recession of one lateral rectus muscle

A large recession of one lateral rectus muscle for exotropia is an infrequently used procedure. In this prospective study, 27 patients (3 to 19 years, mean age of 7) with moderate-angle exodeviation (18-35delta) were treated with large recession (8mm-9mm) of one lateral rectus muscle on their non preferred eye. Initially, there was underaction of the lateral rectus muscle. Within 6 weeks, the lateral rectus muscle regained full abduction, incomitance resolved, and the deviation was eliminated or reduced to a small phoria. Since surgery is confined to the deviating eye alone, operating time, length of anesthesia, and postoperative discomfort is reduced. The average amount of prism diopters needed for correction following operation for 8mm, 8.5mm and 9mm were 20.4delta, 26.4delta, and 31.3delta respectively and esthetically satisfactory results (within 10delta exodeviatior) were obtained in 90.I% of the patients.