Clinical exhibition of increased accommodative loads for binocular fusion in patients with basic intermittent exotropia.

BACKGROUND: To investigate the accommodative loads change needed to maintain binocular fusion in patients with intermittent exotropia (IXT). METHODS: Seventeen consecutive patients with basic IXT and 15 normal controls were recruited. The WAM-5500 autorefractor (GrandSeiko, Fukuyama, Japan) was used to measure refractive error (D) under binocular and monocular viewing conditions at 6 m, 50 cm, 33 cm and 20 cm. The difference between binocular and monocular refractive error (D) at each distance defined the change in the accommodative load. The changes in accommodative load were compared between IXT patients and normal controls. We also investigated the change in accommodative loads according to the fixing preference in patients with IXT. RESULTS: In IXT patients, the mean angles of deviation were 20.2 ± 7.19 and 21.0 ± 8.02 prism diopters at 6 m and 33 cm, respectively. Under binocular viewing, the changes in accommodative loads of each eye in IXT patients were significantly higher at 50, 33 and 20 cm than those of normal controls (p < 0.05, all). The changes in accommodative loads of fixating and deviating eyes at 6 m were not significantly different between IXT patients and normal controls (p = 0.193, 0.155, respectively). The changes in accommodative loads of the fixating eye at each distance were not significantly different from those of the deviating eye in IXT patients (p > 0.05). CONCLUSION: The changes of accommodative loads at near fixation increased more in IXT patients than they did in normal controls while maintaining binocular fusion.

Stability of Y-splitting procedure combined with hang-back recession of the rectus muscle in rabbit eyes.

BACKGROUND: The Y-splitting procedure has been used both to treat up-shoots and down-shoots in Duane syndrome, and as a substitute for posterior fixation suture. The Y-split is often performed in conjunction with a hang-back recession when a large amount of recession or an adjustable suture is necessary. Herein, we evaluated the stability of Y-splitting hang-back recession in the rectus muscle. METHODS: Under general anesthesia, a 5-mm hang-back recession of the superior rectus muscle (SR) with Y-splitting was performed in ten eyes from ten rabbits (hang-back group). A conventional recession was performed in the SR of the fellow eye (control group). Six weeks after the procedure, the distance between the original insertion and the recessed SR (recession amount) and the width between the nasal and temporal halves of the SR were measured. These values were compared to the measurements taken at the time of surgery. RESULTS: The hang-back group had a significantly larger forward displacement than the control group (P < 0.001 for both the nasal and temporal halves). The width change between the nasal and temporal halves was also significantly larger in the hang-back group (4.94 ± 1.32 mm) than in the control group (1.14 ± 0.60 mm, P < 0.001). Additionally, the Y-configuration appeared to be more collapsed in the hang-back group than in the control group. CONCLUSION: Y-splitting of the rectus muscle may be unstable when it is combined with a hang-back recession. Surgeons should consider this possibility when performing Y-splitting procedures.

Change in the location of the equator and recessed muscles in young rabbit eyes.

PURPOSE: To study the changes in the location of the equator and the new insertion of extraocular muscle after recession surgery in a rabbit model. METHOD: An experimental study was performed in ten eyes of five rabbits. Eyes were divided into two groups according to the amount of recession. In right eyes, 5 mm superior recti (SR) muscle recession, approximately 2 mm posterior to the equator, was performed (5 mm recession group), while in the left eyes, 3 mm recession was performed to the location of the equator (3 mm recession group). We measured the distance of the equator from the limbus, as well as the distance between the superior rectus insertion and the equator. The preoperative measurements were compared with the results 2 months after the surgery. The change in location of the superior rectus and the equator was compared between the two eyes. RESULT: The recessed SR muscle did not show any significant change in location in both groups (p = 0.18 and 0.16 respectively). However, the location of the equator of rabbit eye showed movement of about 1 mm posterior to the initial location with the growth of the eyeballs (p = 0.04 and 0.03, respectively). CONCLUSION: The location of the equator moved posteriorly at 2 months postoperatively in young rabbit model while the insertion of the recessed SR did not show any significant movement.

Ultrastructural changes in myotendinous nerve endings induced by injection of botulinum toxin into the extraocular muscle.

BACKGROUND: The myotendinous nerve endings located in the extraocular muscles are considered as proprioceptors. The proprioception of extraocular muscles can be altered if botuminium toxin, which is widely used for the treatment of strabismus, damages the endings. The purpose of this study is to investigate the ultrastructural changes in myotendinous nerve endings after injection of botulinum toxin into the extraocular muscles. METHODS: Under general anesthesia, 5 IU of botulinum toxin (0.1 ml) were injected into the superior and medial rectus muscles of one eye in each of 12 cats, and 0.1 ml of normal saline was injected into the muscles of the other eye. The myotendinous junction was harvested in four cats each at 1, 4, and 12 weeks after injection and examined using electron microscopy. The myotendinous junctions of four normal uninjected cats were also examined as a control group. RESULTS: There were no morphological differences between the control group and saline injection group. In the botox injection group, separation of the myelin sheath and an increase in neurofilaments in axons of myelinated and unmyelinated nerve fibers were observed 1 week after injection and persisted until 12 weeks. Around the terminal nerve endings, incomplete Schwann cells with axonal exposure were observed, and fibroblast-like changes in Schwann cells were detected. These findings were not observed in the control group. CONCLUSIONS: Injection of botulinum toxin into the extraocular muscle induced ultrastructural changes in the myotendinous nerve endings. The possibility that those changes might diminish the proprioceptive abilities of the extraocular muscle should be considered when botulinum toxin is used for the treatment of strabismus.

Role of the equator in the early overcorrection of intermittent exotropia.

PURPOSE: To determine the cause of consecutive esotropia on the basis of the relationship between the location of the equator and a new insertional site of the recessed lateral rectus muscle in cases of intermittent exotropia. METHODS: Ninety-two patients with intermittent exotropia, all of whom underwent recessions of both lateral rectus muscles (5 to 8 mm), were included. The distances from the limbus to the equator (LE distance) and from the equator to the new insertion of the recessed lateral rectus muscle (EIN distance) were calculated using the following formula: (LE = axial length x pi/4 - corneal diameter/2). Overcorrection was defined as esophoria in excess of 5 prism diopters, and all patients were followed up for at least 3 months after surgery. RESULTS: In all patients, the mean LE distance was 12.7 mm in the right eye and 12.6 mm in the left eye. The mean EIN distance in the successfully corrected patients was -0.82 mm in the right eye and -0.95 mm in the left eye. A negative distance value indicates a new insertion anterior to the equator. Overcorrection was detected in 15 patients (16.3%), whose mean EIN distances were -0.93 mm in the right eye and -0.78 mm in the left eye. No significant differences were determined to exist between the corrected and overcorrected patients with regard to the affected eye (P > .05). CONCLUSIONS: Overcorrection of intermittent exotropia did not appear to be related to the location of new insertions of the lateral rectus muscle of up to 8 mm of recession. This may indicate the redistributing of relatively more innervational inputs to the medial rectus muscle after the completion of lateral rectus recession in consecutive esotropia.

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 40 delta XT. Two patients with 70 delta and 85 delta 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 25 delta. 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.

Time and Factors Affecting the Direction of Re-drift in Essential Infantile Esotropia.

PURPOSE: To investigate the development pattern and related factors of postoperative re-drift in infantile esotropia. METHODS: A total of 112 patients with infantile esotropia who underwent surgery before 3 years of age were included. Surgical outcomes were divided into (1) consecutive exotropia: more than 8 prism diopters (PD) of exodeviation; (2) recurrent esotropia: more than 8 PD of esodeviation; and (3) monofixation syndrome: maintenance of deviations within 8 PD. The occurrence rate, time of onset, and associated factors of the re-drift were evaluated. RESULTS: At a mean follow-up of 9.5 years, consecutive exotropia developed in 37 patients (33.0%) and recurrent esotropia in 43 patients (38.4%). Whereas 76.7% of total recurrent esotropia cases were identified within postoperative 1 year, consecutive exotropia occurred constantly over 10 years postoperatively. The mean time to consecutive exotropia development from surgery was 78.6 months, greater than that of recurrent esotropia development (8.9 months) (P < 0.001). In multinomial logistic regression using monofixation syndrome as the reference category, fixation preference before surgery (odds ratio [OR]: 6.64, 95% confidence interval [CI]: 2.07 to 21.32) and the rate of myopic progression (OR: 15.07 per -1.00 D/year, 95% CI: 1.23 to 184.86) were associated with consecutive exotropia, whereas increase in the angle of esodeviation on postoperative day 1 (OR: 1.15, 95% CI: 1.04 to 1.26) was correlated with recurrent esotropia. CONCLUSIONS: This study demonstrates a difference between the development pattern of exotropic and esotropic drift after infantile esotropia surgery. Detailed preoperative assessment and close postoperative observation of deviations and refractive status will help to determine surgical outcomes of infantile esotropia. [J Pediatr Ophthalmol Strabismus. 2018;55(2):128-134.].

Consecutive esotropia in intermittent exotropia 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.

Postnatal development of myosin heavy chain isoforms in rat extraocular muscles.

PURPOSE: To determine the composition of myosin heavy chain (MHC) isoforms in rat extraocular muscles (EOMs) during postnatal development. METHODS: The MHC composition of rat EOMs at postnatal day 0 (P0), postnatal day 14 (P14), and adults was evaluated at mRNA levels by competitive polymerase chain reaction and MHC composition of each six EOM in adult rats. RESULTS: EOMs at P0 revealed predominant expression of neonatal MHC (75.5%) with a lesser percentage of embryonic MHC (12.8%) and 2A MHC (11.5%). 2X MHC was expressed at low levels and other MHC isoforms were not detected. At P14, EOMs expressed mostly 2X MHC (42.4%) and 2A MHC (27.4%). Expression levels of neonatal MHC (14.1%) and embryonic MHC (4.9%) decreased. 2B MHC (8.2%), EOM MHC (1.9%), and beta-cardiac MHC (1.1%) were detected at low levels. In the adult rats, EOMs contained over 80% of three fast MHC isoforms, such as 2X MHC (29.9%), 2A MHC (29.3%), and 2B MHC (24.5%). Each of six adult EOM showed slightly different expression levels of MHC composition. CONCLUSIONS: A strong correlation exists between the composition of fast MHC isoforms and muscle development. MHC isoform followed a neonatal MHC-2X MHC-2B MHC isoform switching pattern after birth. Postnatal development of EOMs had a slightly different expression pattern for MHC isoforms and may have different regulatory roles related to their functional requirement.

Surgical outcomes in correction of Brown syndrome.

PURPOSE: To evaluate the outcomes of surgery for Brown syndrome. METHODS: We reviewed the charts of 15 patients who underwent surgery for Brown syndrome. The limitation of elevation in adduction (LEA) ranged from -2 to -4 degrees. A superior oblique muscle (SO) tenotomy was performed in 4 patients, a silicone expander was inserted in the SO of 9 patients, and a SO recession was performed in 2 patients. The results of surgery were analyzed with a follow-up period of more than 6 months, 42.3 +/- 48.42 months on average. RESULTS: Nine female patients and 6 male patients with unilateral Brown syndrome were selected for this study. The left eye was the affected eye in 9 patients. The degree of preoperative LEA was -2 to -4 in 4 patients in whom SO tenotomy was performed, -3 to -4 in 9 patients treated with the silicone expander, and -2 to -4 in 2 patients treated with SO recession. The LEA was released after surgery in all patients without postoperative adhesion. However, unilateral overaction of the inferior oblique muscle due to excessive weakening of the SO occurred in 1 patient with tenotomy (25%) and in 1 patient with insertion of a silicone expander (11%). CONCLUSIONS: LEA was released after tenotomy, insertion of a silicone expander and recession of the SO in 13 of 15 patients with Brown syndrome. SO palsy due to overcorrection and under-correction with postoperative adhesion should be avoided.

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 approximately 30). The mean restriction of elevation on abduction in the operated eye was -1.6 (-1 approximately -4) and IOOA of the contralateral eye was +2.7 (+2 approximately +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.

Ultrastructural changes of myotendinous nerve endings following recession or resection procedures of extraocular muscle surgeries in cats.

To verify the postoperative ultrastructural changes of the myotendinous nerve endings of feline extraocular muscles, which are known as proprioceptors. Sixteen recti of four cats were used and divided into three groups. In group A, eight lateral recti were recessed. In group B, four medial recti were resected by 10 mm from insertion to include the myotendinous junction. In group C, four medial recti were resected by 4 mm of muscle bellies only, without disturbing the myotendinous junction. Four weeks after surgery, specimens were examined with electron microscopy. In group A, overall neural structures were well maintained with slight axonal degeneration. In group B, only muscle fibers were observed without any regeneration of neural sprouts. In group C, axonal disintegration and shrinkage were evident. These results indicate that myotendinous nerve endings can be damaged in strabismus surgery, and that resection was more invasive than recession in disrupting myotendinous nerve endings.

Deterioration of accommodative esotropia during part-time occlusion therapy.

The authors report two cases of suddenly deteriorated accommodative esotropia with amblyopia during part-time occlusion therapy. A 7-year-old girl with right accommodative esotropia, which was well controlled, showed marked increase in esodeviation after part-time occlusion and regained orthophoria without occlusion. This phenomenon was repeated. Recession of both medial recti was performed and orthophoria was well maintained at both distant and near targets. Accommodative esotropia of a 9-year-old boy with glasses also showed a striking increase in esodeviation after part-time occlusion. The authors recommended wearing only glasses without occlusion or surgery and he recovered fusion. Three months later, orthophoria was maintained at distant target, with 8PD esophoria at near target with glasses. Although this complication should be considered before occlusion therapy, it must be taken continuously if needed, because an increase of the deviation size with occlusion may simply reflect a true deviation and may not be a poor prognostic sign.

Changes in refractive error in patients with accommodative esotropia after being weaned from hyperopic correction.

BACKGROUND: To determine the long-term changes in refractive error and ocular alignment in patients with accommodative esotropia (AET) who were able to discontinue wearing hyperopic glasses because of emmetropisation. METHODS: Forty-seven patients with refractive AET who achieved emmetropisation and orthotropia without hyperopic glasses and were followed up for at least 3 years were enrolled. All of the patients had been prescribed the weakest possible glasses for best corrected vision. Refractive error and ocular alignment were analysed after the cessation of hyperopic glasses use. RESULTS: The mean length of follow-up was 5.7±3.21 years after successful weaning from hyperoptic glasses. The mean spherical equivalent (SE) of the refractive error was -1.01±1.53 dioptres (D), and the mean esotropia (ET) was 1.0±8.70 Δ at the final visit. Myopia developed in 55.3% of all patients. The mean myopic progression rate per year was -0.19±0.23 D/year. Forty-one patients (87.2%) showed orthotropia; in addition, three of the patients (6.4%) developed ET, and three (6.4%) developed exotropia (XT). The six patients who had ET or XT all showed myopia. Two of the three patients who developed ET underwent surgery. Both patients initially had a low degree of hyperopia and a high ratio of accommodative convergence to accommodation (AC/A). The initial hyperopia correlated with the SE refractive error at the final follow-up (p<0.001). CONCLUSIONS: When emmetropisation occurs early in patients with AET, it is necessary to note the development of myopia and the deterioration of ocular alignment.

Effect of watching 3-dimensional television on refractive error in children.

PURPOSE: To investigate the effect of watching 3-dimensional (3D) television (TV) on refractive error in children. METHODS: Sixty healthy volunteers, aged 6 to 12 years, without any ocular abnormalities other than refractive error were recruited for this study. They watched 3D TV for 50 minutes at a viewing distance of 2.8 meters. The image disparity of the 3D contents was from -1 to 1 degree. Refractive errors were measured both before and immediately after watching TV and were rechecked after a 10-minute rest period. The refractive errors before and after watching TV were compared. The amount of refractive change was also compared between myopes and controls. The refractive error of the participants who showed a myopic shift immediately after watching TV were compared across each time point to assure that the myopic shift persisted after a 10-minute rest. RESULTS: The mean age of the participants was 9.23 ± 1.75 years. The baseline manifest refractive error was -1.70 ± 1.79 (-5.50 to +1.25) diopters. The refractive errors immediately after watching and after a 10-minute rest were -1.75 ± 1.85 and -1.69 ± 1.80 diopters, respectively, which were not different from the baseline values. Myopic participants (34 participants), whose spherical equivalent was worse than -0.75 diopters, also did not show any significant refractive change after watching 3D TV. A myopic shift was observed in 31 participants with a mean score of 0.29 ± 0.23 diopters, which resolved after a 10-minute rest. CONCLUSIONS: Watching properly made 3D content on a 3D TV for 50 minutes with a 10-minute intermission at more than 2.8 meters of viewing distance did not affect the refractive error of children.

Specific visual symptoms and signs of Meares-Irlen syndrome in Korean.

PURPOSE: To discriminate the visual symptoms and signs of Meares-Irlen syndrome (MIS) and nonspecific dyslexia from other ophthalmologic diseases (NODs). METHODS: Forty-five patients were enrolled. Thirty four of the patients with MIS whose symptoms improved with tinted lenses comprised MIS group. The other 11 patients whose reading difficulty improved with other ocular therapy and did not require tinted lenses comprised NODs group. The main symptoms causing dyslexia and associated ocular diseases were evaluated. RESULTS: The mean age was 17.9 ± 9.5 years in MIS group, and 19.3 ± 11.0 years in NODs group. In MIS group, the most common symptoms while reading were difficulty to move lines (85%), doubling (53%), and difficulty in bright condition (27%). On the other hand, blurring was the most common symptom in NODs group (45%). The associated ocular diseases in the two groups were refractive error (79% and 73%), dry eye (29% and 18%), and exophoria (6% and 27%), respectively. CONCLUSIONS: Doubling, difficulty to move lines, and difficulty in bright condition while reading are main specific symptoms in MIS compared to nonspecific dyslexia from other ophthalmologic disorders.

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 changes in spatial localization following exotropia surgery.

PURPOSE: To measure changes in spatial localization following exotropia surgery using a computer touch-screen method of measurement. METHODS: Enrolled in the study were 60 exotropia patients, all of whom had undergone corrective muscle surgeries under general anesthesia: 37 patients had undergone unilateral lateral rectus or bilateral lateral rectus muscle recession procedures (recession group) and 23 patients had undergone unilateral lateral and medial rectus muscle resection (R&R), or unilateral medial rectus resection only (resection group). We evaluated spatial localization by having patients point to targets on a computer touch-screen before surgery, and 1 day and 1 month after surgery. The pointing error, Δp, is defined as the difference between the actual location of the target and the pointed-to location of the target by unsigned value, was recorded as the mean of five tests. We compared the extent of postoperative changes in Δp between the two groups. RESULTS: The mean Δp before surgery did not differ statistically between the two groups (p = 0.93). One day after surgery, however, the postoperative change in Δp of the resection group compared with that of the recession group (2.0 ± 0.7° and 0.4 ± 0.5°, respectively) was significant (p = 0.01 and p = 0.86 respectively). CONCLUSIONS: The ability for spatial localization is decreased in patients immediately following medial rectus resection, but is regained by 1 month following surgery.

Risk factors predicting the need for additional surgery in consecutive esotropia.

PURPOSE: To evaluate the risk factors predicting surgical treatment in consecutive esotropia occurring after surgery for intermittent exotropia. METHODS: The clinical records of 52 patients with consecutive esotropia who underwent exotropia surgery were retrospectively reviewed. All patients demonstrated consecutive esotropia with diplopia or suppression for more than 1 month after surgery for exotropia. Patients were divided into two groups (the surgical group and nonsurgical group) depending on whether surgery was required for consecutive esotropia. Surgery for esotropia was performed only in patients with more than 10 prism diopters (PD) esodeviation that persisted for a minimum of 6 months, those who had suppression in 1 eye or diplopia, and those who could not achieve fine stereopsis. The nonsurgical treatment up to 6 months postoperatively was part-time patching and prism therapy in both groups. Patient characteristics were evaluated in the two groups. RESULTS: The surgical group was composed of 17 patients and the nonsurgical group was composed of 35 patients. Age, gender, refractive error, best-corrected visual acuity, and postoperative overcorrection at 1 day were not significantly different in the two groups (P > .05). However, the distance strabismic angle at 1 month postoperatively was 2.5 ± 3.8 PD esodeviation (range: 14 PD esotropia to 4 PD exotropia) in the nonsurgical group and 5.4 ± 5.1 PD esodeviation (range: 20 PD esotropia to orthotropia) in the surgical group; these values were statistically significant (P < .05). CONCLUSIONS: The clinically significant risk factor affecting the surgical decision for consecutive esotropia was a large esotropic angle at 1 month postoperatively in this study.