Comparison between bupivacaine injection and mini-tenotomy in the management of horizontal small angle strabismus in children.

PURPOSE: To compare the outcome of bupivacaine (BUP) injection vs mini-tenotomy of extra-ocular muscles in treating small angle horizontal strabismus in children. METHODS: A prospective comparative study that included a total of 40 patients. Twenty patients received 3 ml of 0.75% Bupivacaine (BUP) injection in both medial recti in case of exotropia and in both lateral recti in case of esotropia. MRI orbit was performed before and 30-60 days' post injection of bupivacaine to estimate changes in muscle size. Mini-tenotomy was done in the other 20 patients, performed on both lateral recti in case of exotropia and on both medial recti in case of esotropia. RESULTS: Mean change of alignment at the end of 6 months in exotropic patients in bupivacaine group was 5.50 ± 4.10 PD and in esotropia patients 4.00 ± 3.38 PD with an average increase in muscle thickness of 0.12 mm ± 0.08 and 0.13 mm ± 0.09 in exotropia and esotropia, respectively. There was an average increase in volume 23 mm3 ± 17.3 and 17.00 mm3 ± 9.50 in exotropia and esotropia, respectively, as measured with MRI. The mean change of alignment in mini-tenotomy was 5.33 ± 4.12 PD, 5.75 ± 4.95 PD in exotropia and esotropia, respectively. CONCLUSION: Bupivacaine and mini-tenotomy are safe and effective alternative treatment, that improved eye alignment in 65% of patients with small angle horizontal deviation.

A Novel Method Ensuring an Immediate Target Angle After Horizontal Strabismus Surgery in Children.

Purpose: Pediatric strabismus surgery has low success rates and high reoperation rates because of difficult alignment measurements and the nature of different strabismus types. Furthermore, adjustable sutures are not easily employed in children on an OPD basis. Methods: This was a retrospective comparative case study of children less than 12 years old who underwent strabismus surgery and were followed up at least 6 months postoperatively. We proposed a novel method that combines adjustable sutures and corneal light reflexes in regular strabismus surgery to improve surgical results. Efficacy and safety were evaluated and compared with those in a regular fixed-suture group. Results: In total, 128 children (88: exotropia and 41: esotropia) in the novel method group (Group 1) and 109 (71: exotropia and 38: esotropia) in the regular fixed-suture group (Group 2) were enrolled. The primary outcome was the immediate target angle (for esotropia within 4 PD of orthotropia and exotropia within 8 PD of esotropia within the first week postoperatively); the secondary outcome was success at the 6-month visit (angle of deviation < 10 PD). Consequently, there was a significantly higher proportion of achieving the immediate target range and success rate in both exotropic and esotropic patients in Group 1 than in Group 2. A significantly lower reoperation rate was also demonstrated in Group 1. No complications were noted in either group.Conclusions: The novel method enabled a higher proportion of subjects to achieve an immediate target range and success rate and a lower chance of reoperation among both esotropic and exotropic patients.

Outcomes of a simplified, fixed surgical dosage calculation for uncomplicated, horizontal, concomitant strabismus in adults.

Purpose: The aim of this study was to evaluate the outcomes of a simplified, fixed surgical dosage calculation for uncomplicated, horizontal, concomitant strabismus in adults. Methods: Outcomes analysis of a fixed-dose calculation method for uncomplicated, horizontal, concomitant strabismus in adults (≥18 years) wherein 1-mm recession/resection equals 2 PD for lateral rectus and 3 PD for medial rectus. This was a retrospective case series. Results: The mean age of the patients was 28.50 ± 8.43 years, the mean amount of preoperative deviation was 35.16 ± 9.97 PD, the mean expected correction was 36.26 ± 9.49 PD, and the mean correction achieved was 35.92 ± 10.74 PD. There were 22 monocular exotropias, six monocular esotropias, eight alternate divergent squints, and two alternate convergent squints. There were 20 cases of sensory strabismus (54.28%). There was no statistically significant difference between the expected correction and correction achieved (P = 0.519), meaning that our fixed-dose calculation method was effective. Thirty-five out of 38 patients had successful outcomes as per our criteria of less than 10-PD deviations from straight in primary position. Therefore, the success rate achieved by this procedure was 92.10%. There was no statistically significant correlation between age and the amount of deviation (P = 0.611). Conclusion: Our case series had a high postoperative success rate in terms of motor alignment. It is hoped that this simplified, fixed-dosage calculation method would help the numerous novice strabismus surgeons, make their starting steps easier and give them the confidence to do strabismus surgeries. They can modify the dosages later as per their own experiences.

Characteristics and long-term surgical outcomes of horizontal strabismus.

PURPOSE: Our aim was to report the characteristics and long-term surgical outcomes of three subgroups of horizontal strabismus in a single institution (divided by strabismus subtype) in a developing country and look into pre-operative factors predictive of surgical success. METHODS: Two hundred and forty-four complete charts of patients, divided into 152 esotropes (ET) and 92 exotropes (XT) who had undergone horizontal strabismus surgeries, were retrospectively reviewed. Charts of patients with muscle palsy, Duane syndrome and consecutive strabismus were excluded; 172 patients were included divided into partially accommodative ET, congenital ET and intermittent XT. Surgical success was defined as a post-operative angle deviation of 12 prism diopters or less. RESULTS: The mean follow-up period of all patients was 31.64 ± 23.12 months. The subgroups were divided into partially accommodative ET (60 patients), congenital ET (60 patients), and intermittent XT (52 patients). Esotropes (both partially accommodative and congenital) presented earlier (p < 0.001). Also, partially accommodative ET had a significantly higher spherical equivalent (SE) compared to congenital ET patients, who had a higher SE than intermittent XT (p < 0.001). Congenital ET patients had a significantly larger angle of deviation (for both far and near) than both partially accommodative ET and intermittent XT patients (p < 0.001). The overall success rate was 72.67% for the whole group with no significant differences among subgroups. Success rate of partially accommodative ET surgery was 78.33% compared to that of congenital ET at 66.67% and intermittent XT at 73.07%. Significant post-operative improvement in sensory fusion was observed mainly for patients with partially accommodative esotropia and intermittent exotropia. CONCLUSION: Our results showed that esotropes (both partially accommodative and congenital) presented earlier, with a higher spherical equivalent in the partially accommodative ET subgroup, while the congenital ET subgroup had the largest angle of deviation for both distance and near. The overall surgical success rate for horizontal strabismus surgery was 72.67% with the 3 subgroups having similar success rates. A younger age at presentation and absence of amblyopia were positively correlated with surgical success in the partially accommodative esotropia group.

Evaluation of Efficacy and Lateral Gaze Incomitance in Symmetrical and Asymmetrical Surgery for Concomitant Esotropia and Exotropia.

PURPOSE: Evaluation of asymmetrical and symmetrical horizontal strabismus surgery as regards efficacy and postoperative lateral gaze incomitance. PATIENTS AND METHODS: This prospective comparative interventional case series study included 40 patients of age more than 3 years with alternating horizontal strabismus. Patients were divided according to the type of horizontal deviation into esotropia and exotropia groups, which were further subdivided into asymmetrical and symmetrical subgroups in each type. The surgery was defined as symmetrical procedure if the surgery was done on the same muscle in the two eyes and it was defined as asymmetric in recess-resect procedures in one eye, and three horizontal muscles surgery. Preoperative and postoperative measurements were done in primary position, right, and left gaze using alternate prism cover test and hand-held orthopedic goniometer. RESULTS: At the end of follow-up period, a statistically insignificant difference (P value = 0.8057) was present in the success rate between the asymmetrical and symmetrical subgroups of esotropia (90 and 86.67%, respectively) and it was 100% in both exotropia subgroups. Lateral gaze incomitance results were different between esotropia and exotropia subgroups. In esotropia, a statistically significant difference was reported at 1 month (0.009), which became insignificant at 6 months (0.077) and 12 months (0.077) between asymmetrical and symmetrical subgroups. In exotropia subgroups, there was a statistically insignificant difference in lateral gaze incomitance at 1, 6, and 12 months (P = 1). CONCLUSION: Asymmetrical procedure had the same efficacy and success rate of symmetrical procedure for the correction of concomitant horizontal deviations in primary gaze without persistent postoperative lateral gaze incomitance, especially in exotropia. CLINICAL TRIAL REGISTRATION: NCT04199286.

Surgical planning of horizontal strabismus using multiple output regression tree.

Strabismus is an eye disease that affects about 0.12%-9.86% of the population, which can cause irreversible sensory damage to vision and psychological problems. The most severe cases require surgical intervention, despite other less invasive techniques being available for a more conservative approach. As for surgeries, the treatment goal is to align the eyes to recover binocular vision, which demands knowledge, training, and experience. One of the leading causes of failure is human error during the measurement of deviation. Thus, this work proposes a new method based on the Decision Tree Regressor algorithms to assist in the surgical planning for horizontal strabismus to predict recoil and resection measures in the lateral and medial rectus muscles. In the presented method, two application approaches were taken, being in the form of multiple single target models, one procedure at a time, and the form of one multiple target model or all surgical procedures together. The method's efficiency is indicated by the average difference between the value indicated by the method and the physician's value. In our most accurate model, an average error of 0.66 mm was obtained for all surgical procedures, both for resection and recoil in the indication of the horizontal strabismus surgical planning. The results present the feasibility of using Decision Tree Regressor algorithms to perform the planning of strabismus surgeries, making it possible to predict correction values for surgical procedures based on medical data analysis and exceeding state-of-art.

First Report of a Pineal Cyst Associated with Corpus Callosum Lipoma.

A 37-year-old man with no medical history, apart from a lifelong horizontal diplopia, underwent brain magnetic resonance imaging, which revealed a curvilinear posterior pericallosal lipoma and a pineal cyst. Corpus callosum lipomas, with an incidence of 0.1%-0.5%, do not require neurosurgical treatment, except in rare cases of malformations causing epilepsy. The indications for surgery of pineal cysts, whose incidence is 0.6%, are controversial, except in case of hydrocephalus. In this case, ophthalmologic examination and magnetic resonance imaging were not consistent for a tectal plate compression and the findings were considered incidental. The association of these 2 abnormalities, which has not been described before, might reflect an interrelated embryologic development for pineal gland and midline lipomas, which derive from aberrant mesenchymal primitive meninx.

Visual outcome and factors influencing surgical outcome of horizontal strabismus surgery in a teaching hospital in Malaysia: A 5-year experience.

PURPOSE: The available data on strabismus surgery in South East Asian countries are scarce. This study aimed to identify visual outcome and factors influencing surgical outcome of horizontal strabismus surgery in a Southeast Asian cohort. MATERIALS AND METHODS: A retrospective review of patients who underwent horizontal strabismus surgery between 2013 and 2017 in Hospital Universiti Sains Malaysia was conducted. Surgery was considered successful if the post-operative deviation was within 10 prism diopters at 6 months' postoperative period. Factors influencing the outcome of surgery at 6 months were identified. Chi-square and Fisher's exact tests were used in data analysis. RESULTS: Ninety-eight patients were included. Both genders were equally affected. Exotropia (58.2%) was the most common type. About 65.3% of patients had alternating strabismus, while 51% had an angle of deviation of more than 45 prism diopters. Amblyopia was documented in 14.3% of patients. Those operated on below 10 years of age comprised 64.3%. Ninety-four patients completed follow-ups at 6 months after the surgery. The success rate was 81.6%. Approximately 92% of the patients had best-corrected visual acuities of 6/12 and better at 6 months' postoperative period. There was no significant association between age of onset, gender, presence of amblyopia, type of deviation, amount of deviation, and postoperative best-corrected visual acuity with surgical outcome at 6 months' postoperative period (P > 0.05). CONCLUSION: The success rate was good. Postoperative best-corrected visual acuity was promising. Age of onset, gender, presence of amblyopia, type of deviation, amount of deviation, and postoperative best-corrected visual acuity did not influence the outcome of horizontal strabismus surgery in our review.

Slanted versus Augmented Recession for Horizontal Strabismus.

PURPOSE: To compare the surgical outcomes of slanted versus augmented recession in patients with horizontal strabismus. METHODS: In this randomized clinical trial, a total of 100 esotropic (ET) and exotropic (XT) patients with a high AC/A ratio which was defined as a difference of ≥ 10 prism diopters (pd) between the distance and near deviations were included if the patients had a distance deviation ≥ 15 pd. Patients were randomly assigned into the slanted (n = 26 in ET and n = 24 in XT group) and augmented recession groups (n = 25 in ET and n = 25 in XT group). In the slanted group, recession was performed on the superior and inferior poles of the muscle based on the distance and near deviations, respectively, while in the augmented recession group, the muscles were recessed 1.00 or 1.50 mm more than the standard amount according to the distance and near difference between 10 and 20 pd or > 20 pd, respectively. RESULTS: The mean age was 9.8 ± 9.6 years and 63% were female. There was a significant postoperative reduction of difference in convergence excess in ET cases compared to patients who underwent the augmented recession procedure (12.65 ± 6.16 vs 8.64 ± 6.1 pd, P = 0.014). Among our XT groups, there was no significant difference in postoperative reduction in the XT angle in the slanted group compared with the augmented group (P > 0.05). CONCLUSION: Slanted recession is recommended in convergence excess ET patients. In XT patients, either slanted or augmented recession may be chosen according to the priority and experience of the surgeon.

Clinical characteristics according to the laterality of ocular torsion in unilateral superior oblique palsy.

BACKGROUND: To compare clinical characteristics according to the laterality of objective ocular torsion in patients with unilateral superior oblique palsy (SOP). METHODS: This retrospective study included all patients with a diagnosis of unilateral SOP. They were classified into subgroups according to correspondence between the paretic eye and the extorted eye using fundus photography. Ocular alignment and muscle action were tested by the prism and alternate cover tests and 4-scale movement measure. Various clinical factors, including the amount of preoperative ocular torsion and change in ocular torsion postoperative, were compared between the accordance and disaccordance groups. RESULTS: A total of 70 Asian patients (140 eyes) were included and underwent fundus photography preoperatively. Excyclotorsion in the paretic eye was defined as accordance (45 patients), excyclotorsion in the nonparetic eye was defined as disaccordance (25 patients). The presence of horizontal strabismus was detected in 28 (62%) patients in the accordance group and only 8 (32%) patients in the disaccordance group (p = 0.024). All horizontal strabismus observed in the accordance group involved exodeviation. The proportion of horizontal strabismus surgery was also significantly larger in the accordance group than the disaccordance group (p = 0.039). Among those patients, there were 26 who underwent fundus photography postoperatively. There was significant reduction in ocular excyclotorsion postoperatively in the accordance group (p = 0.001), but no significant reduction postoperatively in the disaccordance group (p = 0.270). There was no significant correlation between the amount of torsional reduction and the amount of vertical deviation reduction (p = 0.979). CONCLUSIONS: In cases of preoperative excyclotorsion in paretic eyes, careful consideration of combined horizontal misalignment which may require surgical correction is helpful to manage unilateral SOP.

Prism under cover test in alternate fixation horizontal strabismus.

PURPOSE: To evaluate the applicability of the prism under cover test (PUCT) to quantify manifest deviation in horizontal strabismus with alternate fixation when simultaneous prism and cover test (SPCT) is not feasible. METHODS: Children aged 4-11 years, with alternate fixation horizontal strabismus and alternate prism and cover test (APCT) distance deviation (DD) up to 25 PD were eligible. In group 1 of the study, SPCT was not feasible (n = 18), whereas in group 2, it was feasible (n = 24). Refraction, PUCT, APCT, central/peripheral fusion, and stereoacuity were measured. Repeatability of PUCT, agreement between PUCT and SPCT, and Pearson correlations between variables were studied. RESULTS: In group 1, mean DD was 15.6 and 9.5 PD using APCT and PUCT, respectively (intraclass correlation, ICC: 0.90). Mean stereoacuity was 201.1 arc seconds. PUCT was better correlated with stereoacuity than APCT, but not significantly (p = 0.12). Coefficient of repeatability for PUCT was 3.4 PD. In group 2, mean DD was 17.6, 14.1, and 12.5 PD using APCT, PUCT, and SPCT, respectively. Mean stereoacuity was 285.9 arc seconds. Correlations APCT-PUCT (0.87), APCT-SPCT (0.82), and SPCT-PUCT (0.95) were significant. APCT did not show as good correlation with stereoacuity (0.58) as SPCT and PUCT (0.74 and 0.78, respectively). Concordance correlation coefficient between SPCT and PUCT was 0.91, and Bland Altman agreement between the two variables was also good. CONCLUSIONS: PUCT is a procedure with good repeatability, of interest in children to estimate manifest deviation when SPCT is not feasible, and in support of the diagnosis of monofixation syndrome.

Observation of modified fornix-based approach for minimal incision surgery in the treatment of children with the horizontal strabismus / 眼科新进展

Objective To evaluate the modified foruix-based technique with Guyton hook as an approach for the treatment of children with horizontal strabismus.Methods The clinical data of 128 patients (170 eyes) who underwent horizontal strabismus surgery between January 2014 and June 2017 were retrospectively reviewed,including 60 males and 68 females.The mean age was 1.5-17.0 (6.5 ± 1.6) years.All procedures under general anesthesia were performed using the modified fornix-based conjunctival incision with Guyton hook,and the follow-up period was 6 to 12 months.The clinical and cosmetic outcomes of strabismus surgery,the complications and interventions related to the incision were assessed.Results At 3 months after surgery,orthophoria with excellent cosmetics was achieved in 119 patients (93％) with the deviation ≤ ± 10△.Together 102 eyes (60％) had no intraoperative suture.Moreover,the incision was sutured with one stitch in 45 eye (26.5％),in 20 (11.8％) with 2 stitches,and in 3 (1.8％) with 3 stitches.During the follow up period,there was no severe intraoperative or postoperative complications.The swelling and redness of conjunctiva recovered quickly.Patients' discomfort was alleviated in a few days after the surgery.No oblivious scarring was found along the incision lines.Conclusion The modified fornix-based approach with Guyton hook is an effective and safe method for minimal incision surgery in children with horizontal strabis.

Prognostic preoperative factors for successful outcome of surgery in horizontal strabismus.

CONTEXT: Surgery for horizontal strabismus reportedly has a success rate of 60%-80%. However, which preoperative factors are predictive of this success is not clear. AIMS: To identify prognostic factors those are predictive of successful outcome in horizontal strabismus surgery. SETTINGS AND DESIGN: Observational analytical study using multiple logistic regression (MLR). SUBJECTS AND METHODS: We assessed the medical records of patients who had undergone first-time horizontal muscle strabismus surgery between 2002 and 2013, where complete follow-up data were available for ≥6 weeks, and also, we collected data prospectively on patients operated between January 2014 and September 2015. Successful outcome was defined as a postoperative angle of deviation within 10 prism diopter of orthophoria at ≥6 weeks postoperatively. Independent variables considered were age at onset, age at surgery, duration, gender, deviation - type and amount, logMAR visual acuity (VA) - mean and of the poorer eye, mean refractive error, amount of anisometropia, and presence of dense amblyopia. Only those with P < 0.2 on univariate analyses (UAs) were included in the MLR, with significance set at P ≤ 0.05. STATISTICAL ANALYSES: UA (Chi-square for categorical variables and t-tests for continuous variables), followed by logistic regression analysis. RESULTS: Of 113 patients, on UA, type of deviation (P = 0.01), age at surgery (P = 0.16), absence of dense amblyopia (P = 0.002), and logMAR VA of the poorer eye (P = 0.005) qualified for the inclusion in MLR. On MLR, esotropia (ET) (odds ratio [OR]: 4.46) and absence of dense amblyopia (OR: 5.90) were associated with success. CONCLUSIONS: With an overall success rate of 83%, ET and absence of dense amblyopia were significantly predictive of surgical success.

Outcomes of minimally invasive strabismus surgery for horizontal deviation.

OBJECTIVE: To study the outcomes of minimally invasive strabismus surgery (MISS) for treating horizontal deviation METHOD: Case Series of the first 26 consecutive patients operated on using the MISS technique in our hospital from February 2010 to March 2014. RESULTS: A total of 40 eyes were included: 26 patients (mean age: 7.7 years old ± 4.9); 34.61%: male. A total of 43 muscles were operated on: 20 medial, and 23 lateral recti; 28 recessions (range: 3-7.5mm), 6 resections (6-7 mm), and 9 plications (6.5-7.5 mm) were performed. No significant difference was found (P>0.05) for visual acuity at postoperative day 1, and 6 months after surgery. A mild hyperaemia was observed in 29.27%, moderate in 48.78%, and severe in 21.95% at postoperative day 1 and in 63.41%, 31.70% and 4.87%, respectively, at 4 days after surgery. The complications observed were 4 intraoperative conjunctival haemorrhages, 1 scleral perforation, and 2 Tenon's prolapses. A conversion from MISS to a fornix approach was necessary in 1 patient because of bad visualization. The operating time range decreased from 30 to 15 minutes. CONCLUSIONS: The MISS technique has obtained good results in horizontal strabismus surgery. The conjunctival inflammation was mild in most of the cases at postoperative day 4. The visual acuity was stable during follow-up, and operating time decreased after a 4-year learning curve.

Minimally Invasive Strabismus Surgery (MISS) Compared with the Fornix Approach in Pediatric Horizontal Strabismus Surgery.

OBJECTIVE: To compare minimally invasive strabismus surgery (MISS) with the fornix approach in horizontal strabismus operations. PATIENTS AND METHODS: We performed a retrospective study of all patients aged ≤ 12 years who underwent symmetrical surgery of the medial or lateral recti over a 1-year period. MISS was performed in one eye, and fornix opening was performed in the contralateral. We compared pre- and postoperative visual acuity (VA), conjunctival hyperemia, swelling after surgery, and operating time. The techniques were performed by 2 surgeons after a 4-year training period. RESULTS: The sample comprised 16 patients, with a mean age of 6.75 ± 3.02 years. The medial rectus was operated on in 9, the lateral rectus in 7 cases. Recession was performed in 14 muscles (mean dose, 5 mm) and plication in 2 (5.5 mm and 7 mm, respectively). MISS was performed in 12 right eyes and 4 left eyes. Preoperative VA was 0.77 in MISS and 0.80 in the control group. VA was 0.83 in MISS and 0.76 in the control group 1 day after surgery. No significant differences were found for conjunctival hyperemia between the MISS and fornix groups 1 day or 1 week after surgery. Nevertheless, moderate/severe conjunctival hyperemia was less frequent in the MISS group (31.3% versus 62.5%). No significant differences were found for operating time (14.43 minutes [MISS] vs 12.37 minutes [control]). CONCLUSION: The MISS technique was similar to the fornix approach in the early postoperative period with respect to VA, conjunctival inflammation, and operating time in pediatric horizontal strabismus surgery.

Effect of Horizontal Strabismus Surgery on the Refractive Status.

PURPOSE: To evaluate the effects of horizontal strabismus surgery on the refractive and astigmatic status of eyes following horizontal muscle surgery using double-angle vector analysis. MATERIALS AND METHODS: This was a retrospective analysis of 137 patients (250 eyes) conducted between February 1997 and October 2010 in patients who had unilateral or bilateral recession or monocular recession and/or underwent resection of horizontal muscles by a single surgeon. Refraction data were obtained at 1-2 weeks preoperative and at 4-6 weeks and 4-6 months postoperative. Surgically induced refractive changes were calculated using double-angle vector analysis. RESULTS: The mean change in the spherical equivalent (SE) of the refraction was 0.23 ± 0.78 D for surgically induced refractive changes at 4-6 weeks postoperative (SIRC1; p < 0.0001) and 0.14 ± 0.85 D (p = 0.018) for surgically induced refractive changes at 4-6 months postoperative (SIRC2), indicating a small shift in the myopic direction with regression at 4-6 months. The mean amplitudes of the induced cylinders were 0.072 ± 1.22 D (p = 0.262) in SIRC1 and 0.20 ± 1.14 D (p = 0.012) in SIRC2, and the mean axis of the induced plus cylinder was 21.74° in SIRC1, indicating a small shift in the with-the-rule direction, but no statistically significant difference from zero (p = 0.331). The changes in the surgically induced refraction over time (SIRC d), ie, 0.05 ± 0.64 in SE (p = 0.255) and 0.09 ± 0.65 in the cylinder (p = 0.049), were stable. There was no significant correlation between the amounts of horizontal rectus muscle recession and/or resection and the cylinder power of individual induced astigmatism at 4-6 weeks after surgery (p = 0.266) and the myopic shift (p = 0.345). Moreover, there were no significant correlations between the ages of the patients and the spherical equivalent for SIRC1 (p = 0.858) and the induced cylinder for SIRC1 (p = 0.750). CONCLUSION: Horizontal rectus muscle surgery tended to induce a transient, statistically significant change in the spherical equivalent of refraction, with a myopic shift that was clinically not important. Our findings did not strongly support that the astigmatism induced changes. There was no correlation between the amount of recession and/or resection and the amount of induced refractive error.

Surgical planning for horizontal strabismus using Support Vector Regression.

Strabismus is a pathology which affects about 4% of the population, causing esthetic problems (reversible at any age) and irreversible sensory disorders, altering the vision mechanism. Many techniques can be applied to settle the muscular balance, thus eliminating strabismus. However, when the conservative treatment is not enough, the surgical treatment is adopted, applying recoils or resections to the ocular muscles affected. The factors involved in the surgical strategy in cases of strabismus are complex, demanding both theoretical knowledge and experience from the surgeon. So, the present work proposes a methodology based on Support Vector Regression to help the physician with decision related to horizontal strabismus surgeries. The efficiency of the method at the indication of the surgical plan was evaluated through the average difference between the values that it provided and the values indicated by the specialists. In the planning of medial rectus muscles surgeries, the average error was 0.5mm for recoil and 0.7 for resection. For lateral rectus muscles, the mean error was 0.6 for recoil and 0.8 for resection. The results are promising and prove the feasibility of the use of Support Vector Regression in the indication of strabismus surgeries.

Intelligence Quotient (IQ) in Congenital Strabismus.

PURPOSE: To evaluate intelligence quotient (IQ) in patients with congenital strabismus. METHODS: All patients with congenital strabismus scheduled for surgery were enrolled consecutively over a one year period in a cross-sectional study and were evaluated for verbal, performance and total IQ scores, and compared to the mean normal IQ of 100±15. RESULTS: During the study period, 109 patients with mean age of 18.4±10.5 (range, 4-63) years were included. Educational status in most patients (80%) was less than high-school. Most patients (80%) lived in urban areas and 46 patients (42.2%) had some degrees of unilateral or bilateral amblyopia. Mean verbal IQ was 87.2±19.6 (range, 45-127), performance IQ was 81±15.5 (range, 44-111) and total IQ was 83.5±18.3 (range, 40-120). Total IQ was significantly lower in comparison to the normal population (P<0.01) and significantly higher in urban as compared to rural residents (85.1±19.5 versus 77.3±10.8 respectively, P=0.02). Patients with coexisting amblyopia and alternate deviation had lower IQ levels. Verbal IQ was insignificantly higher in myopes than emmetropes and hyperopes. IQ was better with vertical deviations and was higher in esotropes than exotropes; however, these differences were not statistically significant (P>0.05 for all comparisons). CONCLUSION: Patients with congenital strabismus in this study had lower mean IQ scores than the normal population which may be due to genetic background or acquired causes secondary to strabismus.

Clinical Manifestations of Inferior Oblique Overaction in Patients with Horizontal Strabismus

PURPOSE: To investigate the clinical manifestations of and the surgical success rates in patients with horizontal strabismus and inferior oblique overaction (IOOA). METHODS: The patients included in the present study had received myectomy for correction of IOOA and had at least 3 months of follow-up. The patients were divided into 2 groups; patients who received myectomy and surgery for horizontal strabismus simultaneously (combined group, 74 eyes of 49 patients) and patients who received myectomy only (myectomy group, 29 eyes of 24 patients). Chief complaints, head tilt, bilaterality of IOOA, ocular torsion, and the surgical success rates were analyzed. RESULTS: In the combined group, 51% of the chief complaints were horizontal deviation, and in the myectomy group 42% were upward deviation and 29% were head tilt. Objective head tilt was 29% in the combined group and 54% in the myectomy group and the difference was significant. There was no significant difference statistically in the success rate of myectomy. CONCLUSIONS: The frequency of symptoms associated with IOOA in the combined group was lower than in the myectomy group. Therefore, preoperative examination regarding IOOA should be carefully performed in patients who are planning a horizontal strabismus surgery because there was no difference in surgical success rate between the 2 groups, the association with horizontal strabismus may have no effect on the surgical results of IOOA.

Effect of Axial Length (Myopia) on Horizontal Recti Recession in Children with Horizontal Strabismus

PURPOSE: To assess the influence of axial length for surgical outcome of horizontal recti recession in children with horizontal strabismus. METHODS: A retrospective, non-comparative case series. 100 patients, 96 males and 44 females with unilateral or bilateral high myopia and strabismus surgery was performed. All patients had horizontal recti recession and no combined vertical strabismus. There was no history of any ocular trauma or surgery and no history of any other systemic diseases that affect ocular motility. After horizontal recti recession, the patients were followed-up for more than one year. Data was analyzed using SPSS Software for Windows, version 12.0.1. RESULTS: In 100 children, the mean axial length was 23.21 +/- 1.38 mm (range, 19.63-26.50 mm) and the mean age was 7.43 +/- 2.86 years (range, 1-14 years). Lateral rectus recession was in 89 cases, and medial rectus recession was done in 11 cases. After operation, 86 cases were fully corrected, 11 cases were under corrected and 3 cases were over corrected. Binary logistic regression analysis was performed revealing that, preoperative angle of deviation (p-value 0.062) and axial length (p-value 0.05) were highly correlated with surgical outcome. CONCLUSIONS: Age, preoperative angle of deviation, and axial length may influence the surgical outcome of horizontal recti recession in children. In eyes with long axial length, the surgical outcome of horizontal recti recession appears to be poorer than that in eyes with short axial lengths. Adjusting the recession amounts when performing horizontal recti recessions in long axial length eyes may provide better results.