Management of Strabismus in Myopes

Nomogram for predicting secondary surgery in patients with concomitant exotropia

Concomitant exotropia (CX), a common form of strabismus, often requires surgical correction, yet up to 60% of patients undergo secondary surgery (SS) due to recurrence or residual deviation. Current risk prediction tools remain limited by inconsistent variables and short-term follow-up. This study aimed to develop and validate a nomogram integrating long-term follow-up data to predict individualized SS risk in CX patients. This is a retrospective cohort study of patients with CX who underwent surgery at the Peking University First Hospital between January 1, 2008, and December 31, 2010. Of the 355 CX cases included, 70% were randomly assigned to the training set (n = 248) and 30% to the validation set (n = 107). Demographic and clinical variables were ascertained at hospital admission and discharge and screened using multivariate Cox proportional hazards regression analysis to construct predictive models and generate a one-, three-, and six-year alignment rate nomogram. This nomogram provided an estimate of the risk of SS in patients with surgically treated CX. Internal validation was conducted using the concordance index (C-index) and calibration curve for the training and validation sets, respectively. Four independent prognostic factors were identified: age of onset, refraction, types, and deviation angles one week after surgery entered into the nomogram. The proposed nomogram showed favorable discrimination and accuracy in the training and validation sets. The C-indexes of the training and validation sets were 0.83(95%CI:0.71 ~ 0.95) and 0.80(95%CI: 0.70 ~ 0.89), respectively. The proposed nomogram may serve as a predictive tool for prognostic evaluation of CX surgery.

The effects of refractive status on the outcomes of strabismus surgery in patients with esotropia

BACKGROUND

The success of the strabismus surgery can hinge on several factors. One of these factors is refractive condition like hyperopia or myopia. Our study seeks to evaluate the surgical outcomes in patients with esotropia and myopia.

METHODS

This case-control study encompassed all surgical cases of esotropia at Torfe and Negah Hospital between 2016 and 2021, which satisfied our specified inclusion criteria. The initial variables from electronic medical records were collected, including demographic, clinical, and surgery-related factors. At the final follow-up appointment, the level of eye deviation, both at distance and near, was recorded. We considered the operation a "success" for patients with a post-surgery distance eye deviation of 10(Pd) or less. Patients with greater deviation were classified as surgery failure. Statistical analyses were executed using SPSS software (version 16.0), and a P-value less than 0.05 was considered significant.

RESULTS

Of the 194 patients evaluated, 112 were incorporated into the study. Surgical failure was observed in 14.29% of myopic patients, 29.79% of hyperopic patients, and 31.82% of emmetropic patients. The myopia group displayed a 0.19 odd ratio for surgical failure compared to the combined hyperopia and emmetropia groups, not statistically significant (OR: 0.19, CI 95%: 0.03-1.02). Additionally, patients diagnosed with Lateral Rectus Under-action were found to be 6.85 times more likely to experience surgery failure(OR: 6.85, CI 95%: 1.52-30.94). An elevated risk of surgical failure was also identified in patients who underwent Inferior Oblique Weakening procedure, indicated by a 3.77-fold increase in the odds ratio for failure(OR: 3.77, CI 95%: 1.08-13.17).

CONCLUSION

In our study, despite numerical disparities, there was no statistical difference among the success rates of all esotropia patients with different refractive errors. The patients with LRUA or IOOA showed lower success rates. Myopic patients had higher post-op overcorrection with lower reoperation rates compared to hyperopic or emmetropic patients.

Pediatric myopic strabismus fixus: clinical features and surgical outcomes of silicone band loop myopexy

PURPOSE

To evaluate the clinical profile of myopic strabismus fixus (MSF) in children and surgical outcomes of silicone band loop myopexy.

METHOD

We retrospectively reviewed records of children presenting with MSF who underwent silicone band loop myopexy between January 2008 and December 2020 at a tertiary eye care center. Data concerning demographics, refractive error, axial length, extra-ocular motility, and ocular alignment pre-operatively and post-operatively, intra- and post-operative complications, ocular and systemic associations, were evaluated. The long-term effects of band loop myopexy on ocular alignment stability, motility improvement, and myopia progression were analyzed. Surgical outcome was defined as post-operative orthotropia or heterotropia less than or equal to 20 PD.

RESULTS

A total of0 eyes of 7 patients (median age: 5 years; 5 boys and 2 girls) who underwent band loop myopexy were included in the study. Among them, three children underwent bilateral and four children underwent unilateral band loop myopexy. Medial rectus recession was performed only in two patients as a part of initial procedure. The median follow-up duration was 7 years. Most of the children, i.e. six of them presented with esotropia-hypotropia and only one patient presented with exotropia-hypotropia complex. The median pre-operative measurements were esotropia of 62.5 PD, hypotropia of5 PD, and exotropia of4 PD. Postoperative average primary position deviation measured was close to 9-10 PD of esotropia. The overall motility improved to -1 from -3.

CONCLUSION

The clinical profile of MSF in children is almost similar to adults. This condition is a rare entity among adults as well as children. Majority of children with MSF presented with esotropia-hypotropia complex. Silicone band loop myopexy with or without medial rectus recession proves to be a reliable surgical procedure as it provides stable outcomes in terms of ocular alignment and motility among children.

Comparison of Myopia Progression among Myopic Children with Intermittent Exotropia and No Strabismus

SIGNIFICANCE

Myopia is a highly prevalent condition in the pediatric population that is commonly comorbid with intermittent exotropia. Our study found a trend toward significance in the reduction of myopia progression with strabismus correction surgery. Further investigations characterizing the interaction between myopia and strabismus may help inform future management guidelines.

PURPOSE

This study describes and compares myopic progression in the pediatric population with and without intermittent exotropia and its interaction with corrective strabismus surgery.

METHODS

This study analyzed a retrospective cohort of 1239 pediatric myopic patients who were evaluated by pediatric ophthalmologists and optometrists at a tertiary care center from 2012 to 2020. The main outcome measures were the trends in refractive error over time in those with and without intermittent exotropia as well as trends in those who did and did not undergo strabismus surgery.

RESULTS

A total of 275 patients (22%) were identified to have intermittent exotropia, and 12 (4.4%) from this group underwent surgical correction in the study period. No statistically significant difference was identified in myopic progression between those with intermittent exotropia and those without strabismus, and no difference was found in mean annual spherical equivalent change between intermittent exotropia patients who did not undergo surgery compared with those who did.

CONCLUSIONS

Pediatric myopic patients generally experience progression in the condition for several years independent of concurrent intermittent exotropia. Corrective strabismus surgery was not found to alter the natural history of myopia in children, although a reduction in myopic progression in surgically treated patients trended toward significance. Increases in the prevalence of different treatment strategies will necessitate further studies to determine best practices for this population.

Consecutive Esotropia with and without Abduction Limitation - Risk Factors and Surgical Outcomes of Lateral Rectus Advancement

Purpose: To identify risk factors for abduction limitation in consecutive esotropia following surgical correction of exotropia. To study outcomes of lateral rectus advancement for consecutive esotropia correction.Methods: Patients with consecutive esotropia (>10PD) operated between 2007 and 2019 with a minimum follow-up of 2 months were reviewed retrospectively. Preoperative and postoperative alignment and ocular motility were recorded. Patients were classified into those with full abduction (group-A) and with abduction limitation (group-B). Success was defined as deviation ≤10 PD of esotropia or exotropia in the primary position.Results: Forty-cases fulfilled the inclusion criteria (group-A = 28 and group-B = 12). Median age at surgery was five years, median consecutive esotropia was 20PD and follow-up was 29.18 months. Abduction limitation (group-B) was associated with constant exotropia (p = .01) and larger bilateral lateral rectus recession (group-A = 13 mm, group-B = 15 mm; p = .04). Nineteen patients underwent lateral rectus advancement (group-A = 12, group-B = 7), one underwent medial-rectus recession and two were excluded due to lack of postoperative follow-up. Five patients had spontaneous resolution with good alignment (group-A = 3, group-B = 2), two refused surgery, three were observed and eight were lost to follow-up. Success following second surgery was similar in both groups (group-A = 86%, group-B = 77%)(p = 1).Conclusion: Constant exotropia and larger lateral rectus recession were associated with abduction limitation in consecutive esotropia. Lateral rectus advancement produced good outcomes irrespective of abduction limitation.

Quality of life in adult intermittent exotropia and the risk factors

AIM

To study the quality of life of adult patients with intermittent exotropia (IXT) in China and analyze the factors affecting the quality of life in IXT patients.

METHODS

Totally 109 cases of normal eye (control group), 77 cases of IXT (IXT group) and 115 cases of strabismus control group (except IXT) were collected. The quality of life of the patients was assessed by Chinese version of adult strabismus patient's quality of life scale (CAS-20). The differences of general characteristics, visual function and quality of life were analyzed, and the effects of individual factors and visual function on quality of life of patients with IXT were analyzed.

RESULTS

The IXT group had a high proportion of patients with family history, low proportion of patients with amblyopia compared with strabismus control group. The proportion with normal near and far stereopsis of IXT group were lower than that of normal control group. The best corrected visual acuity of IXT group was higher than that of strabismus control group, but lower than the control group. In addition, the median strabismus degree in IXT group was higher than that in other strabismus control group. The median psychosocial scores and median visual function scores of the IXT group was lower than that of the normal control group, but not different from strabismus control group. Occupation status, course of disease, far stereopsis and near stereopsis significantly affected the quality of life in IXT patients.

CONCLUSION

Adult IXT patients in China have a certain proportion of family history and lower quality of life, The main factors affecting the quality of life of IXT patients is stereopsis, course of disease and occupation status.

Nasal loop myopexy as a primary procedure to correct exotropia hypotropia complex in high myopia

PURPOSE

To evaluate success of nasal loop myopexy as a primary procedure in correcting the ocular deviation in primary position when combined with recession and resection procedure (R&R) in exotropia hypotropia complex in high myopia and to explore the probable cause for deviation.

CASE REPORTS

We present a case series of three adult males with exotropia hypotropia complex and high myopia with large angle exotropia and hypotropia, with deflection of the courses of superior and medial recti seen intraoperatively. We performed a conventional recession and resection procedure, which was combined with a nasal loop myopexy between the superior rectus (SR) and medial rectus (MR) in the same session, under local anesthesia, to correct the deflected course of SR and MR; with the aim of correcting the deviation in primary position and improving ocular motility, mainly elevation in abduction.

RESULTS

We present a case series of three adult males with exotropia hypotropia complex, who were operated between March 2017 and October 2017. In all the three cases described above, it was noted that the preoperative exotropia and hypotropia improved following the combination of nasal loop myopexy with a conventional recession and resection procedure, as shown by improvement in ocular deviation in the primary position (measured by prism bar cover test, PBCT). First patient improved from 50 prism exotropia with 16 prism hypotropia to 5 prisms exophoria and 6 prisms hypotropia in left eye. Second patient improved from 45 prism right exotropia and 10 prism hypotropia to 10 prisms exotropia and 6 prism hypotropia. Third patient improved from 40 prism left exotropia and 20 prisms hypotropia to 10 prism esotropia and 5 prisms hypotropia. Ocular motility showed no restriction following surgery in any of the gazes. Limitation of elevation in abduction, caused due to SR deflection, improved due to repositioning of SR and MR in their anatomical positions in all the cases. In the first patient elevation in abduction improved from -4 to -1; in the second and third patients, it improved from -2 to 0. None of the three adult patients experienced any side effects following the procedure.

CONCLUSION

The combination of recession and resection procedures with nasal loop myopexy was found to be effective in correcting the ocular deviation and limitation to elevation in abduction by correcting the deflected course of superior rectus and medial rectus to result in an effective improvement of elevation in abduction. One case had an overcorrection of exotropia. There were no other major complications.

Surgical management of intermittent exotropia: do we have an answer for all?

Intermittent exotropia (X(T)) is one of the most common form of strabismus with surgery being the mainstay of treatment. The main goal of surgery is to preserve binocular vision and stereopsis and to prevent its further loss. The decision to operate is mainly based on four aspects: increasing angle of exodeviation, deteriorating control of X(T), decrease in stereopsis for near or distance and quality of life. Bilateral lateral rectus muscle recession and unilateral lateral rectus recession with medial rectus resection, are the two most common surgical procedures performed and have been studied extensively in basic, divergence excess and convergence insufficiency types of X(T). However, there is no consensus over the relative efficacy of the two procedures in terms of postoperative alignment, residual or recurrent exotropia and consecutive esotropia with widely variable results, which can be attributed to poor understanding of the natural course of the disease. Multiple demographic, clinical and anatomic features that may influence the surgical outcomes have been studied to explain this variability. Moreover, most of the evidence regarding surgical outcomes of X(T) is from retrospective studies and the ongoing randomised prospective trials can shed light on long-term efficacy of these procedures. The goal of this review is to give a comprehensive overview of the outcomes of various surgical techniques in the management of different types of X(T), the preoperative and postoperative factors that may affect the surgical outcomes and to discuss the dilemmas faced by the treating surgeons including the effective management of overcorrection and undercorrection.

Strabismus-associated myopia. Review

INTRODUCTION

The treatment of strabismus associated with myopia is often a therapeutic challenge for the ophthalmologist. The strabismus associated with myopia has certain peculiarities and there are even certain types of strabismus that occur exclusively in myopia, such as strabismus fixus, requiring treatments with specific surgical techniques.

MATERIALS AND METHODS

It is important to make a correct differential diagnosis, because there are many conditions described with this association. A review is presented of strabismus associated with myopia, together with its treatment adjusted to refractive error.

RESULTS

Measurements of strabismus may be altered by the prismatic effect of the spectacles. Surgical results may be unpredictable if myopia is not taken into account. Better results were obtained with the techniques of anatomical replacement described by Yokoyama than with traditional retro-insertion-resection.

CONCLUSION

For the diagnosis and appropriate treatment of strabismus, it is important to make a correct measurement of the angle of deviation, and perform image tests prior to surgery in certain cases. The anatomical characteristics of the myopic eye should also be taken into account during surgery.