How to Better Treat Patients with Intermittent Exotropia: A Review of Surgical Treatment of Intermittent Exotropia

Sensory outcome of exotropia surgery in Thailand: a retrospective multicenter study

AIM

To evaluate the characteristics of exotropia (XT) and motor-sensory outcomes after surgical correction and to determine the factors associated with sensory outcomes of XT surgery.

METHODS

The medical records of all patients that were diagnosed with XT and underwent strabismus surgery in 13 major government hospitals in Thailand; from January 2012 to December 2019, were retrospectively reviewed. Univariable and multivariable logistic regression were performed to identify factors related to binocular vision.

RESULTS

Data of five hundred and thirty-seven patients were analyzed. Two hundred and twenty-six patients were men (42.1%). The median age of onset was 3 years old [Interquartile range (IQR): 1, 8]. The median age at diagnosis was 9.21 years old (IQR; 4.64, 21.06). intermittent exotropia [X(T)] was the most common type (52.1%); 19.5% of the patients had amblyopia. For refractive error, spherical equivalent refraction on right eye (RE) and left eye (LE) were -0.53±2.45 diopters (D) (range -14.88 to +10 D) and -0.48±2.37 D (range -19.50 to +7.75 D), respectively. The mean angle of deviation at distance and near before surgery were 42.06±14.91 prism diopters (PD) and 40.81±16.09 PD, respectively. Follow-up time after first operation was 2.48±2.27y. Four hundred sixty-two patients (86%) needed only one operation and 299 (55.6%) patients had bilateral lateral rectus recession. At final visit, the mean angles of deviation at distance and near decreased to 5.76±8.96 PD and 5.01±8.73 PD, respectively. After surgery, two hundred seventy-three patients (50.8%) were evaluated for binocular function, but the others did not have result. From multivariable logistic regression in 273 patients, the factors related to better binocular function were type of XT which was X(T) [adjusted odds ratio (aOR) 10.35; 95%CI: 4.73, 22.66] compared to constant XT, without amblyopia (aOR 3.97; 95%CI: 1.84, 8.53), underwent only single operation compared with more than 1 operation (aOR 3.80, 95%CI: 1.58, 9.16), the angle of deviation at near in last visit less than 10 PD better than 10-30 PD with aOR 0.42 (95%CI: 0.18, 0.96) and type of refraction revealed isometropia better than anisometropia with aOR 4.13 (95%CI: 1.19, 14.32).

CONCLUSION

The surgical outcomes of XT within one operation in Thailand is 86%. The factors related to achieve binocular function includes type of XT as X(T), without amblyopia, angle of deviation at final visit less than 10 PD, isometropia type of refraction and underwent only one surgical correction.

Virtual reality head-mounted display game for intermittent exotropia in a randomized controlled trial

To evaluate the effects of orthoptic training using a virtual reality (VR) head-mounted display game in patients with intermittent exotropia (IXT), a prospective, randomized, double-blind study was performed in 62 patients ≥ 13 years with IXT of ≥ 8 prism diopters (∆) and with a near ≥ distance angle, i.e., basic type and convergence insufficiency-type IXT. Patients were randomly assigned to a video-game group that induced convergence (exercise group) and a placebo-game group not inducing convergence (control group), and completed the program 15 min/day for 4 weeks. Subjective symptom scores, angle of exodeviation, near point of convergence, stereoacuity, fusional control scores using the Newcastle Control Score (NCS) and the Office Control Score (OCS) were noted. Outcome measures were assessed after 4 weeks, and re-evaluated after a washout period of 4 weeks. After using the VR game for 4 weeks, the near angle of exodeviation significantly decreased from 29.6 ± 9.5∆ to 25.3 ± 9.0∆ in the exercise group (p < 0.001), which was still maintained after 4 weeks of discontinuation (p = 0.008). There were no significant differences in the near angle of exodeviation in the control group at either the 4- or 8-week visits (p = 0.075, 0.093, respectively). The fusional control scores of the NCS and OCS significantly improved at the 4-week (p = 0.001, 0.003, respectively) and 8-week visits (p = 0.004, < 0.001, respectively) only in the exercise group. In conclusion, orthoptic training using a VR game improved the near angle of exodeviation and fusional control scores in IXT.

Physical therapy exercises for improving intermittent exotropia control post-strabismus surgery: A randomized controlled study

Background

Exotropia control is deteriorated by post-strabismus surgery in many cases. Improving this control is considered as an important factor for success of the strabismus surgery like ocular motor alignment.

Objective

To determine the therapeutic effect of postoperative eye exercises on exodeviation eye control after the strabismus surgery.

Methods

Forty patients suffering from intermittent exotropia after strabismus surgery were randomly divided into experimental group and control groups. Both groups received the usual medical care, while the experimental group received different types of eye exercises using physiotherapy modalities in 24 sessions over three months (two sessions a week). The measurement of exotropia control for near target and far target using the office-based scale was done before and after the treatment.

Results

There was a significant improvement in near eye control post-treatment (0 . 45 ± 0 . 61 ) in the experimental group compared with control group (3 . 65 ± 0 . 88 ) as the mean difference was -3.20 and 95% CI of the difference between them was -3.645--2.755 with P < 0 . 01 . Also, far eye control improved post-treatment in the experimental group (0 . 75 ± 0 . 64 ) compared with control group (4 . 00 ± 0 . 86 ) with mean difference of -3.250 and 95% CI of the difference between them was -3.727--2.773 with P < 0 . 01 .

Conclusions

For patients with intermittent exotropia who had undergone strabismus surgery, the addition of physiotherapy exercises for the eye provided significant improvements in exotropia control for near target and far target.

Outcomes for Intermittent Exotropia Using Three Common Surgical Approaches

PURPOSE

To compare a single surgeon's surgical outcomes for treating intermittent exotropia using bilateral lateral rectus recession (BLR), unilateral lateral rectus recession and medial rectus resection (RR), and unilateral lateral rectus recession and medial rectus plication (RP).

METHODS

A retrospective review of all surgeries for basic intermittent exotropia between 2015 and 2023 was performed. Only patients with initial correction using BLR, RR, or RP were included. Exclusion criteria included age older than 18 years, vertical deviation, any nonrefractive ocular diagnoses, prior ocular surgery, and inadequate follow-up.

RESULTS

There were 460 patients identified; 123 met inclusion criteria with 54 in the BLR group, 41 in the RR group, and 28 in the RP group. The average pre-operative distance alignment (and standard error) values for the BLR, RR, and RP groups were 25.07 (7.35), 22.44 (5.95), and 23.84 (6.42) prism diopters (PD), respectively. At 1 year, the postoperative distance alignment values for the BLR, RR, and RP groups were 8.72 (7.89), 7.46 (6.31), and 12.83 (6.82) PD, respectively (P = .03). A subanalysis found a significant difference between the BLR and RP (P = .02) and RR and RP (P = .02) groups. There was no difference between the BLR and RR groups (P = .57).

CONCLUSIONS

This study of three surgical approaches for intermittent exotropia found RP had a significantly larger angle of exodeviation compared to BLR and RR at 1 year of follow-up. Both BLR and RR were equally effective approaches for treating intermittent exotropia. [J Pediatr Ophthalmol Strabismus. 2024;61(4):287-290.].

Experience with Strabologic Surgery on Pediatric Patients with Divergence Excess Exotropia

AIM

This retrospective clinical study evaluates the results of surgical treatment of patients diagnosed with intermittent exotropia of the divergence excess type. The study compares the results of surgery delayed due to the Covid-19 pandemic (patients underwent the surgery after the age of eight), versus a group of younger children.

MATERIALS AND METHODS

The objective angle of deviation and quality of binocular functions were examined. The follow-up period was six months after surgery. The patients were divided into two groups according to age: 4-7 years and 8-13 years. Each group included 20 patients. The second group comprised patients whose surgery was postponed due to restrictions on elective surgery during the ongoing pandemic. The surgery took place at the University Hospital in Pilsen. Angle of deviation and binocular functions were examined before surgery, postoperatively, and three and six months after surgery. Data were collected retrospectively and statistically processed. The main values were plotted in charts.

RESULTS

Accordance between the angle of deviation before surgery in both groups was statistically demonstrated. During the six-month follow-up period, the median angle of deviation was statistically without proof of disparity between the groups. Six months after surgery, an objective angle of deviation within the limit ±5 degrees was achieved in 65% of patients from the first group and in 75% from the second group. Binocular vision before surgery was statistically without proof of difference between both groups. However the statistical processing demonstrated a difference between the two groups six months after the surgery. Better binocular functions were achieved by the younger children in the first group.

CONCLUSION

The objective deviation angle was comparable in both study groups prior to surgery as well as six months after the surgery. The first group of younger patients attained a higher quality of binocular functions within the six-month follow-up period compared to children operated on after the age of eight. This claim was statistically verified.

Systemic evaluation of the risk of reoperations in pediatric populations with exotropia and esotropia: nested case-control study

The study aimed to assess the risk of reoperations for strabismus in the pediatric population and to identify high-risk groups. This was a nationwide population-based study that used data from the Korean National Health Claims Database from 2008 to 2020. Two major cohorts were established based on initial strabismus: age-, sex-, and recruitment year-matched controls were randomly selected. Patients aged ≤ 9 years who underwent initial strabismus surgery for exotropia and esotropia were included, resulting in a total of 24,816 patients included to this study. The cumulative incidence of reoperations was 843 per 10,000 persons for exotropia, 1559 per 10,000 persons for esotropia. To assess the significant exposure factors, conditional logistic regression was performed to obtain odds ratio (OR) in each cohort. In patients with exotropia, the OR of reoperations was 4.26 times higher when the initial surgery is performed at younger age (earlier than 3-year-old) and 6.49 times higher when only one eye underwent than two eye. Similarly, in patients with esotropia, younger age (6.57 times) and unilateral surgery (7.20 times) were identified as common factors that increase the risk of reoperations. Based on the findings, special attention is recommended for patients younger than 3 years, especially those performed unilateral surgery as initial intervention in practical settings.

The Effects of Orthoptic Therapy on the Surgical Outcome in Children with Intermittent Exotropia: Randomised Controlled Clinical Trial

BACKGROUND

To assess the clinical effectiveness of orthoptic therapy in the postoperative stabilisation and rehabilitation of binocular function in children with intermittent exotropia (IXT) after surgery.

METHODS

This was a prospective, parallel, randomised controlled trial. A total of 136 IXT patients (aged from 7 to 17 years) who had been successfully corrected at 1 month after surgery were enrolled in this study, and 117 patients (58 controls) completed the 12-month follow-up visit. The primary outcome was established as the proportion of patients with suboptimal surgical outcomes, which were defined as: (1) exodeviation ≥10 prism diopters (PD) at distance or near using the simultaneous prism and cover test (SPCT), or (2) constant esotropia ≥6 PD at distance or near using SPCT, or (3) loss of 2 or more octaves of stereopsis from baseline. The secondary outcomes were the exodeviation at distance and near using the prism and alternate cover test (PACT), stereopsis, fusional exotropia control and convergence amplitude.

RESULTS

The cumulative probability of suboptimal surgical outcome by 12 months was 20.5% (14/68) in the orthoptic therapy group and 42.6% (29/68) in the control group. There was a significant difference between these two groups (χ² = 7.402, p = 0.007). Improvements in stereopsis, fusional exotropia control and fusional convergence amplitude were found in the orthoptic therapy group. A smaller exodrift was found in the orthoptic therapy group at near fixation (t = 2.26, p = 0.025).

CONCLUSIONS

Early postoperative orthoptic therapy can effectively improve the surgical outcome as well as stereopsis and fusional amplitude.